upstream handler support for model names with forward slash (#298)

The upstream handler would break on model IDs that contained a forward
slash. Model IDs like "aaa/bbb" called at upstream/aaa/bbb would result
in an error. This commit adds support for model IDs with a forward slash
by iteratively searching the path for a match.

Fixes: #229

.coderabbit.yaml

@@ -0,0 +1,15 @@
+# yaml-language-server: $schema=https://coderabbit.ai/integrations/schema.v2.json
+language: "en-US"
+early_access: false
+reviews:
+  profile: "chill"
+  request_changes_workflow: false
+  high_level_summary: true
+  poem: false
+  review_status: true
+  collapse_walkthrough: false
+  auto_review:
+    enabled: true
+    drafts: false
+chat:
+  auto_reply: true

.github/ISSUE_TEMPLATE/bug-report.md

@@ -0,0 +1,39 @@
+---
+name: Bug Report
+about: I found a defect
+title: ''
+labels: 'unconfirmed bug'
+assignees: ''
+
+---
+> [!IMPORTANT]
+> If you have questions about llama-swap please post in the Q&A in Discussions. Use bug reports when you've found a defect and wish to discuss a fix.
+
+**Describe the bug**
+A clear and concise description of what the bug is.
+
+**Expected behaviour**
+A clear and concise description of what you expected to happen.
+
+**Operating system and version**
+
+- OS: (linux, osx, windows, freebsd, etc)
+- GPUs: (list architecture)
+
+**My Configuration**
+
+```yaml
+# copy / paste your configuration here
+```
+
+**Proxy Logs**
+
+```
+# copy / paste from /logs
+```
+
+**Upstream Logs**
+
+```
+# copy/paste from /logs
+```

.github/workflows/closeinactive.yml

@@ -13,11 +13,11 @@ jobs:
     steps:
       - uses: actions/stale@v9
         with:
-          days-before-issue-stale: 30
+          days-before-issue-stale: 14
           days-before-issue-close: 14
           stale-issue-label: "stale"
-          stale-issue-message: "This issue is stale because it has been open for 30 days with no activity."
-          close-issue-message: "This issue was closed because it has been inactive for 14 days since being marked as stale."
+          stale-issue-message: "This issue is stale because it has been open for 2 weeks with no activity."
+          close-issue-message: "This issue was closed because it has been inactive for 2 weeks since being marked as stale."
           days-before-pr-stale: -1
           days-before-pr-close: -1
-          repo-token: ${{ secrets.GITHUB_TOKEN }}
+          repo-token: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/go-ci-windows.yml

@@ -0,0 +1,50 @@
+name: Windows CI
+
+on:
+  push:
+    branches: [ "main" ]
+
+  pull_request:
+    branches: [ "main" ]
+
+  # Allows manual triggering of the workflow
+  workflow_dispatch:
+
+jobs:
+
+  run-tests:
+    runs-on: windows-latest
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Set up Go
+      uses: actions/setup-go@v4
+      with:
+        go-version: '1.23'
+
+    # cache simple-responder to save the build time
+    - name: Restore Simple Responder
+      id: restore-simple-responder
+      uses: actions/cache/restore@v4
+      with:
+        path: ./build
+        key: ${{ runner.os }}-simple-responder-${{ hashFiles('misc/simple-responder/simple-responder.go') }}
+
+    # necessary for testing proxy/Process swapping
+    - name: Create simple-responder
+      if: steps.restore-simple-responder.outputs.cache-hit != 'true'
+      shell: bash
+      run: make simple-responder-windows
+
+    - name: Save Simple Responder
+      # nothing new to save ... skip this step
+      if: steps.restore-simple-responder.outputs.cache-hit != 'true'
+      id: save-simple-responder
+      uses: actions/cache/save@v4
+      with:
+        path: ./build
+        key: ${{ runner.os }}-simple-responder-${{ hashFiles('misc/simple-responder/simple-responder.go') }}
+
+    - name: Test all
+      shell: bash
+      run: make test-all

.github/workflows/go-ci.yml

@@ -1,6 +1,4 @@
-# This workflow will build a golang project
-
-name: CI
+name: Linux CI
 
 on:
   push:
@@ -24,9 +22,33 @@ jobs:
       with:
         go-version: '1.23'
 
+    # Only run in this linux based runner
+    - name: Check Formatting
+      run: |
+        if [ "$(gofmt -l . | grep -v 'event/.*_test.go' | wc -l)" -gt 0 ]; then
+          gofmt -l . | grep -v 'event/.*_test.go'
+          exit 1
+        fi
+    # cache simple-responder to save the build time
+    - name: Restore Simple Responder
+      id: restore-simple-responder
+      uses: actions/cache/restore@v4
+      with:
+        path: ./build
+        key: ${{ runner.os }}-simple-responder-${{ hashFiles('misc/simple-responder/simple-responder.go') }}
+
     # necessary for testing proxy/Process swapping
     - name: Create simple-responder
       run: make simple-responder
 
+    - name: Save Simple Responder
+      # nothing new to save ... skip this step
+      if: steps.restore-simple-responder.outputs.cache-hit != 'true'
+      id: save-simple-responder
+      uses: actions/cache/save@v4
+      with:
+        path: ./build
+        key: ${{ runner.os }}-simple-responder-${{ hashFiles('misc/simple-responder/simple-responder.go') }}
+
     - name: Test all
       run: make test-all

.github/workflows/release.yml

@@ -7,6 +7,10 @@ on:
 
   # Allows manual triggering of the workflow
   workflow_dispatch:
+    inputs:
+      tag:
+        description: 'Tag version to release (e.g. v144)'
+        required: true
 
 permissions:
   contents: write
@@ -20,9 +24,22 @@ jobs:
         uses: actions/checkout@v4
         with:
           fetch-depth: 0
+          ref: ${{ github.event.inputs.tag || github.ref }}
       -
         name: Set up Go
         uses: actions/setup-go@v5
+      -
+        name: Set up Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: '23'
+      -
+        name: Install dependencies and build UI
+        run: |
+          cd ui
+          npm ci
+          npm run build
+
       -
         name: Run GoReleaser
         uses: goreleaser/goreleaser-action@v6
@@ -33,4 +50,30 @@ jobs:
           version: '~> v2'
           args: release --clean
         env:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
+  trigger-tap-update:
+    runs-on: ubuntu-latest
+    needs: goreleaser
+    steps:
+      - name: "Resolve tag to dispatch"
+        id: tag
+        run: |
+          if [[ "${{ github.event_name }}" == "workflow_dispatch" ]]; then
+            echo "tag=${{ github.event.inputs.tag }}" >> "$GITHUB_OUTPUT"
+          else
+            echo "tag=${{ github.ref_name }}" >> "$GITHUB_OUTPUT"
+          fi
+
+      - name: "Trigger tap repository update"
+        uses: peter-evans/repository-dispatch@v2
+        with:
+          token: ${{ secrets.TAP_REPO_PAT }}
+          repository: mostlygeek/homebrew-llama-swap
+          event-type: new-release
+          client-payload: |
+            {
+              "release": {
+                "tag_name": "${{ steps.tag.outputs.tag }}"
+              }
+            }

.gitignore

@@ -4,3 +4,4 @@ build/
 dist/
 .vscode
 .DS_Store
+.dev/

.goreleaser.yaml

@@ -17,14 +17,16 @@ builds:
       - goos: windows
         goarch: arm64
 
-# use zip format for windows
 archives:
   - id: default
-    format: tar.gz
+    formats:
+      - tar.gz
     name_template: "{{ .ProjectName }}_{{ .Version }}_{{ .Os }}_{{ .Arch }}"
     builds_info:
       group: root
       owner: root
     format_overrides:
+      # use zip format for windows
       - goos: windows
-        format: zip
+        formats:
+          - zip

Makefile

@@ -19,24 +19,36 @@ all: mac linux simple-responder
 clean:
 	rm -rf $(BUILD_DIR)
 
-test:
-	go test -short -v ./proxy
+proxy/ui_dist/placeholder.txt:
+	mkdir -p proxy/ui_dist
+	touch $@
 
-test-all:
-	go test -v ./proxy
+test: proxy/ui_dist/placeholder.txt
+	go test -short -v -count=1 ./proxy
+
+test-all: proxy/ui_dist/placeholder.txt
+	go test -v -count=1 ./proxy
+
+ui/node_modules:
+	cd ui && npm install
+
+# build react UI
+ui: ui/node_modules
+	cd ui && npm run build
 
 # Build OSX binary
-mac:
+mac: ui
 	@echo "Building Mac binary..."
 	GOOS=darwin GOARCH=arm64 go build -ldflags="-X main.commit=${GIT_HASH} -X main.version=local_${GIT_HASH} -X main.date=${BUILD_DATE}" -o $(BUILD_DIR)/$(APP_NAME)-darwin-arm64
 
 # Build Linux binary
-linux:
+linux: ui
 	@echo "Building Linux binary..."
 	GOOS=linux GOARCH=amd64 go build -ldflags="-X main.commit=${GIT_HASH} -X main.version=local_${GIT_HASH} -X main.date=${BUILD_DATE}" -o $(BUILD_DIR)/$(APP_NAME)-linux-amd64
+	GOOS=linux GOARCH=arm64 go build -ldflags="-X main.commit=${GIT_HASH} -X main.version=local_${GIT_HASH} -X main.date=${BUILD_DATE}" -o $(BUILD_DIR)/$(APP_NAME)-linux-arm64
 
 # Build Windows binary
-windows:
+windows: ui
 	@echo "Building Windows binary..."
 	GOOS=windows GOARCH=amd64 go build -ldflags="-X main.commit=${GIT_HASH} -X main.version=local_${GIT_HASH} -X main.date=${BUILD_DATE}" -o $(BUILD_DIR)/$(APP_NAME)-windows-amd64.exe
 
@@ -46,6 +58,10 @@ simple-responder:
 	GOOS=darwin GOARCH=arm64 go build -o $(BUILD_DIR)/simple-responder_darwin_arm64 misc/simple-responder/simple-responder.go
 	GOOS=linux GOARCH=amd64 go build -o $(BUILD_DIR)/simple-responder_linux_amd64 misc/simple-responder/simple-responder.go
 
+simple-responder-windows:
+	@echo "Building simple responder for windows"
+	GOOS=windows GOARCH=amd64 go build -o $(BUILD_DIR)/simple-responder.exe misc/simple-responder/simple-responder.go
+
 # Ensure build directory exists
 $(BUILD_DIR):
 	mkdir -p $(BUILD_DIR)
@@ -65,4 +81,4 @@ release:
 	git tag "$$new_tag";
 
 # Phony targets
-.PHONY: all clean mac linux windows simple-responder
+.PHONY: all clean ui mac linux windows simple-responder

README.md

@@ -1,4 +1,4 @@
-![llama-swap header image](header.jpeg)
+![llama-swap header image](header2.png)
 ![GitHub Downloads (all assets, all releases)](https://img.shields.io/github/downloads/mostlygeek/llama-swap/total)
 ![GitHub Actions Workflow Status](https://img.shields.io/github/actions/workflow/status/mostlygeek/llama-swap/go-ci.yml)
 ![GitHub Repo stars](https://img.shields.io/github/stars/mostlygeek/llama-swap)
@@ -7,7 +7,7 @@
 
 llama-swap is a light weight, transparent proxy server that provides automatic model swapping to llama.cpp's server.
 
-Written in golang, it is very easy to install (single binary with no dependancies) and configure (single yaml file). To get started, download a pre-built binary or use the provided docker images.
+Written in golang, it is very easy to install (single binary with no dependencies) and configure (single yaml file). To get started, download a pre-built binary, a provided docker images or Homebrew.
 
 ## Features:
 
@@ -18,142 +18,112 @@ Written in golang, it is very easy to install (single binary with no dependancie
   - `v1/completions`
   - `v1/chat/completions`
   - `v1/embeddings`
-  - `v1/rerank`
   - `v1/audio/speech` ([#36](https://github.com/mostlygeek/llama-swap/issues/36))
   - `v1/audio/transcriptions` ([docs](https://github.com/mostlygeek/llama-swap/issues/41#issuecomment-2722637867))
+- ✅ llama-server (llama.cpp) supported endpoints:
+  - `v1/rerank`, `v1/reranking`, `/rerank`
+  - `/infill` - for code infilling
+  - `/completion` - for completion endpoint
 - ✅ llama-swap custom API endpoints
+  - `/ui` - web UI
   - `/log` - remote log monitoring
   - `/upstream/:model_id` - direct access to upstream HTTP server ([demo](https://github.com/mostlygeek/llama-swap/pull/31))
   - `/unload` - manually unload running models ([#58](https://github.com/mostlygeek/llama-swap/issues/58))
   - `/running` - list currently running models ([#61](https://github.com/mostlygeek/llama-swap/issues/61))
-- ✅ Run multiple models at once with `profiles` ([docs](https://github.com/mostlygeek/llama-swap/issues/53#issuecomment-2660761741))
+  - `/health` - just returns "OK"
+- ✅ Run multiple models at once with `Groups` ([#107](https://github.com/mostlygeek/llama-swap/issues/107))
 - ✅ Automatic unloading of models after timeout by setting a `ttl`
 - ✅ Use any local OpenAI compatible server (llama.cpp, vllm, tabbyAPI, etc)
-- ✅ Docker and Podman support
+- ✅ Reliable Docker and Podman support using `cmd` and `cmdStop` together
 - ✅ Full control over server settings per model
+- ✅ Preload models on startup with `hooks` ([#235](https://github.com/mostlygeek/llama-swap/pull/235))
 
 ## How does llama-swap work?
 
-When a request is made to an OpenAI compatible endpoint, lama-swap will extract the `model` value and load the appropriate server configuration to serve it. If the wrong upstream server is running, it will be replaced with the correct one. This is where the "swap" part comes in. The upstream server is automatically swapped to the correct one to serve the request.
+When a request is made to an OpenAI compatible endpoint, llama-swap will extract the `model` value and load the appropriate server configuration to serve it. If the wrong upstream server is running, it will be replaced with the correct one. This is where the "swap" part comes in. The upstream server is automatically swapped to the correct one to serve the request.
 
-In the most basic configuration llama-swap handles one model at a time. For more advanced use cases, the `profiles` feature can load multiple models at the same time. You have complete control over how your system resources are used.
+In the most basic configuration llama-swap handles one model at a time. For more advanced use cases, the `groups` feature allows multiple models to be loaded at the same time. You have complete control over how your system resources are used.
 
 ## config.yaml
 
-llama-swap's configuration is purposefully simple.
+llama-swap is managed entirely through a yaml configuration file.
+
+It can be very minimal to start:
 
 ```yaml
 models:
   "qwen2.5":
-    proxy: "http://127.0.0.1:9999"
-    cmd: >
-      /app/llama-server
+    cmd: |
+      /path/to/llama-server
       -hf bartowski/Qwen2.5-0.5B-Instruct-GGUF:Q4_K_M
-      --port 9999
-
-  "smollm2":
-    proxy: "http://127.0.0.1:9999"
-    cmd: >
-      /app/llama-server
-      -hf bartowski/SmolLM2-135M-Instruct-GGUF:Q4_K_M
-      --port 9999
+      --port ${PORT}
 ```
 
-<details>
-<summary>But also very powerful ...</summary>
+However, there are many more capabilities that llama-swap supports:
 
-```yaml
-# Seconds to wait for llama.cpp to load and be ready to serve requests
-# Default (and minimum) is 15 seconds
-healthCheckTimeout: 60
+- `groups` to run multiple models at once
+- `ttl` to automatically unload models
+- `macros` for reusable snippets
+- `aliases` to use familiar model names (e.g., "gpt-4o-mini")
+- `env` to pass custom environment variables to inference servers
+- `cmdStop` for to gracefully stop Docker/Podman containers
+- `useModelName` to override model names sent to upstream servers
+- `healthCheckTimeout` to control model startup wait times
+- `${PORT}` automatic port variables for dynamic port assignment
 
-# Valid log levels: debug, info (default), warn, error
-logLevel: info
+See the [configuration documentation](https://github.com/mostlygeek/llama-swap/wiki/Configuration) in the wiki all options and examples.
 
-# define valid model values and the upstream server start
-models:
-  "llama":
-    # multiline for readability
-    cmd: >
-      llama-server --port 8999
-      --model path/to/Qwen2.5-1.5B-Instruct-Q4_K_M.gguf
+## Reverse Proxy Configuration (nginx)
 
-    # environment variables to pass to the command
-    env:
-      - "CUDA_VISIBLE_DEVICES=0"
+If you deploy llama-swap behind nginx, disable response buffering for streaming endpoints. By default, nginx buffers responses which breaks Server‑Sent Events (SSE) and streaming chat completion. ([#236](https://github.com/mostlygeek/llama-swap/issues/236))
 
-    # where to reach the server started by cmd, make sure the ports match
-    proxy: http://127.0.0.1:8999
+Recommended nginx configuration snippets:
 
-    # aliases names to use this model for
-    aliases:
-      - "gpt-4o-mini"
-      - "gpt-3.5-turbo"
+```nginx
+# SSE for UI events/logs
+location /api/events {
+    proxy_pass http://your-llama-swap-backend;
+    proxy_buffering off;
+    proxy_cache off;
+}
 
-    # check this path for an HTTP 200 OK before serving requests
-    # default: /health to match llama.cpp
-    # use "none" to skip endpoint checking, but may cause HTTP errors
-    # until the model is ready
-    checkEndpoint: /custom-endpoint
-
-    # automatically unload the model after this many seconds
-    # ttl values must be a value greater than 0
-    # default: 0 = never unload model
-    ttl: 60
-
-    # `useModelName` overrides the model name in the request
-    # and sends a specific name to the upstream server
-    useModelName: "qwen:qwq"
-
-  # unlisted models do not show up in /v1/models or /upstream lists
-  # but they can still be requested as normal
-  "qwen-unlisted":
-    unlisted: true
-    cmd: llama-server --port 9999 -m Llama-3.2-1B-Instruct-Q4_K_M.gguf -ngl 0
-
-  # Docker Support (v26.1.4+ required!)
-  "docker-llama":
-    proxy: "http://127.0.0.1:9790"
-    cmd: >
-      docker run --name dockertest
-      --init --rm -p 9790:8080 -v /mnt/nvme/models:/models
-      ghcr.io/ggerganov/llama.cpp:server
-      --model '/models/Qwen2.5-Coder-0.5B-Instruct-Q4_K_M.gguf'
-
-# profiles eliminates swapping by running multiple models at the same time
-#
-# Tips:
-#  - each model must be listening on a unique address and port
-#  - the model name is in this format: "profile_name:model", like "coding:qwen"
-#  - the profile will load and unload all models in the profile at the same time
-profiles:
-  coding:
-    - "llama"
-    - "qwen-unlisted"
+# Streaming chat completions (stream=true)
+location /v1/chat/completions {
+    proxy_pass http://your-llama-swap-backend;
+    proxy_buffering off;
+    proxy_cache off;
+}
 ```
 
-### Use Case Examples
+As a safeguard, llama-swap also sets `X-Accel-Buffering: no` on SSE responses. However, explicitly disabling `proxy_buffering` at your reverse proxy is still recommended for reliable streaming behavior.
 
-- [config.example.yaml](config.example.yaml) includes example for supporting `v1/embeddings` and `v1/rerank` endpoints
-- [Speculative Decoding](examples/speculative-decoding/README.md) - using a small draft model can increase inference speeds from 20% to 40%. This example includes a configurations Qwen2.5-Coder-32B (2.5x increase) and Llama-3.1-70B (1.4x increase) in the best cases.
-- [Optimizing Code Generation](examples/benchmark-snakegame/README.md) - find the optimal settings for your machine. This example demonstrates defining multiple configurations and testing which one is fastest.
-- [Restart on Config Change](examples/restart-on-config-change/README.md) - automatically restart llama-swap when trying out different configurations.
+## Web UI
 
-## Configuration
+llama-swap includes a real time web interface for monitoring logs and models:
 
-llama-s
+<img width="1360" height="963" alt="image" src="https://github.com/user-attachments/assets/adef4a8e-de0b-49db-885a-8f6dedae6799" />
 
-</details>
+The Activity Page shows recent requests:
 
-## Docker Install ([download images](https://github.com/mostlygeek/llama-swap/pkgs/container/llama-swap))
+<img width="1360" height="963" alt="image" src="https://github.com/user-attachments/assets/5f3edee6-d03a-4ae5-ae06-b20ac1f135bd" />
 
-Docker is the quickest way to try out llama-swap:
+## Installation
 
-```
-# use CPU inference
+llama-swap can be installed in multiple ways
+
+1. Docker
+2. Homebrew (OSX and Linux)
+3. From release binaries
+4. From source
+
+### Docker Install ([download images](https://github.com/mostlygeek/llama-swap/pkgs/container/llama-swap))
+
+Docker images with llama-swap and llama-server are built nightly.
+
+```shell
+# use CPU inference comes with the example config above
 $ docker run -it --rm -p 9292:8080 ghcr.io/mostlygeek/llama-swap:cpu
 
-
 # qwen2.5 0.5B
 $ curl -s http://localhost:9292/v1/chat/completions \
     -H "Content-Type: application/json" \
@@ -161,7 +131,6 @@ $ curl -s http://localhost:9292/v1/chat/completions \
     -d '{"model":"qwen2.5","messages": [{"role": "user","content": "tell me a joke"}]}' | \
     jq -r '.choices[0].message.content'
 
-
 # SmolLM2 135M
 $ curl -s http://localhost:9292/v1/chat/completions \
     -H "Content-Type: application/json" \
@@ -171,7 +140,7 @@ $ curl -s http://localhost:9292/v1/chat/completions \
 ```
 
 <details>
-<summary>Docker images are nightly ...</summary>
+<summary>Docker images are built nightly with llama-server for cuda, intel, vulcan and musa.</summary>
 
 They include:
 
@@ -185,7 +154,7 @@ Specific versions are also available and are tagged with the llama-swap, archite
 
 Beyond the demo you will likely want to run the containers with your downloaded models and custom configuration.
 
-```
+```shell
 $ docker run -it --rm --runtime nvidia -p 9292:8080 \
   -v /path/to/models:/models \
   -v /path/to/custom/config.yaml:/app/config.yaml \
@@ -194,28 +163,47 @@ $ docker run -it --rm --runtime nvidia -p 9292:8080 \
 
 </details>
 
-## Bare metal Install ([download](https://github.com/mostlygeek/llama-swap/releases))
+### Homebrew Install (macOS/Linux)
 
-Pre-built binaries are available for Linux, FreeBSD and Darwin (OSX). These are automatically published and are likely a few hours ahead of the docker releases. The baremetal install works with any OpenAI compatible server, not just llama-server.
+The latest release of `llama-swap` can be installed via [Homebrew](https://brew.sh).
+
+```shell
+# Set up tap and install formula
+brew tap mostlygeek/llama-swap
+brew install llama-swap
+# Run llama-swap
+llama-swap --config path/to/config.yaml --listen localhost:8080
+```
+
+This will install the `llama-swap` binary and make it available in your path. See the [configuration documentation](https://github.com/mostlygeek/llama-swap/wiki/Configuration)
+
+### Pre-built Binaries ([download](https://github.com/mostlygeek/llama-swap/releases))
+
+Binaries are available for Linux, Mac, Windows and FreeBSD. These are automatically published and are likely a few hours ahead of the docker releases. The binary install works with any OpenAI compatible server, not just llama-server.
 
-1. Create a configuration file, see [config.example.yaml](config.example.yaml)
 1. Download a [release](https://github.com/mostlygeek/llama-swap/releases) appropriate for your OS and architecture.
-1. Run the binary with `llama-swap --config path/to/config.yaml`
+1. Create a configuration file, see the [configuration documentation](https://github.com/mostlygeek/llama-swap/wiki/Configuration).
+1. Run the binary with `llama-swap --config path/to/config.yaml --listen localhost:8080`.
+   Available flags:
+   - `--config`: Path to the configuration file (default: `config.yaml`).
+   - `--listen`: Address and port to listen on (default: `:8080`).
+   - `--version`: Show version information and exit.
+   - `--watch-config`: Automatically reload the configuration file when it changes. This will wait for in-flight requests to complete then stop all running models (default: `false`).
 
 ### Building from source
 
-1. Install golang for your system
-1. `git clone git@github.com:mostlygeek/llama-swap.git`
+1. Build requires golang and nodejs for the user interface.
+1. `git clone https://github.com/mostlygeek/llama-swap.git`
 1. `make clean all`
 1. Binaries will be in `build/` subdirectory
 
 ## Monitoring Logs
 
-Open the `http://<host>/logs` with your browser to get a web interface with streaming logs.
+Open the `http://<host>:<port>/` with your browser to get a web interface with streaming logs.
 
-Of course, CLI access is also supported:
+CLI access is also supported:
 
-```
+```shell
 # sends up to the last 10KB of logs
 curl http://host/logs'
 
@@ -241,36 +229,9 @@ Any OpenAI compatible server would work. llama-swap was originally designed for
 
 For Python based inference servers like vllm or tabbyAPI it is recommended to run them via podman or docker. This provides clean environment isolation as well as responding correctly to `SIGTERM` signals to shutdown.
 
-## Systemd Unit Files
-
-Use this unit file to start llama-swap on boot. This is only tested on Ubuntu.
-
-`/etc/systemd/system/llama-swap.service`
-
-```
-[Unit]
-Description=llama-swap
-After=network.target
-
-[Service]
-User=nobody
-
-# set this to match your environment
-ExecStart=/path/to/llama-swap --config /path/to/llama-swap.config.yml
-
-Restart=on-failure
-RestartSec=3
-StartLimitBurst=3
-StartLimitInterval=30
-
-[Install]
-WantedBy=multi-user.target
-```
-
 ## Star History
 
-<picture>
-   <source media="(prefers-color-scheme: dark)" srcset="https://api.star-history.com/svg?repos=mostlygeek/llama-swap&type=Date&theme=dark" />
-   <source media="(prefers-color-scheme: light)" srcset="https://api.star-history.com/svg?repos=mostlygeek/llama-swap&type=Date" />
-   <img alt="Star History Chart" src="https://api.star-history.com/svg?repos=mostlygeek/llama-swap&type=Date" />
-</picture>
+> [!NOTE]
+> ⭐️ Star this project to help others discover it! 
+
+[![Star History Chart](https://api.star-history.com/svg?repos=mostlygeek/llama-swap&type=Date)](https://www.star-history.com/#mostlygeek/llama-swap&Date)

config.example.yaml

@@ -1,92 +1,249 @@
-# Seconds to wait for llama.cpp to be available to serve requests
-# Default (and minimum): 15 seconds
-healthCheckTimeout: 90
+# llama-swap YAML configuration example
+# -------------------------------------
+#
+# 💡 Tip - Use an LLM with this file!
+# ====================================
+#  This example configuration is written to be LLM friendly. Try
+#  copying this file into an LLM and asking it to explain or generate
+#  sections for you.
+# ====================================
 
-# valid log levels: debug, info (default), warn, error
-logLevel: debug
+# Usage notes:
+# - Below are all the available configuration options for llama-swap.
+# - Settings noted as "required" must be in your configuration file
+# - Settings noted as "optional" can be omitted
 
+# healthCheckTimeout: number of seconds to wait for a model to be ready to serve requests
+# - optional, default: 120
+# - minimum value is 15 seconds, anything less will be set to this value
+healthCheckTimeout: 500
+
+# logLevel: sets the logging value
+# - optional, default: info
+# - Valid log levels: debug, info, warn, error
+logLevel: info
+
+# metricsMaxInMemory: maximum number of metrics to keep in memory
+# - optional, default: 1000
+# - controls how many metrics are stored in memory before older ones are discarded
+# - useful for limiting memory usage when processing large volumes of metrics
+metricsMaxInMemory: 1000
+
+# startPort: sets the starting port number for the automatic ${PORT} macro.
+# - optional, default: 5800
+# - the ${PORT} macro can be used in model.cmd and model.proxy settings
+# - it is automatically incremented for every model that uses it
+startPort: 10001
+
+# macros: a dictionary of string substitutions
+# - optional, default: empty dictionary
+# - macros are reusable snippets
+# - used in a model's cmd, cmdStop, proxy and checkEndpoint
+# - useful for reducing common configuration settings
+macros:
+  "latest-llama": >
+    /path/to/llama-server/llama-server-ec9e0301
+    --port ${PORT}
+
+# models: a dictionary of model configurations
+# - required
+# - each key is the model's ID, used in API requests
+# - model settings have default values that are used if they are not defined here
+# - the model's ID is available in the ${MODEL_ID} macro, also available in macros defined above
+# - below are examples of the all the settings a model can have
 models:
+
+  # keys are the model names used in API requests
   "llama":
-    cmd: >
-      models/llama-server-osx
-      --port 9001
-      -m models/Llama-3.2-1B-Instruct-Q4_0.gguf
-    proxy: http://127.0.0.1:9001
+    # cmd: the command to run to start the inference server.
+    # - required
+    # - it is just a string, similar to what you would run on the CLI
+    # - using `|` allows for comments in the command, these will be parsed out
+    # - macros can be used within cmd
+    cmd: |
+      # ${latest-llama} is a macro that is defined above
+      ${latest-llama}
+      --model path/to/llama-8B-Q4_K_M.gguf
 
-    # list of model name aliases this llama.cpp instance can serve
+    # name: a display name for the model
+    # - optional, default: empty string
+    # - if set, it will be used in the v1/models API response
+    # - if not set, it will be omitted in the JSON model record
+    name: "llama 3.1 8B"
+
+    # description: a description for the model
+    # - optional, default: empty string
+    # - if set, it will be used in the v1/models API response
+    # - if not set, it will be omitted in the JSON model record
+    description: "A small but capable model used for quick testing"
+
+    # env: define an array of environment variables to inject into cmd's environment
+    # - optional, default: empty array
+    # - each value is a single string
+    # - in the format: ENV_NAME=value
+    env:
+      - "CUDA_VISIBLE_DEVICES=0,1,2"
+
+    # proxy: the URL where llama-swap routes API requests
+    # - optional, default: http://localhost:${PORT}
+    # - if you used ${PORT} in cmd this can be omitted
+    # - if you use a custom port in cmd this *must* be set
+    proxy: http://127.0.0.1:8999
+
+    # aliases: alternative model names that this model configuration is used for
+    # - optional, default: empty array
+    # - aliases must be unique globally
+    # - useful for impersonating a specific model
     aliases:
-    - gpt-4o-mini
+      - "gpt-4o-mini"
+      - "gpt-3.5-turbo"
 
-    # check this path for a HTTP 200 response for the server to be ready
-    checkEndpoint: /health
+    # checkEndpoint: URL path to check if the server is ready
+    # - optional, default: /health
+    # - endpoint is expected to return an HTTP 200 response
+    # - all requests wait until the endpoint is ready or fails
+    # - use "none" to skip endpoint health checking
+    checkEndpoint: /custom-endpoint
 
-    # unload model after 5 seconds
-    ttl: 5
+    # ttl: automatically unload the model after ttl seconds
+    # - optional, default: 0
+    # - ttl values must be a value greater than 0
+    # - a value of 0 disables automatic unloading of the model
+    ttl: 60
 
-  "qwen":
-    cmd: models/llama-server-osx --port 9002 -m models/qwen2.5-0.5b-instruct-q8_0.gguf
-    proxy: http://127.0.0.1:9002
-    aliases:
-    - gpt-3.5-turbo
+    # useModelName: override the model name that is sent to upstream server
+    # - optional, default: ""
+    # - useful for when the upstream server expects a specific model name that
+    #   is different from the model's ID
+    useModelName: "qwen:qwq"
 
-  # Embedding example with Nomic
-  # https://huggingface.co/nomic-ai/nomic-embed-text-v1.5-GGUF
-  "nomic":
-    proxy: http://127.0.0.1:9005
-    cmd: >
-      models/llama-server-osx --port 9005
-      -m models/nomic-embed-text-v1.5.Q8_0.gguf
-      --ctx-size 8192
-      --batch-size 8192
-      --rope-scaling yarn
-      --rope-freq-scale 0.75
-      -ngl 99
-      --embeddings
+    # filters: a dictionary of filter settings
+    # - optional, default: empty dictionary
+    # - only strip_params is currently supported
+    filters:
+      # strip_params: a comma separated list of parameters to remove from the request
+      # - optional, default: ""
+      # - useful for server side enforcement of sampling parameters
+      # - the `model` parameter can never be removed
+      # - can be any JSON key in the request body
+      # - recommended to stick to sampling parameters
+      strip_params: "temperature, top_p, top_k"
 
-  # Reranking example with bge-reranker
-  # https://huggingface.co/gpustack/bge-reranker-v2-m3-GGUF
-  "bge-reranker":
-    proxy: http://127.0.0.1:9006
-    cmd: >
-      models/llama-server-osx --port 9006
-      -m models/bge-reranker-v2-m3-Q4_K_M.gguf
-      --ctx-size 8192
-      --reranking
+    # concurrencyLimit: overrides the allowed number of active parallel requests to a model
+    # - optional, default: 0
+    # - useful for limiting the number of active parallel requests a model can process
+    # - must be set per model
+    # - any number greater than 0 will override the internal default value of 10
+    # - any requests that exceeds the limit will receive an HTTP 429 Too Many Requests response
+    # - recommended to be omitted and the default used
+    concurrencyLimit: 0
 
-  # Docker Support (v26.1.4+ required!)
-  "dockertest":
-    proxy: "http://127.0.0.1:9790"
-    cmd: >
-      docker run --name dockertest
-      --init --rm -p 9790:8080 -v /mnt/nvme/models:/models
-      ghcr.io/ggerganov/llama.cpp:server
+  # Unlisted model example:
+  "qwen-unlisted":
+    # unlisted: boolean, true or false
+    # - optional, default: false
+    # - unlisted models do not show up in /v1/models api requests
+    # - can be requested as normal through all apis
+    unlisted: true
+    cmd: llama-server --port ${PORT} -m Llama-3.2-1B-Instruct-Q4_K_M.gguf -ngl 0
+
+  # Docker example:
+  # container runtimes like Docker and Podman can be used reliably with
+  # a combination of cmd, cmdStop, and ${MODEL_ID}
+  "docker-llama":
+    proxy: "http://127.0.0.1:${PORT}"
+    cmd: |
+      docker run --name ${MODEL_ID}
+      --init --rm -p ${PORT}:8080 -v /mnt/nvme/models:/models
+      ghcr.io/ggml-org/llama.cpp:server
       --model '/models/Qwen2.5-Coder-0.5B-Instruct-Q4_K_M.gguf'
 
-  "simple":
-    # example of setting environment variables
-    env:
-      - CUDA_VISIBLE_DEVICES=0,1
-      - env1=hello
-    cmd: build/simple-responder --port 8999
-    proxy: http://127.0.0.1:8999
-    unlisted: true
+    # cmdStop: command to run to stop the model gracefully
+    # - optional, default: ""
+    # - useful for stopping commands managed by another system
+    # - the upstream's process id is available in the ${PID} macro
+    #
+    # When empty, llama-swap has this default behaviour:
+    # - on POSIX systems: a SIGTERM signal is sent
+    # - on Windows, calls taskkill to stop the process
+    # - processes have 5 seconds to shutdown until forceful termination is attempted
+    cmdStop: docker stop ${MODEL_ID}
 
-    # use "none" to skip check. Caution this may cause some requests to fail
-    # until the upstream server is ready for traffic
-    checkEndpoint: none
+# groups: a dictionary of group settings
+# - optional, default: empty dictionary
+# - provides advanced controls over model swapping behaviour
+# - using groups some models can be kept loaded indefinitely, while others are swapped out
+# - model IDs must be defined in the Models section
+# - a model can only be a member of one group
+# - group behaviour is controlled via the `swap`, `exclusive` and `persistent` fields
+# - see issue #109 for details
+#
+# NOTE: the example below uses model names that are not defined above for demonstration purposes
+groups:
+  # group1 works the same as the default behaviour of llama-swap where only one model is allowed
+  # to run a time across the whole llama-swap instance
+  "group1":
+    # swap: controls the model swapping behaviour in within the group
+    # - optional, default: true
+    # - true : only one model is allowed to run at a time
+    # - false: all models can run together, no swapping
+    swap: true
 
-  # don't use these, just for testing if things are broken
-  "broken":
-    cmd: models/llama-server-osx --port 8999 -m models/doesnotexist.gguf
-    proxy: http://127.0.0.1:8999
-    unlisted: true
-  "broken_timeout":
-    cmd: models/llama-server-osx --port 8999 -m models/qwen2.5-0.5b-instruct-q8_0.gguf
-    proxy: http://127.0.0.1:9000
-    unlisted: true
+    # exclusive: controls how the group affects other groups
+    # - optional, default: true
+    # - true: causes all other groups to unload when this group runs a model
+    # - false: does not affect other groups
+    exclusive: true
 
-# creating a coding profile with models for code generation and general questions
-profiles:
-  coding:
-    - "qwen"
-    - "llama"
+    # members references the models defined above
+    # required
+    members:
+      - "llama"
+      - "qwen-unlisted"
+
+  # Example:
+  # - in group2 all models can run at the same time
+  # - when a different group is loaded it causes all running models in this group to unload
+  "group2":
+    swap: false
+
+    # exclusive: false does not unload other groups when a model in group2 is requested
+    # - the models in group2 will be loaded but will not unload any other groups
+    exclusive: false
+    members:
+      - "docker-llama"
+      - "modelA"
+      - "modelB"
+
+  # Example:
+  # - a persistent group, prevents other groups from unloading it
+  "forever":
+    # persistent: prevents over groups from unloading the models in this group
+    # - optional, default: false
+    # - does not affect individual model behaviour
+    persistent: true
+
+    # set swap/exclusive to false to prevent swapping inside the group
+    # and the unloading of other groups
+    swap: false
+    exclusive: false
+    members:
+      - "forever-modelA"
+      - "forever-modelB"
+      - "forever-modelc"
+
+# hooks: a dictionary of event triggers and actions
+# - optional, default: empty dictionary
+# - the only supported hook is on_startup
+hooks:
+  # on_startup: a dictionary of actions to perform on startup
+  # - optional, default: empty dictionary
+  # - the only supported action is preload
+  on_startup:
+        # preload: a list of model ids to load on startup
+        # - optional, default: empty list
+        # - model names must match keys in the models sections
+        # - when preloading multiple models at once, define a group
+        #   otherwise models will be loaded and swapped out
+    preload:
+      - "llama"

docker/config.example.yaml

@@ -1,5 +1,6 @@
 healthCheckTimeout: 300
 logRequests: true
+metricsMaxInMemory: 1000
 
 models:
   "qwen2.5":

event/README.md

@@ -0,0 +1,3 @@
+The code in `event` was originally a part of https://github.com/kelindar/event (v1.5.2)
+
+The original code uses a `time.Ticker` to process the event queue which caused a large increase in CPU usage ([#189](https://github.com/mostlygeek/llama-swap/issues/189)). This code was ported to remove the ticker and instead be more event driven.

event/default.go

@@ -0,0 +1,30 @@
+// Copyright (c) Roman Atachiants and contributore. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for detaile.
+
+package event
+
+import (
+	"context"
+)
+
+// Default initializes a default in-process dispatcher
+var Default = NewDispatcherConfig(25000)
+
+// On subscribes to an event, the type of the event will be automatically
+// inferred from the provided type. Must be constant for this to work. This
+// functions same way as Subscribe() but uses the default dispatcher instead.
+func On[T Event](handler func(T)) context.CancelFunc {
+	return Subscribe(Default, handler)
+}
+
+// OnType subscribes to an event with the specified event type. This functions
+// same way as SubscribeTo() but uses the default dispatcher instead.
+func OnType[T Event](eventType uint32, handler func(T)) context.CancelFunc {
+	return SubscribeTo(Default, eventType, handler)
+}
+
+// Emit writes an event into the dispatcher. This functions same way as
+// Publish() but uses the default dispatcher instead.
+func Emit[T Event](ev T) {
+	Publish(Default, ev)
+}

event/default_test.go

@@ -0,0 +1,54 @@
+// Copyright (c) Roman Atachiants and contributore. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for detaile.
+
+package event
+
+import (
+	"sync"
+	"sync/atomic"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+/*
+cpu: 13th Gen Intel(R) Core(TM) i7-13700K
+BenchmarkSubcribeConcurrent-24    	 1826686	       606.3 ns/op	    1648 B/op	       5 allocs/op
+*/
+func BenchmarkSubscribeConcurrent(b *testing.B) {
+	d := NewDispatcher()
+	b.ReportAllocs()
+	b.ResetTimer()
+
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			unsub := Subscribe(d, func(ev MyEvent1) {})
+			unsub()
+		}
+	})
+}
+
+func TestDefaultPublish(t *testing.T) {
+	var wg sync.WaitGroup
+
+	// Subscribe
+	var count int64
+	defer On(func(ev MyEvent1) {
+		atomic.AddInt64(&count, 1)
+		wg.Done()
+	})()
+
+	defer OnType(TypeEvent1, func(ev MyEvent1) {
+		atomic.AddInt64(&count, 1)
+		wg.Done()
+	})()
+
+	// Publish
+	wg.Add(4)
+	Emit(MyEvent1{})
+	Emit(MyEvent1{})
+
+	// Wait and check
+	wg.Wait()
+	assert.Equal(t, int64(4), count)
+}

event/event.go

@@ -0,0 +1,324 @@
+// Copyright (c) Roman Atachiants and contributors. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for details.
+
+package event
+
+import (
+	"context"
+	"fmt"
+	"reflect"
+	"sort"
+	"strings"
+	"sync"
+	"sync/atomic"
+)
+
+// Event represents an event contract
+type Event interface {
+	Type() uint32
+}
+
+// registry holds an immutable sorted array of event mappings
+type registry struct {
+	keys []uint32 // Event types (sorted)
+	grps []any    // Corresponding subscribers
+}
+
+// ------------------------------------- Dispatcher -------------------------------------
+
+// Dispatcher represents an event dispatcher.
+type Dispatcher struct {
+	subs     atomic.Pointer[registry] // Atomic pointer to immutable array
+	done     chan struct{}            // Cancellation
+	maxQueue int                      // Maximum queue size per consumer
+	mu       sync.Mutex               // Only for writes (subscribe/unsubscribe)
+}
+
+// NewDispatcher creates a new dispatcher of events.
+func NewDispatcher() *Dispatcher {
+	return NewDispatcherConfig(50000)
+}
+
+// NewDispatcherConfig creates a new dispatcher with configurable max queue size
+func NewDispatcherConfig(maxQueue int) *Dispatcher {
+	d := &Dispatcher{
+		done:     make(chan struct{}),
+		maxQueue: maxQueue,
+	}
+
+	d.subs.Store(&registry{
+		keys: make([]uint32, 0, 16),
+		grps: make([]any, 0, 16),
+	})
+	return d
+}
+
+// Close closes the dispatcher
+func (d *Dispatcher) Close() error {
+	close(d.done)
+	return nil
+}
+
+// isClosed returns whether the dispatcher is closed or not
+func (d *Dispatcher) isClosed() bool {
+	select {
+	case <-d.done:
+		return true
+	default:
+		return false
+	}
+}
+
+// findGroup performs a lock-free binary search for the event type
+func (d *Dispatcher) findGroup(eventType uint32) any {
+	reg := d.subs.Load()
+	keys := reg.keys
+
+	// Inlined binary search for better cache locality
+	left, right := 0, len(keys)
+	for left < right {
+		mid := left + (right-left)/2
+		if keys[mid] < eventType {
+			left = mid + 1
+		} else {
+			right = mid
+		}
+	}
+
+	if left < len(keys) && keys[left] == eventType {
+		return reg.grps[left]
+	}
+	return nil
+}
+
+// Subscribe subscribes to an event, the type of the event will be automatically
+// inferred from the provided type. Must be constant for this to work.
+func Subscribe[T Event](broker *Dispatcher, handler func(T)) context.CancelFunc {
+	var event T
+	return SubscribeTo(broker, event.Type(), handler)
+}
+
+// SubscribeTo subscribes to an event with the specified event type.
+func SubscribeTo[T Event](broker *Dispatcher, eventType uint32, handler func(T)) context.CancelFunc {
+	if broker.isClosed() {
+		panic(errClosed)
+	}
+
+	broker.mu.Lock()
+	defer broker.mu.Unlock()
+
+	// Check if group already exists
+	if existing := broker.findGroup(eventType); existing != nil {
+		grp := groupOf[T](eventType, existing)
+		sub := grp.Add(handler)
+		return func() {
+			grp.Del(sub)
+		}
+	}
+
+	// Create new group
+	grp := &group[T]{cond: sync.NewCond(new(sync.Mutex)), maxQueue: broker.maxQueue}
+	sub := grp.Add(handler)
+
+	// Copy-on-write: insert new entry in sorted position
+	old := broker.subs.Load()
+	idx := sort.Search(len(old.keys), func(i int) bool {
+		return old.keys[i] >= eventType
+	})
+
+	// Create new arrays with space for one more element
+	newKeys := make([]uint32, len(old.keys)+1)
+	newGrps := make([]any, len(old.grps)+1)
+
+	// Copy elements before insertion point
+	copy(newKeys[:idx], old.keys[:idx])
+	copy(newGrps[:idx], old.grps[:idx])
+
+	// Insert new element
+	newKeys[idx] = eventType
+	newGrps[idx] = grp
+
+	// Copy elements after insertion point
+	copy(newKeys[idx+1:], old.keys[idx:])
+	copy(newGrps[idx+1:], old.grps[idx:])
+
+	// Atomically store the new registry (mutex ensures no concurrent writers)
+	newReg := &registry{keys: newKeys, grps: newGrps}
+	broker.subs.Store(newReg)
+
+	return func() {
+		grp.Del(sub)
+	}
+}
+
+// Publish writes an event into the dispatcher
+func Publish[T Event](broker *Dispatcher, ev T) {
+	eventType := ev.Type()
+	if sub := broker.findGroup(eventType); sub != nil {
+		group := groupOf[T](eventType, sub)
+		group.Broadcast(ev)
+	}
+}
+
+// Count counts the number of subscribers, this is for testing only.
+func (d *Dispatcher) count(eventType uint32) int {
+	if group := d.findGroup(eventType); group != nil {
+		return group.(interface{ Count() int }).Count()
+	}
+	return 0
+}
+
+// groupOf casts the subscriber group to the specified generic type
+func groupOf[T Event](eventType uint32, subs any) *group[T] {
+	if group, ok := subs.(*group[T]); ok {
+		return group
+	}
+
+	panic(errConflict[T](eventType, subs))
+}
+
+// ------------------------------------- Subscriber -------------------------------------
+
+// consumer represents a consumer with a message queue
+type consumer[T Event] struct {
+	queue []T  // Current work queue
+	stop  bool // Stop signal
+}
+
+// Listen listens to the event queue and processes events
+func (s *consumer[T]) Listen(c *sync.Cond, fn func(T)) {
+	pending := make([]T, 0, 128)
+
+	for {
+		c.L.Lock()
+		for len(s.queue) == 0 {
+			switch {
+			case s.stop:
+				c.L.Unlock()
+				return
+			default:
+				c.Wait()
+			}
+		}
+
+		// Swap buffers and reset the current queue
+		temp := s.queue
+		s.queue = pending[:0]
+		pending = temp
+		c.L.Unlock()
+
+		// Outside of the critical section, process the work
+		for _, event := range pending {
+			fn(event)
+		}
+
+		// Notify potential publishers waiting due to backpressure
+		c.Broadcast()
+	}
+}
+
+// ------------------------------------- Subscriber Group -------------------------------------
+
+// group represents a consumer group
+type group[T Event] struct {
+	cond     *sync.Cond
+	subs     []*consumer[T]
+	maxQueue int // Maximum queue size per consumer
+	maxLen   int // Current maximum queue length across all consumers
+}
+
+// Broadcast sends an event to all consumers
+func (s *group[T]) Broadcast(ev T) {
+	s.cond.L.Lock()
+	defer s.cond.L.Unlock()
+
+	// Calculate current maximum queue length
+	s.maxLen = 0
+	for _, sub := range s.subs {
+		if len(sub.queue) > s.maxLen {
+			s.maxLen = len(sub.queue)
+		}
+	}
+
+	// Backpressure: wait if queues are full
+	for s.maxLen >= s.maxQueue {
+		s.cond.Wait()
+
+		// Recalculate after wakeup
+		s.maxLen = 0
+		for _, sub := range s.subs {
+			if len(sub.queue) > s.maxLen {
+				s.maxLen = len(sub.queue)
+			}
+		}
+	}
+
+	// Add event to all queues and track new maximum
+	newMax := 0
+	for _, sub := range s.subs {
+		sub.queue = append(sub.queue, ev)
+		if len(sub.queue) > newMax {
+			newMax = len(sub.queue)
+		}
+	}
+	s.maxLen = newMax
+	s.cond.Broadcast() // Wake consumers
+}
+
+// Add adds a subscriber to the list
+func (s *group[T]) Add(handler func(T)) *consumer[T] {
+	sub := &consumer[T]{
+		queue: make([]T, 0, 64),
+	}
+
+	// Add the consumer to the list of active consumers
+	s.cond.L.Lock()
+	s.subs = append(s.subs, sub)
+	s.cond.L.Unlock()
+
+	// Start listening
+	go sub.Listen(s.cond, handler)
+	return sub
+}
+
+// Del removes a subscriber from the list
+func (s *group[T]) Del(sub *consumer[T]) {
+	s.cond.L.Lock()
+	defer s.cond.L.Unlock()
+
+	// Search and remove the subscriber
+	sub.stop = true
+	for i, v := range s.subs {
+		if v == sub {
+			copy(s.subs[i:], s.subs[i+1:])
+			s.subs = s.subs[:len(s.subs)-1]
+			break
+		}
+	}
+}
+
+// ------------------------------------- Debugging -------------------------------------
+
+var errClosed = fmt.Errorf("event dispatcher is closed")
+
+// Count returns the number of subscribers in this group
+func (s *group[T]) Count() int {
+	return len(s.subs)
+}
+
+// String returns string representation of the type
+func (s *group[T]) String() string {
+	typ := reflect.TypeOf(s).String()
+	idx := strings.LastIndex(typ, "/")
+	typ = typ[idx+1 : len(typ)-1]
+	return typ
+}
+
+// errConflict returns a conflict message
+func errConflict[T any](eventType uint32, existing any) string {
+	var want T
+	return fmt.Sprintf(
+		"conflicting event type, want=<%T>, registered=<%s>, event=0x%v",
+		want, existing, eventType,
+	)
+}

event/event_test.go

@@ -0,0 +1,324 @@
+// Copyright (c) Roman Atachiants and contributore. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for detaile.
+
+package event
+
+import (
+	"fmt"
+	"sync"
+	"sync/atomic"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestPublish(t *testing.T) {
+	d := NewDispatcher()
+	var wg sync.WaitGroup
+
+	// Subscribe, must be received in order
+	var count int64
+	defer Subscribe(d, func(ev MyEvent1) {
+		assert.Equal(t, int(atomic.AddInt64(&count, 1)), ev.Number)
+		wg.Done()
+	})()
+
+	// Publish
+	wg.Add(3)
+	Publish(d, MyEvent1{Number: 1})
+	Publish(d, MyEvent1{Number: 2})
+	Publish(d, MyEvent1{Number: 3})
+
+	// Wait and check
+	wg.Wait()
+	assert.Equal(t, int64(3), count)
+}
+
+func TestUnsubscribe(t *testing.T) {
+	d := NewDispatcher()
+	assert.Equal(t, 0, d.count(TypeEvent1))
+	unsubscribe := Subscribe(d, func(ev MyEvent1) {
+		// Nothing
+	})
+
+	assert.Equal(t, 1, d.count(TypeEvent1))
+	unsubscribe()
+	assert.Equal(t, 0, d.count(TypeEvent1))
+}
+
+func TestConcurrent(t *testing.T) {
+	const max = 1000000
+	var count int64
+	var wg sync.WaitGroup
+	wg.Add(1)
+
+	d := NewDispatcher()
+	defer Subscribe(d, func(ev MyEvent1) {
+		if current := atomic.AddInt64(&count, 1); current == max {
+			wg.Done()
+		}
+	})()
+
+	// Asynchronously publish
+	go func() {
+		for i := 0; i < max; i++ {
+			Publish(d, MyEvent1{})
+		}
+	}()
+
+	defer Subscribe(d, func(ev MyEvent1) {
+		// Subscriber that does nothing
+	})()
+
+	wg.Wait()
+	assert.Equal(t, max, int(count))
+}
+
+func TestSubscribeDifferentType(t *testing.T) {
+	d := NewDispatcher()
+	assert.Panics(t, func() {
+		SubscribeTo(d, TypeEvent1, func(ev MyEvent1) {})
+		SubscribeTo(d, TypeEvent1, func(ev MyEvent2) {})
+	})
+}
+
+func TestPublishDifferentType(t *testing.T) {
+	d := NewDispatcher()
+	assert.Panics(t, func() {
+		SubscribeTo(d, TypeEvent1, func(ev MyEvent2) {})
+		Publish(d, MyEvent1{})
+	})
+}
+
+func TestCloseDispatcher(t *testing.T) {
+	d := NewDispatcher()
+	defer SubscribeTo(d, TypeEvent1, func(ev MyEvent2) {})()
+
+	assert.NoError(t, d.Close())
+	assert.Panics(t, func() {
+		SubscribeTo(d, TypeEvent1, func(ev MyEvent2) {})
+	})
+}
+
+func TestMatrix(t *testing.T) {
+	const amount = 1000
+	for _, subs := range []int{1, 10, 100} {
+		for _, topics := range []int{1, 10} {
+			expected := subs * topics * amount
+			t.Run(fmt.Sprintf("%dx%d", topics, subs), func(t *testing.T) {
+				var count atomic.Int64
+				var wg sync.WaitGroup
+				wg.Add(expected)
+
+				d := NewDispatcher()
+				for i := 0; i < subs; i++ {
+					for id := 0; id < topics; id++ {
+						defer SubscribeTo(d, uint32(id), func(ev MyEvent3) {
+							count.Add(1)
+							wg.Done()
+						})()
+					}
+				}
+
+				for n := 0; n < amount; n++ {
+					for id := 0; id < topics; id++ {
+						go Publish(d, MyEvent3{ID: id})
+					}
+				}
+
+				wg.Wait()
+				assert.Equal(t, expected, int(count.Load()))
+			})
+		}
+	}
+}
+
+func TestConcurrentSubscriptionRace(t *testing.T) {
+	// This test specifically targets the race condition that occurs when multiple
+	// goroutines try to subscribe to different event types simultaneously.
+	// Without the CAS loop, subscriptions could be lost due to registry corruption.
+
+	const numGoroutines = 100
+	const numEventTypes = 50
+
+	d := NewDispatcher()
+	defer d.Close()
+
+	var wg sync.WaitGroup
+	var receivedCount int64
+	var subscribedTypes sync.Map // Thread-safe map
+
+	wg.Add(numGoroutines)
+
+	// Start multiple goroutines that subscribe to different event types concurrently
+	for i := 0; i < numGoroutines; i++ {
+		go func(goroutineID int) {
+			defer wg.Done()
+
+			// Each goroutine subscribes to a unique event type
+			eventType := uint32(goroutineID%numEventTypes + 1000) // Offset to avoid collision with other tests
+
+			// Subscribe to the event type
+			SubscribeTo(d, eventType, func(ev MyEvent3) {
+				atomic.AddInt64(&receivedCount, 1)
+			})
+
+			// Record that this type was subscribed
+			subscribedTypes.Store(eventType, true)
+		}(i)
+	}
+
+	// Wait for all subscriptions to complete
+	wg.Wait()
+
+	// Count the number of unique event types subscribed
+	expectedTypes := 0
+	subscribedTypes.Range(func(key, value interface{}) bool {
+		expectedTypes++
+		return true
+	})
+
+	// Small delay to ensure all subscriptions are fully processed
+	time.Sleep(10 * time.Millisecond)
+
+	// Publish events to each subscribed type
+	subscribedTypes.Range(func(key, value interface{}) bool {
+		eventType := key.(uint32)
+		Publish(d, MyEvent3{ID: int(eventType)})
+		return true
+	})
+
+	// Wait for all events to be processed
+	time.Sleep(50 * time.Millisecond)
+
+	// Verify that we received at least the expected number of events
+	// (there might be more if multiple goroutines subscribed to the same event type)
+	received := atomic.LoadInt64(&receivedCount)
+	assert.GreaterOrEqual(t, int(received), expectedTypes,
+		"Should have received at least %d events, got %d", expectedTypes, received)
+
+	// Verify that we have the expected number of unique event types
+	assert.Equal(t, numEventTypes, expectedTypes,
+		"Should have exactly %d unique event types", numEventTypes)
+}
+
+func TestConcurrentHandlerRegistration(t *testing.T) {
+	const numGoroutines = 100
+
+	// Test concurrent subscriptions to the same event type
+	t.Run("SameEventType", func(t *testing.T) {
+		d := NewDispatcher()
+		var handlerCount int64
+		var wg sync.WaitGroup
+
+		// Start multiple goroutines subscribing to the same event type (0x1)
+		for i := 0; i < numGoroutines; i++ {
+			wg.Add(1)
+			go func() {
+				defer wg.Done()
+				SubscribeTo(d, uint32(0x1), func(ev MyEvent1) {
+					atomic.AddInt64(&handlerCount, 1)
+				})
+			}()
+		}
+
+		wg.Wait()
+
+		// Verify all handlers were registered by publishing an event
+		atomic.StoreInt64(&handlerCount, 0)
+		Publish(d, MyEvent1{})
+
+		// Small delay to ensure all handlers have executed
+		time.Sleep(10 * time.Millisecond)
+
+		assert.Equal(t, int64(numGoroutines), atomic.LoadInt64(&handlerCount),
+			"Not all handlers were registered due to race condition")
+	})
+
+	// Test concurrent subscriptions to different event types
+	t.Run("DifferentEventTypes", func(t *testing.T) {
+		d := NewDispatcher()
+		var wg sync.WaitGroup
+		receivedEvents := make(map[uint32]*int64)
+
+		// Create multiple event types and subscribe concurrently
+		for i := 0; i < numGoroutines; i++ {
+			eventType := uint32(100 + i)
+			counter := new(int64)
+			receivedEvents[eventType] = counter
+
+			wg.Add(1)
+			go func(et uint32, cnt *int64) {
+				defer wg.Done()
+				SubscribeTo(d, et, func(ev MyEvent3) {
+					atomic.AddInt64(cnt, 1)
+				})
+			}(eventType, counter)
+		}
+
+		wg.Wait()
+
+		// Publish events to all types
+		for eventType := uint32(100); eventType < uint32(100+numGoroutines); eventType++ {
+			Publish(d, MyEvent3{ID: int(eventType)})
+		}
+
+		// Small delay to ensure all handlers have executed
+		time.Sleep(10 * time.Millisecond)
+
+		// Verify all event types received their events
+		for eventType, counter := range receivedEvents {
+			assert.Equal(t, int64(1), atomic.LoadInt64(counter),
+				"Event type %d did not receive its event", eventType)
+		}
+	})
+}
+
+func TestBackpressure(t *testing.T) {
+	d := NewDispatcher()
+	d.maxQueue = 10
+
+	var processedCount int64
+	unsub := SubscribeTo(d, uint32(0x200), func(ev MyEvent3) {
+		atomic.AddInt64(&processedCount, 1)
+	})
+	defer unsub()
+
+	const eventsToPublish = 1000
+	for i := 0; i < eventsToPublish; i++ {
+		Publish(d, MyEvent3{ID: 0x200})
+	}
+
+	time.Sleep(100 * time.Millisecond)
+
+	// Verify all events were eventually processed
+	finalProcessed := atomic.LoadInt64(&processedCount)
+	assert.Equal(t, int64(eventsToPublish), finalProcessed)
+	t.Logf("Events processed: %d/%d", finalProcessed, eventsToPublish)
+}
+
+// ------------------------------------- Test Events -------------------------------------
+
+const (
+	TypeEvent1 = 0x1
+	TypeEvent2 = 0x2
+)
+
+type MyEvent1 struct {
+	Number int
+}
+
+func (t MyEvent1) Type() uint32 { return TypeEvent1 }
+
+type MyEvent2 struct {
+	Text string
+}
+
+func (t MyEvent2) Type() uint32 { return TypeEvent2 }
+
+type MyEvent3 struct {
+	ID int
+}
+
+func (t MyEvent3) Type() uint32 { return uint32(t.ID) }

go.mod

@@ -3,8 +3,9 @@ module github.com/mostlygeek/llama-swap
 go 1.23.0
 
 require (
+	github.com/billziss-gh/golib v0.2.0
+	github.com/fsnotify/fsnotify v1.9.0
 	github.com/gin-gonic/gin v1.10.0
-	github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510
 	github.com/stretchr/testify v1.9.0
 	github.com/tidwall/gjson v1.18.0
 	github.com/tidwall/sjson v1.2.5
@@ -37,7 +38,7 @@ require (
 	github.com/ugorji/go/codec v1.2.12 // indirect
 	golang.org/x/arch v0.8.0 // indirect
 	golang.org/x/crypto v0.36.0 // indirect
-	golang.org/x/net v0.37.0 // indirect
+	golang.org/x/net v0.38.0 // indirect
 	golang.org/x/sys v0.31.0 // indirect
 	golang.org/x/text v0.23.0 // indirect
 	google.golang.org/protobuf v1.34.1 // indirect

go.sum

@@ -1,3 +1,5 @@
+github.com/billziss-gh/golib v0.2.0 h1:NyvcAQdfvM8xokKkKotiligKjKXzuQD4PPykg1nKc/8=
+github.com/billziss-gh/golib v0.2.0/go.mod h1:mZpUYANXZkDKSnyYbX9gfnyxwe0ddRhUtfXcsD5r8dw=
 github.com/bytedance/sonic v1.11.6 h1:oUp34TzMlL+OY1OUWxHqsdkgC/Zfc85zGqw9siXjrc0=
 github.com/bytedance/sonic v1.11.6/go.mod h1:LysEHSvpvDySVdC2f87zGWf6CIKJcAvqab1ZaiQtds4=
 github.com/bytedance/sonic/loader v0.1.1 h1:c+e5Pt1k/cy5wMveRDyk2X4B9hF4g7an8N3zCYjJFNM=
@@ -9,12 +11,16 @@ github.com/cloudwego/iasm v0.2.0/go.mod h1:8rXZaNYT2n95jn+zTI1sDr+IgcD2GVs0nlbbQ
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/fsnotify/fsnotify v1.9.0 h1:2Ml+OJNzbYCTzsxtv8vKSFD9PbJjmhYF14k/jKC7S9k=
+github.com/fsnotify/fsnotify v1.9.0/go.mod h1:8jBTzvmWwFyi3Pb8djgCCO5IBqzKJ/Jwo8TRcHyHii0=
 github.com/gabriel-vasile/mimetype v1.4.3 h1:in2uUcidCuFcDKtdcBxlR0rJ1+fsokWf+uqxgUFjbI0=
 github.com/gabriel-vasile/mimetype v1.4.3/go.mod h1:d8uq/6HKRL6CGdk+aubisF/M5GcPfT7nKyLpA0lbSSk=
 github.com/gin-contrib/sse v0.1.0 h1:Y/yl/+YNO8GZSjAhjMsSuLt29uWRFHdHYUb5lYOV9qE=
 github.com/gin-contrib/sse v0.1.0/go.mod h1:RHrZQHXnP2xjPF+u1gW/2HnVO7nvIa9PG3Gm+fLHvGI=
 github.com/gin-gonic/gin v1.10.0 h1:nTuyha1TYqgedzytsKYqna+DfLos46nTv2ygFy86HFU=
 github.com/gin-gonic/gin v1.10.0/go.mod h1:4PMNQiOhvDRa013RKVbsiNwoyezlm2rm0uX/T7kzp5Y=
+github.com/go-playground/assert/v2 v2.2.0 h1:JvknZsQTYeFEAhQwI4qEt9cyV5ONwRHC+lYKSsYSR8s=
+github.com/go-playground/assert/v2 v2.2.0/go.mod h1:VDjEfimB/XKnb+ZQfWdccd7VUvScMdVu0Titje2rxJ4=
 github.com/go-playground/locales v0.14.1 h1:EWaQ/wswjilfKLTECiXz7Rh+3BjFhfDFKv/oXslEjJA=
 github.com/go-playground/locales v0.14.1/go.mod h1:hxrqLVvrK65+Rwrd5Fc6F2O76J/NuW9t0sjnWqG1slY=
 github.com/go-playground/universal-translator v0.18.1 h1:Bcnm0ZwsGyWbCzImXv+pAJnYK9S473LQFuzCbDbfSFY=
@@ -23,9 +29,9 @@ github.com/go-playground/validator/v10 v10.20.0 h1:K9ISHbSaI0lyB2eWMPJo+kOS/FBEx
 github.com/go-playground/validator/v10 v10.20.0/go.mod h1:dbuPbCMFw/DrkbEynArYaCwl3amGuJotoKCe95atGMM=
 github.com/goccy/go-json v0.10.2 h1:CrxCmQqYDkv1z7lO7Wbh2HN93uovUHgrECaO5ZrCXAU=
 github.com/goccy/go-json v0.10.2/go.mod h1:6MelG93GURQebXPDq3khkgXZkazVtN9CRI+MGFi0w8I=
+github.com/google/go-cmp v0.5.5 h1:Khx7svrCpmxxtHBq5j2mp/xVjsi8hQMfNLvJFAlrGgU=
+github.com/google/go-cmp v0.5.5/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/gofuzz v1.0.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
-github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510 h1:El6M4kTTCOh6aBiKaUGG7oYTSPP8MxqL4YI3kZKwcP4=
-github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510/go.mod h1:pupxD2MaaD3pAXIBCelhxNneeOaAeabZDe5s4K6zSpQ=
 github.com/json-iterator/go v1.1.12 h1:PV8peI4a0ysnczrg+LtxykD8LfKY9ML6u2jnxaEnrnM=
 github.com/json-iterator/go v1.1.12/go.mod h1:e30LSqwooZae/UwlEbR2852Gd8hjQvJoHmT4TnhNGBo=
 github.com/klauspost/cpuid/v2 v2.0.9/go.mod h1:FInQzS24/EEf25PyTYn52gqo7WaD8xa0213Md/qVLRg=
@@ -74,32 +80,18 @@ github.com/ugorji/go/codec v1.2.12/go.mod h1:UNopzCgEMSXjBc6AOMqYvWC1ktqTAfzJZUZ
 golang.org/x/arch v0.0.0-20210923205945-b76863e36670/go.mod h1:5om86z9Hs0C8fWVUuoMHwpExlXzs5Tkyp9hOrfG7pp8=
 golang.org/x/arch v0.8.0 h1:3wRIsP3pM4yUptoR96otTUOXI367OS0+c9eeRi9doIc=
 golang.org/x/arch v0.8.0/go.mod h1:FEVrYAQjsQXMVJ1nsMoVVXPZg6p2JE2mx8psSWTDQys=
-golang.org/x/crypto v0.23.0 h1:dIJU/v2J8Mdglj/8rJ6UUOM3Zc9zLZxVZwwxMooUSAI=
-golang.org/x/crypto v0.23.0/go.mod h1:CKFgDieR+mRhux2Lsu27y0fO304Db0wZe70UKqHu0v8=
-golang.org/x/crypto v0.31.0 h1:ihbySMvVjLAeSH1IbfcRTkD/iNscyz8rGzjF/E5hV6U=
-golang.org/x/crypto v0.31.0/go.mod h1:kDsLvtWBEx7MV9tJOj9bnXsPbxwJQ6csT/x4KIN4Ssk=
 golang.org/x/crypto v0.36.0 h1:AnAEvhDddvBdpY+uR+MyHmuZzzNqXSe/GvuDeob5L34=
 golang.org/x/crypto v0.36.0/go.mod h1:Y4J0ReaxCR1IMaabaSMugxJES1EpwhBHhv2bDHklZvc=
-golang.org/x/net v0.25.0 h1:d/OCCoBEUq33pjydKrGQhw7IlUPI2Oylr+8qLx49kac=
-golang.org/x/net v0.25.0/go.mod h1:JkAGAh7GEvH74S6FOH42FLoXpXbE/aqXSrIQjXgsiwM=
-golang.org/x/net v0.33.0 h1:74SYHlV8BIgHIFC/LrYkOGIwL19eTYXQ5wc6TBuO36I=
-golang.org/x/net v0.33.0/go.mod h1:HXLR5J+9DxmrqMwG9qjGCxZ+zKXxBru04zlTvWlWuN4=
-golang.org/x/net v0.37.0 h1:1zLorHbz+LYj7MQlSf1+2tPIIgibq2eL5xkrGk6f+2c=
-golang.org/x/net v0.37.0/go.mod h1:ivrbrMbzFq5J41QOQh0siUuly180yBYtLp+CKbEaFx8=
+golang.org/x/net v0.38.0 h1:vRMAPTMaeGqVhG5QyLJHqNDwecKTomGeqbnfZyKlBI8=
+golang.org/x/net v0.38.0/go.mod h1:ivrbrMbzFq5J41QOQh0siUuly180yBYtLp+CKbEaFx8=
 golang.org/x/sys v0.5.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.20.0 h1:Od9JTbYCk261bKm4M/mw7AklTlFYIa0bIp9BgSm1S8Y=
-golang.org/x/sys v0.20.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
-golang.org/x/sys v0.28.0 h1:Fksou7UEQUWlKvIdsqzJmUmCX3cZuD2+P3XyyzwMhlA=
-golang.org/x/sys v0.28.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/sys v0.31.0 h1:ioabZlmFYtWhL+TRYpcnNlLwhyxaM9kWTDEmfnprqik=
 golang.org/x/sys v0.31.0/go.mod h1:BJP2sWEmIv4KK5OTEluFJCKSidICx8ciO85XgH3Ak8k=
-golang.org/x/text v0.15.0 h1:h1V/4gjBv8v9cjcR6+AR5+/cIYK5N/WAgiv4xlsEtAk=
-golang.org/x/text v0.15.0/go.mod h1:18ZOQIKpY8NJVqYksKHtTdi31H5itFRjB5/qKTNYzSU=
-golang.org/x/text v0.21.0 h1:zyQAAkrwaneQ066sspRyJaG9VNi/YJ1NfzcGB3hZ/qo=
-golang.org/x/text v0.21.0/go.mod h1:4IBbMaMmOPCJ8SecivzSH54+73PCFmPWxNTLm+vZkEQ=
 golang.org/x/text v0.23.0 h1:D71I7dUrlY+VX0gQShAThNGHFxZ13dGLBHQLVl1mJlY=
 golang.org/x/text v0.23.0/go.mod h1:/BLNzu4aZCJ1+kcD0DNRotWKage4q2rGVAg4o22unh4=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 google.golang.org/protobuf v1.34.1 h1:9ddQBjfCyZPOHPUiPxpYESBLc+T8P3E+Vo4IbKZgFWg=
 google.golang.org/protobuf v1.34.1/go.mod h1:c6P6GXX6sHbq/GpV6MGZEdwhWPcYBgnhAHhKbcUYpos=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=

llama-swap.go

@@ -1,25 +1,35 @@
 package main
 
 import (
+	"context"
 	"flag"
 	"fmt"
+	"log"
+	"net/http"
 	"os"
 	"os/signal"
+	"path/filepath"
 	"syscall"
+	"time"
 
+	"github.com/fsnotify/fsnotify"
 	"github.com/gin-gonic/gin"
+	"github.com/mostlygeek/llama-swap/event"
 	"github.com/mostlygeek/llama-swap/proxy"
 )
 
-var version string = "0"
-var commit string = "abcd1234"
-var date = "unknown"
+var (
+	version string = "0"
+	commit  string = "abcd1234"
+	date    string = "unknown"
+)
 
 func main() {
 	// Define a command-line flag for the port
 	configPath := flag.String("config", "config.yaml", "config file name")
 	listenStr := flag.String("listen", ":8080", "listen ip/port")
 	showVersion := flag.Bool("version", false, "show version of build")
+	watchConfig := flag.Bool("watch-config", false, "Automatically reload config file on change")
 
 	flag.Parse() // Parse the command-line flags
 
@@ -34,26 +44,145 @@ func main() {
 		os.Exit(1)
 	}
 
+	if len(config.Profiles) > 0 {
+		fmt.Println("WARNING: Profile functionality has been removed in favor of Groups. See the README for more information.")
+	}
+
 	if mode := os.Getenv("GIN_MODE"); mode != "" {
 		gin.SetMode(mode)
 	} else {
 		gin.SetMode(gin.ReleaseMode)
 	}
 
-	proxyManager := proxy.New(config)
-
+	// Setup channels for server management
+	exitChan := make(chan struct{})
 	sigChan := make(chan os.Signal, 1)
 	signal.Notify(sigChan, syscall.SIGINT, syscall.SIGTERM)
+
+	// Create server with initial handler
+	srv := &http.Server{
+		Addr: *listenStr,
+	}
+
+	// Support for watching config and reloading when it changes
+	reloadProxyManager := func() {
+		if currentPM, ok := srv.Handler.(*proxy.ProxyManager); ok {
+			config, err = proxy.LoadConfig(*configPath)
+			if err != nil {
+				fmt.Printf("Warning, unable to reload configuration: %v\n", err)
+				return
+			}
+
+			fmt.Println("Configuration Changed")
+			currentPM.Shutdown()
+			srv.Handler = proxy.New(config)
+			fmt.Println("Configuration Reloaded")
+
+			// wait a few seconds and tell any UI to reload
+			time.AfterFunc(3*time.Second, func() {
+				event.Emit(proxy.ConfigFileChangedEvent{
+					ReloadingState: proxy.ReloadingStateEnd,
+				})
+			})
+		} else {
+			config, err = proxy.LoadConfig(*configPath)
+			if err != nil {
+				fmt.Printf("Error, unable to load configuration: %v\n", err)
+				os.Exit(1)
+			}
+			srv.Handler = proxy.New(config)
+		}
+	}
+
+	// load the initial proxy manager
+	reloadProxyManager()
+	debouncedReload := debounce(time.Second, reloadProxyManager)
+	if *watchConfig {
+		defer event.On(func(e proxy.ConfigFileChangedEvent) {
+			if e.ReloadingState == proxy.ReloadingStateStart {
+				debouncedReload()
+			}
+		})()
+
+		fmt.Println("Watching Configuration for changes")
+		go func() {
+			absConfigPath, err := filepath.Abs(*configPath)
+			if err != nil {
+				fmt.Printf("Error getting absolute path for watching config file: %v\n", err)
+				return
+			}
+			watcher, err := fsnotify.NewWatcher()
+			if err != nil {
+				fmt.Printf("Error creating file watcher: %v. File watching disabled.\n", err)
+				return
+			}
+
+			configDir := filepath.Dir(absConfigPath)
+			err = watcher.Add(configDir)
+			if err != nil {
+				fmt.Printf("Error adding config path directory (%s) to watcher: %v. File watching disabled.", configDir, err)
+				return
+			}
+
+			defer watcher.Close()
+			for {
+				select {
+				case changeEvent := <-watcher.Events:
+					if changeEvent.Name == absConfigPath && (changeEvent.Has(fsnotify.Write) || changeEvent.Has(fsnotify.Create) || changeEvent.Has(fsnotify.Remove)) {
+						event.Emit(proxy.ConfigFileChangedEvent{
+							ReloadingState: proxy.ReloadingStateStart,
+						})
+					} else if changeEvent.Name == filepath.Join(configDir, "..data") && changeEvent.Has(fsnotify.Create) {
+						// the change for k8s configmap
+						event.Emit(proxy.ConfigFileChangedEvent{
+							ReloadingState: proxy.ReloadingStateStart,
+						})
+					}
+
+				case err := <-watcher.Errors:
+					log.Printf("File watcher error: %v", err)
+				}
+			}
+		}()
+	}
+
+	// shutdown on signal
 	go func() {
-		<-sigChan
-		fmt.Println("Shutting down llama-swap")
-		proxyManager.Shutdown()
-		os.Exit(0)
+		sig := <-sigChan
+		fmt.Printf("Received signal %v, shutting down...\n", sig)
+		ctx, cancel := context.WithTimeout(context.Background(), time.Second*5)
+		defer cancel()
+
+		if pm, ok := srv.Handler.(*proxy.ProxyManager); ok {
+			pm.Shutdown()
+		} else {
+			fmt.Println("srv.Handler is not of type *proxy.ProxyManager")
+		}
+
+		if err := srv.Shutdown(ctx); err != nil {
+			fmt.Printf("Server shutdown error: %v\n", err)
+		}
+		close(exitChan)
 	}()
 
-	fmt.Println("llama-swap listening on " + *listenStr)
-	if err := proxyManager.Run(*listenStr); err != nil {
-		fmt.Printf("Server error: %v\n", err)
-		os.Exit(1)
+	// Start server
+	fmt.Printf("llama-swap listening on %s\n", *listenStr)
+	go func() {
+		if err := srv.ListenAndServe(); err != nil && err != http.ErrServerClosed {
+			log.Fatalf("Fatal server error: %v\n", err)
+		}
+	}()
+
+	// Wait for exit signal
+	<-exitChan
+}
+
+func debounce(interval time.Duration, f func()) func() {
+	var timer *time.Timer
+	return func() {
+		if timer != nil {
+			timer.Stop()
+		}
+		timer = time.AfterFunc(interval, f)
 	}
 }

misc/benchmark-chatcompletion/main.go

@@ -0,0 +1,159 @@
+package main
+
+// created for issue: #252 https://github.com/mostlygeek/llama-swap/issues/252
+// this simple benchmark tool sends a lot of small chat completion requests to llama-swap
+// to make sure all the requests are accounted for.
+//
+// requests can be sent in parallel, and the tool will report the results.
+// usage: go run main.go -baseurl http://localhost:8080/v1 -model llama3 -requests 1000 -par 5
+
+import (
+	"bytes"
+	"flag"
+	"fmt"
+	"io"
+	"log"
+	"net/http"
+	"os"
+	"sync"
+	"time"
+)
+
+func main() {
+	// ----- CLI arguments ----------------------------------------------------
+	var (
+		baseurl         string
+		modelName       string
+		totalRequests   int
+		parallelization int
+	)
+
+	flag.StringVar(&baseurl, "baseurl", "http://localhost:8080/v1", "Base URL of the API (e.g., https://api.example.com)")
+	flag.StringVar(&modelName, "model", "", "Model name to use")
+	flag.IntVar(&totalRequests, "requests", 1, "Total number of requests to send")
+	flag.IntVar(&parallelization, "par", 1, "Maximum number of concurrent requests")
+	flag.Parse()
+
+	if baseurl == "" || modelName == "" {
+		fmt.Println("Error: both -baseurl and -model are required.")
+		flag.Usage()
+		os.Exit(1)
+	}
+	if totalRequests <= 0 {
+		fmt.Println("Error: -requests must be greater than 0.")
+		os.Exit(1)
+	}
+	if parallelization <= 0 {
+		fmt.Println("Error: -parallelization must be greater than 0.")
+		os.Exit(1)
+	}
+
+	// ----- HTTP client -------------------------------------------------------
+	client := &http.Client{
+		Timeout: 30 * time.Second,
+	}
+
+	// ----- Tracking response codes -------------------------------------------
+	statusCounts := make(map[int]int) // map[statusCode]count
+	var mu sync.Mutex                 // protects statusCounts
+
+	// ----- Request queue (buffered channel) ----------------------------------
+	requests := make(chan int, 10) // Buffered channel with capacity 10
+
+	// Goroutine to fill the request queue
+	go func() {
+		for i := 0; i < totalRequests; i++ {
+			requests <- i + 1
+		}
+		close(requests)
+	}()
+
+	// ----- Worker pool -------------------------------------------------------
+	var wg sync.WaitGroup
+	for i := 0; i < parallelization; i++ {
+		wg.Add(1)
+		go func(workerID int) {
+			defer wg.Done()
+
+			for reqID := range requests {
+				// Build request payload as a single line JSON string
+				payload := `{"model":"` + modelName + `","max_tokens":100,"stream":false,"messages":[{"role":"user","content":"write a snake game in python"}]}`
+
+				// Send POST request
+				req, err := http.NewRequest(http.MethodPost,
+					fmt.Sprintf("%s/chat/completions", baseurl),
+					bytes.NewReader([]byte(payload)))
+				if err != nil {
+					log.Printf("[worker %d][req %d] request creation error: %v", workerID, reqID, err)
+					mu.Lock()
+					statusCounts[-1]++
+					mu.Unlock()
+					continue
+				}
+				req.Header.Set("Content-Type", "application/json")
+
+				resp, err := client.Do(req)
+				if err != nil {
+					log.Printf("[worker %d][req %d] HTTP request error: %v", workerID, reqID, err)
+					mu.Lock()
+					statusCounts[-1]++
+					mu.Unlock()
+					continue
+				}
+				io.Copy(io.Discard, resp.Body)
+				resp.Body.Close()
+
+				// Record status code
+				mu.Lock()
+				statusCounts[resp.StatusCode]++
+				mu.Unlock()
+			}
+		}(i + 1)
+	}
+
+	// ----- Status ticker (prints every second) -------------------------------
+	done := make(chan struct{})
+	tickerDone := make(chan struct{})
+	go func() {
+		ticker := time.NewTicker(1 * time.Second)
+		startTime := time.Now()
+		for {
+			select {
+			case <-ticker.C:
+				mu.Lock()
+				// Compute how many requests have completed so far
+				completed := 0
+				for _, cnt := range statusCounts {
+					completed += cnt
+				}
+				// Calculate duration and progress
+				duration := time.Since(startTime)
+				progress := completed * 100 / totalRequests
+				fmt.Printf("Duration: %v, Completed: %d%% requests\n", duration, progress)
+				mu.Unlock()
+			case <-done:
+				duration := time.Since(startTime)
+				fmt.Printf("Duration: %v, Completed: %d%% requests\n", duration, 100)
+				close(tickerDone)
+				return
+			}
+		}
+	}()
+
+	// Wait for all workers to finish
+	wg.Wait()
+	close(done)  // stops the status-update goroutine
+	<-tickerDone // give ticker time to finish / print
+
+	// ----- Summary ------------------------------------------------------------
+	fmt.Println("\n\n=== HTTP response code summary ===")
+	mu.Lock()
+	for code, cnt := range statusCounts {
+		if code == -1 {
+			fmt.Printf("Client-side errors (no HTTP response): %d\n", cnt)
+		} else {
+			fmt.Printf("%d : %d\n", code, cnt)
+		}
+	}
+	mu.Unlock()
+}

misc/process-cmd-test/main.go

@@ -0,0 +1,91 @@
+package main
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"os"
+	"os/exec"
+	"os/signal"
+	"syscall"
+	"time"
+)
+
+/*
+**
+Test how exec.Cmd.CommandContext behaves under certain conditions:*
+
+  - process is killed externally, what happens with cmd.Wait() *
+    ✔︎ it returns. catches crashes.*
+
+  - process ignores SIGTERM*
+    ✔︎ `kill()` is called after cmd.WaitDelay*
+
+  - this process exits, what happens with children (kill -9 <this process' pid>)*
+    x they stick around. have to be manually killed.*
+
+  - .WithTimeout()'s cancel is called *
+    ✔︎ process is killed after it ignores sigterm, cmd.Wait() catches it.*
+
+  - parent receives SIGINT/SIGTERM, what happens
+    ✔︎ waits for child process to exit, then exits gracefully.
+*/
+func main() {
+
+	// swap between these to use kill -9 <pid> on the cli to sim external crash
+	ctx, cancel := context.WithCancel(context.Background())
+	//ctx, cancel := context.WithTimeout(context.Background(), 1000*time.Millisecond)
+	defer cancel()
+
+	//cmd := exec.CommandContext(ctx, "sleep", "1")
+	cmd := exec.CommandContext(ctx,
+		"../../build/simple-responder_darwin_arm64",
+		//"-ignore-sig-term", /* so it doesn't exit on receiving SIGTERM, test cmd.WaitTimeout */
+	)
+	cmd.Stdin = os.Stdin
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+
+	// set a wait delay before signing sig kill
+	cmd.WaitDelay = 500 * time.Millisecond
+	cmd.Cancel = func() error {
+		fmt.Println("✔︎ Cancel() called, sending SIGTERM")
+		cmd.Process.Signal(syscall.SIGTERM)
+
+		//return nil
+
+		// this error is returned by cmd.Wait(), and can be used to
+		// single an error when the process couldn't be normally terminated
+		// but since a SIGTERM is sent, it's probably ok to return a nil
+		// as WaitDelay timing out will override the any error set here.
+		//
+		// test by enabling/disabling -ignore-sig-term on the process
+		// with -ignore-sig-term enabled, cmd.Wait() will have "signal: killed"
+		// without it, it will show the "new error from cancel"
+		return errors.New("error from cmd.Cancel()") // sets error returned by cmd.Wait()
+	}
+
+	if err := cmd.Start(); err != nil {
+		fmt.Println("Error starting process:", err)
+		return
+	}
+
+	// catch signals. Calls cancel() which will cause cmd.Wait() to return and
+	// this program to eventually exit gracefully.
+	sigChan := make(chan os.Signal, 1)
+	signal.Notify(sigChan, syscall.SIGINT, syscall.SIGTERM)
+	go func() {
+		signal := <-sigChan
+		fmt.Printf("✔︎ Received signal: %d, Killing process... with cancel before exiting\n", signal)
+		cancel()
+	}()
+
+	fmt.Printf("✔︎ Parent Pid: %d, Process Pid: %d\n", os.Getpid(), cmd.Process.Pid)
+	fmt.Println("✔︎ Process started, cmd.Wait() ... ")
+	if err := cmd.Wait(); err != nil {
+		fmt.Println("✔︎ cmd.Wait returned, Error:", err)
+	} else {
+		fmt.Println("✔︎ cmd.Wait returned, Process exited on its own")
+	}
+	fmt.Println("✔︎ Child process exited, Done.")
+}

misc/simple-responder/simple-responder.go

@@ -26,6 +26,8 @@ func main() {
 
 	silent := flag.Bool("silent", false, "disable all logging")
 
+	ignoreSigTerm := flag.Bool("ignore-sig-term", false, "ignore SIGTERM signal")
+
 	flag.Parse() // Parse the command-line flags
 
 	// Create a new Gin router
@@ -33,14 +35,90 @@ func main() {
 
 	// Set up the handler function using the provided response message
 	r.POST("/v1/chat/completions", func(c *gin.Context) {
-		c.Header("Content-Type", "text/plain")
+		bodyBytes, _ := io.ReadAll(c.Request.Body)
 
-		// add a wait to simulate a slow query
-		if wait, err := time.ParseDuration(c.Query("wait")); err == nil {
-			time.Sleep(wait)
+		// Check if streaming is requested
+		// Query is checked instead of JSON body since that event stream conflicts with other tests
+		isStreaming := c.Query("stream") == "true"
+
+		if isStreaming {
+			// Set headers for streaming
+			c.Header("Content-Type", "text/event-stream")
+			c.Header("Cache-Control", "no-cache")
+			c.Header("Connection", "keep-alive")
+			c.Header("Transfer-Encoding", "chunked")
+
+			// add a wait to simulate a slow query
+			if wait, err := time.ParseDuration(c.Query("wait")); err == nil {
+				time.Sleep(wait)
+			}
+
+			// Send 10 "asdf" tokens
+			for i := 0; i < 10; i++ {
+				data := gin.H{
+					"created": time.Now().Unix(),
+					"choices": []gin.H{
+						{
+							"index": 0,
+							"delta": gin.H{
+								"content": "asdf",
+							},
+							"finish_reason": nil,
+						},
+					},
+				}
+				c.SSEvent("message", data)
+				c.Writer.Flush()
+			}
+
+			// Send final data with usage info
+			finalData := gin.H{
+				"usage": gin.H{
+					"completion_tokens": 10,
+					"prompt_tokens":     25,
+					"total_tokens":      35,
+				},
+				// add timings to simulate llama.cpp
+				"timings": gin.H{
+					"prompt_n":             25,
+					"prompt_ms":            13,
+					"predicted_n":          10,
+					"predicted_ms":         17,
+					"predicted_per_second": 10,
+				},
+			}
+			c.SSEvent("message", finalData)
+			c.Writer.Flush()
+
+			// Send [DONE]
+			c.SSEvent("message", "[DONE]")
+			c.Writer.Flush()
+		} else {
+			c.Header("Content-Type", "application/json")
+
+			// add a wait to simulate a slow query
+			if wait, err := time.ParseDuration(c.Query("wait")); err == nil {
+				time.Sleep(wait)
+			}
+
+			c.JSON(http.StatusOK, gin.H{
+				"responseMessage":  *responseMessage,
+				"h_content_length": c.Request.Header.Get("Content-Length"),
+				"request_body":     string(bodyBytes),
+				"usage": gin.H{
+					"completion_tokens": 10,
+					"prompt_tokens":     25,
+					"total_tokens":      35,
+				},
+				"timings": gin.H{
+					"prompt_n":             25,
+					"prompt_ms":            13,
+					"predicted_n":          10,
+					"predicted_ms":         17,
+					"predicted_per_second": 10,
+				},
+			})
 		}
-
-		c.String(200, *responseMessage)
 	})
 
 	// for issue #62 to check model name strips profile slug
@@ -63,8 +141,29 @@ func main() {
 	})
 
 	r.POST("/v1/completions", func(c *gin.Context) {
-		c.Header("Content-Type", "text/plain")
-		c.String(200, *responseMessage)
+		c.Header("Content-Type", "application/json")
+		c.JSON(http.StatusOK, gin.H{
+			"responseMessage": *responseMessage,
+			"usage": gin.H{
+				"completion_tokens": 10,
+				"prompt_tokens":     25,
+				"total_tokens":      35,
+			},
+		})
+
+	})
+
+	// llama-server compatibility: /completion
+	r.POST("/completion", func(c *gin.Context) {
+		c.Header("Content-Type", "application/json")
+		c.JSON(http.StatusOK, gin.H{
+			"responseMessage": *responseMessage,
+			"usage": gin.H{
+				"completion_tokens": 10,
+				"prompt_tokens":     25,
+				"total_tokens":      35,
+			},
+		})
 	})
 
 	// issue #41
@@ -104,6 +203,10 @@ func main() {
 		c.JSON(http.StatusOK, gin.H{
 			"text":  fmt.Sprintf("The length of the file is %d bytes", fileSize),
 			"model": model,
+
+			// expose some header values for testing
+			"h_content_type":   c.GetHeader("Content-Type"),
+			"h_content_length": c.GetHeader("Content-Length"),
 		})
 	})
 
@@ -180,6 +283,10 @@ func main() {
 		log.SetOutput(io.Discard)
 	}
 
+	if !*silent {
+		fmt.Printf("My PID: %d\n", os.Getpid())
+	}
+
 	go func() {
 		log.Printf("simple-responder listening on %s\n", address)
 		// service connections
@@ -190,11 +297,36 @@ func main() {
 
 	// Wait for interrupt signal to gracefully shutdown the server with
 	// a timeout of 5 seconds.
-	quit := make(chan os.Signal, 1)
+	sigChan := make(chan os.Signal, 1)
 	// kill (no param) default send syscall.SIGTERM
 	// kill -2 is syscall.SIGINT
 	// kill -9 is syscall.SIGKILL but can't be catch, so don't need add it
-	signal.Notify(quit, syscall.SIGINT, syscall.SIGTERM)
-	<-quit
+	signal.Notify(sigChan, syscall.SIGINT, syscall.SIGTERM)
+
+	countSigInt := 0
+
+runloop:
+	for {
+		signal := <-sigChan
+		switch signal {
+		case syscall.SIGINT:
+			countSigInt++
+			if countSigInt > 1 {
+				break runloop
+			} else {
+				log.Println("Received SIGINT, send another SIGINT to shutdown")
+			}
+		case syscall.SIGTERM:
+			if *ignoreSigTerm {
+				log.Println("Ignoring SIGTERM")
+			} else {
+				log.Println("Received SIGTERM, shutting down")
+				break runloop
+			}
+		default:
+			break runloop
+		}
+	}
+
 	log.Println("simple-responder shutting down")
 }

proxy/.gitignore

@@ -0,0 +1 @@
+ui_dist/*

proxy/config.go

@@ -2,15 +2,24 @@ package proxy
 
 import (
 	"fmt"
+	"io"
 	"os"
+	"regexp"
+	"runtime"
+	"slices"
+	"sort"
+	"strconv"
 	"strings"
 
-	"github.com/google/shlex"
+	"github.com/billziss-gh/golib/shlex"
 	"gopkg.in/yaml.v3"
 )
 
+const DEFAULT_GROUP_ID = "(default)"
+
 type ModelConfig struct {
 	Cmd           string   `yaml:"cmd"`
+	CmdStop       string   `yaml:"cmdStop"`
 	Proxy         string   `yaml:"proxy"`
 	Aliases       []string `yaml:"aliases"`
 	Env           []string `yaml:"env"`
@@ -18,21 +27,145 @@ type ModelConfig struct {
 	UnloadAfter   int      `yaml:"ttl"`
 	Unlisted      bool     `yaml:"unlisted"`
 	UseModelName  string   `yaml:"useModelName"`
+
+	// #179 for /v1/models
+	Name        string `yaml:"name"`
+	Description string `yaml:"description"`
+
+	// Limit concurrency of HTTP requests to process
+	ConcurrencyLimit int `yaml:"concurrencyLimit"`
+
+	// Model filters see issue #174
+	Filters ModelFilters `yaml:"filters"`
+}
+
+func (m *ModelConfig) UnmarshalYAML(unmarshal func(interface{}) error) error {
+	type rawModelConfig ModelConfig
+	defaults := rawModelConfig{
+		Cmd:              "",
+		CmdStop:          "",
+		Proxy:            "http://localhost:${PORT}",
+		Aliases:          []string{},
+		Env:              []string{},
+		CheckEndpoint:    "/health",
+		UnloadAfter:      0,
+		Unlisted:         false,
+		UseModelName:     "",
+		ConcurrencyLimit: 0,
+		Name:             "",
+		Description:      "",
+	}
+
+	// the default cmdStop to taskkill /f /t /pid ${PID}
+	if runtime.GOOS == "windows" {
+		defaults.CmdStop = "taskkill /f /t /pid ${PID}"
+	}
+
+	if err := unmarshal(&defaults); err != nil {
+		return err
+	}
+
+	*m = ModelConfig(defaults)
+	return nil
 }
 
 func (m *ModelConfig) SanitizedCommand() ([]string, error) {
 	return SanitizeCommand(m.Cmd)
 }
 
+// ModelFilters see issue #174
+type ModelFilters struct {
+	StripParams string `yaml:"strip_params"`
+}
+
+func (m *ModelFilters) UnmarshalYAML(unmarshal func(interface{}) error) error {
+	type rawModelFilters ModelFilters
+	defaults := rawModelFilters{
+		StripParams: "",
+	}
+
+	if err := unmarshal(&defaults); err != nil {
+		return err
+	}
+
+	*m = ModelFilters(defaults)
+	return nil
+}
+
+func (f ModelFilters) SanitizedStripParams() ([]string, error) {
+	if f.StripParams == "" {
+		return nil, nil
+	}
+
+	params := strings.Split(f.StripParams, ",")
+	cleaned := make([]string, 0, len(params))
+
+	for _, param := range params {
+		trimmed := strings.TrimSpace(param)
+		if trimmed == "model" || trimmed == "" {
+			continue
+		}
+		cleaned = append(cleaned, trimmed)
+	}
+
+	// sort cleaned
+	slices.Sort(cleaned)
+	return cleaned, nil
+}
+
+type GroupConfig struct {
+	Swap       bool     `yaml:"swap"`
+	Exclusive  bool     `yaml:"exclusive"`
+	Persistent bool     `yaml:"persistent"`
+	Members    []string `yaml:"members"`
+}
+
+// set default values for GroupConfig
+func (c *GroupConfig) UnmarshalYAML(unmarshal func(interface{}) error) error {
+	type rawGroupConfig GroupConfig
+	defaults := rawGroupConfig{
+		Swap:       true,
+		Exclusive:  true,
+		Persistent: false,
+		Members:    []string{},
+	}
+
+	if err := unmarshal(&defaults); err != nil {
+		return err
+	}
+
+	*c = GroupConfig(defaults)
+	return nil
+}
+
+type HooksConfig struct {
+	OnStartup HookOnStartup `yaml:"on_startup"`
+}
+
+type HookOnStartup struct {
+	Preload []string `yaml:"preload"`
+}
+
 type Config struct {
 	HealthCheckTimeout int                    `yaml:"healthCheckTimeout"`
 	LogRequests        bool                   `yaml:"logRequests"`
 	LogLevel           string                 `yaml:"logLevel"`
-	Models             map[string]ModelConfig `yaml:"models"`
+	MetricsMaxInMemory int                    `yaml:"metricsMaxInMemory"`
+	Models             map[string]ModelConfig `yaml:"models"` /* key is model ID */
 	Profiles           map[string][]string    `yaml:"profiles"`
+	Groups             map[string]GroupConfig `yaml:"groups"` /* key is group ID */
+
+	// for key/value replacements in model's cmd, cmdStop, proxy, checkEndPoint
+	Macros map[string]string `yaml:"macros"`
 
 	// map aliases to actual model IDs
 	aliases map[string]string
+
+	// automatic port assignments
+	StartPort int `yaml:"startPort"`
+
+	// hooks, see: #209
+	Hooks HooksConfig `yaml:"hooks"`
 }
 
 func (c *Config) RealModelName(search string) (string, bool) {
@@ -53,42 +186,256 @@ func (c *Config) FindConfig(modelName string) (ModelConfig, string, bool) {
 	}
 }
 
-func LoadConfig(path string) (*Config, error) {
-	data, err := os.ReadFile(path)
+func LoadConfig(path string) (Config, error) {
+	file, err := os.Open(path)
 	if err != nil {
-		return nil, err
+		return Config{}, err
+	}
+	defer file.Close()
+	return LoadConfigFromReader(file)
+}
+
+func LoadConfigFromReader(r io.Reader) (Config, error) {
+	data, err := io.ReadAll(r)
+	if err != nil {
+		return Config{}, err
 	}
 
-	var config Config
+	// default configuration values
+	config := Config{
+		HealthCheckTimeout: 120,
+		StartPort:          5800,
+		LogLevel:           "info",
+		MetricsMaxInMemory: 1000,
+	}
 	err = yaml.Unmarshal(data, &config)
 	if err != nil {
-		return nil, err
+		return Config{}, err
 	}
 
 	if config.HealthCheckTimeout < 15 {
+		// set a minimum of 15 seconds
 		config.HealthCheckTimeout = 15
 	}
 
+	if config.StartPort < 1 {
+		return Config{}, fmt.Errorf("startPort must be greater than 1")
+	}
+
 	// Populate the aliases map
 	config.aliases = make(map[string]string)
 	for modelName, modelConfig := range config.Models {
 		for _, alias := range modelConfig.Aliases {
+			if _, found := config.aliases[alias]; found {
+				return Config{}, fmt.Errorf("duplicate alias %s found in model: %s", alias, modelName)
+			}
 			config.aliases[alias] = modelName
 		}
 	}
 
-	return &config, nil
+	/* check macro constraint rules:
+
+	- name must fit the regex ^[a-zA-Z0-9_-]+$
+	- names must be less than 64 characters (no reason, just cause)
+	- name can not be any reserved macros: PORT, MODEL_ID
+	- macro values must be less than 1024 characters
+	*/
+	macroNameRegex := regexp.MustCompile(`^[a-zA-Z0-9_-]+$`)
+	for macroName, macroValue := range config.Macros {
+		if len(macroName) >= 64 {
+			return Config{}, fmt.Errorf("macro name '%s' exceeds maximum length of 63 characters", macroName)
+		}
+		if !macroNameRegex.MatchString(macroName) {
+			return Config{}, fmt.Errorf("macro name '%s' contains invalid characters, must match pattern ^[a-zA-Z0-9_-]+$", macroName)
+		}
+		if len(macroValue) >= 1024 {
+			return Config{}, fmt.Errorf("macro value for '%s' exceeds maximum length of 1024 characters", macroName)
+		}
+		switch macroName {
+		case "PORT":
+		case "MODEL_ID":
+			return Config{}, fmt.Errorf("macro name '%s' is reserved and cannot be used", macroName)
+		}
+	}
+
+	// Get and sort all model IDs first, makes testing more consistent
+	modelIds := make([]string, 0, len(config.Models))
+	for modelId := range config.Models {
+		modelIds = append(modelIds, modelId)
+	}
+	sort.Strings(modelIds) // This guarantees stable iteration order
+
+	nextPort := config.StartPort
+	for _, modelId := range modelIds {
+		modelConfig := config.Models[modelId]
+
+		// Strip comments from command fields before macro expansion
+		modelConfig.Cmd = StripComments(modelConfig.Cmd)
+		modelConfig.CmdStop = StripComments(modelConfig.CmdStop)
+
+		// go through model config fields: cmd, cmdStop, proxy, checkEndPoint and replace macros with macro values
+		for macroName, macroValue := range config.Macros {
+			macroSlug := fmt.Sprintf("${%s}", macroName)
+			modelConfig.Cmd = strings.ReplaceAll(modelConfig.Cmd, macroSlug, macroValue)
+			modelConfig.CmdStop = strings.ReplaceAll(modelConfig.CmdStop, macroSlug, macroValue)
+			modelConfig.Proxy = strings.ReplaceAll(modelConfig.Proxy, macroSlug, macroValue)
+			modelConfig.CheckEndpoint = strings.ReplaceAll(modelConfig.CheckEndpoint, macroSlug, macroValue)
+			modelConfig.Filters.StripParams = strings.ReplaceAll(modelConfig.Filters.StripParams, macroSlug, macroValue)
+		}
+
+		// enforce ${PORT} used in both cmd and proxy
+		if !strings.Contains(modelConfig.Cmd, "${PORT}") && strings.Contains(modelConfig.Proxy, "${PORT}") {
+			return Config{}, fmt.Errorf("model %s: proxy uses ${PORT} but cmd does not - ${PORT} is only available when used in cmd", modelId)
+		}
+
+		// only iterate over models that use ${PORT} to keep port numbers from increasing unnecessarily
+		if strings.Contains(modelConfig.Cmd, "${PORT}") || strings.Contains(modelConfig.Proxy, "${PORT}") || strings.Contains(modelConfig.CmdStop, "${PORT}") {
+			nextPortStr := strconv.Itoa(nextPort)
+			modelConfig.Cmd = strings.ReplaceAll(modelConfig.Cmd, "${PORT}", nextPortStr)
+			modelConfig.CmdStop = strings.ReplaceAll(modelConfig.CmdStop, "${PORT}", nextPortStr)
+			modelConfig.Proxy = strings.ReplaceAll(modelConfig.Proxy, "${PORT}", nextPortStr)
+			nextPort++
+		}
+
+		if strings.Contains(modelConfig.Cmd, "${MODEL_ID}") || strings.Contains(modelConfig.CmdStop, "${MODEL_ID}") {
+			modelConfig.Cmd = strings.ReplaceAll(modelConfig.Cmd, "${MODEL_ID}", modelId)
+			modelConfig.CmdStop = strings.ReplaceAll(modelConfig.CmdStop, "${MODEL_ID}", modelId)
+		}
+
+		// make sure there are no unknown macros that have not been replaced
+		macroPattern := regexp.MustCompile(`\$\{([a-zA-Z0-9_-]+)\}`)
+		fieldMap := map[string]string{
+			"cmd":           modelConfig.Cmd,
+			"cmdStop":       modelConfig.CmdStop,
+			"proxy":         modelConfig.Proxy,
+			"checkEndpoint": modelConfig.CheckEndpoint,
+		}
+
+		for fieldName, fieldValue := range fieldMap {
+			matches := macroPattern.FindAllStringSubmatch(fieldValue, -1)
+			for _, match := range matches {
+				macroName := match[1]
+				if macroName == "PID" && fieldName == "cmdStop" {
+					continue // this is ok, has to be replaced by process later
+				}
+				if _, exists := config.Macros[macroName]; !exists {
+					return Config{}, fmt.Errorf("unknown macro '${%s}' found in %s.%s", macroName, modelId, fieldName)
+				}
+			}
+		}
+
+		config.Models[modelId] = modelConfig
+	}
+
+	config = AddDefaultGroupToConfig(config)
+	// check that members are all unique in the groups
+	memberUsage := make(map[string]string) // maps member to group it appears in
+	for groupID, groupConfig := range config.Groups {
+		prevSet := make(map[string]bool)
+		for _, member := range groupConfig.Members {
+			// Check for duplicates within this group
+			if _, found := prevSet[member]; found {
+				return Config{}, fmt.Errorf("duplicate model member %s found in group: %s", member, groupID)
+			}
+			prevSet[member] = true
+
+			// Check if member is used in another group
+			if existingGroup, exists := memberUsage[member]; exists {
+				return Config{}, fmt.Errorf("model member %s is used in multiple groups: %s and %s", member, existingGroup, groupID)
+			}
+			memberUsage[member] = groupID
+		}
+	}
+
+	// clean up hooks preload
+	if len(config.Hooks.OnStartup.Preload) > 0 {
+		var toPreload []string
+		for _, modelID := range config.Hooks.OnStartup.Preload {
+			modelID = strings.TrimSpace(modelID)
+			if modelID == "" {
+				continue
+			}
+			if real, found := config.RealModelName(modelID); found {
+				toPreload = append(toPreload, real)
+			}
+		}
+
+		config.Hooks.OnStartup.Preload = toPreload
+	}
+
+	return config, nil
+}
+
+// rewrites the yaml to include a default group with any orphaned models
+func AddDefaultGroupToConfig(config Config) Config {
+
+	if config.Groups == nil {
+		config.Groups = make(map[string]GroupConfig)
+	}
+
+	defaultGroup := GroupConfig{
+		Swap:      true,
+		Exclusive: true,
+		Members:   []string{},
+	}
+	// if groups is empty, create a default group and put
+	// all models into it
+	if len(config.Groups) == 0 {
+		for modelName := range config.Models {
+			defaultGroup.Members = append(defaultGroup.Members, modelName)
+		}
+	} else {
+		// iterate over existing group members and add non-grouped models into the default group
+		for modelName, _ := range config.Models {
+			foundModel := false
+		found:
+			// search for the model in existing groups
+			for _, groupConfig := range config.Groups {
+				for _, member := range groupConfig.Members {
+					if member == modelName {
+						foundModel = true
+						break found
+					}
+				}
+			}
+
+			if !foundModel {
+				defaultGroup.Members = append(defaultGroup.Members, modelName)
+			}
+		}
+	}
+
+	sort.Strings(defaultGroup.Members) // make consistent ordering for testing
+	config.Groups[DEFAULT_GROUP_ID] = defaultGroup
+
+	return config
 }
 
 func SanitizeCommand(cmdStr string) ([]string, error) {
-	// Remove trailing backslashes
-	cmdStr = strings.ReplaceAll(cmdStr, "\\ \n", " ")
-	cmdStr = strings.ReplaceAll(cmdStr, "\\\n", " ")
+	var cleanedLines []string
+	for _, line := range strings.Split(cmdStr, "\n") {
+		trimmed := strings.TrimSpace(line)
+		// Skip comment lines
+		if strings.HasPrefix(trimmed, "#") {
+			continue
+		}
+		// Handle trailing backslashes by replacing with space
+		if strings.HasSuffix(trimmed, "\\") {
+			cleanedLines = append(cleanedLines, strings.TrimSuffix(trimmed, "\\")+" ")
+		} else {
+			cleanedLines = append(cleanedLines, line)
+		}
+	}
+
+	// put it back together
+	cmdStr = strings.Join(cleanedLines, "\n")
 
 	// Split the command into arguments
-	args, err := shlex.Split(cmdStr)
-	if err != nil {
-		return nil, err
+	var args []string
+	if runtime.GOOS == "windows" {
+		args = shlex.Windows.Split(cmdStr)
+	} else {
+		args = shlex.Posix.Split(cmdStr)
 	}
 
 	// Ensure the command is not empty
@@ -98,3 +445,16 @@ func SanitizeCommand(cmdStr string) ([]string, error) {
 
 	return args, nil
 }
+
+func StripComments(cmdStr string) string {
+	var cleanedLines []string
+	for _, line := range strings.Split(cmdStr, "\n") {
+		trimmed := strings.TrimSpace(line)
+		// Skip comment lines
+		if strings.HasPrefix(trimmed, "#") {
+			continue
+		}
+		cleanedLines = append(cleanedLines, line)
+	}
+	return strings.Join(cleanedLines, "\n")
+}

proxy/config_posix_test.go

@@ -0,0 +1,242 @@
+//go:build !windows
+
+package proxy
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestConfig_SanitizeCommand(t *testing.T) {
+	// Test a command with spaces and newlines
+	args, err := SanitizeCommand(`python model1.py \
+		-a "double quotes" \
+		--arg2 'single quotes'
+		-s
+		# comment 1
+		--arg3 123 \
+
+		  # comment 2
+		--arg4 '"string in string"'
+
+
+		# this will get stripped out as well as the white space above
+		-c "'single quoted'"
+		`)
+	assert.NoError(t, err)
+	assert.Equal(t, []string{
+		"python", "model1.py",
+		"-a", "double quotes",
+		"--arg2", "single quotes",
+		"-s",
+		"--arg3", "123",
+		"--arg4", `"string in string"`,
+		"-c", `'single quoted'`,
+	}, args)
+
+	// Test an empty command
+	args, err = SanitizeCommand("")
+	assert.Error(t, err)
+	assert.Nil(t, args)
+}
+
+// Test the default values are automatically set for global, model and group configurations
+// after loading the configuration
+func TestConfig_DefaultValuesPosix(t *testing.T) {
+	content := `
+models:
+  model1:
+    cmd: path/to/cmd --port ${PORT}
+`
+
+	config, err := LoadConfigFromReader(strings.NewReader(content))
+	assert.NoError(t, err)
+	assert.Equal(t, 120, config.HealthCheckTimeout)
+	assert.Equal(t, 5800, config.StartPort)
+	assert.Equal(t, "info", config.LogLevel)
+
+	// Test default group exists
+	defaultGroup, exists := config.Groups["(default)"]
+	assert.True(t, exists, "default group should exist")
+	if assert.NotNil(t, defaultGroup, "default group should not be nil") {
+		assert.Equal(t, true, defaultGroup.Swap)
+		assert.Equal(t, true, defaultGroup.Exclusive)
+		assert.Equal(t, false, defaultGroup.Persistent)
+		assert.Equal(t, []string{"model1"}, defaultGroup.Members)
+	}
+
+	model1, exists := config.Models["model1"]
+	assert.True(t, exists, "model1 should exist")
+	if assert.NotNil(t, model1, "model1 should not be nil") {
+		assert.Equal(t, "path/to/cmd --port 5800", model1.Cmd) // has the port replaced
+		assert.Equal(t, "", model1.CmdStop)
+		assert.Equal(t, "http://localhost:5800", model1.Proxy)
+		assert.Equal(t, "/health", model1.CheckEndpoint)
+		assert.Equal(t, []string{}, model1.Aliases)
+		assert.Equal(t, []string{}, model1.Env)
+		assert.Equal(t, 0, model1.UnloadAfter)
+		assert.Equal(t, false, model1.Unlisted)
+		assert.Equal(t, "", model1.UseModelName)
+		assert.Equal(t, 0, model1.ConcurrencyLimit)
+	}
+
+	// default empty filter exists
+	assert.Equal(t, "", model1.Filters.StripParams)
+}
+
+func TestConfig_LoadPosix(t *testing.T) {
+	// Create a temporary YAML file for testing
+	tempDir, err := os.MkdirTemp("", "test-config")
+	if err != nil {
+		t.Fatalf("Failed to create temporary directory: %v", err)
+	}
+	defer os.RemoveAll(tempDir)
+
+	tempFile := filepath.Join(tempDir, "config.yaml")
+	content := `
+macros:
+  svr-path: "path/to/server"
+hooks:
+  on_startup:
+    preload: ["model1", "model2"]
+models:
+  model1:
+    cmd: path/to/cmd --arg1 one
+    proxy: "http://localhost:8080"
+    name: "Model 1"
+    description: "This is model 1"
+    aliases:
+      - "m1"
+      - "model-one"
+    env:
+      - "VAR1=value1"
+      - "VAR2=value2"
+    checkEndpoint: "/health"
+  model2:
+    cmd: ${svr-path} --arg1 one
+    proxy: "http://localhost:8081"
+    aliases:
+      - "m2"
+    checkEndpoint: "/"
+  model3:
+    cmd: path/to/cmd --arg1 one
+    proxy: "http://localhost:8081"
+    aliases:
+      - "mthree"
+    checkEndpoint: "/"
+  model4:
+    cmd: path/to/cmd --arg1 one
+    proxy: "http://localhost:8082"
+    checkEndpoint: "/"
+
+healthCheckTimeout: 15
+profiles:
+  test:
+    - model1
+    - model2
+groups:
+  group1:
+    swap: true
+    exclusive: false
+    members: ["model2"]
+  forever:
+    exclusive: false
+    persistent: true
+    members:
+      - "model4"
+`
+
+	if err := os.WriteFile(tempFile, []byte(content), 0644); err != nil {
+		t.Fatalf("Failed to write temporary file: %v", err)
+	}
+
+	// Load the config and verify
+	config, err := LoadConfig(tempFile)
+	if err != nil {
+		t.Fatalf("Failed to load config: %v", err)
+	}
+
+	expected := Config{
+		LogLevel:  "info",
+		StartPort: 5800,
+		Macros: map[string]string{
+			"svr-path": "path/to/server",
+		},
+		Hooks: HooksConfig{
+			OnStartup: HookOnStartup{
+				Preload: []string{"model1", "model2"},
+			},
+		},
+		Models: map[string]ModelConfig{
+			"model1": {
+				Cmd:           "path/to/cmd --arg1 one",
+				Proxy:         "http://localhost:8080",
+				Aliases:       []string{"m1", "model-one"},
+				Env:           []string{"VAR1=value1", "VAR2=value2"},
+				CheckEndpoint: "/health",
+				Name:          "Model 1",
+				Description:   "This is model 1",
+			},
+			"model2": {
+				Cmd:           "path/to/server --arg1 one",
+				Proxy:         "http://localhost:8081",
+				Aliases:       []string{"m2"},
+				Env:           []string{},
+				CheckEndpoint: "/",
+			},
+			"model3": {
+				Cmd:           "path/to/cmd --arg1 one",
+				Proxy:         "http://localhost:8081",
+				Aliases:       []string{"mthree"},
+				Env:           []string{},
+				CheckEndpoint: "/",
+			},
+			"model4": {
+				Cmd:           "path/to/cmd --arg1 one",
+				Proxy:         "http://localhost:8082",
+				CheckEndpoint: "/",
+				Aliases:       []string{},
+				Env:           []string{},
+			},
+		},
+		HealthCheckTimeout: 15,
+		MetricsMaxInMemory: 1000,
+		Profiles: map[string][]string{
+			"test": {"model1", "model2"},
+		},
+		aliases: map[string]string{
+			"m1":        "model1",
+			"model-one": "model1",
+			"m2":        "model2",
+			"mthree":    "model3",
+		},
+		Groups: map[string]GroupConfig{
+			DEFAULT_GROUP_ID: {
+				Swap:      true,
+				Exclusive: true,
+				Members:   []string{"model1", "model3"},
+			},
+			"group1": {
+				Swap:      true,
+				Exclusive: false,
+				Members:   []string{"model2"},
+			},
+			"forever": {
+				Swap:       true,
+				Exclusive:  false,
+				Persistent: true,
+				Members:    []string{"model4"},
+			},
+		},
+	}
+
+	assert.Equal(t, expected, config)
+
+	realname, found := config.RealModelName("m1")
+	assert.True(t, found)
+	assert.Equal(t, "model1", realname)
+}

proxy/config_test.go

@@ -1,90 +1,68 @@
 package proxy
 
 import (
-	"os"
-	"path/filepath"
+	"slices"
+	"strings"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
 )
 
-func TestConfig_Load(t *testing.T) {
-	// Create a temporary YAML file for testing
-	tempDir, err := os.MkdirTemp("", "test-config")
-	if err != nil {
-		t.Fatalf("Failed to create temporary directory: %v", err)
-	}
-	defer os.RemoveAll(tempDir)
+func TestConfig_GroupMemberIsUnique(t *testing.T) {
+	content := `
+models:
+  model1:
+    cmd: path/to/cmd --arg1 one
+    proxy: "http://localhost:8080"
+  model2:
+    cmd: path/to/cmd --arg1 one
+    proxy: "http://localhost:8081"
+    checkEndpoint: "/"
+  model3:
+    cmd: path/to/cmd --arg1 one
+    proxy: "http://localhost:8081"
+    checkEndpoint: "/"
 
-	tempFile := filepath.Join(tempDir, "config.yaml")
+healthCheckTimeout: 15
+groups:
+  group1:
+    swap: true
+    exclusive: false
+    members: ["model2"]
+  group2:
+    swap: true
+    exclusive: false
+    members: ["model2"]
+`
+	// Load the config and verify
+	_, err := LoadConfigFromReader(strings.NewReader(content))
+
+	// a Contains as order of the map is not guaranteed
+	assert.Contains(t, err.Error(), "model member model2 is used in multiple groups:")
+}
+
+func TestConfig_ModelAliasesAreUnique(t *testing.T) {
 	content := `
 models:
   model1:
     cmd: path/to/cmd --arg1 one
     proxy: "http://localhost:8080"
     aliases:
-      - "m1"
-      - "model-one"
-    env:
-      - "VAR1=value1"
-      - "VAR2=value2"
-    checkEndpoint: "/health"
+      - m1
   model2:
     cmd: path/to/cmd --arg1 one
     proxy: "http://localhost:8081"
-    aliases:
-      - "m2"
     checkEndpoint: "/"
-healthCheckTimeout: 15
-profiles:
-  test:
-    - model1
-    - model2
+    aliases:
+      - m1
+      - m2
 `
-
-	if err := os.WriteFile(tempFile, []byte(content), 0644); err != nil {
-		t.Fatalf("Failed to write temporary file: %v", err)
-	}
-
 	// Load the config and verify
-	config, err := LoadConfig(tempFile)
-	if err != nil {
-		t.Fatalf("Failed to load config: %v", err)
-	}
+	_, err := LoadConfigFromReader(strings.NewReader(content))
 
-	expected := &Config{
-		Models: map[string]ModelConfig{
-			"model1": {
-				Cmd:           "path/to/cmd --arg1 one",
-				Proxy:         "http://localhost:8080",
-				Aliases:       []string{"m1", "model-one"},
-				Env:           []string{"VAR1=value1", "VAR2=value2"},
-				CheckEndpoint: "/health",
-			},
-			"model2": {
-				Cmd:           "path/to/cmd --arg1 one",
-				Proxy:         "http://localhost:8081",
-				Aliases:       []string{"m2"},
-				Env:           nil,
-				CheckEndpoint: "/",
-			},
-		},
-		HealthCheckTimeout: 15,
-		Profiles: map[string][]string{
-			"test": {"model1", "model2"},
-		},
-		aliases: map[string]string{
-			"m1":        "model1",
-			"model-one": "model1",
-			"m2":        "model2",
-		},
-	}
-
-	assert.Equal(t, expected, config)
-
-	realname, found := config.RealModelName("m1")
-	assert.True(t, found)
-	assert.Equal(t, "model1", realname)
+	// this is a contains because it could be `model1` or `model2` depending on the order
+	// go decided on the order of the map
+	assert.Contains(t, err.Error(), "duplicate alias m1 found in model: model")
 }
 
 func TestConfig_ModelConfigSanitizedCommand(t *testing.T) {
@@ -147,30 +125,359 @@ func TestConfig_FindConfig(t *testing.T) {
 	assert.Equal(t, ModelConfig{}, modelConfig)
 }
 
-func TestConfig_SanitizeCommand(t *testing.T) {
+func TestConfig_AutomaticPortAssignments(t *testing.T) {
 
-	// Test a command with spaces and newlines
-	args, err := SanitizeCommand(`python model1.py \
-    -a "double quotes" \
-    --arg2 'single quotes'
-	-s
-	--arg3 123 \
-	--arg4 '"string in string"'
-	-c "'single quoted'"
-	`)
-	assert.NoError(t, err)
-	assert.Equal(t, []string{
-		"python", "model1.py",
-		"-a", "double quotes",
-		"--arg2", "single quotes",
-		"-s",
-		"--arg3", "123",
-		"--arg4", `"string in string"`,
-		"-c", `'single quoted'`,
-	}, args)
+	t.Run("Default Port Ranges", func(t *testing.T) {
+		content := ``
+		config, err := LoadConfigFromReader(strings.NewReader(content))
+		if !assert.NoError(t, err) {
+			t.Fatalf("Failed to load config: %v", err)
+		}
 
-	// Test an empty command
-	args, err = SanitizeCommand("")
-	assert.Error(t, err)
-	assert.Nil(t, args)
+		assert.Equal(t, 5800, config.StartPort)
+	})
+	t.Run("User specific port ranges", func(t *testing.T) {
+		content := `startPort: 1000`
+		config, err := LoadConfigFromReader(strings.NewReader(content))
+		if !assert.NoError(t, err) {
+			t.Fatalf("Failed to load config: %v", err)
+		}
+
+		assert.Equal(t, 1000, config.StartPort)
+	})
+
+	t.Run("Invalid start port", func(t *testing.T) {
+		content := `startPort: abcd`
+		_, err := LoadConfigFromReader(strings.NewReader(content))
+		assert.NotNil(t, err)
+	})
+
+	t.Run("start port must be greater than 1", func(t *testing.T) {
+		content := `startPort: -99`
+		_, err := LoadConfigFromReader(strings.NewReader(content))
+		assert.NotNil(t, err)
+	})
+
+	t.Run("Automatic port assignments", func(t *testing.T) {
+		content := `
+startPort: 5800
+models:
+  model1:
+    cmd: svr --port ${PORT}
+  model2:
+    cmd: svr --port ${PORT}
+    proxy: "http://172.11.22.33:${PORT}"
+  model3:
+    cmd: svr --port 1999
+    proxy: "http://1.2.3.4:1999"
+`
+		config, err := LoadConfigFromReader(strings.NewReader(content))
+		if !assert.NoError(t, err) {
+			t.Fatalf("Failed to load config: %v", err)
+		}
+
+		assert.Equal(t, 5800, config.StartPort)
+		assert.Equal(t, "svr --port 5800", config.Models["model1"].Cmd)
+		assert.Equal(t, "http://localhost:5800", config.Models["model1"].Proxy)
+
+		assert.Equal(t, "svr --port 5801", config.Models["model2"].Cmd)
+		assert.Equal(t, "http://172.11.22.33:5801", config.Models["model2"].Proxy)
+
+		assert.Equal(t, "svr --port 1999", config.Models["model3"].Cmd)
+		assert.Equal(t, "http://1.2.3.4:1999", config.Models["model3"].Proxy)
+
+	})
+
+	t.Run("Proxy value required if no ${PORT} in cmd", func(t *testing.T) {
+		content := `
+models:
+  model1:
+    cmd: svr --port 111
+`
+		_, err := LoadConfigFromReader(strings.NewReader(content))
+		assert.Equal(t, "model model1: proxy uses ${PORT} but cmd does not - ${PORT} is only available when used in cmd", err.Error())
+	})
+}
+
+func TestConfig_MacroReplacement(t *testing.T) {
+	content := `
+startPort: 9990
+macros:
+  svr-path: "path/to/server"
+  argOne: "--arg1"
+  argTwo: "--arg2"
+  autoPort: "--port ${PORT}"
+
+models:
+  model1:
+    cmd: |
+      ${svr-path} ${argTwo}
+      # the automatic ${PORT} is replaced
+      ${autoPort}
+      ${argOne}
+      --arg3 three
+    cmdStop: |
+      /path/to/stop.sh --port ${PORT} ${argTwo}
+`
+
+	config, err := LoadConfigFromReader(strings.NewReader(content))
+	assert.NoError(t, err)
+	sanitizedCmd, err := SanitizeCommand(config.Models["model1"].Cmd)
+	assert.NoError(t, err)
+	assert.Equal(t, "path/to/server --arg2 --port 9990 --arg1 --arg3 three", strings.Join(sanitizedCmd, " "))
+
+	sanitizedCmdStop, err := SanitizeCommand(config.Models["model1"].CmdStop)
+	assert.NoError(t, err)
+	assert.Equal(t, "/path/to/stop.sh --port 9990 --arg2", strings.Join(sanitizedCmdStop, " "))
+}
+
+func TestConfig_MacroErrorOnUnknownMacros(t *testing.T) {
+	tests := []struct {
+		name    string
+		field   string
+		content string
+	}{
+		{
+			name:  "unknown macro in cmd",
+			field: "cmd",
+			content: `
+startPort: 9990
+macros:
+  svr-path: "path/to/server"
+models:
+  model1:
+    cmd: |
+      ${svr-path} --port ${PORT}
+      ${unknownMacro}
+`,
+		},
+		{
+			name:  "unknown macro in cmdStop",
+			field: "cmdStop",
+			content: `
+startPort: 9990
+macros:
+  svr-path: "path/to/server"
+models:
+  model1:
+    cmd: "${svr-path} --port ${PORT}"
+    cmdStop: "kill ${unknownMacro}"
+`,
+		},
+		{
+			name:  "unknown macro in proxy",
+			field: "proxy",
+			content: `
+startPort: 9990
+macros:
+  svr-path: "path/to/server"
+models:
+  model1:
+    cmd: "${svr-path} --port ${PORT}"
+    proxy: "http://localhost:${unknownMacro}"
+`,
+		},
+		{
+			name:  "unknown macro in checkEndpoint",
+			field: "checkEndpoint",
+			content: `
+startPort: 9990
+macros:
+  svr-path: "path/to/server"
+models:
+  model1:
+    cmd: "${svr-path} --port ${PORT}"
+    checkEndpoint: "http://localhost:${unknownMacro}/health"
+`,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			_, err := LoadConfigFromReader(strings.NewReader(tt.content))
+			assert.Error(t, err)
+			assert.Contains(t, err.Error(), "unknown macro '${unknownMacro}' found in model1."+tt.field)
+			//t.Log(err)
+		})
+	}
+}
+
+func TestConfig_ModelFilters(t *testing.T) {
+	content := `
+macros:
+  default_strip: "temperature, top_p"
+models:
+  model1:
+    cmd: path/to/cmd --port ${PORT}
+    filters:
+      strip_params: "model, top_k, ${default_strip}, , ,"
+`
+	config, err := LoadConfigFromReader(strings.NewReader(content))
+	assert.NoError(t, err)
+	modelConfig, ok := config.Models["model1"]
+	if !assert.True(t, ok) {
+		t.FailNow()
+	}
+
+	// make sure `model` and enmpty strings are not in the list
+	assert.Equal(t, "model, top_k, temperature, top_p, , ,", modelConfig.Filters.StripParams)
+	sanitized, err := modelConfig.Filters.SanitizedStripParams()
+	if assert.NoError(t, err) {
+		assert.Equal(t, []string{"temperature", "top_k", "top_p"}, sanitized)
+	}
+}
+
+func TestStripComments(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    string
+		expected string
+	}{
+		{
+			name:     "no comments",
+			input:    "echo hello\necho world",
+			expected: "echo hello\necho world",
+		},
+		{
+			name:     "single comment line",
+			input:    "# this is a comment\necho hello",
+			expected: "echo hello",
+		},
+		{
+			name:     "multiple comment lines",
+			input:    "# comment 1\necho hello\n# comment 2\necho world",
+			expected: "echo hello\necho world",
+		},
+		{
+			name:     "comment with spaces",
+			input:    "   # indented comment\necho hello",
+			expected: "echo hello",
+		},
+		{
+			name:     "empty lines preserved",
+			input:    "echo hello\n\necho world",
+			expected: "echo hello\n\necho world",
+		},
+		{
+			name:     "only comments",
+			input:    "# comment 1\n# comment 2",
+			expected: "",
+		},
+		{
+			name:     "empty string",
+			input:    "",
+			expected: "",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := StripComments(tt.input)
+			if result != tt.expected {
+				t.Errorf("StripComments() = %q, expected %q", result, tt.expected)
+			}
+		})
+	}
+}
+
+func TestConfig_MacroInCommentStrippedBeforeExpansion(t *testing.T) {
+	// Test case that reproduces the original bug where a macro in a comment
+	// would get expanded and cause the comment text to be included in the command
+	content := `
+startPort: 9990
+macros:
+  "latest-llama": >
+    /user/llama.cpp/build/bin/llama-server
+    --port ${PORT}
+
+models:
+  "test-model":
+    cmd: |
+      # ${latest-llama} is a macro that is defined above
+      ${latest-llama}
+      --model /path/to/model.gguf
+      -ngl 99
+`
+
+	config, err := LoadConfigFromReader(strings.NewReader(content))
+	assert.NoError(t, err)
+
+	// Get the sanitized command
+	sanitizedCmd, err := SanitizeCommand(config.Models["test-model"].Cmd)
+	assert.NoError(t, err)
+
+	// Join the command for easier inspection
+	cmdStr := strings.Join(sanitizedCmd, " ")
+
+	// Verify that comment text is NOT present in the final command as separate arguments
+	commentWords := []string{"is", "macro", "that", "defined", "above"}
+	for _, word := range commentWords {
+		found := slices.Contains(sanitizedCmd, word)
+		assert.False(t, found, "Comment text '%s' should not be present as a separate argument in final command", word)
+	}
+
+	// Verify that the actual command components ARE present
+	expectedParts := []string{
+		"/user/llama.cpp/build/bin/llama-server",
+		"--port",
+		"9990",
+		"--model",
+		"/path/to/model.gguf",
+		"-ngl",
+		"99",
+	}
+
+	for _, part := range expectedParts {
+		assert.Contains(t, cmdStr, part, "Expected command part '%s' not found in final command", part)
+	}
+
+	// Verify the server path appears exactly once (not duplicated due to macro expansion)
+	serverPath := "/user/llama.cpp/build/bin/llama-server"
+	count := strings.Count(cmdStr, serverPath)
+	assert.Equal(t, 1, count, "Expected exactly 1 occurrence of server path, found %d", count)
+
+	// Verify the expected final command structure
+	expectedCmd := "/user/llama.cpp/build/bin/llama-server --port 9990 --model /path/to/model.gguf -ngl 99"
+	assert.Equal(t, expectedCmd, cmdStr, "Final command does not match expected structure")
+}
+
+func TestConfig_MacroModelId(t *testing.T) {
+	content := `
+startPort: 9000
+macros:
+  "docker-llama": docker run --name ${MODEL_ID} -p ${PORT}:8080 docker_img
+  "docker-stop": docker stop ${MODEL_ID}
+
+models:
+  model1:
+    cmd: /path/to/server -p ${PORT} -hf ${MODEL_ID}
+
+  model2:
+    cmd: ${docker-llama}
+    cmdStop: ${docker-stop}
+
+  author/model:F16:
+    cmd: /path/to/server -p ${PORT} -hf ${MODEL_ID}
+    cmdStop: stop
+`
+
+	config, err := LoadConfigFromReader(strings.NewReader(content))
+	assert.NoError(t, err)
+	sanitizedCmd, err := SanitizeCommand(config.Models["model1"].Cmd)
+	assert.NoError(t, err)
+	assert.Equal(t, "/path/to/server -p 9001 -hf model1", strings.Join(sanitizedCmd, " "))
+
+	assert.Equal(t, "docker stop ${MODEL_ID}", config.Macros["docker-stop"])
+
+	sanitizedCmd2, err := SanitizeCommand(config.Models["model2"].Cmd)
+	assert.NoError(t, err)
+	assert.Equal(t, "docker run --name model2 -p 9002:8080 docker_img", strings.Join(sanitizedCmd2, " "))
+
+	sanitizedCmdStop, err := SanitizeCommand(config.Models["model2"].CmdStop)
+	assert.NoError(t, err)
+	assert.Equal(t, "docker stop model2", strings.Join(sanitizedCmdStop, " "))
+
+	sanitizedCmd3, err := SanitizeCommand(config.Models["author/model:F16"].Cmd)
+	assert.NoError(t, err)
+	assert.Equal(t, "/path/to/server -p 9000 -hf author/model:F16", strings.Join(sanitizedCmd3, " "))
 }

proxy/config_windows_test.go

@@ -0,0 +1,231 @@
+//go:build windows
+
+package proxy
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestConfig_SanitizeCommand(t *testing.T) {
+	// does not support single quoted strings like in config_posix_test.go
+	args, err := SanitizeCommand(`python model1.py \
+
+	-a "double quotes" \
+	-s
+	--arg3 123 \
+
+	   # comment 2
+	--arg4 '"string in string"'
+
+
+
+	# this will get stripped out as well as the white space above
+	-c "'single quoted'"
+	`)
+	assert.NoError(t, err)
+	assert.Equal(t, []string{
+		"python", "model1.py",
+		"-a", "double quotes",
+		"-s",
+		"--arg3", "123",
+		"--arg4", "'string in string'", // this is a little weird but the lexer says so...?
+		"-c", `'single quoted'`,
+	}, args)
+
+	// Test an empty command
+	args, err = SanitizeCommand("")
+	assert.Error(t, err)
+	assert.Nil(t, args)
+}
+
+func TestConfig_DefaultValuesWindows(t *testing.T) {
+	content := `
+models:
+  model1:
+    cmd: path/to/cmd --port ${PORT}
+`
+
+	config, err := LoadConfigFromReader(strings.NewReader(content))
+	assert.NoError(t, err)
+	assert.Equal(t, 120, config.HealthCheckTimeout)
+	assert.Equal(t, 5800, config.StartPort)
+	assert.Equal(t, "info", config.LogLevel)
+
+	// Test default group exists
+	defaultGroup, exists := config.Groups["(default)"]
+	assert.True(t, exists, "default group should exist")
+	if assert.NotNil(t, defaultGroup, "default group should not be nil") {
+		assert.Equal(t, true, defaultGroup.Swap)
+		assert.Equal(t, true, defaultGroup.Exclusive)
+		assert.Equal(t, false, defaultGroup.Persistent)
+		assert.Equal(t, []string{"model1"}, defaultGroup.Members)
+	}
+
+	model1, exists := config.Models["model1"]
+	assert.True(t, exists, "model1 should exist")
+	if assert.NotNil(t, model1, "model1 should not be nil") {
+		assert.Equal(t, "path/to/cmd --port 5800", model1.Cmd) // has the port replaced
+		assert.Equal(t, "taskkill /f /t /pid ${PID}", model1.CmdStop)
+		assert.Equal(t, "http://localhost:5800", model1.Proxy)
+		assert.Equal(t, "/health", model1.CheckEndpoint)
+		assert.Equal(t, []string{}, model1.Aliases)
+		assert.Equal(t, []string{}, model1.Env)
+		assert.Equal(t, 0, model1.UnloadAfter)
+		assert.Equal(t, false, model1.Unlisted)
+		assert.Equal(t, "", model1.UseModelName)
+		assert.Equal(t, 0, model1.ConcurrencyLimit)
+	}
+
+	// default empty filter exists
+	assert.Equal(t, "", model1.Filters.StripParams)
+}
+
+func TestConfig_LoadWindows(t *testing.T) {
+	// Create a temporary YAML file for testing
+	tempDir, err := os.MkdirTemp("", "test-config")
+	if err != nil {
+		t.Fatalf("Failed to create temporary directory: %v", err)
+	}
+	defer os.RemoveAll(tempDir)
+
+	tempFile := filepath.Join(tempDir, "config.yaml")
+	content := `
+macros:
+  svr-path: "path/to/server"
+models:
+  model1:
+    cmd: path/to/cmd --arg1 one
+    proxy: "http://localhost:8080"
+    aliases:
+      - "m1"
+      - "model-one"
+    env:
+      - "VAR1=value1"
+      - "VAR2=value2"
+    checkEndpoint: "/health"
+  model2:
+    cmd: ${svr-path} --arg1 one
+    proxy: "http://localhost:8081"
+    aliases:
+      - "m2"
+    checkEndpoint: "/"
+  model3:
+    cmd: path/to/cmd --arg1 one
+    proxy: "http://localhost:8081"
+    aliases:
+      - "mthree"
+    checkEndpoint: "/"
+  model4:
+    cmd: path/to/cmd --arg1 one
+    proxy: "http://localhost:8082"
+    checkEndpoint: "/"
+
+healthCheckTimeout: 15
+profiles:
+  test:
+    - model1
+    - model2
+groups:
+  group1:
+    swap: true
+    exclusive: false
+    members: ["model2"]
+  forever:
+    exclusive: false
+    persistent: true
+    members:
+      - "model4"
+`
+
+	if err := os.WriteFile(tempFile, []byte(content), 0644); err != nil {
+		t.Fatalf("Failed to write temporary file: %v", err)
+	}
+
+	// Load the config and verify
+	config, err := LoadConfig(tempFile)
+	if err != nil {
+		t.Fatalf("Failed to load config: %v", err)
+	}
+
+	expected := Config{
+		LogLevel:  "info",
+		StartPort: 5800,
+		Macros: map[string]string{
+			"svr-path": "path/to/server",
+		},
+		Models: map[string]ModelConfig{
+			"model1": {
+				Cmd:           "path/to/cmd --arg1 one",
+				CmdStop:       "taskkill /f /t /pid ${PID}",
+				Proxy:         "http://localhost:8080",
+				Aliases:       []string{"m1", "model-one"},
+				Env:           []string{"VAR1=value1", "VAR2=value2"},
+				CheckEndpoint: "/health",
+			},
+			"model2": {
+				Cmd:           "path/to/server --arg1 one",
+				CmdStop:       "taskkill /f /t /pid ${PID}",
+				Proxy:         "http://localhost:8081",
+				Aliases:       []string{"m2"},
+				Env:           []string{},
+				CheckEndpoint: "/",
+			},
+			"model3": {
+				Cmd:           "path/to/cmd --arg1 one",
+				CmdStop:       "taskkill /f /t /pid ${PID}",
+				Proxy:         "http://localhost:8081",
+				Aliases:       []string{"mthree"},
+				Env:           []string{},
+				CheckEndpoint: "/",
+			},
+			"model4": {
+				Cmd:           "path/to/cmd --arg1 one",
+				CmdStop:       "taskkill /f /t /pid ${PID}",
+				Proxy:         "http://localhost:8082",
+				CheckEndpoint: "/",
+				Aliases:       []string{},
+				Env:           []string{},
+			},
+		},
+		HealthCheckTimeout: 15,
+		MetricsMaxInMemory: 1000,
+		Profiles: map[string][]string{
+			"test": {"model1", "model2"},
+		},
+		aliases: map[string]string{
+			"m1":        "model1",
+			"model-one": "model1",
+			"m2":        "model2",
+			"mthree":    "model3",
+		},
+		Groups: map[string]GroupConfig{
+			DEFAULT_GROUP_ID: {
+				Swap:      true,
+				Exclusive: true,
+				Members:   []string{"model1", "model3"},
+			},
+			"group1": {
+				Swap:      true,
+				Exclusive: false,
+				Members:   []string{"model2"},
+			},
+			"forever": {
+				Swap:       true,
+				Exclusive:  false,
+				Persistent: true,
+				Members:    []string{"model4"},
+			},
+		},
+	}
+
+	assert.Equal(t, expected, config)
+
+	realname, found := config.RealModelName("m1")
+	assert.True(t, found)
+	assert.Equal(t, "model1", realname)
+}

proxy/discardWriter.go

@@ -0,0 +1,27 @@
+package proxy
+
+import "net/http"
+
+// Custom discard writer that implements http.ResponseWriter but just discards everything
+type DiscardWriter struct {
+	header http.Header
+	status int
+}
+
+func (w *DiscardWriter) Header() http.Header {
+	if w.header == nil {
+		w.header = make(http.Header)
+	}
+	return w.header
+}
+
+func (w *DiscardWriter) Write(data []byte) (int, error) {
+	return len(data), nil
+}
+
+func (w *DiscardWriter) WriteHeader(code int) {
+	w.status = code
+}
+
+// Satisfy the http.Flusher interface for streaming responses
+func (w *DiscardWriter) Flush() {}

proxy/events.go

@@ -0,0 +1,60 @@
+package proxy
+
+// package level registry of the different event types
+
+const ProcessStateChangeEventID = 0x01
+const ChatCompletionStatsEventID = 0x02
+const ConfigFileChangedEventID = 0x03
+const LogDataEventID = 0x04
+const TokenMetricsEventID = 0x05
+const ModelPreloadedEventID = 0x06
+
+type ProcessStateChangeEvent struct {
+	ProcessName string
+	NewState    ProcessState
+	OldState    ProcessState
+}
+
+func (e ProcessStateChangeEvent) Type() uint32 {
+	return ProcessStateChangeEventID
+}
+
+type ChatCompletionStats struct {
+	TokensGenerated int
+}
+
+func (e ChatCompletionStats) Type() uint32 {
+	return ChatCompletionStatsEventID
+}
+
+type ReloadingState int
+
+const (
+	ReloadingStateStart ReloadingState = iota
+	ReloadingStateEnd
+)
+
+type ConfigFileChangedEvent struct {
+	ReloadingState ReloadingState
+}
+
+func (e ConfigFileChangedEvent) Type() uint32 {
+	return ConfigFileChangedEventID
+}
+
+type LogDataEvent struct {
+	Data []byte
+}
+
+func (e LogDataEvent) Type() uint32 {
+	return LogDataEventID
+}
+
+type ModelPreloadedEvent struct {
+	ModelName string
+	Success   bool
+}
+
+func (e ModelPreloadedEvent) Type() uint32 {
+	return ModelPreloadedEventID
+}

proxy/helpers_test.go

@@ -9,11 +9,14 @@ import (
 	"testing"
 
 	"github.com/gin-gonic/gin"
+	"gopkg.in/yaml.v3"
 )
 
 var (
-	nextTestPort int = 12000
-	portMutex    sync.Mutex
+	nextTestPort        int = 12000
+	portMutex           sync.Mutex
+	testLogger          = NewLogMonitorWriter(os.Stdout)
+	simpleResponderPath = getSimpleResponderPath()
 )
 
 // Check if the binary exists
@@ -26,6 +29,17 @@ func TestMain(m *testing.M) {
 
 	gin.SetMode(gin.TestMode)
 
+	switch os.Getenv("LOG_LEVEL") {
+	case "debug":
+		testLogger.SetLogLevel(LevelDebug)
+	case "warn":
+		testLogger.SetLogLevel(LevelWarn)
+	case "info":
+		testLogger.SetLogLevel(LevelInfo)
+	default:
+		testLogger.SetLogLevel(LevelWarn)
+	}
+
 	m.Run()
 }
 
@@ -33,26 +47,39 @@ func TestMain(m *testing.M) {
 func getSimpleResponderPath() string {
 	goos := runtime.GOOS
 	goarch := runtime.GOARCH
-	return filepath.Join("..", "build", fmt.Sprintf("simple-responder_%s_%s", goos, goarch))
+
+	if goos == "windows" {
+		return filepath.Join("..", "build", "simple-responder.exe")
+	} else {
+		return filepath.Join("..", "build", fmt.Sprintf("simple-responder_%s_%s", goos, goarch))
+	}
 }
 
-func getTestSimpleResponderConfig(expectedMessage string) ModelConfig {
+func getTestPort() int {
 	portMutex.Lock()
 	defer portMutex.Unlock()
 
 	port := nextTestPort
 	nextTestPort++
 
-	return getTestSimpleResponderConfigPort(expectedMessage, port)
+	return port
+}
+
+func getTestSimpleResponderConfig(expectedMessage string) ModelConfig {
+	return getTestSimpleResponderConfigPort(expectedMessage, getTestPort())
 }
 
 func getTestSimpleResponderConfigPort(expectedMessage string, port int) ModelConfig {
-	binaryPath := getSimpleResponderPath()
+	// Create a YAML string with just the values we want to set
+	yamlStr := fmt.Sprintf(`
+cmd: '%s --port %d --silent --respond %s'
+proxy: "http://127.0.0.1:%d"
+`, simpleResponderPath, port, expectedMessage, port)
 
-	// Create a process configuration
-	return ModelConfig{
-		Cmd:           fmt.Sprintf("%s --port %d --silent --respond %s", binaryPath, port, expectedMessage),
-		Proxy:         fmt.Sprintf("http://127.0.0.1:%d", port),
-		CheckEndpoint: "/health",
+	var cfg ModelConfig
+	if err := yaml.Unmarshal([]byte(yamlStr), &cfg); err != nil {
+		panic(fmt.Sprintf("failed to unmarshal test config: %v in [%s]", err, yamlStr))
 	}
+
+	return cfg
 }

proxy/html/index.html

@@ -1,14 +0,0 @@
-<!DOCTYPE html>
-<html lang="en">
-<head>
-    <meta charset="UTF-8">
-    <meta name="viewport" content="width=device-width, initial-scale=1.0">
-    <title>llama-swap</title>
-</head>
-<body>
-    <h1>llama-swap</h1>
-    <p>
-        <a href="/logs">view logs</a> | <a href="/upstream">configured models</a> | <a href="https://github.com/mostlygeek/llama-swap">github</a>
-    </p>
-</body>
-</html>

proxy/html/logs.html

@@ -1,258 +0,0 @@
-<!DOCTYPE html>
-<html lang="en">
-<head>
-    <meta charset="UTF-8">
-    <meta name="viewport" content="width=device-width, initial-scale=1.0">
-    <title>Logs</title>
-    <style>
-        body {
-            margin: 0;
-            height: 100vh;
-            display: flex;
-            flex-direction: column;
-            font-family: "Courier New", Courier, monospace;
-        }
-        .log-container {
-            display: flex;
-            flex: 1;
-            gap: 0.5em;
-            margin: 0.5em;
-            min-height: 0;
-        }
-        .log-column {
-            display: flex;
-            flex-direction: column;
-            flex: 1;
-            min-width: 0;
-            transition: flex 0.3s ease;
-        }
-        .log-column.minimized {
-            flex: 0.1;
-            max-width: 50px;
-            border: 1px solid #777;
-            color: green;
-        }
-        .log-controls {
-            display: grid;
-            grid-template-columns: 1fr auto;
-            gap: 0.5em;
-            margin-bottom: 0.5em;
-        }
-        .log-controls input {
-            width: 100%;
-            padding: 4px;
-        }
-        .log-controls input:focus {
-           outline: none;
-        }
-        .log-stream {
-            flex: 1;
-            padding: 1em;
-            background: #f4f4f4;
-            overflow-y: auto;
-            white-space: pre-wrap;
-            word-wrap: break-word;
-            min-height: 0;
-        }
-
-        .regex-error {
-            background-color: #ff0000 !important;
-        }
-
-        /* Make headers clickable and show pointer cursor */
-        h2 {
-            cursor: pointer;
-            user-select: none;
-            margin: 0 0 0.5em 0;
-            padding: 0.5em;
-        }
-
-        h2:hover {
-            background-color: rgba(0, 0, 0, 0.05);
-        }
-
-        /* Dark mode styles */
-        @media (prefers-color-scheme: dark) {
-            body {
-                background-color: #333;
-                color: #fff;
-            }
-
-            .log-stream {
-                background: #444;
-                color: #fff;
-            }
-
-            .log-controls input {
-                background: #555;
-                color: #fff;
-                border: 1px solid #777;
-            }
-
-            .log-controls button {
-                background: #555;
-                color: #fff;
-                border: 1px solid #777;
-            }
-
-            h2:hover {
-                background-color: rgba(255, 255, 255, 0.1);
-            }
-        }
-
-        /* Hide content when minimized */
-        .log-column.minimized .log-controls,
-        .log-column.minimized .log-stream {
-            display: none;
-        }
-
-        .log-column.minimized h2 {
-            writing-mode: vertical-rl;
-            text-orientation: mixed;
-            transform: rotate(180deg);
-            white-space: nowrap;
-            margin: auto;
-        }
-    </style>
-</head>
-<body>
-    <div class="log-container">
-        <div class="log-column">
-            <h2>Proxy Logs</h2>
-            <div class="log-controls">
-                <input type="text" id="proxy-filter-input" placeholder="proxy regex filter">
-                <button id="proxy-clear-button">clear</button>
-            </div>
-            <pre class="log-stream" id="proxy-log-stream">Waiting for proxy logs...</pre>
-        </div>
-        <div class="log-column minimized">
-            <h2>Upstream Logs</h2>
-            <div class="log-controls">
-                <input type="text" id="upstream-filter-input" placeholder="upstream regex filter">
-                <button id="upstream-clear-button">clear</button>
-            </div>
-            <pre class="log-stream" id="upstream-log-stream">Waiting for upstream logs...</pre>
-        </div>
-    </div>
-    <script>
-        class LogStream {
-            constructor(streamElement, filterInput, clearButton, endpoint) {
-                this.streamElement = streamElement;
-                this.filterInput = filterInput;
-                this.clearButton = clearButton;
-                this.endpoint = endpoint;
-                this.logData = "";
-                this.regexFilter = null;
-                this.eventSource = null;
-
-                this.initialize();
-            }
-
-            initialize() {
-                this.filterInput.addEventListener('input', () => this.updateFilter());
-                this.clearButton.addEventListener('click', () => {
-                    this.filterInput.value = "";
-                    this.regexFilter = null;
-                    this.render();
-                });
-                this.setupEventSource();
-            }
-
-            setupEventSource() {
-                if (typeof(EventSource) === "undefined") {
-                    this.logData = "SSE Not supported by this browser.";
-                    this.render();
-                    return;
-                }
-
-                const connect = () => {
-                    this.eventSource = new EventSource(this.endpoint);
-
-                    this.eventSource.onmessage = (event) => {
-                        this.logData += event.data;
-                        this.render();
-                    };
-
-                    this.eventSource.onerror = (err) => {
-                        // Close the current connection
-                        this.eventSource.close();
-
-                        this.logData += "\nConnection lost. Retrying in 5 seconds...\n";
-                        this.render();
-
-                        // Attempt to reconnect after 5 seconds
-                        setTimeout(() => {
-                            this.logData += "Attempting to reconnect...\n";
-                            this.render();
-                            connect();
-                        }, 5000);
-                    };
-                };
-
-                // Initial connection
-                connect();
-            }
-
-            render() {
-                let content = this.logData;
-
-                if (this.regexFilter) {
-                    const lines = content.split('\n');
-                    const filteredLines = lines.filter(line => this.regexFilter.test(line));
-                    content = filteredLines.length > 0 ? filteredLines.join('\n') + '\n' : "";
-                }
-
-                this.streamElement.textContent = content;
-                this.streamElement.scrollTop = this.streamElement.scrollHeight;
-            }
-
-            updateFilter() {
-                const pattern = this.filterInput.value.trim();
-                this.filterInput.classList.remove('regex-error');
-
-                if (!pattern) {
-                    this.regexFilter = null;
-                    this.render();
-                    return;
-                }
-
-                try {
-                    this.regexFilter = new RegExp(pattern);
-                } catch (e) {
-                    console.error("Invalid regex pattern:", e);
-                    this.regexFilter = null;
-                    this.filterInput.classList.add('regex-error');
-                    return;
-                }
-
-                this.render();
-            }
-        }
-
-        // Initialize both log streams
-        document.addEventListener('DOMContentLoaded', () => {
-            new LogStream(
-                document.getElementById('proxy-log-stream'),
-                document.getElementById('proxy-filter-input'),
-                document.getElementById('proxy-clear-button'),
-                "/logs/streamSSE/proxy"
-            );
-
-            new LogStream(
-                document.getElementById('upstream-log-stream'),
-                document.getElementById('upstream-filter-input'),
-                document.getElementById('upstream-clear-button'),
-                "/logs/streamSSE/upstream"
-            );
-
-            // Initialize clickable headers
-            document.querySelectorAll('h2').forEach(header => {
-                header.addEventListener('click', () => {
-                    const column = header.closest('.log-column');
-                    column.classList.toggle('minimized');
-                });
-            });
-        });
-    </script>
-</body>
-</html>

proxy/html_files.go

@@ -1,10 +0,0 @@
-package proxy
-
-import "embed"
-
-//go:embed html
-var htmlFiles embed.FS
-
-func getHTMLFile(path string) ([]byte, error) {
-	return htmlFiles.ReadFile("html/" + path)
-}

proxy/logMonitor.go

@@ -2,10 +2,13 @@ package proxy
 
 import (
 	"container/ring"
+	"context"
 	"fmt"
 	"io"
 	"os"
 	"sync"
+
+	"github.com/mostlygeek/llama-swap/event"
 )
 
 type LogLevel int
@@ -18,7 +21,7 @@ const (
 )
 
 type LogMonitor struct {
-	clients  map[chan []byte]bool
+	eventbus *event.Dispatcher
 	mu       sync.RWMutex
 	buffer   *ring.Ring
 	bufferMu sync.RWMutex
@@ -37,11 +40,11 @@ func NewLogMonitor() *LogMonitor {
 
 func NewLogMonitorWriter(stdout io.Writer) *LogMonitor {
 	return &LogMonitor{
-		clients: make(map[chan []byte]bool),
-		buffer:  ring.New(10 * 1024), // keep 10KB of buffered logs
-		stdout:  stdout,
-		level:   LevelInfo,
-		prefix:  "",
+		eventbus: event.NewDispatcherConfig(1000),
+		buffer:   ring.New(10 * 1024), // keep 10KB of buffered logs
+		stdout:   stdout,
+		level:    LevelInfo,
+		prefix:   "",
 	}
 }
 
@@ -81,34 +84,14 @@ func (w *LogMonitor) GetHistory() []byte {
 	return history
 }
 
-func (w *LogMonitor) Subscribe() chan []byte {
-	w.mu.Lock()
-	defer w.mu.Unlock()
-
-	ch := make(chan []byte, 100)
-	w.clients[ch] = true
-	return ch
-}
-
-func (w *LogMonitor) Unsubscribe(ch chan []byte) {
-	w.mu.Lock()
-	defer w.mu.Unlock()
-
-	delete(w.clients, ch)
-	close(ch)
+func (w *LogMonitor) OnLogData(callback func(data []byte)) context.CancelFunc {
+	return event.Subscribe(w.eventbus, func(e LogDataEvent) {
+		callback(e.Data)
+	})
 }
 
 func (w *LogMonitor) broadcast(msg []byte) {
-	w.mu.RLock()
-	defer w.mu.RUnlock()
-
-	for client := range w.clients {
-		select {
-		case client <- msg:
-		default:
-			// If client buffer is full, skip
-		}
-	}
+	event.Publish(w.eventbus, LogDataEvent{Data: msg})
 }
 
 func (w *LogMonitor) SetPrefix(prefix string) {

proxy/logMonitor_test.go

@@ -10,38 +10,29 @@ import (
 func TestLogMonitor(t *testing.T) {
 	logMonitor := NewLogMonitorWriter(io.Discard)
 
-	// Test subscription
-	client1 := logMonitor.Subscribe()
-	client2 := logMonitor.Subscribe()
-
-	defer logMonitor.Unsubscribe(client1)
-	defer logMonitor.Unsubscribe(client2)
+	// A WaitGroup is used to wait for all the expected writes to complete
+	var wg sync.WaitGroup
 
 	client1Messages := make([]byte, 0)
 	client2Messages := make([]byte, 0)
 
-	var wg sync.WaitGroup
-	wg.Add(1)
+	defer logMonitor.OnLogData(func(data []byte) {
+		client1Messages = append(client1Messages, data...)
+		wg.Done()
+	})()
 
-	go func() {
-		defer wg.Done()
-		for {
-			select {
-			case data := <-client1:
-				client1Messages = append(client1Messages, data...)
-			case data := <-client2:
-				client2Messages = append(client2Messages, data...)
-			default:
-				return
-			}
-		}
-	}()
+	defer logMonitor.OnLogData(func(data []byte) {
+		client2Messages = append(client2Messages, data...)
+		wg.Done()
+	})()
+
+	wg.Add(6) // 2 x 3 writes
 
 	logMonitor.Write([]byte("1"))
 	logMonitor.Write([]byte("2"))
 	logMonitor.Write([]byte("3"))
 
-	// Wait for the goroutine to finish
+	// wait for all writes to complete
 	wg.Wait()
 
 	// Check the buffer

proxy/metrics_middleware.go

@@ -0,0 +1,184 @@
+package proxy
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"net/http"
+	"strings"
+	"time"
+
+	"github.com/gin-gonic/gin"
+	"github.com/tidwall/gjson"
+)
+
+type MetricsRecorder struct {
+	metricsMonitor *MetricsMonitor
+	realModelName  string
+	//	isStreaming    bool
+	startTime time.Time
+}
+
+// MetricsMiddleware sets up the MetricsResponseWriter for capturing upstream requests
+func MetricsMiddleware(pm *ProxyManager) gin.HandlerFunc {
+	return func(c *gin.Context) {
+		bodyBytes, err := io.ReadAll(c.Request.Body)
+		if err != nil {
+			pm.sendErrorResponse(c, http.StatusBadRequest, "could not ready request body")
+			c.Abort()
+			return
+		}
+		c.Request.Body = io.NopCloser(bytes.NewBuffer(bodyBytes))
+
+		requestedModel := gjson.GetBytes(bodyBytes, "model").String()
+		if requestedModel == "" {
+			pm.sendErrorResponse(c, http.StatusBadRequest, "missing or invalid 'model' key")
+			c.Abort()
+			return
+		}
+
+		realModelName, found := pm.config.RealModelName(requestedModel)
+		if !found {
+			pm.sendErrorResponse(c, http.StatusBadRequest, fmt.Sprintf("could not find real modelID for %s", requestedModel))
+			c.Abort()
+			return
+		}
+
+		writer := &MetricsResponseWriter{
+			ResponseWriter: c.Writer,
+			metricsRecorder: &MetricsRecorder{
+				metricsMonitor: pm.metricsMonitor,
+				realModelName:  realModelName,
+				startTime:      time.Now(),
+			},
+		}
+		c.Writer = writer
+		c.Next()
+
+		// check for streaming response
+		if strings.Contains(c.Writer.Header().Get("Content-Type"), "text/event-stream") {
+			writer.metricsRecorder.processStreamingResponse(writer.body)
+		} else {
+			writer.metricsRecorder.processNonStreamingResponse(writer.body)
+		}
+	}
+}
+
+func (rec *MetricsRecorder) parseAndRecordMetrics(jsonData gjson.Result) bool {
+	usage := jsonData.Get("usage")
+	timings := jsonData.Get("timings")
+	if !usage.Exists() && !timings.Exists() {
+		return false
+	}
+
+	// default values
+	cachedTokens := -1 // unknown or missing data
+	outputTokens := 0
+	inputTokens := 0
+
+	// timings data
+	tokensPerSecond := -1.0
+	promptPerSecond := -1.0
+	durationMs := int(time.Since(rec.startTime).Milliseconds())
+
+	if usage.Exists() {
+		outputTokens = int(jsonData.Get("usage.completion_tokens").Int())
+		inputTokens = int(jsonData.Get("usage.prompt_tokens").Int())
+	}
+
+	// use llama-server's timing data for tok/sec and duration as it is more accurate
+	if timings.Exists() {
+		inputTokens = int(jsonData.Get("timings.prompt_n").Int())
+		outputTokens = int(jsonData.Get("timings.predicted_n").Int())
+		promptPerSecond = jsonData.Get("timings.prompt_per_second").Float()
+		tokensPerSecond = jsonData.Get("timings.predicted_per_second").Float()
+		durationMs = int(jsonData.Get("timings.prompt_ms").Float() + jsonData.Get("timings.predicted_ms").Float())
+
+		if cachedValue := jsonData.Get("timings.cache_n"); cachedValue.Exists() {
+			cachedTokens = int(cachedValue.Int())
+		}
+	}
+
+	rec.metricsMonitor.addMetrics(TokenMetrics{
+		Timestamp:       time.Now(),
+		Model:           rec.realModelName,
+		CachedTokens:    cachedTokens,
+		InputTokens:     inputTokens,
+		OutputTokens:    outputTokens,
+		PromptPerSecond: promptPerSecond,
+		TokensPerSecond: tokensPerSecond,
+		DurationMs:      durationMs,
+	})
+
+	return true
+}
+
+func (rec *MetricsRecorder) processStreamingResponse(body []byte) {
+	// Iterate **backwards** through the lines looking for the data payload with
+	// usage data
+	lines := bytes.Split(body, []byte("\n"))
+
+	for i := len(lines) - 1; i >= 0; i-- {
+		line := bytes.TrimSpace(lines[i])
+		if len(line) == 0 {
+			continue
+		}
+
+		// SSE payload always follows "data:"
+		prefix := []byte("data:")
+		if !bytes.HasPrefix(line, prefix) {
+			continue
+		}
+		data := bytes.TrimSpace(line[len(prefix):])
+
+		if len(data) == 0 {
+			continue
+		}
+
+		if bytes.Equal(data, []byte("[DONE]")) {
+			// [DONE] line itself contains nothing of interest.
+			continue
+		}
+
+		if gjson.ValidBytes(data) {
+			if rec.parseAndRecordMetrics(gjson.ParseBytes(data)) {
+				return // short circuit if a metric was recorded
+			}
+		}
+	}
+}
+
+func (rec *MetricsRecorder) processNonStreamingResponse(body []byte) {
+	if len(body) == 0 {
+		return
+	}
+
+	// Parse JSON to extract usage information
+	if gjson.ValidBytes(body) {
+		rec.parseAndRecordMetrics(gjson.ParseBytes(body))
+	}
+}
+
+// MetricsResponseWriter captures the entire response for non-streaming
+type MetricsResponseWriter struct {
+	gin.ResponseWriter
+	body            []byte
+	metricsRecorder *MetricsRecorder
+}
+
+func (w *MetricsResponseWriter) Write(b []byte) (int, error) {
+	n, err := w.ResponseWriter.Write(b)
+	if err != nil {
+		return n, err
+	}
+	w.body = append(w.body, b...)
+	return n, nil
+}
+
+func (w *MetricsResponseWriter) WriteHeader(statusCode int) {
+	w.ResponseWriter.WriteHeader(statusCode)
+}
+
+func (w *MetricsResponseWriter) Header() http.Header {
+	return w.ResponseWriter.Header()
+}

proxy/metrics_monitor.go

@@ -0,0 +1,83 @@
+package proxy
+
+import (
+	"encoding/json"
+	"sync"
+	"time"
+
+	"github.com/mostlygeek/llama-swap/event"
+)
+
+// TokenMetrics represents parsed token statistics from llama-server logs
+type TokenMetrics struct {
+	ID              int       `json:"id"`
+	Timestamp       time.Time `json:"timestamp"`
+	Model           string    `json:"model"`
+	CachedTokens    int       `json:"cache_tokens"`
+	InputTokens     int       `json:"input_tokens"`
+	OutputTokens    int       `json:"output_tokens"`
+	PromptPerSecond float64   `json:"prompt_per_second"`
+	TokensPerSecond float64   `json:"tokens_per_second"`
+	DurationMs      int       `json:"duration_ms"`
+}
+
+// TokenMetricsEvent represents a token metrics event
+type TokenMetricsEvent struct {
+	Metrics TokenMetrics
+}
+
+func (e TokenMetricsEvent) Type() uint32 {
+	return TokenMetricsEventID // defined in events.go
+}
+
+// MetricsMonitor parses llama-server output for token statistics
+type MetricsMonitor struct {
+	mu         sync.RWMutex
+	metrics    []TokenMetrics
+	maxMetrics int
+	nextID     int
+}
+
+func NewMetricsMonitor(config *Config) *MetricsMonitor {
+	maxMetrics := config.MetricsMaxInMemory
+	if maxMetrics <= 0 {
+		maxMetrics = 1000 // Default fallback
+	}
+
+	mp := &MetricsMonitor{
+		maxMetrics: maxMetrics,
+	}
+
+	return mp
+}
+
+// addMetrics adds a new metric to the collection and publishes an event
+func (mp *MetricsMonitor) addMetrics(metric TokenMetrics) {
+	mp.mu.Lock()
+	defer mp.mu.Unlock()
+
+	metric.ID = mp.nextID
+	mp.nextID++
+	mp.metrics = append(mp.metrics, metric)
+	if len(mp.metrics) > mp.maxMetrics {
+		mp.metrics = mp.metrics[len(mp.metrics)-mp.maxMetrics:]
+	}
+	event.Emit(TokenMetricsEvent{Metrics: metric})
+}
+
+// GetMetrics returns a copy of the current metrics
+func (mp *MetricsMonitor) GetMetrics() []TokenMetrics {
+	mp.mu.RLock()
+	defer mp.mu.RUnlock()
+
+	result := make([]TokenMetrics, len(mp.metrics))
+	copy(result, mp.metrics)
+	return result
+}
+
+// GetMetricsJSON returns metrics as JSON
+func (mp *MetricsMonitor) GetMetricsJSON() ([]byte, error) {
+	mp.mu.RLock()
+	defer mp.mu.RUnlock()
+	return json.Marshal(mp.metrics)
+}

proxy/process.go

@@ -5,13 +5,17 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"net"
 	"net/http"
 	"net/url"
 	"os/exec"
+	"strconv"
 	"strings"
 	"sync"
 	"syscall"
 	"time"
+
+	"github.com/mostlygeek/llama-swap/event"
 )
 
 type ProcessState string
@@ -22,18 +26,28 @@ const (
 	StateReady    ProcessState = ProcessState("ready")
 	StateStopping ProcessState = ProcessState("stopping")
 
-	// failed a health check on start and will not be recovered
-	StateFailed ProcessState = ProcessState("failed")
-
 	// process is shutdown and will not be restarted
 	StateShutdown ProcessState = ProcessState("shutdown")
 )
 
+type StopStrategy int
+
+const (
+	StopImmediately StopStrategy = iota
+	StopWaitForInflightRequest
+)
+
 type Process struct {
 	ID     string
 	config ModelConfig
 	cmd    *exec.Cmd
 
+	// PR #155 called to cancel the upstream process
+	cancelUpstream context.CancelFunc
+
+	// closed when command exits
+	cmdWaitChan chan struct{}
+
 	processLogger *LogMonitor
 	proxyLogger   *LogMonitor
 
@@ -50,24 +64,40 @@ type Process struct {
 	// used to block on multiple start() calls
 	waitStarting sync.WaitGroup
 
-	// for managing shutdown state
-	shutdownCtx    context.Context
-	shutdownCancel context.CancelFunc
+	// for managing concurrency limits
+	concurrencyLimitSemaphore chan struct{}
+
+	// used for testing to override the default value
+	gracefulStopTimeout time.Duration
+
+	// track the number of failed starts
+	failedStartCount int
 }
 
 func NewProcess(ID string, healthCheckTimeout int, config ModelConfig, processLogger *LogMonitor, proxyLogger *LogMonitor) *Process {
-	ctx, cancel := context.WithCancel(context.Background())
+	concurrentLimit := 10
+	if config.ConcurrencyLimit > 0 {
+		concurrentLimit = config.ConcurrencyLimit
+	}
+
 	return &Process{
 		ID:                      ID,
 		config:                  config,
 		cmd:                     nil,
+		cancelUpstream:          nil,
 		processLogger:           processLogger,
 		proxyLogger:             proxyLogger,
 		healthCheckTimeout:      healthCheckTimeout,
 		healthCheckLoopInterval: 5 * time.Second, /* default, can not be set by user - used for testing */
 		state:                   StateStopped,
-		shutdownCtx:             ctx,
-		shutdownCancel:          cancel,
+
+		// concurrency limit
+		concurrencyLimitSemaphore: make(chan struct{}, concurrentLimit),
+
+		// To be removed when migration over exec.CommandContext is complete
+		// stop timeout
+		gracefulStopTimeout: 10 * time.Second,
+		cmdWaitChan:         make(chan struct{}),
 	}
 }
 
@@ -89,16 +119,18 @@ func (p *Process) swapState(expectedState, newState ProcessState) (ProcessState,
 	defer p.stateMutex.Unlock()
 
 	if p.state != expectedState {
+		p.proxyLogger.Warnf("<%s> swapState() Unexpected current state %s, expected %s", p.ID, p.state, expectedState)
 		return p.state, ErrExpectedStateMismatch
 	}
 
 	if !isValidTransition(p.state, newState) {
-		p.proxyLogger.Warnf("Invalid state transition from %s to %s", p.state, newState)
+		p.proxyLogger.Warnf("<%s> swapState() Invalid state transition from %s to %s", p.ID, p.state, newState)
 		return p.state, ErrInvalidStateTransition
 	}
 
-	p.proxyLogger.Debugf("State transition from %s to %s", expectedState, newState)
 	p.state = newState
+	p.proxyLogger.Debugf("<%s> swapState() State transitioned from %s to %s", p.ID, expectedState, newState)
+	event.Emit(ProcessStateChangeEvent{ProcessName: p.ID, NewState: newState, OldState: expectedState})
 	return p.state, nil
 }
 
@@ -108,12 +140,12 @@ func isValidTransition(from, to ProcessState) bool {
 	case StateStopped:
 		return to == StateStarting
 	case StateStarting:
-		return to == StateReady || to == StateFailed || to == StateStopping
+		return to == StateReady || to == StateStopping || to == StateStopped
 	case StateReady:
 		return to == StateStopping
 	case StateStopping:
 		return to == StateStopped || to == StateShutdown
-	case StateFailed, StateShutdown:
+	case StateShutdown:
 		return false // No transitions allowed from these states
 	}
 	return false
@@ -160,25 +192,37 @@ func (p *Process) start() error {
 
 	p.waitStarting.Add(1)
 	defer p.waitStarting.Done()
+	cmdContext, ctxCancelUpstream := context.WithCancel(context.Background())
 
-	p.cmd = exec.Command(args[0], args[1:]...)
+	p.cmd = exec.CommandContext(cmdContext, args[0], args[1:]...)
 	p.cmd.Stdout = p.processLogger
 	p.cmd.Stderr = p.processLogger
-	p.cmd.Env = p.config.Env
+	p.cmd.Env = append(p.cmd.Environ(), p.config.Env...)
+	p.cmd.Cancel = p.cmdStopUpstreamProcess
+	p.cmd.WaitDelay = p.gracefulStopTimeout
+	p.cancelUpstream = ctxCancelUpstream
+	p.cmdWaitChan = make(chan struct{})
 
+	p.failedStartCount++ // this will be reset to zero when the process has successfully started
+
+	p.proxyLogger.Debugf("<%s> Executing start command: %s, env: %s", p.ID, strings.Join(args, " "), strings.Join(p.config.Env, ", "))
 	err = p.cmd.Start()
 
 	// Set process state to failed
 	if err != nil {
-		if curState, swapErr := p.swapState(StateStarting, StateFailed); swapErr != nil {
+		if curState, swapErr := p.swapState(StateStarting, StateStopped); swapErr != nil {
+			p.state = StateStopped // force it into a stopped state
 			return fmt.Errorf(
-				"failed to start command and state swap failed. command error: %v, current state: %v, state swap error: %v",
-				err, curState, swapErr,
+				"failed to start command '%s' and state swap failed. command error: %v, current state: %v, state swap error: %v",
+				strings.Join(args, " "), err, curState, swapErr,
 			)
 		}
-		return fmt.Errorf("start() failed: %v", err)
+		return fmt.Errorf("start() failed for command '%s': %v", strings.Join(args, " "), err)
 	}
 
+	// Capture the exit error for later signalling
+	go p.waitForCmd()
+
 	// One of three things can happen at this stage:
 	// 1. The command exits unexpectedly
 	// 2. The health check fails
@@ -193,51 +237,38 @@ func (p *Process) start() error {
 
 	// a "none" means don't check for health ... I could have picked a better word :facepalm:
 	if checkEndpoint != "none" {
-		// keep default behaviour
-		if checkEndpoint == "" {
-			checkEndpoint = "/health"
-		}
-
 		proxyTo := p.config.Proxy
 		healthURL, err := url.JoinPath(proxyTo, checkEndpoint)
 		if err != nil {
 			return fmt.Errorf("failed to create health check URL proxy=%s and checkEndpoint=%s", proxyTo, checkEndpoint)
 		}
 
-		checkDeadline, cancelHealthCheck := context.WithDeadline(
-			context.Background(),
-			checkStartTime.Add(maxDuration),
-		)
-		defer cancelHealthCheck()
-
-	loop:
 		// Ready Check loop
 		for {
-			select {
-			case <-checkDeadline.Done():
-				if curState, err := p.swapState(StateStarting, StateFailed); err != nil {
-					return fmt.Errorf("health check timed out after %vs AND state swap failed: %v, current state: %v", maxDuration.Seconds(), err, curState)
-				} else {
-					return fmt.Errorf("health check timed out after %vs", maxDuration.Seconds())
+			currentState := p.CurrentState()
+			if currentState != StateStarting {
+				if currentState == StateStopped {
+					return fmt.Errorf("upstream command exited prematurely but successfully")
 				}
-			case <-p.shutdownCtx.Done():
 				return errors.New("health check interrupted due to shutdown")
-			default:
-				if err := p.checkHealthEndpoint(healthURL); err == nil {
-					p.proxyLogger.Infof("Health check passed on %s", healthURL)
-					cancelHealthCheck()
-					break loop
-				} else {
-					if strings.Contains(err.Error(), "connection refused") {
-						endTime, _ := checkDeadline.Deadline()
-						ttl := time.Until(endTime)
-						p.proxyLogger.Infof("Connection refused on %s, retrying in %.0fs", healthURL, ttl.Seconds())
-					} else {
-						p.proxyLogger.Infof("Health check error on %s, %v", healthURL, err)
-					}
-				}
 			}
 
+			if time.Since(checkStartTime) > maxDuration {
+				p.stopCommand()
+				return fmt.Errorf("health check timed out after %vs", maxDuration.Seconds())
+			}
+
+			if err := p.checkHealthEndpoint(healthURL); err == nil {
+				p.proxyLogger.Infof("<%s> Health check passed on %s", p.ID, healthURL)
+				break
+			} else {
+				if strings.Contains(err.Error(), "connection refused") {
+					ttl := time.Until(checkStartTime.Add(maxDuration))
+					p.proxyLogger.Debugf("<%s> Connection refused on %s, giving up in %.0fs (normal during startup)", p.ID, healthURL, ttl.Seconds())
+				} else {
+					p.proxyLogger.Debugf("<%s> Health check error on %s, %v (normal during startup)", p.ID, healthURL, err)
+				}
+			}
 			<-time.After(p.healthCheckLoopInterval)
 		}
 	}
@@ -257,8 +288,7 @@ func (p *Process) start() error {
 				p.inFlightRequests.Wait()
 
 				if time.Since(p.lastRequestHandled) > maxDuration {
-
-					p.proxyLogger.Infof("Unloading model %s, TTL of %ds reached.", p.ID, p.config.UnloadAfter)
+					p.proxyLogger.Infof("<%s> Unloading model, TTL of %ds reached", p.ID, p.config.UnloadAfter)
 					p.Stop()
 					return
 				}
@@ -269,89 +299,83 @@ func (p *Process) start() error {
 	if curState, err := p.swapState(StateStarting, StateReady); err != nil {
 		return fmt.Errorf("failed to set Process state to ready: current state: %v, error: %v", curState, err)
 	} else {
+		p.failedStartCount = 0
 		return nil
 	}
 }
 
+// Stop will wait for inflight requests to complete before stopping the process.
 func (p *Process) Stop() {
-	// wait for any inflight requests before proceeding
-	p.inFlightRequests.Wait()
-
-	// calling Stop() when state is invalid is a no-op
-	if curState, err := p.swapState(StateReady, StateStopping); err != nil {
-		p.proxyLogger.Infof("Stop() Ready -> StateStopping err: %v, current state: %v", err, curState)
+	if !isValidTransition(p.CurrentState(), StateStopping) {
 		return
 	}
 
-	// stop the process with a graceful exit timeout
-	p.stopCommand(5 * time.Second)
+	// wait for any inflight requests before proceeding
+	p.proxyLogger.Debugf("<%s> Stop(): Waiting for inflight requests to complete", p.ID)
+	p.inFlightRequests.Wait()
+	p.StopImmediately()
+}
 
-	if curState, err := p.swapState(StateStopping, StateStopped); err != nil {
-		p.proxyLogger.Infof("Stop() StateStopping -> StateStopped err: %v, current state: %v", err, curState)
+// StopImmediately will transition the process to the stopping state and stop the process with a SIGTERM.
+// If the process does not stop within the specified timeout, it will be forcefully stopped with a SIGKILL.
+func (p *Process) StopImmediately() {
+	if !isValidTransition(p.CurrentState(), StateStopping) {
+		return
 	}
+
+	p.proxyLogger.Debugf("<%s> Stopping process, current state: %s", p.ID, p.CurrentState())
+	if curState, err := p.swapState(StateReady, StateStopping); err != nil {
+		p.proxyLogger.Infof("<%s> Stop() Ready -> StateStopping err: %v, current state: %v", p.ID, err, curState)
+		return
+	}
+
+	p.stopCommand()
 }
 
 // Shutdown is called when llama-swap is shutting down. It will give a little bit
 // of time for any inflight requests to complete before shutting down. If the Process
-// is in the state of starting, it will cancel it and shut it down
+// is in the state of starting, it will cancel it and shut it down. Once a process is in
+// the StateShutdown state, it can not be started again.
 func (p *Process) Shutdown() {
-	p.shutdownCancel()
-	p.stopCommand(5 * time.Second)
+	if !isValidTransition(p.CurrentState(), StateStopping) {
+		return
+	}
+
+	p.stopCommand()
+	// just force it to this state since there is no recovery from shutdown
 	p.state = StateShutdown
 }
 
 // stopCommand will send a SIGTERM to the process and wait for it to exit.
 // If it does not exit within 5 seconds, it will send a SIGKILL.
-func (p *Process) stopCommand(sigtermTTL time.Duration) {
+func (p *Process) stopCommand() {
 	stopStartTime := time.Now()
 	defer func() {
-		p.proxyLogger.Debugf("Process [%s] stopCommand took %v", p.ID, time.Since(stopStartTime))
+		p.proxyLogger.Debugf("<%s> stopCommand took %v", p.ID, time.Since(stopStartTime))
 	}()
 
-	sigtermTimeout, cancelTimeout := context.WithTimeout(context.Background(), sigtermTTL)
-	defer cancelTimeout()
-
-	sigtermNormal := make(chan error, 1)
-	go func() {
-		sigtermNormal <- p.cmd.Wait()
-	}()
-
-	if p.cmd == nil || p.cmd.Process == nil {
-		p.proxyLogger.Warnf("Process [%s] cmd or cmd.Process is nil", p.ID)
+	if p.cancelUpstream == nil {
+		p.proxyLogger.Errorf("<%s> stopCommand has a nil p.cancelUpstream()", p.ID)
 		return
 	}
 
-	if err := p.terminateProcess(); err != nil {
-		p.proxyLogger.Infof("Failed to gracefully terminate process [%s]: %v", p.ID, err)
-	}
-
-	select {
-	case <-sigtermTimeout.Done():
-		p.proxyLogger.Infof("Process [%s] timed out waiting to stop, sending KILL signal", p.ID)
-		p.cmd.Process.Kill()
-	case err := <-sigtermNormal:
-		if err != nil {
-			if errno, ok := err.(syscall.Errno); ok {
-				p.proxyLogger.Errorf("Process [%s] errno >> %v", p.ID, errno)
-			} else if exitError, ok := err.(*exec.ExitError); ok {
-				if strings.Contains(exitError.String(), "signal: terminated") {
-					p.proxyLogger.Infof("Process [%s] stopped OK", p.ID)
-				} else if strings.Contains(exitError.String(), "signal: interrupt") {
-					p.proxyLogger.Infof("Process [%s] interrupted OK", p.ID)
-				} else {
-					p.proxyLogger.Warnf("Process [%s] ExitError >> %v, exit code: %d", p.ID, exitError, exitError.ExitCode())
-				}
-			} else {
-				p.proxyLogger.Errorf("Process [%s] exited >> %v", p.ID, err)
-			}
-		}
-	}
+	p.cancelUpstream()
+	<-p.cmdWaitChan
 }
 
 func (p *Process) checkHealthEndpoint(healthURL string) error {
 
 	client := &http.Client{
-		Timeout: 500 * time.Millisecond,
+		// wait a short time for a tcp connection to be established
+		Transport: &http.Transport{
+			DialContext: (&net.Dialer{
+				Timeout: 500 * time.Millisecond,
+			}).DialContext,
+		},
+
+		// give a long time to respond to the health check endpoint
+		// after the connection is established. See issue: 276
+		Timeout: 5000 * time.Millisecond,
 	}
 
 	req, err := http.NewRequest("GET", healthURL, nil)
@@ -379,11 +403,19 @@ func (p *Process) ProxyRequest(w http.ResponseWriter, r *http.Request) {
 
 	// prevent new requests from being made while stopping or irrecoverable
 	currentState := p.CurrentState()
-	if currentState == StateFailed || currentState == StateShutdown || currentState == StateStopping {
+	if currentState == StateShutdown || currentState == StateStopping {
 		http.Error(w, fmt.Sprintf("Process can not ProxyRequest, state is %s", currentState), http.StatusServiceUnavailable)
 		return
 	}
 
+	select {
+	case p.concurrencyLimitSemaphore <- struct{}{}:
+		defer func() { <-p.concurrencyLimitSemaphore }()
+	default:
+		http.Error(w, "Too many requests", http.StatusTooManyRequests)
+		return
+	}
+
 	p.inFlightRequests.Add(1)
 	defer func() {
 		p.lastRequestHandled = time.Now()
@@ -409,6 +441,12 @@ func (p *Process) ProxyRequest(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 	req.Header = r.Header.Clone()
+
+	contentLength, err := strconv.ParseInt(req.Header.Get("content-length"), 10, 64)
+	if err == nil {
+		req.ContentLength = contentLength
+	}
+
 	resp, err := client.Do(req)
 	if err != nil {
 		http.Error(w, err.Error(), http.StatusBadGateway)
@@ -420,6 +458,10 @@ func (p *Process) ProxyRequest(w http.ResponseWriter, r *http.Request) {
 			w.Header().Add(k, v)
 		}
 	}
+	// prevent nginx from buffering streaming responses (e.g., SSE)
+	if strings.Contains(strings.ToLower(resp.Header.Get("Content-Type")), "text/event-stream") {
+		w.Header().Set("X-Accel-Buffering", "no")
+	}
 	w.WriteHeader(resp.StatusCode)
 
 	// faster than io.Copy when streaming
@@ -444,6 +486,82 @@ func (p *Process) ProxyRequest(w http.ResponseWriter, r *http.Request) {
 	}
 
 	totalTime := time.Since(requestBeginTime)
-	p.proxyLogger.Debugf("Process [%s] request %s - start: %v, total: %v",
+	p.proxyLogger.Debugf("<%s> request %s - start: %v, total: %v",
 		p.ID, r.RequestURI, startDuration, totalTime)
 }
+
+// waitForCmd waits for the command to exit and handles exit conditions depending on current state
+func (p *Process) waitForCmd() {
+	exitErr := p.cmd.Wait()
+	p.proxyLogger.Debugf("<%s> cmd.Wait() returned error: %v", p.ID, exitErr)
+
+	if exitErr != nil {
+		if errno, ok := exitErr.(syscall.Errno); ok {
+			p.proxyLogger.Errorf("<%s> errno >> %v", p.ID, errno)
+		} else if exitError, ok := exitErr.(*exec.ExitError); ok {
+			if strings.Contains(exitError.String(), "signal: terminated") {
+				p.proxyLogger.Debugf("<%s> Process stopped OK", p.ID)
+			} else if strings.Contains(exitError.String(), "signal: interrupt") {
+				p.proxyLogger.Debugf("<%s> Process interrupted OK", p.ID)
+			} else {
+				p.proxyLogger.Warnf("<%s> ExitError >> %v, exit code: %d", p.ID, exitError, exitError.ExitCode())
+			}
+		} else {
+			if exitErr.Error() != "context canceled" /* this is normal */ {
+				p.proxyLogger.Errorf("<%s> Process exited >> %v", p.ID, exitErr)
+			}
+		}
+	}
+
+	currentState := p.CurrentState()
+	switch currentState {
+	case StateStopping:
+		if curState, err := p.swapState(StateStopping, StateStopped); err != nil {
+			p.proxyLogger.Errorf("<%s> Process exited but could not swap to StateStopped. curState=%s, err: %v", p.ID, curState, err)
+			p.state = StateStopped
+		}
+	default:
+		p.proxyLogger.Infof("<%s> process exited but not StateStopping, current state: %s", p.ID, currentState)
+		p.state = StateStopped // force it to be in this state
+	}
+	close(p.cmdWaitChan)
+}
+
+// cmdStopUpstreamProcess attemps to stop the upstream process gracefully
+func (p *Process) cmdStopUpstreamProcess() error {
+	p.processLogger.Debugf("<%s> cmdStopUpstreamProcess() initiating graceful stop of upstream process", p.ID)
+
+	// this should never happen ...
+	if p.cmd == nil || p.cmd.Process == nil {
+		p.proxyLogger.Debugf("<%s> cmd or cmd.Process is nil (normal during config reload)", p.ID)
+		return fmt.Errorf("<%s> process is nil or cmd is nil, skipping graceful stop", p.ID)
+	}
+
+	if p.config.CmdStop != "" {
+		// replace ${PID} with the pid of the process
+		stopArgs, err := SanitizeCommand(strings.ReplaceAll(p.config.CmdStop, "${PID}", fmt.Sprintf("%d", p.cmd.Process.Pid)))
+		if err != nil {
+			p.proxyLogger.Errorf("<%s> Failed to sanitize stop command: %v", p.ID, err)
+			return err
+		}
+
+		p.proxyLogger.Debugf("<%s> Executing stop command: %s", p.ID, strings.Join(stopArgs, " "))
+
+		stopCmd := exec.Command(stopArgs[0], stopArgs[1:]...)
+		stopCmd.Stdout = p.processLogger
+		stopCmd.Stderr = p.processLogger
+		stopCmd.Env = p.cmd.Env
+
+		if err := stopCmd.Run(); err != nil {
+			p.proxyLogger.Errorf("<%s> Failed to exec stop command: %v", p.ID, err)
+			return err
+		}
+	} else {
+		if err := p.cmd.Process.Signal(syscall.SIGTERM); err != nil {
+			p.proxyLogger.Errorf("<%s> Failed to send SIGTERM to process: %v", p.ID, err)
+			return err
+		}
+	}
+
+	return nil
+}

proxy/process_stop.go

@@ -1,9 +0,0 @@
-//go:build !windows
-
-package proxy
-
-import "syscall"
-
-func (p *Process) terminateProcess() error {
-	return p.cmd.Process.Signal(syscall.SIGTERM)
-}

proxy/process_stop_windows.go

@@ -1,14 +0,0 @@
-//go:build windows
-
-package proxy
-
-import (
-	"fmt"
-	"os/exec"
-)
-
-func (p *Process) terminateProcess() error {
-	pid := fmt.Sprintf("%d", p.cmd.Process.Pid)
-	cmd := exec.Command("taskkill", "/f", "/t", "/pid", pid)
-	return cmd.Run()
-}

proxy/process_test.go

@@ -2,9 +2,10 @@ package proxy
 
 import (
 	"fmt"
-	"io"
 	"net/http"
 	"net/http/httptest"
+	"os"
+	"runtime"
 	"sync"
 	"testing"
 	"time"
@@ -13,16 +14,25 @@ import (
 )
 
 var (
-	discardLogger = NewLogMonitorWriter(io.Discard)
+	debugLogger = NewLogMonitorWriter(os.Stdout)
 )
 
+func init() {
+	// flip to help with debugging tests
+	if false {
+		debugLogger.SetLogLevel(LevelDebug)
+	} else {
+		debugLogger.SetLogLevel(LevelError)
+	}
+}
+
 func TestProcess_AutomaticallyStartsUpstream(t *testing.T) {
 
 	expectedMessage := "testing91931"
 	config := getTestSimpleResponderConfig(expectedMessage)
 
 	// Create a process
-	process := NewProcess("test-process", 5, config, discardLogger, discardLogger)
+	process := NewProcess("test-process", 5, config, debugLogger, debugLogger)
 	defer process.Stop()
 
 	req := httptest.NewRequest("GET", "/test", nil)
@@ -58,7 +68,7 @@ func TestProcess_WaitOnMultipleStarts(t *testing.T) {
 	expectedMessage := "testing91931"
 	config := getTestSimpleResponderConfig(expectedMessage)
 
-	process := NewProcess("test-process", 5, config, discardLogger, discardLogger)
+	process := NewProcess("test-process", 5, config, debugLogger, debugLogger)
 	defer process.Stop()
 
 	var wg sync.WaitGroup
@@ -86,7 +96,7 @@ func TestProcess_BrokenModelConfig(t *testing.T) {
 		CheckEndpoint: "/health",
 	}
 
-	process := NewProcess("broken", 1, config, discardLogger, discardLogger)
+	process := NewProcess("broken", 1, config, debugLogger, debugLogger)
 
 	req := httptest.NewRequest("GET", "/", nil)
 	w := httptest.NewRecorder()
@@ -96,8 +106,8 @@ func TestProcess_BrokenModelConfig(t *testing.T) {
 
 	w = httptest.NewRecorder()
 	process.ProxyRequest(w, req)
-	assert.Equal(t, http.StatusServiceUnavailable, w.Code)
-	assert.Contains(t, w.Body.String(), "Process can not ProxyRequest, state is failed")
+	assert.Equal(t, http.StatusBadGateway, w.Code)
+	assert.Contains(t, w.Body.String(), "start() failed for command 'nonexistent-command':")
 }
 
 func TestProcess_UnloadAfterTTL(t *testing.T) {
@@ -111,7 +121,7 @@ func TestProcess_UnloadAfterTTL(t *testing.T) {
 	config.UnloadAfter = 3 // seconds
 	assert.Equal(t, 3, config.UnloadAfter)
 
-	process := NewProcess("ttl_test", 2, config, discardLogger, discardLogger)
+	process := NewProcess("ttl_test", 2, config, debugLogger, debugLogger)
 	defer process.Stop()
 
 	// this should take 4 seconds
@@ -153,7 +163,7 @@ func TestProcess_LowTTLValue(t *testing.T) {
 	config.UnloadAfter = 1 // second
 	assert.Equal(t, 1, config.UnloadAfter)
 
-	process := NewProcess("ttl", 2, config, discardLogger, discardLogger)
+	process := NewProcess("ttl", 2, config, debugLogger, debugLogger)
 	defer process.Stop()
 
 	for i := 0; i < 100; i++ {
@@ -180,7 +190,7 @@ func TestProcess_HTTPRequestsHaveTimeToFinish(t *testing.T) {
 
 	expectedMessage := "12345"
 	config := getTestSimpleResponderConfig(expectedMessage)
-	process := NewProcess("t", 10, config, discardLogger, discardLogger)
+	process := NewProcess("t", 10, config, debugLogger, debugLogger)
 	defer process.Stop()
 
 	results := map[string]string{
@@ -238,18 +248,14 @@ func TestProcess_SwapState(t *testing.T) {
 	}{
 		{"Stopped to Starting", StateStopped, StateStopped, StateStarting, nil, StateStarting},
 		{"Starting to Ready", StateStarting, StateStarting, StateReady, nil, StateReady},
-		{"Starting to Failed", StateStarting, StateStarting, StateFailed, nil, StateFailed},
 		{"Starting to Stopping", StateStarting, StateStarting, StateStopping, nil, StateStopping},
+		{"Starting to Stopped", StateStarting, StateStarting, StateStopped, nil, StateStopped},
 		{"Ready to Stopping", StateReady, StateReady, StateStopping, nil, StateStopping},
 		{"Stopping to Stopped", StateStopping, StateStopping, StateStopped, nil, StateStopped},
 		{"Stopping to Shutdown", StateStopping, StateStopping, StateShutdown, nil, StateShutdown},
 		{"Stopped to Ready", StateStopped, StateStopped, StateReady, ErrInvalidStateTransition, StateStopped},
-		{"Starting to Stopped", StateStarting, StateStarting, StateStopped, ErrInvalidStateTransition, StateStarting},
 		{"Ready to Starting", StateReady, StateReady, StateStarting, ErrInvalidStateTransition, StateReady},
-		{"Ready to Failed", StateReady, StateReady, StateFailed, ErrInvalidStateTransition, StateReady},
 		{"Stopping to Ready", StateStopping, StateStopping, StateReady, ErrInvalidStateTransition, StateStopping},
-		{"Failed to Stopped", StateFailed, StateFailed, StateStopped, ErrInvalidStateTransition, StateFailed},
-		{"Failed to Starting", StateFailed, StateFailed, StateStarting, ErrInvalidStateTransition, StateFailed},
 		{"Shutdown to Stopped", StateShutdown, StateShutdown, StateStopped, ErrInvalidStateTransition, StateShutdown},
 		{"Shutdown to Starting", StateShutdown, StateShutdown, StateStarting, ErrInvalidStateTransition, StateShutdown},
 		{"Expected state mismatch", StateStopped, StateStarting, StateStarting, ErrExpectedStateMismatch, StateStopped},
@@ -257,7 +263,7 @@ func TestProcess_SwapState(t *testing.T) {
 
 	for _, test := range tests {
 		t.Run(test.name, func(t *testing.T) {
-			p := NewProcess("test", 10, getTestSimpleResponderConfig("test"), discardLogger, discardLogger)
+			p := NewProcess("test", 10, getTestSimpleResponderConfig("test"), debugLogger, debugLogger)
 			p.state = test.currentState
 
 			resultState, err := p.swapState(test.expectedState, test.newState)
@@ -290,7 +296,7 @@ func TestProcess_ShutdownInterruptsHealthCheck(t *testing.T) {
 	config.Proxy = "http://localhost:9998/test"
 
 	healthCheckTTLSeconds := 30
-	process := NewProcess("test-process", healthCheckTTLSeconds, config, discardLogger, discardLogger)
+	process := NewProcess("test-process", healthCheckTTLSeconds, config, debugLogger, debugLogger)
 
 	// make it a lot faster
 	process.healthCheckLoopInterval = time.Second
@@ -311,3 +317,177 @@ func TestProcess_ShutdownInterruptsHealthCheck(t *testing.T) {
 	assert.ErrorContains(t, err, "health check interrupted due to shutdown")
 	assert.Equal(t, StateShutdown, process.CurrentState())
 }
+
+func TestProcess_ExitInterruptsHealthCheck(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping Exit Interrupts Health Check test")
+	}
+
+	// should run and exit but interrupt the long checkHealthTimeout
+	checkHealthTimeout := 5
+	config := ModelConfig{
+		Cmd:           "sleep 1",
+		Proxy:         "http://127.0.0.1:9913",
+		CheckEndpoint: "/health",
+	}
+
+	process := NewProcess("sleepy", checkHealthTimeout, config, debugLogger, debugLogger)
+	process.healthCheckLoopInterval = time.Second // make it faster
+	err := process.start()
+	assert.Equal(t, "upstream command exited prematurely but successfully", err.Error())
+	assert.Equal(t, process.CurrentState(), StateStopped)
+}
+
+func TestProcess_ConcurrencyLimit(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping long concurrency limit test")
+	}
+
+	expectedMessage := "concurrency_limit_test"
+	config := getTestSimpleResponderConfig(expectedMessage)
+
+	// only allow 1 concurrent request at a time
+	config.ConcurrencyLimit = 1
+
+	process := NewProcess("ttl_test", 2, config, debugLogger, debugLogger)
+	assert.Equal(t, 1, cap(process.concurrencyLimitSemaphore))
+	defer process.Stop()
+
+	// launch a goroutine first to take up the semaphore
+	go func() {
+		req1 := httptest.NewRequest("GET", "/slow-respond?echo=12345&delay=75ms", nil)
+		w := httptest.NewRecorder()
+		process.ProxyRequest(w, req1)
+		assert.Equal(t, http.StatusOK, w.Code)
+	}()
+
+	// let the goroutine start
+	<-time.After(time.Millisecond * 25)
+
+	denied := httptest.NewRequest("GET", "/test", nil)
+	w := httptest.NewRecorder()
+	process.ProxyRequest(w, denied)
+	assert.Equal(t, http.StatusTooManyRequests, w.Code)
+}
+
+func TestProcess_StopImmediately(t *testing.T) {
+	expectedMessage := "test_stop_immediate"
+	config := getTestSimpleResponderConfig(expectedMessage)
+
+	process := NewProcess("stop_immediate", 2, config, debugLogger, debugLogger)
+	defer process.Stop()
+
+	err := process.start()
+	assert.Nil(t, err)
+	assert.Equal(t, process.CurrentState(), StateReady)
+	go func() {
+		// slow, but will get killed by StopImmediate
+		req := httptest.NewRequest("GET", "/slow-respond?echo=12345&delay=1s", nil)
+		w := httptest.NewRecorder()
+		process.ProxyRequest(w, req)
+	}()
+	<-time.After(time.Millisecond)
+	process.StopImmediately()
+	assert.Equal(t, process.CurrentState(), StateStopped)
+}
+
+// Test that SIGKILL is sent when gracefulStopTimeout is reached and properly terminates
+// the upstream command
+func TestProcess_ForceStopWithKill(t *testing.T) {
+	if runtime.GOOS == "windows" {
+		t.Skip("skipping SIGTERM test on Windows ")
+	}
+
+	expectedMessage := "test_sigkill"
+	binaryPath := getSimpleResponderPath()
+	port := getTestPort()
+
+	config := ModelConfig{
+		// note --ignore-sig-term which ignores the SIGTERM signal so a SIGKILL must be sent
+		// to force the process to exit
+		Cmd:           fmt.Sprintf("%s --port %d --respond %s --silent --ignore-sig-term", binaryPath, port, expectedMessage),
+		Proxy:         fmt.Sprintf("http://127.0.0.1:%d", port),
+		CheckEndpoint: "/health",
+	}
+
+	process := NewProcess("stop_immediate", 2, config, debugLogger, debugLogger)
+	defer process.Stop()
+
+	// reduce to make testing go faster
+	process.gracefulStopTimeout = time.Second
+
+	err := process.start()
+	assert.Nil(t, err)
+	assert.Equal(t, process.CurrentState(), StateReady)
+
+	waitChan := make(chan struct{})
+	go func() {
+		// slow, but will get killed by StopImmediate
+		req := httptest.NewRequest("GET", "/slow-respond?echo=12345&delay=2s", nil)
+		w := httptest.NewRecorder()
+		process.ProxyRequest(w, req)
+
+		// StatusOK because that was already sent before the kill
+		assert.Equal(t, http.StatusOK, w.Code)
+
+		// unexpected EOF because the kill happened, the "1" is sent before the kill
+		// then the unexpected EOF is sent after the kill
+		if runtime.GOOS == "windows" {
+			assert.Contains(t, w.Body.String(), "wsarecv: An existing connection was forcibly closed by the remote host")
+		} else {
+			assert.Contains(t, w.Body.String(), "unexpected EOF")
+		}
+
+		close(waitChan)
+	}()
+
+	<-time.After(time.Millisecond)
+	process.StopImmediately()
+	assert.Equal(t, process.CurrentState(), StateStopped)
+
+	// the request should have been interrupted by SIGKILL
+	<-waitChan
+}
+
+func TestProcess_StopCmd(t *testing.T) {
+	config := getTestSimpleResponderConfig("test_stop_cmd")
+
+	if runtime.GOOS == "windows" {
+		config.CmdStop = "taskkill /f /t /pid ${PID}"
+	} else {
+		config.CmdStop = "kill -TERM ${PID}"
+	}
+
+	process := NewProcess("testStopCmd", 2, config, debugLogger, debugLogger)
+	defer process.Stop()
+
+	err := process.start()
+	assert.Nil(t, err)
+	assert.Equal(t, process.CurrentState(), StateReady)
+	process.StopImmediately()
+	assert.Equal(t, process.CurrentState(), StateStopped)
+}
+
+func TestProcess_EnvironmentSetCorrectly(t *testing.T) {
+	expectedMessage := "test_env_not_emptied"
+	config := getTestSimpleResponderConfig(expectedMessage)
+
+	// ensure that the the default config does not blank out the inherited environment
+	configWEnv := config
+
+	// ensure the additiona variables are appended to the process' environment
+	configWEnv.Env = append(configWEnv.Env, "TEST_ENV1=1", "TEST_ENV2=2")
+
+	process1 := NewProcess("env_test", 2, config, debugLogger, debugLogger)
+	process2 := NewProcess("env_test", 2, configWEnv, debugLogger, debugLogger)
+
+	process1.start()
+	defer process1.Stop()
+	process2.start()
+	defer process2.Stop()
+
+	assert.NotZero(t, len(process1.cmd.Environ()))
+	assert.NotZero(t, len(process2.cmd.Environ()))
+	assert.Equal(t, len(process1.cmd.Environ())+2, len(process2.cmd.Environ()), "process2 should have 2 more environment variables than process1")
+
+}

proxy/processgroup.go

@@ -0,0 +1,124 @@
+package proxy
+
+import (
+	"fmt"
+	"net/http"
+	"slices"
+	"sync"
+)
+
+type ProcessGroup struct {
+	sync.Mutex
+
+	config     Config
+	id         string
+	swap       bool
+	exclusive  bool
+	persistent bool
+
+	proxyLogger    *LogMonitor
+	upstreamLogger *LogMonitor
+
+	// map of current processes
+	processes       map[string]*Process
+	lastUsedProcess string
+}
+
+func NewProcessGroup(id string, config Config, proxyLogger *LogMonitor, upstreamLogger *LogMonitor) *ProcessGroup {
+	groupConfig, ok := config.Groups[id]
+	if !ok {
+		panic("Unable to find configuration for group id: " + id)
+	}
+
+	pg := &ProcessGroup{
+		id:             id,
+		config:         config,
+		swap:           groupConfig.Swap,
+		exclusive:      groupConfig.Exclusive,
+		persistent:     groupConfig.Persistent,
+		proxyLogger:    proxyLogger,
+		upstreamLogger: upstreamLogger,
+		processes:      make(map[string]*Process),
+	}
+
+	// Create a Process for each member in the group
+	for _, modelID := range groupConfig.Members {
+		modelConfig, modelID, _ := pg.config.FindConfig(modelID)
+		process := NewProcess(modelID, pg.config.HealthCheckTimeout, modelConfig, pg.upstreamLogger, pg.proxyLogger)
+		pg.processes[modelID] = process
+	}
+
+	return pg
+}
+
+// ProxyRequest proxies a request to the specified model
+func (pg *ProcessGroup) ProxyRequest(modelID string, writer http.ResponseWriter, request *http.Request) error {
+	if !pg.HasMember(modelID) {
+		return fmt.Errorf("model %s not part of group %s", modelID, pg.id)
+	}
+
+	if pg.swap {
+		pg.Lock()
+		if pg.lastUsedProcess != modelID {
+
+			// is there something already running?
+			if pg.lastUsedProcess != "" {
+				pg.processes[pg.lastUsedProcess].Stop()
+			}
+
+			// wait for the request to the new model to be fully handled
+			// and prevent race conditions see issue #277
+			pg.processes[modelID].ProxyRequest(writer, request)
+			pg.lastUsedProcess = modelID
+
+			// short circuit and exit
+			pg.Unlock()
+			return nil
+		}
+		pg.Unlock()
+	}
+
+	pg.processes[modelID].ProxyRequest(writer, request)
+	return nil
+}
+
+func (pg *ProcessGroup) HasMember(modelName string) bool {
+	return slices.Contains(pg.config.Groups[pg.id].Members, modelName)
+}
+
+func (pg *ProcessGroup) StopProcesses(strategy StopStrategy) {
+	pg.Lock()
+	defer pg.Unlock()
+
+	if len(pg.processes) == 0 {
+		return
+	}
+
+	// stop Processes in parallel
+	var wg sync.WaitGroup
+	for _, process := range pg.processes {
+		wg.Add(1)
+		go func(process *Process) {
+			defer wg.Done()
+			switch strategy {
+			case StopImmediately:
+				process.StopImmediately()
+			default:
+				process.Stop()
+			}
+		}(process)
+	}
+	wg.Wait()
+}
+
+func (pg *ProcessGroup) Shutdown() {
+	var wg sync.WaitGroup
+	for _, process := range pg.processes {
+		wg.Add(1)
+		go func(process *Process) {
+			defer wg.Done()
+			process.Shutdown()
+		}(process)
+	}
+	wg.Wait()
+}

proxy/processgroup_test.go

@@ -0,0 +1,114 @@
+package proxy
+
+import (
+	"bytes"
+	"net/http"
+	"net/http/httptest"
+	"sync"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+var processGroupTestConfig = AddDefaultGroupToConfig(Config{
+	HealthCheckTimeout: 15,
+	Models: map[string]ModelConfig{
+		"model1": getTestSimpleResponderConfig("model1"),
+		"model2": getTestSimpleResponderConfig("model2"),
+		"model3": getTestSimpleResponderConfig("model3"),
+		"model4": getTestSimpleResponderConfig("model4"),
+		"model5": getTestSimpleResponderConfig("model5"),
+	},
+	Groups: map[string]GroupConfig{
+		"G1": {
+			Swap:      true,
+			Exclusive: true,
+			Members:   []string{"model1", "model2"},
+		},
+		"G2": {
+			Swap:      false,
+			Exclusive: true,
+			Members:   []string{"model3", "model4"},
+		},
+	},
+})
+
+func TestProcessGroup_DefaultHasCorrectModel(t *testing.T) {
+	pg := NewProcessGroup(DEFAULT_GROUP_ID, processGroupTestConfig, testLogger, testLogger)
+	assert.True(t, pg.HasMember("model5"))
+}
+
+func TestProcessGroup_HasMember(t *testing.T) {
+	pg := NewProcessGroup("G1", processGroupTestConfig, testLogger, testLogger)
+	assert.True(t, pg.HasMember("model1"))
+	assert.True(t, pg.HasMember("model2"))
+	assert.False(t, pg.HasMember("model3"))
+}
+
+// TestProcessGroup_ProxyRequestSwapIsTrueParallel tests that when swap is true
+// and multiple requests are made in parallel, only one process is running at a time.
+func TestProcessGroup_ProxyRequestSwapIsTrueParallel(t *testing.T) {
+	var processGroupTestConfig = AddDefaultGroupToConfig(Config{
+		HealthCheckTimeout: 15,
+		Models: map[string]ModelConfig{
+			// use the same listening so if a model is already running, it will fail
+			// this is a way to test that swap isolation is working
+			// properly when there are parallel requests made at the
+			// same time.
+			"model1": getTestSimpleResponderConfigPort("model1", 9832),
+			"model2": getTestSimpleResponderConfigPort("model2", 9832),
+			"model3": getTestSimpleResponderConfigPort("model3", 9832),
+			"model4": getTestSimpleResponderConfigPort("model4", 9832),
+			"model5": getTestSimpleResponderConfigPort("model5", 9832),
+		},
+		Groups: map[string]GroupConfig{
+			"G1": {
+				Swap:    true,
+				Members: []string{"model1", "model2", "model3", "model4", "model5"},
+			},
+		},
+	})
+
+	pg := NewProcessGroup("G1", processGroupTestConfig, testLogger, testLogger)
+	defer pg.StopProcesses(StopWaitForInflightRequest)
+
+	tests := []string{"model1", "model2", "model3", "model4", "model5"}
+
+	var wg sync.WaitGroup
+
+	wg.Add(len(tests))
+	for _, modelName := range tests {
+		go func(modelName string) {
+			defer wg.Done()
+			req := httptest.NewRequest("POST", "/v1/chat/completions", nil)
+			w := httptest.NewRecorder()
+			assert.NoError(t, pg.ProxyRequest(modelName, w, req))
+			assert.Equal(t, http.StatusOK, w.Code)
+			assert.Contains(t, w.Body.String(), modelName)
+		}(modelName)
+	}
+	wg.Wait()
+}
+
+func TestProcessGroup_ProxyRequestSwapIsFalse(t *testing.T) {
+	pg := NewProcessGroup("G2", processGroupTestConfig, testLogger, testLogger)
+	defer pg.StopProcesses(StopWaitForInflightRequest)
+
+	tests := []string{"model3", "model4"}
+
+	for _, modelName := range tests {
+		t.Run(modelName, func(t *testing.T) {
+			reqBody := `{"x", "y"}`
+			req := httptest.NewRequest("POST", "/v1/chat/completions", bytes.NewBufferString(reqBody))
+			w := httptest.NewRecorder()
+			assert.NoError(t, pg.ProxyRequest(modelName, w, req))
+			assert.Equal(t, http.StatusOK, w.Code)
+			assert.Contains(t, w.Body.String(), modelName)
+		})
+	}
+
+	// make sure all the processes are running
+	for _, process := range pg.processes {
+		assert.Equal(t, StateReady, process.CurrentState())
+	}
+}

proxy/proxymanager.go

@@ -2,7 +2,7 @@ package proxy
 
 import (
 	"bytes"
-	"encoding/json"
+	"context"
 	"fmt"
 	"io"
 	"mime/multipart"
@@ -15,6 +15,7 @@ import (
 	"time"
 
 	"github.com/gin-gonic/gin"
+	"github.com/mostlygeek/llama-swap/event"
 	"github.com/tidwall/gjson"
 	"github.com/tidwall/sjson"
 )
@@ -26,17 +27,24 @@ const (
 type ProxyManager struct {
 	sync.Mutex
 
-	config           *Config
-	currentProcesses map[string]*Process
-	ginEngine        *gin.Engine
+	config    Config
+	ginEngine *gin.Engine
 
 	// logging
 	proxyLogger    *LogMonitor
 	upstreamLogger *LogMonitor
 	muxLogger      *LogMonitor
+
+	metricsMonitor *MetricsMonitor
+
+	processGroups map[string]*ProcessGroup
+
+	// shutdown signaling
+	shutdownCtx    context.Context
+	shutdownCancel context.CancelFunc
 }
 
-func New(config *Config) *ProxyManager {
+func New(config Config) *ProxyManager {
 	// set up loggers
 	stdoutLogger := NewLogMonitorWriter(os.Stdout)
 	upstreamLogger := NewLogMonitorWriter(stdoutLogger)
@@ -49,26 +57,79 @@ func New(config *Config) *ProxyManager {
 	switch strings.ToLower(strings.TrimSpace(config.LogLevel)) {
 	case "debug":
 		proxyLogger.SetLogLevel(LevelDebug)
+		upstreamLogger.SetLogLevel(LevelDebug)
 	case "info":
 		proxyLogger.SetLogLevel(LevelInfo)
+		upstreamLogger.SetLogLevel(LevelInfo)
 	case "warn":
 		proxyLogger.SetLogLevel(LevelWarn)
+		upstreamLogger.SetLogLevel(LevelWarn)
 	case "error":
 		proxyLogger.SetLogLevel(LevelError)
+		upstreamLogger.SetLogLevel(LevelError)
 	default:
 		proxyLogger.SetLogLevel(LevelInfo)
+		upstreamLogger.SetLogLevel(LevelInfo)
 	}
 
+	shutdownCtx, shutdownCancel := context.WithCancel(context.Background())
+
 	pm := &ProxyManager{
-		config:           config,
-		currentProcesses: make(map[string]*Process),
-		ginEngine:        gin.New(),
+		config:    config,
+		ginEngine: gin.New(),
 
 		proxyLogger:    proxyLogger,
 		muxLogger:      stdoutLogger,
 		upstreamLogger: upstreamLogger,
+
+		metricsMonitor: NewMetricsMonitor(&config),
+
+		processGroups: make(map[string]*ProcessGroup),
+
+		shutdownCtx:    shutdownCtx,
+		shutdownCancel: shutdownCancel,
 	}
 
+	// create the process groups
+	for groupID := range config.Groups {
+		processGroup := NewProcessGroup(groupID, config, proxyLogger, upstreamLogger)
+		pm.processGroups[groupID] = processGroup
+	}
+
+	pm.setupGinEngine()
+
+	// run any startup hooks
+	if len(config.Hooks.OnStartup.Preload) > 0 {
+		// do it in the background, don't block startup -- not sure if good idea yet
+		go func() {
+			discardWriter := &DiscardWriter{}
+			for _, realModelName := range config.Hooks.OnStartup.Preload {
+				proxyLogger.Infof("Preloading model: %s", realModelName)
+				processGroup, _, err := pm.swapProcessGroup(realModelName)
+
+				if err != nil {
+					event.Emit(ModelPreloadedEvent{
+						ModelName: realModelName,
+						Success:   false,
+					})
+					proxyLogger.Errorf("Failed to preload model %s: %v", realModelName, err)
+					continue
+				} else {
+					req, _ := http.NewRequest("GET", "/", nil)
+					processGroup.ProxyRequest(realModelName, discardWriter, req)
+					event.Emit(ModelPreloadedEvent{
+						ModelName: realModelName,
+						Success:   true,
+					})
+				}
+			}
+		}()
+	}
+
+	return pm
+}
+
+func (pm *ProxyManager) setupGinEngine() {
 	pm.ginEngine.Use(func(c *gin.Context) {
 		// Start timer
 		start := time.Now()
@@ -123,14 +184,27 @@ func New(config *Config) *ProxyManager {
 		c.Next()
 	})
 
-	// Set up routes using the Gin engine
-	pm.ginEngine.POST("/v1/chat/completions", pm.proxyOAIHandler)
-	// Support legacy /v1/completions api, see issue #12
-	pm.ginEngine.POST("/v1/completions", pm.proxyOAIHandler)
+	mm := MetricsMiddleware(pm)
 
-	// Support embeddings
-	pm.ginEngine.POST("/v1/embeddings", pm.proxyOAIHandler)
-	pm.ginEngine.POST("/v1/rerank", pm.proxyOAIHandler)
+	// Set up routes using the Gin engine
+	pm.ginEngine.POST("/v1/chat/completions", mm, pm.proxyOAIHandler)
+	// Support legacy /v1/completions api, see issue #12
+	pm.ginEngine.POST("/v1/completions", mm, pm.proxyOAIHandler)
+
+	// Support embeddings and reranking
+	pm.ginEngine.POST("/v1/embeddings", mm, pm.proxyOAIHandler)
+
+	// llama-server's /reranking endpoint + aliases
+	pm.ginEngine.POST("/reranking", mm, pm.proxyOAIHandler)
+	pm.ginEngine.POST("/rerank", mm, pm.proxyOAIHandler)
+	pm.ginEngine.POST("/v1/rerank", mm, pm.proxyOAIHandler)
+	pm.ginEngine.POST("/v1/reranking", mm, pm.proxyOAIHandler)
+
+	// llama-server's /infill endpoint for code infilling
+	pm.ginEngine.POST("/infill", mm, pm.proxyOAIHandler)
+
+	// llama-server's /completion endpoint
+	pm.ginEngine.POST("/completion", mm, pm.proxyOAIHandler)
 
 	// Support audio/speech endpoint
 	pm.ginEngine.POST("/v1/audio/speech", pm.proxyOAIHandler)
@@ -141,245 +215,230 @@ func New(config *Config) *ProxyManager {
 	// in proxymanager_loghandlers.go
 	pm.ginEngine.GET("/logs", pm.sendLogsHandlers)
 	pm.ginEngine.GET("/logs/stream", pm.streamLogsHandler)
-	pm.ginEngine.GET("/logs/streamSSE", pm.streamLogsHandlerSSE)
 	pm.ginEngine.GET("/logs/stream/:logMonitorID", pm.streamLogsHandler)
-	pm.ginEngine.GET("/logs/streamSSE/:logMonitorID", pm.streamLogsHandlerSSE)
 
-	pm.ginEngine.GET("/upstream", pm.upstreamIndex)
-	pm.ginEngine.Any("/upstream/:model_id/*upstreamPath", pm.proxyToUpstream)
+	/**
+	 * User Interface Endpoints
+	 */
+	pm.ginEngine.GET("/", func(c *gin.Context) {
+		c.Redirect(http.StatusFound, "/ui")
+	})
+
+	pm.ginEngine.GET("/upstream", func(c *gin.Context) {
+		c.Redirect(http.StatusFound, "/ui/models")
+	})
+	pm.ginEngine.Any("/upstream/*upstreamPath", pm.proxyToUpstream)
 
 	pm.ginEngine.GET("/unload", pm.unloadAllModelsHandler)
-
 	pm.ginEngine.GET("/running", pm.listRunningProcessesHandler)
-
-	pm.ginEngine.GET("/", func(c *gin.Context) {
-		// Set the Content-Type header to text/html
-		c.Header("Content-Type", "text/html")
-
-		// Write the embedded HTML content to the response
-		htmlData, err := getHTMLFile("index.html")
-		if err != nil {
-			c.String(http.StatusInternalServerError, err.Error())
-			return
-		}
-		_, err = c.Writer.Write(htmlData)
-		if err != nil {
-			c.String(http.StatusInternalServerError, fmt.Sprintf("failed to write response: %v", err))
-			return
-		}
+	pm.ginEngine.GET("/health", func(c *gin.Context) {
+		c.String(http.StatusOK, "OK")
 	})
 
 	pm.ginEngine.GET("/favicon.ico", func(c *gin.Context) {
-		if data, err := getHTMLFile("favicon.ico"); err == nil {
+		if data, err := reactStaticFS.ReadFile("ui_dist/favicon.ico"); err == nil {
 			c.Data(http.StatusOK, "image/x-icon", data)
 		} else {
 			c.String(http.StatusInternalServerError, err.Error())
 		}
 	})
 
+	reactFS, err := GetReactFS()
+	if err != nil {
+		pm.proxyLogger.Errorf("Failed to load React filesystem: %v", err)
+	} else {
+
+		// serve files that exist under /ui/*
+		pm.ginEngine.StaticFS("/ui", reactFS)
+
+		// server SPA for UI under /ui/*
+		pm.ginEngine.NoRoute(func(c *gin.Context) {
+			if !strings.HasPrefix(c.Request.URL.Path, "/ui") {
+				c.AbortWithStatus(http.StatusNotFound)
+				return
+			}
+
+			file, err := reactFS.Open("index.html")
+			if err != nil {
+				c.String(http.StatusInternalServerError, err.Error())
+				return
+			}
+			defer file.Close()
+			http.ServeContent(c.Writer, c.Request, "index.html", time.Now(), file)
+
+		})
+	}
+
+	// see: proxymanager_api.go
+	// add API handler functions
+	addApiHandlers(pm)
+
 	// Disable console color for testing
 	gin.DisableConsoleColor()
-
-	return pm
 }
 
-func (pm *ProxyManager) Run(addr ...string) error {
-	return pm.ginEngine.Run(addr...)
-}
-
-func (pm *ProxyManager) HandlerFunc(w http.ResponseWriter, r *http.Request) {
+// ServeHTTP implements http.Handler interface
+func (pm *ProxyManager) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	pm.ginEngine.ServeHTTP(w, r)
 }
 
-func (pm *ProxyManager) StopProcesses() {
+// StopProcesses acquires a lock and stops all running upstream processes.
+// This is the public method safe for concurrent calls.
+// Unlike Shutdown, this method only stops the processes but doesn't perform
+// a complete shutdown, allowing for process replacement without full termination.
+func (pm *ProxyManager) StopProcesses(strategy StopStrategy) {
 	pm.Lock()
 	defer pm.Unlock()
 
-	pm.stopProcesses()
-}
-
-// for internal usage
-func (pm *ProxyManager) stopProcesses() {
-	if len(pm.currentProcesses) == 0 {
-		return
-	}
-
 	// stop Processes in parallel
 	var wg sync.WaitGroup
-	for _, process := range pm.currentProcesses {
+	for _, processGroup := range pm.processGroups {
 		wg.Add(1)
-		go func(process *Process) {
+		go func(processGroup *ProcessGroup) {
 			defer wg.Done()
-			process.Stop()
-		}(process)
+			processGroup.StopProcesses(strategy)
+		}(processGroup)
 	}
-	wg.Wait()
 
-	pm.currentProcesses = make(map[string]*Process)
+	wg.Wait()
 }
 
-// Shutdown is called to shutdown all upstream processes
-// when llama-swap is shutting down.
+// Shutdown stops all processes managed by this ProxyManager
 func (pm *ProxyManager) Shutdown() {
 	pm.Lock()
 	defer pm.Unlock()
 
-	// shutdown process in parallel
+	pm.proxyLogger.Debug("Shutdown() called in proxy manager")
+
 	var wg sync.WaitGroup
-	for _, process := range pm.currentProcesses {
+	// Send shutdown signal to all process in groups
+	for _, processGroup := range pm.processGroups {
 		wg.Add(1)
-		go func(process *Process) {
+		go func(processGroup *ProcessGroup) {
 			defer wg.Done()
-			process.Shutdown()
-		}(process)
+			processGroup.Shutdown()
+		}(processGroup)
 	}
 	wg.Wait()
+	pm.shutdownCancel()
+}
+
+func (pm *ProxyManager) swapProcessGroup(requestedModel string) (*ProcessGroup, string, error) {
+	// de-alias the real model name and get a real one
+	realModelName, found := pm.config.RealModelName(requestedModel)
+	if !found {
+		return nil, realModelName, fmt.Errorf("could not find real modelID for %s", requestedModel)
+	}
+
+	processGroup := pm.findGroupByModelName(realModelName)
+	if processGroup == nil {
+		return nil, realModelName, fmt.Errorf("could not find process group for model %s", requestedModel)
+	}
+
+	if processGroup.exclusive {
+		pm.proxyLogger.Debugf("Exclusive mode for group %s, stopping other process groups", processGroup.id)
+		for groupId, otherGroup := range pm.processGroups {
+			if groupId != processGroup.id && !otherGroup.persistent {
+				otherGroup.StopProcesses(StopWaitForInflightRequest)
+			}
+		}
+	}
+
+	return processGroup, realModelName, nil
 }
 
 func (pm *ProxyManager) listModelsHandler(c *gin.Context) {
-	data := []interface{}{}
+	data := make([]gin.H, 0, len(pm.config.Models))
+	createdTime := time.Now().Unix()
+
 	for id, modelConfig := range pm.config.Models {
 		if modelConfig.Unlisted {
 			continue
 		}
 
-		data = append(data, map[string]interface{}{
+		record := gin.H{
 			"id":       id,
 			"object":   "model",
-			"created":  time.Now().Unix(),
+			"created":  createdTime,
 			"owned_by": "llama-swap",
-		})
+		}
+
+		if name := strings.TrimSpace(modelConfig.Name); name != "" {
+			record["name"] = name
+		}
+		if desc := strings.TrimSpace(modelConfig.Description); desc != "" {
+			record["description"] = desc
+		}
+
+		data = append(data, record)
 	}
 
-	// Set the Content-Type header to application/json
-	c.Header("Content-Type", "application/json")
+	// Sort by the "id" key
+	sort.Slice(data, func(i, j int) bool {
+		si, _ := data[i]["id"].(string)
+		sj, _ := data[j]["id"].(string)
+		return si < sj
+	})
 
-	if origin := c.Request.Header.Get("Origin"); origin != "" {
+	// Set CORS headers if origin exists
+	if origin := c.GetHeader("Origin"); origin != "" {
 		c.Header("Access-Control-Allow-Origin", origin)
 	}
 
-	// Encode the data as JSON and write it to the response writer
-	if err := json.NewEncoder(c.Writer).Encode(map[string]interface{}{"data": data}); err != nil {
-		pm.sendErrorResponse(c, http.StatusInternalServerError, fmt.Sprintf("error encoding JSON %s", err.Error()))
-		return
-	}
-}
-
-func (pm *ProxyManager) swapModel(requestedModel string) (*Process, error) {
-	pm.Lock()
-	defer pm.Unlock()
-
-	// Check if requestedModel contains a PROFILE_SPLIT_CHAR
-	profileName, modelName := splitRequestedModel(requestedModel)
-
-	if profileName != "" {
-		if _, found := pm.config.Profiles[profileName]; !found {
-			return nil, fmt.Errorf("model group not found %s", profileName)
-		}
-	}
-
-	// de-alias the real model name and get a real one
-	realModelName, found := pm.config.RealModelName(modelName)
-	if !found {
-		return nil, fmt.Errorf("could not find modelID for %s", requestedModel)
-	}
-
-	// check if model is part of the profile
-	if profileName != "" {
-		found := false
-		for _, item := range pm.config.Profiles[profileName] {
-			if item == realModelName {
-				found = true
-				break
-			}
-		}
-
-		if !found {
-			return nil, fmt.Errorf("model %s part of profile %s", realModelName, profileName)
-		}
-	}
-
-	// exit early when already running, otherwise stop everything and swap
-	requestedProcessKey := ProcessKeyName(profileName, realModelName)
-
-	if process, found := pm.currentProcesses[requestedProcessKey]; found {
-		pm.proxyLogger.Debugf("No-swap, using existing process for model [%s]", requestedModel)
-		return process, nil
-	}
-
-	// stop all running models
-	pm.proxyLogger.Infof("Swapping model to [%s]", requestedModel)
-	pm.stopProcesses()
-	if profileName == "" {
-		modelConfig, modelID, found := pm.config.FindConfig(realModelName)
-		if !found {
-			return nil, fmt.Errorf("could not find configuration for %s", realModelName)
-		}
-
-		process := NewProcess(modelID, pm.config.HealthCheckTimeout, modelConfig, pm.upstreamLogger, pm.proxyLogger)
-		processKey := ProcessKeyName(profileName, modelID)
-		pm.currentProcesses[processKey] = process
-	} else {
-		for _, modelName := range pm.config.Profiles[profileName] {
-			if realModelName, found := pm.config.RealModelName(modelName); found {
-				modelConfig, modelID, found := pm.config.FindConfig(realModelName)
-				if !found {
-					return nil, fmt.Errorf("could not find configuration for %s in group %s", realModelName, profileName)
-				}
-
-				process := NewProcess(modelID, pm.config.HealthCheckTimeout, modelConfig, pm.upstreamLogger, pm.proxyLogger)
-				processKey := ProcessKeyName(profileName, modelID)
-				pm.currentProcesses[processKey] = process
-			}
-		}
-	}
-
-	// requestedProcessKey should exist due to swap
-	return pm.currentProcesses[requestedProcessKey], nil
+	// Use gin's JSON method which handles content-type and encoding
+	c.JSON(http.StatusOK, gin.H{
+		"object": "list",
+		"data":   data,
+	})
 }
 
 func (pm *ProxyManager) proxyToUpstream(c *gin.Context) {
-	requestedModel := c.Param("model_id")
+	upstreamPath := c.Param("upstreamPath")
 
-	if requestedModel == "" {
+	// split the upstream path by / and search for the model name
+	parts := strings.Split(strings.TrimSpace(upstreamPath), "/")
+	if len(parts) == 0 {
 		pm.sendErrorResponse(c, http.StatusBadRequest, "model id required in path")
 		return
 	}
 
-	if process, err := pm.swapModel(requestedModel); err != nil {
-		pm.sendErrorResponse(c, http.StatusNotFound, fmt.Sprintf("unable to swap to model, %s", err.Error()))
-	} else {
-		// rewrite the path
-		c.Request.URL.Path = c.Param("upstreamPath")
-		process.ProxyRequest(c.Writer, c.Request)
-	}
-}
-
-func (pm *ProxyManager) upstreamIndex(c *gin.Context) {
-	var html strings.Builder
-
-	html.WriteString("<!doctype HTML>\n<html><body><h1>Available Models</h1><ul>")
-
-	// Extract keys and sort them
-	var modelIDs []string
-	for modelID, modelConfig := range pm.config.Models {
-		if modelConfig.Unlisted {
+	modelFound := false
+	searchModelName := ""
+	var modelName, remainingPath string
+	for i, part := range parts {
+		if parts[i] == "" {
 			continue
 		}
 
-		modelIDs = append(modelIDs, modelID)
-	}
-	sort.Strings(modelIDs)
+		if searchModelName == "" {
+			searchModelName = part
+		} else {
+			searchModelName = searchModelName + "/" + parts[i]
+		}
 
-	// Iterate over sorted keys
-	for _, modelID := range modelIDs {
-		html.WriteString(fmt.Sprintf("<li><a href=\"/upstream/%s\">%s</a></li>", modelID, modelID))
+		if real, ok := pm.config.RealModelName(searchModelName); ok {
+			modelName = real
+			remainingPath = "/" + strings.Join(parts[i+1:], "/")
+			modelFound = true
+			break
+		}
 	}
-	html.WriteString("</ul></body></html>")
-	c.Header("Content-Type", "text/html")
-	c.String(http.StatusOK, html.String())
+
+	if !modelFound {
+		pm.sendErrorResponse(c, http.StatusBadRequest, "model id required in path")
+		return
+	}
+
+	processGroup, realModelName, err := pm.swapProcessGroup(modelName)
+	if err != nil {
+		pm.sendErrorResponse(c, http.StatusInternalServerError, fmt.Sprintf("error swapping process group: %s", err.Error()))
+		return
+	}
+
+	// rewrite the path
+	c.Request.URL.Path = remainingPath
+	processGroup.ProxyRequest(realModelName, c.Writer, c.Request)
 }
-
 func (pm *ProxyManager) proxyOAIHandler(c *gin.Context) {
 	bodyBytes, err := io.ReadAll(c.Request.Body)
 	if err != nil {
@@ -390,28 +449,41 @@ func (pm *ProxyManager) proxyOAIHandler(c *gin.Context) {
 	requestedModel := gjson.GetBytes(bodyBytes, "model").String()
 	if requestedModel == "" {
 		pm.sendErrorResponse(c, http.StatusBadRequest, "missing or invalid 'model' key")
+		return
 	}
 
-	process, err := pm.swapModel(requestedModel)
+	realModelName, found := pm.config.RealModelName(requestedModel)
+	if !found {
+		pm.sendErrorResponse(c, http.StatusBadRequest, fmt.Sprintf("could not find real modelID for %s", requestedModel))
+		return
+	}
 
+	processGroup, _, err := pm.swapProcessGroup(realModelName)
 	if err != nil {
-		pm.sendErrorResponse(c, http.StatusNotFound, fmt.Sprintf("unable to swap to model, %s", err.Error()))
+		pm.sendErrorResponse(c, http.StatusInternalServerError, fmt.Sprintf("error swapping process group: %s", err.Error()))
 		return
 	}
 
 	// issue #69 allow custom model names to be sent to upstream
-	if process.config.UseModelName != "" {
-		bodyBytes, err = sjson.SetBytes(bodyBytes, "model", process.config.UseModelName)
+	useModelName := pm.config.Models[realModelName].UseModelName
+	if useModelName != "" {
+		bodyBytes, err = sjson.SetBytes(bodyBytes, "model", useModelName)
 		if err != nil {
-			pm.sendErrorResponse(c, http.StatusInternalServerError, fmt.Sprintf("error updating JSON: %s", err.Error()))
+			pm.sendErrorResponse(c, http.StatusInternalServerError, fmt.Sprintf("error rewriting model name in JSON: %s", err.Error()))
 			return
 		}
+	}
+
+	// issue #174 strip parameters from the JSON body
+	stripParams, err := pm.config.Models[realModelName].Filters.SanitizedStripParams()
+	if err != nil { // just log it and continue
+		pm.proxyLogger.Errorf("Error sanitizing strip params string: %s, %s", pm.config.Models[realModelName].Filters.StripParams, err.Error())
 	} else {
-		profileName, modelName := splitRequestedModel(requestedModel)
-		if profileName != "" {
-			bodyBytes, err = sjson.SetBytes(bodyBytes, "model", modelName)
+		for _, param := range stripParams {
+			pm.proxyLogger.Debugf("<%s> stripping param: %s", realModelName, param)
+			bodyBytes, err = sjson.DeleteBytes(bodyBytes, param)
 			if err != nil {
-				pm.sendErrorResponse(c, http.StatusInternalServerError, fmt.Sprintf("error updating JSON: %s", err.Error()))
+				pm.sendErrorResponse(c, http.StatusInternalServerError, fmt.Sprintf("error deleting parameter %s from request", param))
 				return
 			}
 		}
@@ -421,18 +493,17 @@ func (pm *ProxyManager) proxyOAIHandler(c *gin.Context) {
 
 	// dechunk it as we already have all the body bytes see issue #11
 	c.Request.Header.Del("transfer-encoding")
-	c.Request.Header.Add("content-length", strconv.Itoa(len(bodyBytes)))
-
-	process.ProxyRequest(c.Writer, c.Request)
+	c.Request.Header.Set("content-length", strconv.Itoa(len(bodyBytes)))
+	c.Request.ContentLength = int64(len(bodyBytes))
 
+	if err := processGroup.ProxyRequest(realModelName, c.Writer, c.Request); err != nil {
+		pm.sendErrorResponse(c, http.StatusInternalServerError, fmt.Sprintf("error proxying request: %s", err.Error()))
+		pm.proxyLogger.Errorf("Error Proxying Request for processGroup %s and model %s", processGroup.id, realModelName)
+		return
+	}
 }
 
 func (pm *ProxyManager) proxyOAIPostFormHandler(c *gin.Context) {
-	// We need to reconstruct the multipart form in any case since the body is consumed
-	// Create a new buffer for the reconstructed request
-	var requestBuffer bytes.Buffer
-	multipartWriter := multipart.NewWriter(&requestBuffer)
-
 	// Parse multipart form
 	if err := c.Request.ParseMultipartForm(32 << 20); err != nil { // 32MB max memory, larger files go to tmp disk
 		pm.sendErrorResponse(c, http.StatusBadRequest, fmt.Sprintf("error parsing multipart form: %s", err.Error()))
@@ -446,15 +517,16 @@ func (pm *ProxyManager) proxyOAIPostFormHandler(c *gin.Context) {
 		return
 	}
 
-	// Swap to the requested model
-	process, err := pm.swapModel(requestedModel)
+	processGroup, realModelName, err := pm.swapProcessGroup(requestedModel)
 	if err != nil {
-		pm.sendErrorResponse(c, http.StatusNotFound, fmt.Sprintf("unable to swap to model, %s", err.Error()))
+		pm.sendErrorResponse(c, http.StatusInternalServerError, fmt.Sprintf("error swapping process group: %s", err.Error()))
 		return
 	}
 
-	// Get profile name and model name from the requested model
-	profileName, modelName := splitRequestedModel(requestedModel)
+	// We need to reconstruct the multipart form in any case since the body is consumed
+	// Create a new buffer for the reconstructed request
+	var requestBuffer bytes.Buffer
+	multipartWriter := multipart.NewWriter(&requestBuffer)
 
 	// Copy all form values
 	for key, values := range c.Request.MultipartForm.Value {
@@ -462,10 +534,13 @@ func (pm *ProxyManager) proxyOAIPostFormHandler(c *gin.Context) {
 			fieldValue := value
 			// If this is the model field and we have a profile, use just the model name
 			if key == "model" {
-				if process.config.UseModelName != "" {
-					fieldValue = process.config.UseModelName
-				} else if profileName != "" {
-					fieldValue = modelName
+				// # issue #69 allow custom model names to be sent to upstream
+				useModelName := pm.config.Models[realModelName].UseModelName
+
+				if useModelName != "" {
+					fieldValue = useModelName
+				} else {
+					fieldValue = requestedModel
 				}
 			}
 			field, err := multipartWriter.CreateFormField(key)
@@ -526,8 +601,16 @@ func (pm *ProxyManager) proxyOAIPostFormHandler(c *gin.Context) {
 	modifiedReq.Header = c.Request.Header.Clone()
 	modifiedReq.Header.Set("Content-Type", multipartWriter.FormDataContentType())
 
+	// set the content length of the body
+	modifiedReq.Header.Set("Content-Length", strconv.Itoa(requestBuffer.Len()))
+	modifiedReq.ContentLength = int64(requestBuffer.Len())
+
 	// Use the modified request for proxying
-	process.ProxyRequest(c.Writer, modifiedReq)
+	if err := processGroup.ProxyRequest(realModelName, c.Writer, modifiedReq); err != nil {
+		pm.sendErrorResponse(c, http.StatusInternalServerError, fmt.Sprintf("error proxying request: %s", err.Error()))
+		pm.proxyLogger.Errorf("Error Proxying Request for processGroup %s and model %s", processGroup.id, realModelName)
+		return
+	}
 }
 
 func (pm *ProxyManager) sendErrorResponse(c *gin.Context, statusCode int, message string) {
@@ -541,7 +624,7 @@ func (pm *ProxyManager) sendErrorResponse(c *gin.Context, statusCode int, messag
 }
 
 func (pm *ProxyManager) unloadAllModelsHandler(c *gin.Context) {
-	pm.StopProcesses()
+	pm.StopProcesses(StopImmediately)
 	c.String(http.StatusOK, "OK")
 }
 
@@ -549,14 +632,15 @@ func (pm *ProxyManager) listRunningProcessesHandler(context *gin.Context) {
 	context.Header("Content-Type", "application/json")
 	runningProcesses := make([]gin.H, 0) // Default to an empty response.
 
-	for _, process := range pm.currentProcesses {
-
-		// Append the process ID and State (multiple entries if profiles are being used).
-		runningProcesses = append(runningProcesses, gin.H{
-			"model": process.ID,
-			"state": process.state,
-		})
-
+	for _, processGroup := range pm.processGroups {
+		for _, process := range processGroup.processes {
+			if process.CurrentState() == StateReady {
+				runningProcesses = append(runningProcesses, gin.H{
+					"model": process.ID,
+					"state": process.state,
+				})
+			}
+		}
 	}
 
 	// Put the results under the `running` key.
@@ -567,15 +651,11 @@ func (pm *ProxyManager) listRunningProcessesHandler(context *gin.Context) {
 	context.JSON(http.StatusOK, response) // Always return 200 OK
 }
 
-func ProcessKeyName(groupName, modelName string) string {
-	return groupName + PROFILE_SPLIT_CHAR + modelName
-}
-
-func splitRequestedModel(requestedModel string) (string, string) {
-	profileName, modelName := "", requestedModel
-	if idx := strings.Index(requestedModel, PROFILE_SPLIT_CHAR); idx != -1 {
-		profileName = requestedModel[:idx]
-		modelName = requestedModel[idx+1:]
+func (pm *ProxyManager) findGroupByModelName(modelName string) *ProcessGroup {
+	for _, group := range pm.processGroups {
+		if group.HasMember(modelName) {
+			return group
+		}
 	}
-	return profileName, modelName
+	return nil
 }

proxy/proxymanager_api.go

@@ -0,0 +1,204 @@
+package proxy
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+	"sort"
+
+	"github.com/gin-gonic/gin"
+	"github.com/mostlygeek/llama-swap/event"
+)
+
+type Model struct {
+	Id          string `json:"id"`
+	Name        string `json:"name"`
+	Description string `json:"description"`
+	State       string `json:"state"`
+	Unlisted    bool   `json:"unlisted"`
+}
+
+func addApiHandlers(pm *ProxyManager) {
+	// Add API endpoints for React to consume
+	apiGroup := pm.ginEngine.Group("/api")
+	{
+		apiGroup.POST("/models/unload", pm.apiUnloadAllModels)
+		apiGroup.GET("/events", pm.apiSendEvents)
+		apiGroup.GET("/metrics", pm.apiGetMetrics)
+	}
+}
+
+func (pm *ProxyManager) apiUnloadAllModels(c *gin.Context) {
+	pm.StopProcesses(StopImmediately)
+	c.JSON(http.StatusOK, gin.H{"msg": "ok"})
+}
+
+func (pm *ProxyManager) getModelStatus() []Model {
+	// Extract keys and sort them
+	models := []Model{}
+
+	modelIDs := make([]string, 0, len(pm.config.Models))
+	for modelID := range pm.config.Models {
+		modelIDs = append(modelIDs, modelID)
+	}
+	sort.Strings(modelIDs)
+
+	// Iterate over sorted keys
+	for _, modelID := range modelIDs {
+		// Get process state
+		processGroup := pm.findGroupByModelName(modelID)
+		state := "unknown"
+		if processGroup != nil {
+			process := processGroup.processes[modelID]
+			if process != nil {
+				var stateStr string
+				switch process.CurrentState() {
+				case StateReady:
+					stateStr = "ready"
+				case StateStarting:
+					stateStr = "starting"
+				case StateStopping:
+					stateStr = "stopping"
+				case StateShutdown:
+					stateStr = "shutdown"
+				case StateStopped:
+					stateStr = "stopped"
+				default:
+					stateStr = "unknown"
+				}
+				state = stateStr
+			}
+		}
+		models = append(models, Model{
+			Id:          modelID,
+			Name:        pm.config.Models[modelID].Name,
+			Description: pm.config.Models[modelID].Description,
+			State:       state,
+			Unlisted:    pm.config.Models[modelID].Unlisted,
+		})
+	}
+
+	return models
+}
+
+type messageType string
+
+const (
+	msgTypeModelStatus messageType = "modelStatus"
+	msgTypeLogData     messageType = "logData"
+	msgTypeMetrics     messageType = "metrics"
+)
+
+type messageEnvelope struct {
+	Type messageType `json:"type"`
+	Data string      `json:"data"`
+}
+
+// sends a stream of different message types that happen on the server
+func (pm *ProxyManager) apiSendEvents(c *gin.Context) {
+	c.Header("Content-Type", "text/event-stream")
+	c.Header("Cache-Control", "no-cache")
+	c.Header("Connection", "keep-alive")
+	c.Header("X-Content-Type-Options", "nosniff")
+	// prevent nginx from buffering SSE
+	c.Header("X-Accel-Buffering", "no")
+
+	sendBuffer := make(chan messageEnvelope, 25)
+	ctx, cancel := context.WithCancel(c.Request.Context())
+	sendModels := func() {
+		data, err := json.Marshal(pm.getModelStatus())
+		if err == nil {
+			msg := messageEnvelope{Type: msgTypeModelStatus, Data: string(data)}
+			select {
+			case sendBuffer <- msg:
+			case <-ctx.Done():
+				return
+			default:
+			}
+
+		}
+	}
+
+	sendLogData := func(source string, data []byte) {
+		data, err := json.Marshal(gin.H{
+			"source": source,
+			"data":   string(data),
+		})
+		if err == nil {
+			select {
+			case sendBuffer <- messageEnvelope{Type: msgTypeLogData, Data: string(data)}:
+			case <-ctx.Done():
+				return
+			default:
+			}
+		}
+	}
+
+	sendMetrics := func(metrics []TokenMetrics) {
+		jsonData, err := json.Marshal(metrics)
+		if err == nil {
+			select {
+			case sendBuffer <- messageEnvelope{Type: msgTypeMetrics, Data: string(jsonData)}:
+			case <-ctx.Done():
+				return
+			default:
+			}
+		}
+	}
+
+	/**
+	 * Send updated models list
+	 */
+	defer event.On(func(e ProcessStateChangeEvent) {
+		sendModels()
+	})()
+	defer event.On(func(e ConfigFileChangedEvent) {
+		sendModels()
+	})()
+
+	/**
+	 * Send Log data
+	 */
+	defer pm.proxyLogger.OnLogData(func(data []byte) {
+		sendLogData("proxy", data)
+	})()
+	defer pm.upstreamLogger.OnLogData(func(data []byte) {
+		sendLogData("upstream", data)
+	})()
+
+	/**
+	 * Send Metrics data
+	 */
+	defer event.On(func(e TokenMetricsEvent) {
+		sendMetrics([]TokenMetrics{e.Metrics})
+	})()
+
+	// send initial batch of data
+	sendLogData("proxy", pm.proxyLogger.GetHistory())
+	sendLogData("upstream", pm.upstreamLogger.GetHistory())
+	sendModels()
+	sendMetrics(pm.metricsMonitor.GetMetrics())
+
+	for {
+		select {
+		case <-c.Request.Context().Done():
+			cancel()
+			return
+		case <-pm.shutdownCtx.Done():
+			cancel()
+			return
+		case msg := <-sendBuffer:
+			c.SSEvent("message", msg)
+			c.Writer.Flush()
+		}
+	}
+}
+
+func (pm *ProxyManager) apiGetMetrics(c *gin.Context) {
+	jsonData, err := pm.metricsMonitor.GetMetricsJSON()
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "failed to get metrics"})
+		return
+	}
+	c.Data(http.StatusOK, "application/json", jsonData)
+}

proxy/proxymanager_loghandlers.go

@@ -1,6 +1,7 @@
 package proxy
 
 import (
+	"context"
 	"fmt"
 	"net/http"
 	"strings"
@@ -11,20 +12,7 @@ import (
 func (pm *ProxyManager) sendLogsHandlers(c *gin.Context) {
 	accept := c.GetHeader("Accept")
 	if strings.Contains(accept, "text/html") {
-		// Set the Content-Type header to text/html
-		c.Header("Content-Type", "text/html")
-
-		// Write the embedded HTML content to the response
-		logsHTML, err := getHTMLFile("logs.html")
-		if err != nil {
-			c.String(http.StatusInternalServerError, err.Error())
-			return
-		}
-		_, err = c.Writer.Write(logsHTML)
-		if err != nil {
-			c.String(http.StatusInternalServerError, fmt.Sprintf("failed to write response: %v", err))
-			return
-		}
+		c.Redirect(http.StatusFound, "/ui/")
 	} else {
 		c.Header("Content-Type", "text/plain")
 		history := pm.muxLogger.GetHistory()
@@ -40,6 +28,8 @@ func (pm *ProxyManager) streamLogsHandler(c *gin.Context) {
 	c.Header("Content-Type", "text/plain")
 	c.Header("Transfer-Encoding", "chunked")
 	c.Header("X-Content-Type-Options", "nosniff")
+	// prevent nginx from buffering streamed logs
+	c.Header("X-Accel-Buffering", "no")
 
 	logMonitorId := c.Param("logMonitorID")
 	logger, err := pm.getLogger(logMonitorId)
@@ -47,10 +37,7 @@ func (pm *ProxyManager) streamLogsHandler(c *gin.Context) {
 		c.String(http.StatusBadRequest, err.Error())
 		return
 	}
-	ch := logger.Subscribe()
-	defer logger.Unsubscribe(ch)
 
-	notify := c.Request.Context().Done()
 	flusher, ok := c.Writer.(http.Flusher)
 	if !ok {
 		c.AbortWithError(http.StatusInternalServerError, fmt.Errorf("streaming unsupported"))
@@ -68,57 +55,28 @@ func (pm *ProxyManager) streamLogsHandler(c *gin.Context) {
 		}
 	}
 
-	// Stream new logs
+	sendChan := make(chan []byte, 10)
+	ctx, cancel := context.WithCancel(c.Request.Context())
+	defer logger.OnLogData(func(data []byte) {
+		select {
+		case sendChan <- data:
+		case <-ctx.Done():
+			return
+		default:
+		}
+	})()
+
 	for {
 		select {
-		case msg := <-ch:
-			_, err := c.Writer.Write(msg)
-			if err != nil {
-				// just break the loop if we can't write for some reason
-				return
-			}
+		case <-c.Request.Context().Done():
+			cancel()
+			return
+		case <-pm.shutdownCtx.Done():
+			cancel()
+			return
+		case data := <-sendChan:
+			c.Writer.Write(data)
 			flusher.Flush()
-		case <-notify:
-			return
-		}
-	}
-}
-
-func (pm *ProxyManager) streamLogsHandlerSSE(c *gin.Context) {
-	c.Header("Content-Type", "text/event-stream")
-	c.Header("Cache-Control", "no-cache")
-	c.Header("Connection", "keep-alive")
-	c.Header("X-Content-Type-Options", "nosniff")
-
-	logMonitorId := c.Param("logMonitorID")
-	logger, err := pm.getLogger(logMonitorId)
-	if err != nil {
-		c.String(http.StatusBadRequest, err.Error())
-		return
-	}
-	ch := logger.Subscribe()
-	defer logger.Unsubscribe(ch)
-
-	notify := c.Request.Context().Done()
-
-	// Send history first if not skipped
-	_, skipHistory := c.GetQuery("no-history")
-	if !skipHistory {
-		history := logger.GetHistory()
-		if len(history) != 0 {
-			c.SSEvent("message", string(history))
-			c.Writer.Flush()
-		}
-	}
-
-	// Stream new logs
-	for {
-		select {
-		case msg := <-ch:
-			c.SSEvent("message", string(msg))
-			c.Writer.Flush()
-		case <-notify:
-			return
 		}
 	}
 }

proxy/ui_embed.go

@@ -0,0 +1,24 @@
+package proxy
+
+import (
+	"embed"
+	"io/fs"
+	"net/http"
+)
+
+//go:embed ui_dist
+var reactStaticFS embed.FS
+
+// GetReactFS returns the embedded React filesystem
+func GetReactFS() (http.FileSystem, error) {
+	subFS, err := fs.Sub(reactStaticFS, "ui_dist")
+	if err != nil {
+		return nil, err
+	}
+	return http.FS(subFS), nil
+}
+
+// GetReactIndexHTML returns the main index.html for the React app
+func GetReactIndexHTML() ([]byte, error) {
+	return reactStaticFS.ReadFile("ui_dist/index.html")
+}

scripts/install.sh

@@ -0,0 +1,213 @@
+#!/bin/sh
+# This script installs llama-swap on Linux.
+# It detects the current operating system architecture and installs the appropriate version of llama-swap.
+
+set -eu
+
+LLAMA_SWAP_DEFAULT_ADDRESS=${LLAMA_SWAP_DEFAULT_ADDRESS:-"127.0.0.1:8080"}
+
+red="$( (/usr/bin/tput bold || :; /usr/bin/tput setaf 1 || :) 2>&-)"
+plain="$( (/usr/bin/tput sgr0 || :) 2>&-)"
+
+status() { echo ">>> $*" >&2; }
+error() { echo "${red}ERROR:${plain} $*"; exit 1; }
+warning() { echo "${red}WARNING:${plain} $*"; }
+
+available() { command -v "$1" >/dev/null; }
+require() {
+    _MISSING=''
+    for TOOL in "$@"; do
+        if ! available "$TOOL"; then
+            _MISSING="$_MISSING $TOOL"
+        fi
+    done
+
+    echo "$_MISSING"
+}
+
+SUDO=
+if [ "$(id -u)" -ne 0 ]; then
+    if ! available sudo; then
+        error "This script requires superuser permissions. Please re-run as root."
+    fi
+
+    SUDO="sudo"
+fi
+
+NEEDS=$(require tee tar python3 mktemp)
+if [ -n "$NEEDS" ]; then
+    status "ERROR: The following tools are required but missing:"
+    for NEED in $NEEDS; do
+        echo "  - $NEED"
+    done
+    exit 1
+fi
+
+[ "$(uname -s)" = "Linux" ] || error 'This script is intended to run on Linux only.'
+
+ARCH=$(uname -m)
+case "$ARCH" in
+    x86_64) ARCH="amd64" ;;
+    aarch64|arm64) ARCH="arm64" ;;
+    *) error "Unsupported architecture: $ARCH" ;;
+esac
+
+IS_WSL2=false
+
+KERN=$(uname -r)
+case "$KERN" in
+    *icrosoft*WSL2 | *icrosoft*wsl2) IS_WSL2=true;;
+    *icrosoft) error "Microsoft WSL1 is not currently supported. Please use WSL2 with 'wsl --set-version <distro> 2'" ;;
+    *) ;;
+esac
+
+download_binary() {
+    ASSET_NAME="linux_$ARCH"
+
+    TMPDIR=$(mktemp -d)
+    trap 'rm -rf "${TMPDIR}"' EXIT INT TERM HUP
+    PYTHON_SCRIPT=$(cat <<EOF
+import os
+import json
+import sys
+import urllib.request
+
+ASSET_NAME = "${ASSET_NAME}"
+
+with urllib.request.urlopen("https://api.github.com/repos/mostlygeek/llama-swap/releases/latest") as resp:
+    data = json.load(resp)
+    for asset in data.get("assets", []):
+        if ASSET_NAME in asset.get("name", ""):
+            url = asset["browser_download_url"]
+            break
+    else:
+        print("ERROR: Matching asset not found.", file=sys.stderr)
+        exit(1)
+
+print("Downloading:", url, file=sys.stderr)
+output_path = os.path.join("${TMPDIR}", "llama-swap.tar.gz")
+urllib.request.urlretrieve(url, output_path)
+print(output_path)
+EOF
+)
+
+    TARFILE=$(python3 -c "$PYTHON_SCRIPT")
+    if [ ! -f "$TARFILE" ]; then
+        error "Failed to download binary."
+    fi
+
+    status "Extracting to /usr/local/bin"
+    $SUDO tar -xzf "$TARFILE" -C /usr/local/bin llama-swap
+}
+download_binary
+
+configure_systemd() {
+    if ! id llama-swap >/dev/null 2>&1; then
+        status "Creating llama-swap user..."
+        $SUDO useradd -r -s /bin/false -U -m -d /usr/share/llama-swap llama-swap
+    fi
+    if getent group render >/dev/null 2>&1; then
+        status "Adding llama-swap user to render group..."
+        $SUDO usermod -a -G render llama-swap
+    fi
+    if getent group video >/dev/null 2>&1; then
+        status "Adding llama-swap user to video group..."
+        $SUDO usermod -a -G video llama-swap
+    fi
+    if getent group docker >/dev/null 2>&1; then
+        status "Adding llama-swap user to docker group..."
+        $SUDO usermod -a -G docker llama-swap
+    fi
+
+    status "Adding current user to llama-swap group..."
+    $SUDO usermod -a -G llama-swap "$(whoami)"
+
+    if [ ! -f "/usr/share/llama-swap/config.yaml" ]; then
+        status "Creating default config.yaml..."
+        cat <<EOF | $SUDO -u llama-swap tee /usr/share/llama-swap/config.yaml >/dev/null
+# default 15s likely to fail for default models due to downloading models
+healthCheckTimeout: 60
+
+models:
+  "qwen2.5":
+    cmd: |
+      docker run
+        --rm
+        -p \${PORT}:8080
+        --name qwen2.5
+      ghcr.io/ggml-org/llama.cpp:server
+        -hf bartowski/Qwen2.5-0.5B-Instruct-GGUF:Q4_K_M
+    cmdStop: docker stop qwen2.5
+
+  "smollm2":
+    cmd: |
+      docker run
+        --rm
+        -p \${PORT}:8080
+        --name smollm2
+      ghcr.io/ggml-org/llama.cpp:server
+        -hf bartowski/SmolLM2-135M-Instruct-GGUF:Q4_K_M
+    cmdStop: docker stop smollm2
+EOF
+    fi
+
+    status "Creating llama-swap systemd service..."
+    cat <<EOF | $SUDO tee /etc/systemd/system/llama-swap.service >/dev/null
+[Unit]
+Description=llama-swap
+After=network.target
+
+[Service]
+User=llama-swap
+Group=llama-swap
+
+# set this to match your environment
+ExecStart=/usr/local/bin/llama-swap --config /usr/share/llama-swap/config.yaml --watch-config -listen ${LLAMA_SWAP_DEFAULT_ADDRESS}
+
+Restart=on-failure
+RestartSec=3
+StartLimitBurst=3
+StartLimitInterval=30
+
+[Install]
+WantedBy=multi-user.target
+EOF
+    SYSTEMCTL_RUNNING="$(systemctl is-system-running || true)"
+    case $SYSTEMCTL_RUNNING in
+        running|degraded)
+            status "Enabling and starting llama-swap service..."
+            $SUDO systemctl daemon-reload
+            $SUDO systemctl enable llama-swap
+
+            start_service() { $SUDO systemctl restart llama-swap; }
+            trap start_service EXIT
+            ;;
+        *)
+            warning "systemd is not running"
+            if [ "$IS_WSL2" = true ]; then
+                warning "see https://learn.microsoft.com/en-us/windows/wsl/systemd#how-to-enable-systemd to enable it"
+            fi
+            ;;
+    esac
+}
+
+if available systemctl; then
+    configure_systemd
+fi
+
+install_success() {
+    status "The llama-swap API is now available at http://${LLAMA_SWAP_DEFAULT_ADDRESS}"
+    status 'Customize the config file at /usr/share/llama-swap/config.yaml.'
+    status 'Install complete.'
+}
+
+# WSL2 only supports GPUs via nvidia passthrough
+# so check for nvidia-smi to determine if GPU is available
+if [ "$IS_WSL2" = true ]; then
+    if available nvidia-smi && [ -n "$(nvidia-smi | grep -o "CUDA Version: [0-9]*\.[0-9]*")" ]; then
+        status "Nvidia GPU detected."
+    fi
+    exit 0
+fi
+
+install_success

scripts/uninstall.sh

@@ -0,0 +1,68 @@
+#!/bin/sh
+# This script uninstalls llama-swap on Linux.
+# It removes the binary, systemd service, config.yaml (optional), and llama-swap user and group.
+
+set -eu
+
+red="$( (/usr/bin/tput bold || :; /usr/bin/tput setaf 1 || :) 2>&-)"
+plain="$( (/usr/bin/tput sgr0 || :) 2>&-)"
+
+status() { echo ">>> $*" >&2; }
+error() { echo "${red}ERROR:${plain} $*"; exit 1; }
+warning() { echo "${red}WARNING:${plain} $*"; }
+
+available() { command -v $1 >/dev/null; }
+
+SUDO=
+if [ "$(id -u)" -ne 0 ]; then
+    if ! available sudo; then
+        error "This script requires superuser permissions. Please re-run as root."
+    fi
+
+    SUDO="sudo"
+fi
+
+configure_systemd() {
+    status "Stopping llama-swap service..."
+    $SUDO systemctl stop llama-swap
+
+    status "Disabling llama-swap service..."
+    $SUDO systemctl disable llama-swap
+}
+if available systemctl; then
+    configure_systemd
+fi
+
+if available llama-swap; then
+    status "Removing llama-swap binary..."
+    $SUDO rm $(which llama-swap)
+fi
+
+if [ -f "/usr/share/llama-swap/config.yaml" ]; then
+    while true; do
+        printf "Delete config.yaml (/usr/share/llama-swap/config.yaml)? [y/N] " >&2
+        read answer
+        case "$answer" in
+            [Yy]* ) 
+                $SUDO rm -r /usr/share/llama-swap
+                break
+                ;;
+            [Nn]* | "" ) 
+                break
+                ;;
+            * ) 
+                echo "Invalid input. Please enter y or n."
+                ;;
+        esac
+    done
+fi
+
+if id llama-swap >/dev/null 2>&1; then
+    status "Removing llama-swap user..."
+    $SUDO userdel llama-swap
+fi
+
+if getent group llama-swap >/dev/null 2>&1; then
+    status "Removing llama-swap group..."
+    $SUDO groupdel llama-swap
+fi

ui/.gitignore

@@ -0,0 +1,25 @@
+.vite
+# Logs
+logs
+*.log
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+pnpm-debug.log*
+lerna-debug.log*
+
+node_modules
+dist
+dist-ssr
+*.local
+
+# Editor directories and files
+.vscode/*
+!.vscode/extensions.json
+.idea
+.DS_Store
+*.suo
+*.ntvs*
+*.njsproj
+*.sln
+*.sw?

ui/README.md

@@ -0,0 +1,54 @@
+# React + TypeScript + Vite
+
+This template provides a minimal setup to get React working in Vite with HMR and some ESLint rules.
+
+Currently, two official plugins are available:
+
+- [@vitejs/plugin-react](https://github.com/vitejs/vite-plugin-react/blob/main/packages/plugin-react) uses [Babel](https://babeljs.io/) for Fast Refresh
+- [@vitejs/plugin-react-swc](https://github.com/vitejs/vite-plugin-react/blob/main/packages/plugin-react-swc) uses [SWC](https://swc.rs/) for Fast Refresh
+
+## Expanding the ESLint configuration
+
+If you are developing a production application, we recommend updating the configuration to enable type-aware lint rules:
+
+```js
+export default tseslint.config({
+  extends: [
+    // Remove ...tseslint.configs.recommended and replace with this
+    ...tseslint.configs.recommendedTypeChecked,
+    // Alternatively, use this for stricter rules
+    ...tseslint.configs.strictTypeChecked,
+    // Optionally, add this for stylistic rules
+    ...tseslint.configs.stylisticTypeChecked,
+  ],
+  languageOptions: {
+    // other options...
+    parserOptions: {
+      project: ['./tsconfig.node.json', './tsconfig.app.json'],
+      tsconfigRootDir: import.meta.dirname,
+    },
+  },
+})
+```
+
+You can also install [eslint-plugin-react-x](https://github.com/Rel1cx/eslint-react/tree/main/packages/plugins/eslint-plugin-react-x) and [eslint-plugin-react-dom](https://github.com/Rel1cx/eslint-react/tree/main/packages/plugins/eslint-plugin-react-dom) for React-specific lint rules:
+
+```js
+// eslint.config.js
+import reactX from 'eslint-plugin-react-x'
+import reactDom from 'eslint-plugin-react-dom'
+
+export default tseslint.config({
+  plugins: {
+    // Add the react-x and react-dom plugins
+    'react-x': reactX,
+    'react-dom': reactDom,
+  },
+  rules: {
+    // other rules...
+    // Enable its recommended typescript rules
+    ...reactX.configs['recommended-typescript'].rules,
+    ...reactDom.configs.recommended.rules,
+  },
+})
+```

ui/eslint.config.js

@@ -0,0 +1,28 @@
+import js from '@eslint/js'
+import globals from 'globals'
+import reactHooks from 'eslint-plugin-react-hooks'
+import reactRefresh from 'eslint-plugin-react-refresh'
+import tseslint from 'typescript-eslint'
+
+export default tseslint.config(
+  { ignores: ['dist'] },
+  {
+    extends: [js.configs.recommended, ...tseslint.configs.recommended],
+    files: ['**/*.{ts,tsx}'],
+    languageOptions: {
+      ecmaVersion: 2020,
+      globals: globals.browser,
+    },
+    plugins: {
+      'react-hooks': reactHooks,
+      'react-refresh': reactRefresh,
+    },
+    rules: {
+      ...reactHooks.configs.recommended.rules,
+      'react-refresh/only-export-components': [
+        'warn',
+        { allowConstantExport: true },
+      ],
+    },
+  },
+)

ui/index.html

@@ -0,0 +1,17 @@
+<!doctype html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <link rel="icon" type="image/png" href="/favicon-96x96.png" sizes="96x96" />
+    <link rel="icon" type="image/svg+xml" href="/favicon.svg" />
+    <link rel="shortcut icon" href="/favicon.ico" />
+    <link rel="apple-touch-icon" sizes="180x180" href="/apple-touch-icon.png" />
+    <link rel="manifest" href="/site.webmanifest" />
+    <title>llama-swap</title>
+  </head>
+  <body >
+    <div id="root"></div>
+    <script type="module" src="/src/main.tsx"></script>
+  </body>
+</html>

ui/package.json

@@ -0,0 +1,35 @@
+{
+  "name": "ui",
+  "private": true,
+  "version": "0.0.0",
+  "type": "module",
+  "scripts": {
+    "dev": "vite",
+    "build": "tsc -b && vite build --emptyOutDir",
+    "lint": "eslint .",
+    "preview": "vite preview"
+  },
+  "dependencies": {
+    "@tailwindcss/vite": "^4.1.8",
+    "@tanstack/react-query": "^5.80.6",
+    "react": "^19.1.0",
+    "react-dom": "^19.1.0",
+    "react-icons": "^5.5.0",
+    "react-resizable-panels": "^3.0.4",
+    "react-router-dom": "^7.6.2",
+    "tailwindcss": "^4.1.8"
+  },
+  "devDependencies": {
+    "@eslint/js": "^9.25.0",
+    "@types/react": "^19.1.2",
+    "@types/react-dom": "^19.1.2",
+    "@vitejs/plugin-react": "^4.4.1",
+    "eslint": "^9.25.0",
+    "eslint-plugin-react-hooks": "^5.2.0",
+    "eslint-plugin-react-refresh": "^0.4.19",
+    "globals": "^16.0.0",
+    "typescript": "~5.8.3",
+    "typescript-eslint": "^8.30.1",
+    "vite": "^6.3.5"
+  }
+}

ui/public/site.webmanifest

@@ -0,0 +1,21 @@
+{
+  "name": "llama-swap",
+  "short_name": "llama-swap",
+  "icons": [
+    {
+      "src": "/web-app-manifest-192x192.png",
+      "sizes": "192x192",
+      "type": "image/png",
+      "purpose": "maskable"
+    },
+    {
+      "src": "/web-app-manifest-512x512.png",
+      "sizes": "512x512",
+      "type": "image/png",
+      "purpose": "maskable"
+    }
+  ],
+  "theme_color": "#ffffff",
+  "background_color": "#ffffff",
+  "display": "standalone"
+}

ui/src/App.css

@@ -0,0 +1,6 @@
+#root {
+  max-width: 1280px;
+  margin: 0 auto;
+  padding: 2rem;
+  text-align: center;
+}

ui/src/App.tsx

@@ -0,0 +1,80 @@
+import { useEffect, useCallback } from "react";
+import { BrowserRouter as Router, Routes, Route, Navigate, NavLink } from "react-router-dom";
+import { useTheme } from "./contexts/ThemeProvider";
+import { useAPI } from "./contexts/APIProvider";
+import LogViewerPage from "./pages/LogViewer";
+import ModelPage from "./pages/Models";
+import ActivityPage from "./pages/Activity";
+import ConnectionStatusIcon from "./components/ConnectionStatus";
+import { RiSunFill, RiMoonFill } from "react-icons/ri";
+
+function App() {
+  const { isNarrow, toggleTheme, isDarkMode, appTitle, setAppTitle, setConnectionState } = useTheme();
+  const handleTitleChange = useCallback(
+    (newTitle: string) => {
+      setAppTitle(newTitle.replace(/\n/g, "").trim().substring(0, 64) || "llama-swap");
+    },
+    [setAppTitle]
+  );
+
+  const { connectionStatus } = useAPI();
+
+  // Synchronize the window.title connections state with the actual connection state
+  useEffect(() => {
+    setConnectionState(connectionStatus);
+  }, [connectionStatus]);
+
+  return (
+    <Router basename="/ui/">
+      <div className="flex flex-col h-screen">
+        <nav className="bg-surface border-b border-border p-2 h-[75px]">
+          <div className="flex items-center justify-between mx-auto px-4 h-full">
+            {!isNarrow && (
+              <h1
+                contentEditable
+                suppressContentEditableWarning
+                className="flex items-center p-0 outline-none hover:bg-gray-100 dark:hover:bg-gray-700 rounded px-1"
+                onBlur={(e) => handleTitleChange(e.currentTarget.textContent || "(set title)")}
+                onKeyDown={(e) => {
+                  if (e.key === "Enter") {
+                    e.preventDefault();
+                    handleTitleChange(e.currentTarget.textContent || "(set title)");
+                    e.currentTarget.blur();
+                  }
+                }}
+              >
+                {appTitle}
+              </h1>
+            )}
+            <div className="flex items-center space-x-4">
+              <NavLink to="/" className={({ isActive }) => (isActive ? "navlink active" : "navlink")}>
+                Logs
+              </NavLink>
+              <NavLink to="/models" className={({ isActive }) => (isActive ? "navlink active" : "navlink")}>
+                Models
+              </NavLink>
+              <NavLink to="/activity" className={({ isActive }) => (isActive ? "navlink active" : "navlink")}>
+                Activity
+              </NavLink>
+              <button className="" onClick={toggleTheme}>
+                {isDarkMode ? <RiMoonFill /> : <RiSunFill />}
+              </button>
+              <ConnectionStatusIcon />
+            </div>
+          </div>
+        </nav>
+
+        <main className="flex-1 overflow-auto p-4">
+          <Routes>
+            <Route path="/" element={<LogViewerPage />} />
+            <Route path="/models" element={<ModelPage />} />
+            <Route path="/activity" element={<ActivityPage />} />
+            <Route path="*" element={<Navigate to="/" replace />} />
+          </Routes>
+        </main>
+      </div>
+    </Router>
+  );
+}
+
+export default App;

ui/src/assets/react.svg

@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" aria-hidden="true" role="img" class="iconify iconify--logos" width="35.93" height="32" preserveAspectRatio="xMidYMid meet" viewBox="0 0 256 228"><path fill="#00D8FF" d="M210.483 73.824a171.49 171.49 0 0 0-8.24-2.597c.465-1.9.893-3.777 1.273-5.621c6.238-30.281 2.16-54.676-11.769-62.708c-13.355-7.7-35.196.329-57.254 19.526a171.23 171.23 0 0 0-6.375 5.848a155.866 155.866 0 0 0-4.241-3.917C100.759 3.829 77.587-4.822 63.673 3.233C50.33 10.957 46.379 33.89 51.995 62.588a170.974 170.974 0 0 0 1.892 8.48c-3.28.932-6.445 1.924-9.474 2.98C17.309 83.498 0 98.307 0 113.668c0 15.865 18.582 31.778 46.812 41.427a145.52 145.52 0 0 0 6.921 2.165a167.467 167.467 0 0 0-2.01 9.138c-5.354 28.2-1.173 50.591 12.134 58.266c13.744 7.926 36.812-.22 59.273-19.855a145.567 145.567 0 0 0 5.342-4.923a168.064 168.064 0 0 0 6.92 6.314c21.758 18.722 43.246 26.282 56.54 18.586c13.731-7.949 18.194-32.003 12.4-61.268a145.016 145.016 0 0 0-1.535-6.842c1.62-.48 3.21-.974 4.76-1.488c29.348-9.723 48.443-25.443 48.443-41.52c0-15.417-17.868-30.326-45.517-39.844Zm-6.365 70.984c-1.4.463-2.836.91-4.3 1.345c-3.24-10.257-7.612-21.163-12.963-32.432c5.106-11 9.31-21.767 12.459-31.957c2.619.758 5.16 1.557 7.61 2.4c23.69 8.156 38.14 20.213 38.14 29.504c0 9.896-15.606 22.743-40.946 31.14Zm-10.514 20.834c2.562 12.94 2.927 24.64 1.23 33.787c-1.524 8.219-4.59 13.698-8.382 15.893c-8.067 4.67-25.32-1.4-43.927-17.412a156.726 156.726 0 0 1-6.437-5.87c7.214-7.889 14.423-17.06 21.459-27.246c12.376-1.098 24.068-2.894 34.671-5.345a134.17 134.17 0 0 1 1.386 6.193ZM87.276 214.515c-7.882 2.783-14.16 2.863-17.955.675c-8.075-4.657-11.432-22.636-6.853-46.752a156.923 156.923 0 0 1 1.869-8.499c10.486 2.32 22.093 3.988 34.498 4.994c7.084 9.967 14.501 19.128 21.976 27.15a134.668 134.668 0 0 1-4.877 4.492c-9.933 8.682-19.886 14.842-28.658 17.94ZM50.35 144.747c-12.483-4.267-22.792-9.812-29.858-15.863c-6.35-5.437-9.555-10.836-9.555-15.216c0-9.322 13.897-21.212 37.076-29.293c2.813-.98 5.757-1.905 8.812-2.773c3.204 10.42 7.406 21.315 12.477 32.332c-5.137 11.18-9.399 22.249-12.634 32.792a134.718 134.718 0 0 1-6.318-1.979Zm12.378-84.26c-4.811-24.587-1.616-43.134 6.425-47.789c8.564-4.958 27.502 2.111 47.463 19.835a144.318 144.318 0 0 1 3.841 3.545c-7.438 7.987-14.787 17.08-21.808 26.988c-12.04 1.116-23.565 2.908-34.161 5.309a160.342 160.342 0 0 1-1.76-7.887Zm110.427 27.268a347.8 347.8 0 0 0-7.785-12.803c8.168 1.033 15.994 2.404 23.343 4.08c-2.206 7.072-4.956 14.465-8.193 22.045a381.151 381.151 0 0 0-7.365-13.322Zm-45.032-43.861c5.044 5.465 10.096 11.566 15.065 18.186a322.04 322.04 0 0 0-30.257-.006c4.974-6.559 10.069-12.652 15.192-18.18ZM82.802 87.83a323.167 323.167 0 0 0-7.227 13.238c-3.184-7.553-5.909-14.98-8.134-22.152c7.304-1.634 15.093-2.97 23.209-3.984a321.524 321.524 0 0 0-7.848 12.897Zm8.081 65.352c-8.385-.936-16.291-2.203-23.593-3.793c2.26-7.3 5.045-14.885 8.298-22.6a321.187 321.187 0 0 0 7.257 13.246c2.594 4.48 5.28 8.868 8.038 13.147Zm37.542 31.03c-5.184-5.592-10.354-11.779-15.403-18.433c4.902.192 9.899.29 14.978.29c5.218 0 10.376-.117 15.453-.343c-4.985 6.774-10.018 12.97-15.028 18.486Zm52.198-57.817c3.422 7.8 6.306 15.345 8.596 22.52c-7.422 1.694-15.436 3.058-23.88 4.071a382.417 382.417 0 0 0 7.859-13.026a347.403 347.403 0 0 0 7.425-13.565Zm-16.898 8.101a358.557 358.557 0 0 1-12.281 19.815a329.4 329.4 0 0 1-23.444.823c-7.967 0-15.716-.248-23.178-.732a310.202 310.202 0 0 1-12.513-19.846h.001a307.41 307.41 0 0 1-10.923-20.627a310.278 310.278 0 0 1 10.89-20.637l-.001.001a307.318 307.318 0 0 1 12.413-19.761c7.613-.576 15.42-.876 23.31-.876H128c7.926 0 15.743.303 23.354.883a329.357 329.357 0 0 1 12.335 19.695a358.489 358.489 0 0 1 11.036 20.54a329.472 329.472 0 0 1-11 20.722Zm22.56-122.124c8.572 4.944 11.906 24.881 6.52 51.026c-.344 1.668-.73 3.367-1.15 5.09c-10.622-2.452-22.155-4.275-34.23-5.408c-7.034-10.017-14.323-19.124-21.64-27.008a160.789 160.789 0 0 1 5.888-5.4c18.9-16.447 36.564-22.941 44.612-18.3ZM128 90.808c12.625 0 22.86 10.235 22.86 22.86s-10.235 22.86-22.86 22.86s-22.86-10.235-22.86-22.86s10.235-22.86 22.86-22.86Z"></path></svg>

ui/src/components/ConnectionStatus.tsx

@@ -0,0 +1,26 @@
+import { useAPI } from "../contexts/APIProvider";
+import { useMemo } from "react";
+
+const ConnectionStatusIcon = () => {
+  const { connectionStatus } = useAPI();
+
+  const eventStatusColor = useMemo(() => {
+    switch (connectionStatus) {
+      case "connected":
+        return "bg-green-500";
+      case "connecting":
+        return "bg-yellow-500";
+      case "disconnected":
+      default:
+        return "bg-red-500";
+    }
+  }, [connectionStatus]);
+
+  return (
+    <div className="flex items-center" title={`event stream: ${connectionStatus}`}>
+      <span className={`inline-block w-3 h-3 rounded-full ${eventStatusColor} mr-2`}></span>
+    </div>
+  );
+};
+
+export default ConnectionStatusIcon;

ui/src/contexts/APIProvider.tsx

@@ -0,0 +1,230 @@
+import { createContext, useState, useContext, useEffect, useCallback, useMemo, type ReactNode } from "react";
+import type { ConnectionState } from "../lib/types";
+
+type ModelStatus = "ready" | "starting" | "stopping" | "stopped" | "shutdown" | "unknown";
+const LOG_LENGTH_LIMIT = 1024 * 100; /* 100KB of log data */
+
+export interface Model {
+  id: string;
+  state: ModelStatus;
+  name: string;
+  description: string;
+  unlisted: boolean;
+}
+
+interface APIProviderType {
+  models: Model[];
+  listModels: () => Promise<Model[]>;
+  unloadAllModels: () => Promise<void>;
+  loadModel: (model: string) => Promise<void>;
+  enableAPIEvents: (enabled: boolean) => void;
+  proxyLogs: string;
+  upstreamLogs: string;
+  metrics: Metrics[];
+  connectionStatus: ConnectionState;
+}
+
+interface Metrics {
+  id: number;
+  timestamp: string;
+  model: string;
+  cache_tokens: number;
+  input_tokens: number;
+  output_tokens: number;
+  prompt_per_second: number;
+  tokens_per_second: number;
+  duration_ms: number;
+}
+
+interface LogData {
+  source: "upstream" | "proxy";
+  data: string;
+}
+interface APIEventEnvelope {
+  type: "modelStatus" | "logData" | "metrics";
+  data: string;
+}
+
+const APIContext = createContext<APIProviderType | undefined>(undefined);
+type APIProviderProps = {
+  children: ReactNode;
+  autoStartAPIEvents?: boolean;
+};
+
+let apiEventSource: EventSource | null = null;
+
+export function APIProvider({ children, autoStartAPIEvents = true }: APIProviderProps) {
+  const [proxyLogs, setProxyLogs] = useState("");
+  const [upstreamLogs, setUpstreamLogs] = useState("");
+  const [metrics, setMetrics] = useState<Metrics[]>([]);
+  const [connectionStatus, setConnectionState] = useState<ConnectionState>("disconnected");
+  //const apiEventSource = useRef<EventSource | null>(null);
+
+  const [models, setModels] = useState<Model[]>([]);
+
+  const appendLog = useCallback((newData: string, setter: React.Dispatch<React.SetStateAction<string>>) => {
+    setter((prev) => {
+      const updatedLog = prev + newData;
+      return updatedLog.length > LOG_LENGTH_LIMIT ? updatedLog.slice(-LOG_LENGTH_LIMIT) : updatedLog;
+    });
+  }, []);
+
+  const enableAPIEvents = useCallback((enabled: boolean) => {
+    if (!enabled) {
+      apiEventSource?.close();
+      apiEventSource = null;
+      setMetrics([]);
+      return;
+    }
+
+    let retryCount = 0;
+    const initialDelay = 1000; // 1 second
+
+    const connect = () => {
+      apiEventSource?.close();
+      apiEventSource = new EventSource("/api/events");
+
+      setConnectionState("connecting");
+
+      apiEventSource.onopen = () => {
+        // clear everything out on connect to keep things in sync
+        setProxyLogs("");
+        setUpstreamLogs("");
+        setMetrics([]); // clear metrics on reconnect
+        setModels([]); // clear models on reconnect
+        retryCount = 0;
+        setConnectionState("connected");
+      };
+
+      apiEventSource.onmessage = (e: MessageEvent) => {
+        try {
+          const message = JSON.parse(e.data) as APIEventEnvelope;
+          switch (message.type) {
+            case "modelStatus":
+              {
+                const models = JSON.parse(message.data) as Model[];
+
+                // sort models by name and id
+                models.sort((a, b) => {
+                  return (a.name + a.id).localeCompare(b.name + b.id);
+                });
+
+                setModels(models);
+              }
+              break;
+
+            case "logData":
+              const logData = JSON.parse(message.data) as LogData;
+              switch (logData.source) {
+                case "proxy":
+                  appendLog(logData.data, setProxyLogs);
+                  break;
+                case "upstream":
+                  appendLog(logData.data, setUpstreamLogs);
+                  break;
+              }
+              break;
+
+            case "metrics":
+              {
+                const newMetrics = JSON.parse(message.data) as Metrics[];
+                setMetrics((prevMetrics) => {
+                  return [...newMetrics, ...prevMetrics];
+                });
+              }
+              break;
+          }
+        } catch (err) {
+          console.error(e.data, err);
+        }
+      };
+
+      apiEventSource.onerror = () => {
+        apiEventSource?.close();
+        retryCount++;
+        const delay = Math.min(initialDelay * Math.pow(2, retryCount - 1), 5000);
+        setConnectionState("disconnected");
+        setTimeout(connect, delay);
+      };
+    };
+
+    connect();
+  }, []);
+
+  useEffect(() => {
+    if (autoStartAPIEvents) {
+      enableAPIEvents(true);
+    }
+
+    return () => {
+      enableAPIEvents(false);
+    };
+  }, [enableAPIEvents, autoStartAPIEvents]);
+
+  const listModels = useCallback(async (): Promise<Model[]> => {
+    try {
+      const response = await fetch("/api/models/");
+      if (!response.ok) {
+        throw new Error(`HTTP error! status: ${response.status}`);
+      }
+      const data = await response.json();
+      return data || [];
+    } catch (error) {
+      console.error("Failed to fetch models:", error);
+      return []; // Return empty array as fallback
+    }
+  }, []);
+
+  const unloadAllModels = useCallback(async () => {
+    try {
+      const response = await fetch(`/api/models/unload/`, {
+        method: "POST",
+      });
+      if (!response.ok) {
+        throw new Error(`Failed to unload models: ${response.status}`);
+      }
+    } catch (error) {
+      console.error("Failed to unload models:", error);
+      throw error; // Re-throw to let calling code handle it
+    }
+  }, []);
+
+  const loadModel = useCallback(async (model: string) => {
+    try {
+      const response = await fetch(`/upstream/${model}/`, {
+        method: "GET",
+      });
+      if (!response.ok) {
+        throw new Error(`Failed to load model: ${response.status}`);
+      }
+    } catch (error) {
+      console.error("Failed to load model:", error);
+      throw error; // Re-throw to let calling code handle it
+    }
+  }, []);
+
+  const value = useMemo(
+    () => ({
+      models,
+      listModels,
+      unloadAllModels,
+      loadModel,
+      enableAPIEvents,
+      proxyLogs,
+      upstreamLogs,
+      metrics,
+      connectionStatus,
+    }),
+    [models, listModels, unloadAllModels, loadModel, enableAPIEvents, proxyLogs, upstreamLogs, metrics]
+  );
+
+  return <APIContext.Provider value={value}>{children}</APIContext.Provider>;
+}
+
+export function useAPI() {
+  const context = useContext(APIContext);
+  if (context === undefined) {
+    throw new Error("useAPI must be used within an APIProvider");
+  }
+  return context;
+}

ui/src/contexts/ThemeProvider.tsx

@@ -0,0 +1,97 @@
+import { createContext, useContext, useEffect, type ReactNode, useMemo, useState } from "react";
+import { usePersistentState } from "../hooks/usePersistentState";
+import type { ConnectionState } from "../lib/types";
+
+type ScreenWidth = "xs" | "sm" | "md" | "lg" | "xl" | "2xl";
+type ThemeContextType = {
+  isDarkMode: boolean;
+  screenWidth: ScreenWidth;
+  isNarrow: boolean;
+  toggleTheme: () => void;
+
+  // for managing the window title and connection state information
+  appTitle: string;
+  setAppTitle: (title: string) => void;
+  setConnectionState: (state: ConnectionState) => void;
+};
+
+const ThemeContext = createContext<ThemeContextType | undefined>(undefined);
+
+type ThemeProviderProps = {
+  children: ReactNode;
+};
+
+export function ThemeProvider({ children }: ThemeProviderProps) {
+  const [appTitle, setAppTitle] = usePersistentState("app-title", "llama-swap");
+  const [connectionState, setConnectionState] = useState<ConnectionState>("disconnected");
+
+  /**
+   * Set the document.title with informative information
+   */
+  useEffect(() => {
+    const connectionIcon = connectionState === "connecting" ? "🟡" : connectionState === "connected" ? "🟢" : "🔴";
+    document.title = connectionIcon + " " + appTitle; // Set initial title
+  }, [appTitle, connectionState]);
+
+  const [isDarkMode, setIsDarkMode] = usePersistentState<boolean>("theme", false);
+  const [screenWidth, setScreenWidth] = useState<ScreenWidth>("md"); // Default to md
+
+  // matches tailwind classes
+  // https://tailwindcss.com/docs/responsive-design
+  useEffect(() => {
+    const checkInnerWidth = () => {
+      const innerWidth = window.innerWidth;
+      if (innerWidth < 640) {
+        setScreenWidth("xs");
+      } else if (innerWidth < 768) {
+        setScreenWidth("sm");
+      } else if (innerWidth < 1024) {
+        setScreenWidth("md");
+      } else if (innerWidth < 1280) {
+        setScreenWidth("lg");
+      } else if (innerWidth < 1536) {
+        setScreenWidth("xl");
+      } else {
+        setScreenWidth("2xl");
+      }
+    };
+
+    checkInnerWidth();
+    window.addEventListener("resize", checkInnerWidth);
+
+    return () => window.removeEventListener("resize", checkInnerWidth);
+  }, []);
+
+  useEffect(() => {
+    document.documentElement.setAttribute("data-theme", isDarkMode ? "dark" : "light");
+  }, [isDarkMode]);
+
+  const toggleTheme = () => setIsDarkMode((prev) => !prev);
+  const isNarrow = useMemo(() => {
+    return screenWidth === "xs" || screenWidth === "sm" || screenWidth === "md";
+  }, [screenWidth]);
+
+  return (
+    <ThemeContext.Provider
+      value={{
+        isDarkMode,
+        toggleTheme,
+        screenWidth,
+        isNarrow,
+        appTitle,
+        setAppTitle,
+        setConnectionState,
+      }}
+    >
+      {children}
+    </ThemeContext.Provider>
+  );
+}
+
+export function useTheme(): ThemeContextType {
+  const context = useContext(ThemeContext);
+  if (context === undefined) {
+    throw new Error("useTheme must be used within a ThemeProvider");
+  }
+  return context;
+}

ui/src/hooks/usePersistentState.ts

@@ -0,0 +1,39 @@
+import { useState, useEffect, useCallback } from "react";
+
+export function usePersistentState<T>(key: string, initialValue: T): [T, (value: T | ((prevState: T) => T)) => void] {
+  const [state, setState] = useState<T>(() => {
+    if (typeof window === "undefined") return initialValue;
+    try {
+      const saved = localStorage.getItem(key);
+      return saved !== null ? JSON.parse(saved) : initialValue;
+    } catch (e) {
+      console.error(`Error parsing stored value for ${key}`, e);
+      return initialValue;
+    }
+  });
+
+  const setPersistentState = useCallback(
+    (value: T | ((prevState: T) => T)) => {
+      setState((prev) => {
+        const nextValue = typeof value === "function" ? (value as (prevState: T) => T)(prev) : value;
+        try {
+          localStorage.setItem(key, JSON.stringify(nextValue));
+        } catch (e) {
+          console.error(`Error saving value for ${key}`, e);
+        }
+        return nextValue;
+      });
+    },
+    [key]
+  );
+
+  useEffect(() => {
+    try {
+      localStorage.setItem(key, JSON.stringify(state));
+    } catch (e) {
+      console.error(`Error saving value for ${key}`, e);
+    }
+  }, [key, state]);
+
+  return [state, setPersistentState];
+}

ui/src/index.css

@@ -0,0 +1,168 @@
+@import "tailwindcss";
+@custom-variant dark (&:where([data-theme=dark], [data-theme=dark] *));
+
+@theme {
+  --color-background: rgba(252, 252, 249, 1);
+  --color-surface: rgba(255, 255, 253, 1);
+
+  /* text colors */
+  --color-txtmain: rgba(19, 52, 59, 1);
+  --color-txtsecondary: rgba(98, 108, 113, 1);
+  --color-navlink-active: rgba(245, 245, 245, 1);
+
+  --color-primary: rgba(50, 184, 198, 1);
+
+  --color-primary-hover: rgba(29, 116, 128, 1);
+  --color-primary-active: rgba(26, 104, 115, 1);
+  --color-secondary: rgba(94, 82, 64, 0.12);
+  --color-secondary-hover: rgba(94, 82, 64, 0.2);
+  --color-secondary-active: rgba(94, 82, 64, 0.25);
+  --color-border: rgba(94, 82, 64, 0.3);
+  --color-btn-primary-text: rgba(252, 252, 249, 1);
+  --color-card-border: rgba(94, 82, 64, 0.12);
+  --color-card-border-inner: rgba(94, 82, 64, 0.12);
+  --color-error: rgba(192, 21, 47, 1);
+  --color-success: rgba(33, 128, 141, 1);
+  --color-warning: rgb(244, 155, 0);
+  --color-info: rgba(98, 108, 113, 1);
+  --color-focus-ring: rgba(33, 128, 141, 0.4);
+  --color-select-caret: rgba(19, 52, 59, 0.8);
+  --color-btn-border: rgba(94, 82, 64, 0.7);
+}
+
+@layer theme {
+  /* over ride theme for dark mode */
+  [data-theme="dark"] {
+    --color-background: rgba(31, 33, 33, 1);
+    --color-surface: rgba(38, 40, 40, 1);
+    /* text colors */
+    --color-txtmain: rgba(245, 245, 245, 1);
+    --color-txtsecondary: rgba(167, 169, 169, 0.7);
+
+    --color-navlink-active: rgba(245, 245, 245, 1);
+
+    --color-primary: rgba(33, 128, 141, 1);
+    --color-primary-hover: rgba(45, 166, 178, 1);
+    --color-primary-active: rgba(41, 150, 161, 1);
+    --color-secondary: rgba(119, 124, 124, 0.15);
+    --color-secondary-hover: rgba(119, 124, 124, 0.25);
+    --color-secondary-active: rgba(119, 124, 124, 0.3);
+    --color-border: rgba(119, 124, 124, 0.3);
+    --color-error: rgba(255, 84, 89, 1);
+    --color-success: rgba(50, 184, 198, 1);
+    --color-warning: rgb(244, 155, 0);
+    --color-info: rgba(167, 169, 169, 1);
+    --color-focus-ring: rgba(50, 184, 198, 0.4);
+    --color-btn-primary-text: rgba(19, 52, 59, 1);
+    --color-card-border: rgba(119, 124, 124, 0.2);
+    --color-card-border-inner: rgba(119, 124, 124, 0.15);
+    --shadow-inset-sm: inset 0 1px 0 rgba(255, 255, 255, 0.1), inset 0 -1px 0 rgba(0, 0, 0, 0.15);
+    --button-border-secondary: rgba(119, 124, 124, 0.2);
+  }
+}
+
+@layer base {
+  body {
+    /* example of how colors using theme colors*/
+    @apply bg-background text-txtmain;
+  }
+
+  h1 {
+    @apply text-4xl text-txtmain font-bold pb-4;
+  }
+  h2 {
+    @apply text-3xl text-txtmain font-bold pb-4;
+  }
+  h3 {
+    @apply text-2xl text-txtmain font-bold pb-4;
+  }
+  h4 {
+    @apply text-xl text-txtmain font-bold pb-4;
+  }
+  h5 {
+    @apply text-lg text-txtmain font-bold pb-4;
+  }
+  h6 {
+    @apply text-base text-txtmain font-bold pb-4;
+  }
+}
+
+/* define CSS classes here for specific types of components */
+@layer components {
+  .container {
+    @apply px-4;
+  }
+
+  /* Navigation Header */
+
+  .navlink {
+    @apply text-txtsecondary hover:bg-secondary hover:text-txtmain rounded-lg p-2;
+  }
+  .navlink.active {
+    @apply bg-primary text-navlink-active;
+  }
+
+  /* Card component */
+  .card {
+    @apply bg-surface rounded-lg border border-card-border shadow-sm overflow-hidden p-4;
+  }
+
+  .card:hover {
+    @apply shadow-md;
+  }
+
+  .card__body {
+    @apply p-4;
+  }
+
+  .card__header,
+  .card__footer {
+    @apply p-4 border-b border-card-border-inner;
+  }
+
+  /* Status Badges */
+  .status {
+    @apply inline-block px-2 py-1 text-xs font-medium rounded-full;
+  }
+
+  .status--ready {
+    @apply bg-success/10 text-success;
+  }
+
+  .status--starting,
+  .status--stopping {
+    @apply bg-warning/10 text-warning;
+  }
+
+  .status--stopped {
+    @apply bg-error/10 text-error;
+  }
+
+  /* Buttons */
+  .btn {
+    @apply bg-surface p-2 px-4 text-sm rounded-full border border-2 transition-colors duration-200 border-btn-border;
+  }
+
+  .btn:hover {
+    cursor: pointer;
+  }
+
+  .btn--sm {
+    @apply px-2 py-0.5 text-xs;
+  }
+
+  .btn:disabled {
+    @apply opacity-50 cursor-not-allowed;
+  }
+}
+
+@layer utilities {
+  .ml-2 {
+    margin-left: 0.5rem;
+  }
+
+  .my-8 {
+    margin-top: 2rem;
+    margin-bottom: 2rem;
+  }
+}

ui/src/lib/types.ts

@@ -0,0 +1 @@
+export type ConnectionState = "connected" | "connecting" | "disconnected";

ui/src/main.tsx

@@ -0,0 +1,16 @@
+import { StrictMode } from "react";
+import { createRoot } from "react-dom/client";
+import "./index.css";
+import App from "./App.tsx";
+import { ThemeProvider } from "./contexts/ThemeProvider";
+import { APIProvider } from "./contexts/APIProvider";
+
+createRoot(document.getElementById("root")!).render(
+  <StrictMode>
+    <ThemeProvider>
+      <APIProvider>
+        <App />
+      </APIProvider>
+    </ThemeProvider>
+  </StrictMode>
+);

ui/src/pages/Activity.tsx

@@ -0,0 +1,121 @@
+import { useMemo } from "react";
+import { useAPI } from "../contexts/APIProvider";
+
+const formatSpeed = (speed: number): string => {
+  return speed < 0 ? "unknown" : speed.toFixed(2) + " t/s";
+};
+
+const formatDuration = (ms: number): string => {
+  return (ms / 1000).toFixed(2) + "s";
+};
+
+const formatRelativeTime = (timestamp: string): string => {
+  const now = new Date();
+  const date = new Date(timestamp);
+  const diffInSeconds = Math.floor((now.getTime() - date.getTime()) / 1000);
+
+  // Handle future dates by returning "just now"
+  if (diffInSeconds < 5) {
+    return "now";
+  }
+
+  if (diffInSeconds < 60) {
+    return `${diffInSeconds}s ago`;
+  }
+
+  const diffInMinutes = Math.floor(diffInSeconds / 60);
+  if (diffInMinutes < 60) {
+    return `${diffInMinutes}m ago`;
+  }
+
+  const diffInHours = Math.floor(diffInMinutes / 60);
+  if (diffInHours < 24) {
+    return `${diffInHours}h ago`;
+  }
+
+  return "a while ago";
+};
+
+const ActivityPage = () => {
+  const { metrics } = useAPI();
+  const sortedMetrics = useMemo(() => {
+    return [...metrics].sort((a, b) => b.id - a.id);
+  }, [metrics]);
+
+  return (
+    <div className="p-6">
+      <h1 className="text-2xl font-bold mb-4">Activity</h1>
+
+      {metrics.length === 0 ? (
+        <div className="text-center py-8">
+          <p className="text-gray-600">No metrics data available</p>
+        </div>
+      ) : (
+        <div className="overflow-x-auto">
+          <table className="min-w-full divide-y">
+            <thead>
+              <tr>
+                <th className="px-4 py-3 text-left text-xs font-medium uppercase tracking-wider">ID</th>
+                <th className="px-6 py-3 text-left text-xs font-medium uppercase tracking-wider">Time</th>
+                <th className="px-6 py-3 text-left text-xs font-medium uppercase tracking-wider">Model</th>
+                <th className="px-6 py-3 text-left text-xs font-medium uppercase tracking-wider">
+                  Cached <Tooltip content="prompt tokens from cache" />
+                </th>
+                <th className="px-6 py-3 text-left text-xs font-medium uppercase tracking-wider">
+                  Prompt <Tooltip content="new prompt tokens processed" />
+                </th>
+                <th className="px-6 py-3 text-left text-xs font-medium uppercase tracking-wider">Generated</th>
+                <th className="px-6 py-3 text-left text-xs font-medium uppercase tracking-wider">Prompt Processing</th>
+                <th className="px-6 py-3 text-left text-xs font-medium uppercase tracking-wider">Generation Speed</th>
+                <th className="px-6 py-3 text-left text-xs font-medium uppercase tracking-wider">Duration</th>
+              </tr>
+            </thead>
+            <tbody className="divide-y">
+              {sortedMetrics.map((metric) => (
+                <tr key={`metric_${metric.id}`}>
+                  <td className="px-4 py-4 whitespace-nowrap text-sm">{metric.id + 1 /* un-zero index */}</td>
+                  <td className="px-6 py-4 whitespace-nowrap text-sm">{formatRelativeTime(metric.timestamp)}</td>
+                  <td className="px-6 py-4 whitespace-nowrap text-sm">{metric.model}</td>
+                  <td className="px-6 py-4 whitespace-nowrap text-sm">
+                    {metric.cache_tokens > 0 ? metric.cache_tokens.toLocaleString() : "-"}
+                  </td>
+                  <td className="px-6 py-4 whitespace-nowrap text-sm">{metric.input_tokens.toLocaleString()}</td>
+                  <td className="px-6 py-4 whitespace-nowrap text-sm">{metric.output_tokens.toLocaleString()}</td>
+                  <td className="px-6 py-4 whitespace-nowrap text-sm">{formatSpeed(metric.prompt_per_second)}</td>
+                  <td className="px-6 py-4 whitespace-nowrap text-sm">{formatSpeed(metric.tokens_per_second)}</td>
+                  <td className="px-6 py-4 whitespace-nowrap text-sm">{formatDuration(metric.duration_ms)}</td>
+                </tr>
+              ))}
+            </tbody>
+          </table>
+        </div>
+      )}
+    </div>
+  );
+};
+
+interface TooltipProps {
+  content: string;
+}
+
+const Tooltip: React.FC<TooltipProps> = ({ content }) => {
+  return (
+    <div className="relative group inline-block">
+      ⓘ
+      <div
+        className="absolute top-full left-1/2 transform -translate-x-1/2 mt-2
+                     px-3 py-2 bg-gray-900 text-white text-sm rounded-md
+                     opacity-0 group-hover:opacity-100 transition-opacity
+                     duration-200 pointer-events-none whitespace-nowrap z-50 normal-case"
+      >
+        {content}
+        <div
+          className="absolute bottom-full left-1/2 transform -translate-x-1/2
+                       border-4 border-transparent border-b-gray-900"
+        ></div>
+      </div>
+    </div>
+  );
+};
+
+export default ActivityPage;

ui/src/pages/LogViewer.tsx

@@ -0,0 +1,162 @@
+import { useState, useEffect, useRef, useMemo, useCallback } from "react";
+import { useAPI } from "../contexts/APIProvider";
+import { usePersistentState } from "../hooks/usePersistentState";
+import { Panel, PanelGroup, PanelResizeHandle } from "react-resizable-panels";
+import {
+  RiTextWrap,
+  RiAlignJustify,
+  RiFontSize,
+  RiMenuSearchLine,
+  RiMenuSearchFill,
+  RiCloseCircleFill,
+} from "react-icons/ri";
+import { useTheme } from "../contexts/ThemeProvider";
+
+const LogViewer = () => {
+  const { proxyLogs, upstreamLogs } = useAPI();
+  const { isNarrow } = useTheme();
+  const direction = isNarrow ? "vertical" : "horizontal";
+
+  return (
+    <PanelGroup direction={direction} className="gap-2" autoSaveId="logviewer-panel-group">
+      <Panel id="proxy" defaultSize={50} minSize={5} maxSize={100} collapsible={true}>
+        <LogPanel id="proxy" title="Proxy Logs" logData={proxyLogs} />
+      </Panel>
+      <PanelResizeHandle
+        className={
+          direction === "horizontal"
+            ? "w-2 h-full bg-primary hover:bg-success transition-colors rounded"
+            : "w-full h-2 bg-primary hover:bg-success transition-colors rounded"
+        }
+      />
+      <Panel id="upstream" defaultSize={50} minSize={5} maxSize={100} collapsible={true}>
+        <LogPanel id="upstream" title="Upstream Logs" logData={upstreamLogs} />
+      </Panel>
+    </PanelGroup>
+  );
+};
+
+interface LogPanelProps {
+  id: string;
+  title: string;
+  logData: string;
+}
+export const LogPanel = ({ id, title, logData }: LogPanelProps) => {
+  const [filterRegex, setFilterRegex] = useState("");
+  const [fontSize, setFontSize] = usePersistentState<"xxs" | "xs" | "small" | "normal">(
+    `logPanel-${id}-fontSize`,
+    "normal"
+  );
+  const [wrapText, setTextWrap] = usePersistentState(`logPanel-${id}-wrapText`, false);
+  const [showFilter, setShowFilter] = usePersistentState(`logPanel-${id}-showFilter`, false);
+
+  const textWrapClass = useMemo(() => {
+    return wrapText ? "whitespace-pre-wrap" : "whitespace-pre";
+  }, [wrapText]);
+
+  const toggleFontSize = useCallback(() => {
+    setFontSize((prev) => {
+      switch (prev) {
+        case "xxs":
+          return "xs";
+        case "xs":
+          return "small";
+        case "small":
+          return "normal";
+        case "normal":
+          return "xxs";
+      }
+    });
+  }, []);
+
+  const toggleWrapText = useCallback(() => {
+    setTextWrap((prev) => !prev);
+  }, []);
+
+  const toggleFilter = useCallback(() => {
+    if (showFilter) {
+      setShowFilter(false);
+      setFilterRegex(""); // Clear filter when closing
+    } else {
+      setShowFilter(true);
+    }
+  }, [filterRegex, setFilterRegex, showFilter]);
+
+  const fontSizeClass = useMemo(() => {
+    switch (fontSize) {
+      case "xxs":
+        return "text-[0.5rem]"; // 0.5rem (8px)
+      case "xs":
+        return "text-[0.75rem]"; // 0.75rem (12px)
+      case "small":
+        return "text-[0.875rem]"; // 0.875rem (14px)
+      case "normal":
+        return "text-base"; // 1rem (16px)
+    }
+  }, [fontSize]);
+
+  const filteredLogs = useMemo(() => {
+    if (!filterRegex) return logData;
+    try {
+      const regex = new RegExp(filterRegex, "i");
+      const lines = logData.split("\n");
+      const filtered = lines.filter((line) => regex.test(line));
+      return filtered.join("\n");
+    } catch (e) {
+      return logData; // Return unfiltered if regex is invalid
+    }
+  }, [logData, filterRegex]);
+
+  // auto scroll to bottom
+  const preTagRef = useRef<HTMLPreElement>(null);
+  useEffect(() => {
+    if (!preTagRef.current) return;
+    preTagRef.current.scrollTop = preTagRef.current.scrollHeight;
+  }, [filteredLogs]);
+
+  return (
+    <div className="bg-surface border border-border rounded-lg overflow-hidden flex flex-col h-full">
+      <div className="p-4 border-b border-border bg-secondary">
+        <div className="flex items-center justify-between">
+          <h3 className="m-0 text-lg p-0">{title}</h3>
+
+          <div className="flex gap-2 items-center">
+            <button className="btn" onClick={toggleFontSize}>
+              <RiFontSize />
+            </button>
+            <button className="btn" onClick={toggleWrapText}>
+              {wrapText ? <RiTextWrap /> : <RiAlignJustify />}
+            </button>
+            <button className="btn" onClick={toggleFilter}>
+              {showFilter ? <RiMenuSearchFill /> : <RiMenuSearchLine />}
+            </button>
+          </div>
+        </div>
+
+        {/* Filtering Options - Full width on mobile, normal on desktop */}
+        {showFilter && (
+          <div className="mt-2 w-full">
+            <div className="flex gap-2 items-center w-full">
+              <input
+                type="text"
+                className="w-full text-sm border p-2 rounded"
+                placeholder="Filter logs..."
+                value={filterRegex}
+                onChange={(e) => setFilterRegex(e.target.value)}
+              />
+              <button className="pl-2" onClick={() => setFilterRegex("")}>
+                <RiCloseCircleFill size="24" />
+              </button>
+            </div>
+          </div>
+        )}
+      </div>
+      <div className="bg-background font-mono text-sm flex-1 overflow-hidden">
+        <pre ref={preTagRef} className={`${textWrapClass} ${fontSizeClass} h-full overflow-auto p-4`}>
+          {filteredLogs}
+        </pre>
+      </div>
+    </div>
+  );
+};
+export default LogViewer;

ui/src/pages/Models.tsx

@@ -0,0 +1,173 @@
+import { useState, useCallback, useMemo } from "react";
+import { useAPI } from "../contexts/APIProvider";
+import { LogPanel } from "./LogViewer";
+import { usePersistentState } from "../hooks/usePersistentState";
+import { Panel, PanelGroup, PanelResizeHandle } from "react-resizable-panels";
+import { useTheme } from "../contexts/ThemeProvider";
+import { RiEyeFill, RiEyeOffFill, RiStopCircleLine, RiSwapBoxFill } from "react-icons/ri";
+
+export default function ModelsPage() {
+  const { isNarrow } = useTheme();
+  const direction = isNarrow ? "vertical" : "horizontal";
+  const { upstreamLogs } = useAPI();
+
+  return (
+    <PanelGroup direction={direction} className="gap-2" autoSaveId={"models-panel-group"}>
+      <Panel id="models" defaultSize={50} minSize={isNarrow ? 0 : 25} maxSize={100} collapsible={isNarrow}>
+        <ModelsPanel />
+      </Panel>
+
+      <PanelResizeHandle
+        className={
+          direction === "horizontal"
+            ? "w-2 h-full bg-primary hover:bg-success transition-colors rounded"
+            : "w-full h-2 bg-primary hover:bg-success transition-colors rounded"
+        }
+      />
+      <Panel collapsible={true} defaultSize={50} minSize={0}>
+        <div className="flex flex-col h-full space-y-4">
+          {direction === "horizontal" && <StatsPanel />}
+          <div className="flex-1 min-h-0">
+            <LogPanel id="modelsupstream" title="Upstream Logs" logData={upstreamLogs} />
+          </div>
+        </div>
+      </Panel>
+    </PanelGroup>
+  );
+}
+
+function ModelsPanel() {
+  const { models, loadModel, unloadAllModels } = useAPI();
+  const [isUnloading, setIsUnloading] = useState(false);
+  const [showUnlisted, setShowUnlisted] = usePersistentState("showUnlisted", true);
+  const [showIdorName, setShowIdorName] = usePersistentState<"id" | "name">("showIdorName", "id"); // true = show ID, false = show name
+
+  const filteredModels = useMemo(() => {
+    return models.filter((model) => showUnlisted || !model.unlisted);
+  }, [models, showUnlisted]);
+
+  const handleUnloadAllModels = useCallback(async () => {
+    setIsUnloading(true);
+    try {
+      await unloadAllModels();
+    } catch (e) {
+      console.error(e);
+    } finally {
+      setTimeout(() => {
+        setIsUnloading(false);
+      }, 1000);
+    }
+  }, [unloadAllModels]);
+
+  const toggleIdorName = useCallback(() => {
+    setShowIdorName((prev) => (prev === "name" ? "id" : "name"));
+  }, [showIdorName]);
+
+  return (
+    <div className="card h-full flex flex-col">
+      <div className="shrink-0">
+        <h2>Models</h2>
+        <div className="flex justify-between">
+          <div className="flex gap-2">
+            <button className="btn flex items-center gap-2" onClick={toggleIdorName} style={{ lineHeight: "1.2" }}>
+              <RiSwapBoxFill /> {showIdorName === "id" ? "ID" : "Name"}
+            </button>
+
+            <button
+              className="btn flex items-center gap-2"
+              onClick={() => setShowUnlisted(!showUnlisted)}
+              style={{ lineHeight: "1.2" }}
+            >
+              {showUnlisted ? <RiEyeFill /> : <RiEyeOffFill />} unlisted
+            </button>
+          </div>
+          <button className="btn flex items-center gap-2" onClick={handleUnloadAllModels} disabled={isUnloading}>
+            <RiStopCircleLine size="24" /> {isUnloading ? "Unloading..." : "Unload"}
+          </button>
+        </div>
+      </div>
+
+      <div className="flex-1 overflow-y-auto">
+        <table className="w-full">
+          <thead className="sticky top-0 bg-card z-10">
+            <tr className="border-b border-primary bg-surface">
+              <th className="text-left p-2">{showIdorName === "id" ? "Model ID" : "Name"}</th>
+              <th className="text-left p-2"></th>
+              <th className="text-left p-2">State</th>
+            </tr>
+          </thead>
+          <tbody>
+            {filteredModels.map((model) => (
+              <tr key={model.id} className="border-b hover:bg-secondary-hover border-border">
+                <td className={`p-2 ${model.unlisted ? "text-txtsecondary" : ""}`}>
+                  <a href={`/upstream/${model.id}/`} className={`underline`} target="_blank">
+                    {showIdorName === "id" ? model.id : model.name !== "" ? model.name : model.id}
+                  </a>
+                  {model.description !== "" && (
+                    <p className={model.unlisted ? "text-opacity-70" : ""}>
+                      <em>{model.description}</em>
+                    </p>
+                  )}
+                </td>
+                <td className="p-2 w-[50px]">
+                  <button
+                    className="btn btn--sm"
+                    disabled={model.state !== "stopped"}
+                    onClick={() => loadModel(model.id)}
+                  >
+                    Load
+                  </button>
+                </td>
+                <td className="p-2 w-[75px]">
+                  <span className={`status status--${model.state}`}>{model.state}</span>
+                </td>
+              </tr>
+            ))}
+          </tbody>
+        </table>
+      </div>
+    </div>
+  );
+}
+
+function StatsPanel() {
+  const { metrics } = useAPI();
+
+  const [totalRequests, totalInputTokens, totalOutputTokens, avgTokensPerSecond] = useMemo(() => {
+    const totalRequests = metrics.length;
+    if (totalRequests === 0) {
+      return [0, 0, 0];
+    }
+    const totalInputTokens = metrics.reduce((sum, m) => sum + m.input_tokens, 0);
+    const totalOutputTokens = metrics.reduce((sum, m) => sum + m.output_tokens, 0);
+    const avgTokensPerSecond = (metrics.reduce((sum, m) => sum + m.tokens_per_second, 0) / totalRequests).toFixed(2);
+    return [totalRequests, totalInputTokens, totalOutputTokens, avgTokensPerSecond];
+  }, [metrics]);
+
+  return (
+    <div className="card">
+      <div className="rounded-lg overflow-hidden border border-gray-200">
+        <table className="w-full">
+          <tbody>
+            <tr>
+              <th className="p-2 font-medium border-b border-gray-200 text-right">Requests</th>
+              <th className="p-2 font-medium border-l border-b border-gray-200 text-right">Processed</th>
+              <th className="p-2 font-medium border-l border-b border-gray-200 text-right">Generated</th>
+              <th className="p-2 font-medium border-l border-b border-gray-200 text-right">Tokens/Sec</th>
+            </tr>
+            <tr>
+              <td className="p-2 text-right border-r border-gray-200">{totalRequests}</td>
+              <td className="p-2 text-right border-r border-gray-200">
+                {new Intl.NumberFormat().format(totalInputTokens)}
+              </td>
+              <td className="p-2 text-right border-r border-gray-200">
+                {new Intl.NumberFormat().format(totalOutputTokens)}
+              </td>
+              <td className="p-2 text-right">{avgTokensPerSecond}</td>
+            </tr>
+          </tbody>
+        </table>
+      </div>
+    </div>
+  );
+}

ui/src/vite-env.d.ts

@@ -0,0 +1 @@
+/// <reference types="vite/client" />

ui/tsconfig.app.json

@@ -0,0 +1,27 @@
+{
+  "compilerOptions": {
+    "tsBuildInfoFile": "./node_modules/.tmp/tsconfig.app.tsbuildinfo",
+    "target": "ES2020",
+    "useDefineForClassFields": true,
+    "lib": ["ES2020", "DOM", "DOM.Iterable"],
+    "module": "ESNext",
+    "skipLibCheck": true,
+
+    /* Bundler mode */
+    "moduleResolution": "bundler",
+    "allowImportingTsExtensions": true,
+    "verbatimModuleSyntax": true,
+    "moduleDetection": "force",
+    "noEmit": true,
+    "jsx": "react-jsx",
+
+    /* Linting */
+    "strict": true,
+    "noUnusedLocals": true,
+    "noUnusedParameters": true,
+    "erasableSyntaxOnly": true,
+    "noFallthroughCasesInSwitch": true,
+    "noUncheckedSideEffectImports": true
+  },
+  "include": ["src"]
+}

ui/tsconfig.json

@@ -0,0 +1,7 @@
+{
+  "files": [],
+  "references": [
+    { "path": "./tsconfig.app.json" },
+    { "path": "./tsconfig.node.json" }
+  ]
+}

ui/tsconfig.node.json

@@ -0,0 +1,25 @@
+{
+  "compilerOptions": {
+    "tsBuildInfoFile": "./node_modules/.tmp/tsconfig.node.tsbuildinfo",
+    "target": "ES2022",
+    "lib": ["ES2023"],
+    "module": "ESNext",
+    "skipLibCheck": true,
+
+    /* Bundler mode */
+    "moduleResolution": "bundler",
+    "allowImportingTsExtensions": true,
+    "verbatimModuleSyntax": true,
+    "moduleDetection": "force",
+    "noEmit": true,
+
+    /* Linting */
+    "strict": true,
+    "noUnusedLocals": true,
+    "noUnusedParameters": true,
+    "erasableSyntaxOnly": true,
+    "noFallthroughCasesInSwitch": true,
+    "noUncheckedSideEffectImports": true
+  },
+  "include": ["vite.config.ts"]
+}

ui/vite.config.ts

@@ -0,0 +1,20 @@
+import { defineConfig } from "vite";
+import react from "@vitejs/plugin-react";
+import tailwindcss from "@tailwindcss/vite";
+
+// https://vite.dev/config/
+export default defineConfig({
+  plugins: [react(), tailwindcss()],
+  base: "/ui/",
+  build: {
+    outDir: "../proxy/ui_dist",
+    assetsDir: "assets",
+  },
+  server: {
+    proxy: {
+      "/api": "http://localhost:8080", // Proxy API calls to Go backend during development
+      "/logs": "http://localhost:8080",
+      "/upstream": "http://localhost:8080",
+    },
+  },
+});