Make checkHealthTimeout Interruptable during startup (#102)

interrupt and exit Process.start() early if the upstream process exits prematurely or unexpectedly.

.goreleaser.yaml

@@ -16,3 +16,15 @@ builds:
         goarch: arm64
       - goos: windows
         goarch: arm64
+
+# use zip format for windows
+archives:
+  - id: default
+    format: tar.gz
+    name_template: "{{ .ProjectName }}_{{ .Version }}_{{ .Os }}_{{ .Arch }}"
+    builds_info:
+      group: root
+      owner: root
+    format_overrides:
+      - goos: windows
+        format: zip

README.md

@@ -1,4 +1,7 @@
-![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)
 
 # llama-swap
 
@@ -64,13 +67,20 @@ models:
 # Default (and minimum) is 15 seconds
 healthCheckTimeout: 60
 
-# Write HTTP logs (useful for troubleshooting), defaults to false
+# Valid log levels: debug, info (default), warn, error
-logRequests: true
+logLevel: info
 
 # define valid model values and the upstream server start
 models:
   "llama":
-    cmd: llama-server --port 8999 -m Llama-3.2-1B-Instruct-Q4_K_M.gguf
+    # multiline for readability
+    cmd: >
+      llama-server --port 8999
+      --model path/to/Qwen2.5-1.5B-Instruct-Q4_K_M.gguf
+
+    # environment variables to pass to the command
+    env:
+      - "CUDA_VISIBLE_DEVICES=0"
 
     # where to reach the server started by cmd, make sure the ports match
     proxy: http://127.0.0.1:8999
@@ -91,16 +101,9 @@ models:
     # default: 0 = never unload model
     ttl: 60
 
-  "qwen":
+    # `useModelName` overrides the model name in the request
-    # environment variables to pass to the command
+    # and sends a specific name to the upstream server
-    env:
+    useModelName: "qwen:qwq"
-      - "CUDA_VISIBLE_DEVICES=0"
-
-    # multiline for readability
-    cmd: >
-      llama-server --port 8999
-      --model path/to/Qwen2.5-1.5B-Instruct-Q4_K_M.gguf
-    proxy: http://127.0.0.1:8999
 
   # unlisted models do not show up in /v1/models or /upstream lists
   # but they can still be requested as normal
@@ -117,14 +120,7 @@ models:
       ghcr.io/ggerganov/llama.cpp:server
       --model '/models/Qwen2.5-Coder-0.5B-Instruct-Q4_K_M.gguf'
 
-  # `useModelName` will send a specific model name to the upstream server
+# profiles eliminates swapping by running multiple models at the same time
-  # overriding whatever was set in the request
-  "qwq":
-    proxy: http://127.0.0.1:11434
-    cmd: my-server
-    useModelName: "qwen:qwq"
-
-# profiles make it easy to managing multi model (and gpu) configurations.
 #
 # Tips:
 #  - each model must be listening on a unique address and port
@@ -132,8 +128,8 @@ models:
 #  - the profile will load and unload all models in the profile at the same time
 profiles:
   coding:
-    - "qwen"
     - "llama"
+    - "qwen-unlisted"
 ```
 
 ### Use Case Examples
@@ -223,9 +219,15 @@ Of course, CLI access is also supported:
 # sends up to the last 10KB of logs
 curl http://host/logs'
 
-# streams logs
+# streams combined logs
 curl -Ns 'http://host/logs/stream'
 
+# just llama-swap's logs
+curl -Ns 'http://host/logs/stream/proxy'
+
+# just upstream's logs
+curl -Ns 'http://host/logs/stream/upstream'
+
 # stream and filter logs with linux pipes
 curl -Ns http://host/logs/stream | grep 'eval time'
 
@@ -267,8 +269,4 @@ WantedBy=multi-user.target
 
 ## Star History
 
-<picture>
+[![Star History Chart](https://api.star-history.com/svg?repos=mostlygeek/llama-swap&type=Date)](https://www.star-history.com/#mostlygeek/llama-swap&Date)
-   <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>

config.example.yaml

@@ -1,9 +1,9 @@
 # Seconds to wait for llama.cpp to be available to serve requests
 # Default (and minimum): 15 seconds
-healthCheckTimeout: 15
+healthCheckTimeout: 90
 
-# Log HTTP requests helpful for troubleshoot, defaults to False
+# valid log levels: debug, info (default), warn, error
-logRequests: true
+logLevel: debug
 
 models:
   "llama":

examples/aider-qwq-coder/README.md

@@ -0,0 +1,153 @@
+# aider, QwQ, Qwen-Coder 2.5 and llama-swap
+
+This guide show how to use aider and llama-swap to get a 100% local coding co-pilot setup. The focus is on the trickest part which is configuring aider, llama-swap and llama-server to work together.
+
+## Here's what you you need:
+
+- aider - [installation docs](https://aider.chat/docs/install.html)
+- llama-server - [download latest release](https://github.com/ggml-org/llama.cpp/releases)
+- llama-swap - [download latest release](https://github.com/mostlygeek/llama-swap/releases)
+- [QwQ 32B](https://huggingface.co/bartowski/Qwen_QwQ-32B-GGUF) and [Qwen Coder 2.5 32B](https://huggingface.co/bartowski/Qwen2.5-Coder-32B-Instruct-GGUF) models
+- 24GB VRAM video card
+
+## Running aider
+
+The goal is getting this command line to work:
+
+```sh
+aider --architect \
+    --no-show-model-warnings \
+    --model openai/QwQ \
+    --editor-model openai/qwen-coder-32B \
+    --model-settings-file aider.model.settings.yml \
+    --openai-api-key "sk-na" \
+    --openai-api-base "http://10.0.1.24:8080/v1" \
+```
+
+Set `--openai-api-base` to the IP and port where your llama-swap is running.
+
+## Create an aider model settings file
+
+```yaml
+# aider.model.settings.yml
+
+#
+# !!! important: model names must match llama-swap configuration names !!!
+#
+
+- name: "openai/QwQ"
+  edit_format: diff
+  extra_params:
+    max_tokens: 16384
+    top_p: 0.95
+    top_k: 40
+    presence_penalty: 0.1
+    repetition_penalty: 1
+    num_ctx: 16384
+  use_temperature: 0.6
+  reasoning_tag: think
+  weak_model_name: "openai/qwen-coder-32B"
+  editor_model_name: "openai/qwen-coder-32B"
+
+- name: "openai/qwen-coder-32B"
+  edit_format: diff
+  extra_params:
+    max_tokens: 16384
+    top_p: 0.8
+    top_k: 20
+    repetition_penalty: 1.05
+  use_temperature: 0.6
+  reasoning_tag: think
+  editor_edit_format: editor-diff
+  editor_model_name: "openai/qwen-coder-32B"
+```
+
+## llama-swap configuration
+
+```yaml
+# config.yaml
+
+# The parameters are tweaked to fit model+context into 24GB VRAM GPUs
+models:
+  "qwen-coder-32B":
+    proxy: "http://127.0.0.1:8999"
+    cmd: >
+      /path/to/llama-server
+      --host 127.0.0.1 --port 8999 --flash-attn --slots
+      --ctx-size 16000
+      --cache-type-k q8_0 --cache-type-v q8_0
+       -ngl 99
+      --model /path/to/Qwen2.5-Coder-32B-Instruct-Q4_K_M.gguf
+
+  "QwQ":
+    proxy: "http://127.0.0.1:9503"
+    cmd: >
+      /path/to/llama-server
+      --host 127.0.0.1 --port 9503 --flash-attn --metrics--slots
+      --cache-type-k q8_0 --cache-type-v q8_0
+      --ctx-size 32000
+      --samplers "top_k;top_p;min_p;temperature;dry;typ_p;xtc"
+      --temp 0.6 --repeat-penalty 1.1 --dry-multiplier 0.5
+      --min-p 0.01 --top-k 40 --top-p 0.95
+      -ngl 99
+      --model /mnt/nvme/models/bartowski/Qwen_QwQ-32B-Q4_K_M.gguf
+```
+
+## Advanced, Dual GPU Configuration
+
+If you have _dual 24GB GPUs_ you can use llama-swap profiles to avoid swapping between QwQ and Qwen Coder.
+
+In llama-swap's configuration file:
+
+1. add a `profiles` section with `aider` as the profile name
+2. using the `env` field to specify the GPU IDs for each model
+
+```yaml
+# config.yaml
+
+# Add a profile for aider
+profiles:
+  aider:
+    - qwen-coder-32B
+    - QwQ
+
+models:
+  "qwen-coder-32B":
+    # manually set the GPU to run on
+    env:
+      - "CUDA_VISIBLE_DEVICES=0"
+    proxy: "http://127.0.0.1:8999"
+    cmd: /path/to/llama-server ...
+
+  "QwQ":
+    # manually set the GPU to run on
+    env:
+      - "CUDA_VISIBLE_DEVICES=1"
+    proxy: "http://127.0.0.1:9503"
+    cmd: /path/to/llama-server ...
+```
+
+Append the profile tag, `aider:`, to the model names in the model settings file
+
+```yaml
+# aider.model.settings.yml
+- name: "openai/aider:QwQ"
+  weak_model_name: "openai/aider:qwen-coder-32B-aider"
+  editor_model_name: "openai/aider:qwen-coder-32B-aider"
+
+- name: "openai/aider:qwen-coder-32B"
+  editor_model_name: "openai/aider:qwen-coder-32B-aider"
+```
+
+Run aider with:
+
+```sh
+$ aider --architect \
+    --no-show-model-warnings \
+    --model openai/aider:QwQ \
+    --editor-model openai/aider:qwen-coder-32B \
+    --config aider.conf.yml \
+    --model-settings-file aider.model.settings.yml
+    --openai-api-key "sk-na" \
+    --openai-api-base "http://10.0.1.24:8080/v1"
+```

examples/aider-qwq-coder/aider.model.settings.dualgpu.yml

@@ -0,0 +1,28 @@
+# this makes use of llama-swap's profile feature to
+# keep the architect and editor models in VRAM on different GPUs
+
+- name: "openai/aider:QwQ"
+  edit_format: diff
+  extra_params:
+    max_tokens: 16384
+    top_p: 0.95
+    top_k: 40
+    presence_penalty: 0.1
+    repetition_penalty: 1
+    num_ctx: 16384
+  use_temperature: 0.6
+  reasoning_tag: think
+  weak_model_name: "openai/aider:qwen-coder-32B"
+  editor_model_name: "openai/aider:qwen-coder-32B"
+
+- name: "openai/aider:qwen-coder-32B"
+  edit_format: diff
+  extra_params:
+    max_tokens: 16384
+    top_p: 0.8
+    top_k: 20
+    repetition_penalty: 1.05
+  use_temperature: 0.6
+  reasoning_tag: think
+  editor_edit_format: editor-diff
+  editor_model_name: "openai/aider:qwen-coder-32B"

examples/aider-qwq-coder/aider.model.settings.yml

@@ -0,0 +1,26 @@
+- name: "openai/QwQ"
+  edit_format: diff
+  extra_params:
+    max_tokens: 16384
+    top_p: 0.95
+    top_k: 40
+    presence_penalty: 0.1
+    repetition_penalty: 1
+    num_ctx: 16384
+  use_temperature: 0.6
+  reasoning_tag: think
+  weak_model_name: "openai/qwen-coder-32B"
+  editor_model_name: "openai/qwen-coder-32B"
+
+- name: "openai/qwen-coder-32B"
+  edit_format: diff
+  extra_params:
+    max_tokens: 16384
+    top_p: 0.8
+    top_k: 20
+    repetition_penalty: 1.05
+  use_temperature: 0.6
+  reasoning_tag: think
+  editor_edit_format: editor-diff
+  editor_model_name: "openai/qwen-coder-32B"
+

examples/aider-qwq-coder/llama-swap.yaml

@@ -0,0 +1,49 @@
+healthCheckTimeout: 300
+logLevel: debug
+
+profiles:
+    aider:
+      - qwen-coder-32B
+      - QwQ
+
+models:
+  "qwen-coder-32B":
+    env:
+      - "CUDA_VISIBLE_DEVICES=0"
+    aliases:
+      - coder
+    proxy: "http://127.0.0.1:8999"
+
+    # set appropriate paths for your environment
+    cmd: >
+      /path/to/llama-server
+      --host 127.0.0.1 --port 8999 --flash-attn --slots
+      --ctx-size 16000
+      --ctx-size-draft 16000
+      --model /path/to/Qwen2.5-Coder-32B-Instruct-Q4_K_M.gguf
+      --model-draft /path/to/Qwen2.5-Coder-1.5B-Instruct-Q8_0.gguf
+      -ngl 99 -ngld 99
+      --draft-max 16 --draft-min 4 --draft-p-min 0.4
+      --cache-type-k q8_0 --cache-type-v q8_0
+  "QwQ":
+    env:
+      - "CUDA_VISIBLE_DEVICES=1"
+    proxy: "http://127.0.0.1:9503"
+
+    # set appropriate paths for your environment
+    cmd: >
+      /path/to/llama-server
+      --host 127.0.0.1 --port 9503
+      --flash-attn --metrics
+      --slots
+      --model /path/to/Qwen_QwQ-32B-Q4_K_M.gguf
+      --cache-type-k q8_0 --cache-type-v q8_0
+      --ctx-size 32000
+      --samplers "top_k;top_p;min_p;temperature;dry;typ_p;xtc"
+      --temp 0.6
+      --repeat-penalty 1.1
+      --dry-multiplier 0.5
+      --min-p 0.01
+      --top-k 40
+      --top-p 0.95
+      -ngl 99 -ngld 99

go.mod

@@ -37,7 +37,7 @@ 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

@@ -86,6 +86,8 @@ 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=

proxy/config.go

@@ -27,6 +27,7 @@ func (m *ModelConfig) SanitizedCommand() ([]string, error) {
 type Config struct {
 	HealthCheckTimeout int                    `yaml:"healthCheckTimeout"`
 	LogRequests        bool                   `yaml:"logRequests"`
+	LogLevel           string                 `yaml:"logLevel"`
 	Models             map[string]ModelConfig `yaml:"models"`
 	Profiles           map[string][]string    `yaml:"profiles"`
 

proxy/html/logs.html

@@ -12,32 +12,65 @@
             flex-direction: column;
             font-family: "Courier New", Courier, monospace;
         }
-        #log-controls {
+        .log-container {
-            margin: 0.5em;
             display: flex;
-            align-items: center;
-            justify-content: space-between; /* Spaces out elements evenly */
-        }
-        #log-controls input {
-            flex: 1;
-        }
-        #log-controls input:focus {
-           outline: none; /* Ensures no outline is shown when the input is focused */
-        }
-        #log-stream {
             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; /* Ensures line wrapping */
+            white-space: pre-wrap;
-            word-wrap: break-word; /* Ensures long words 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 {
@@ -45,101 +78,181 @@
                 color: #fff;
             }
 
-            #log-stream {
+            .log-stream {
                 background: #444;
                 color: #fff;
             }
 
-            #log-controls input {
+            .log-controls input {
                 background: #555;
                 color: #fff;
                 border: 1px solid #777;
             }
 
-            #log-controls button {
+            .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>
-    <pre id="log-stream">Waiting for logs...</pre>
+    <div class="log-container">
-    <div id="log-controls">
+        <div class="log-column">
-        <input type="text" id="filter-input" placeholder="regex filter">
+            <h2>Proxy Logs</h2>
-        <button id="clear-button">clear</button>
+            <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>
-        const logStream = document.getElementById('log-stream');
+        class LogStream {
-        const filterInput = document.getElementById('filter-input');
+            constructor(streamElement, filterInput, clearButton, endpoint) {
-        var logData = "";
+                this.streamElement = streamElement;
-        let regexFilter = null;
+                this.filterInput = filterInput;
+                this.clearButton = clearButton;
+                this.endpoint = endpoint;
+                this.logData = "";
+                this.regexFilter = null;
+                this.eventSource = null;
 
-        function setupEventSource() {
+                this.initialize();
-            if (typeof(EventSource) !== "undefined") {
-                const eventSource = new EventSource("/logs/streamSSE");
-
-                eventSource.onmessage = function(event) {
-                    logData += event.data;
-                    render()
-                };
-
-                eventSource.onerror = function(err) {
-                    logData = "EventSource failed: " + err.message;
-                };
-            } else {
-                logData = "SSE Not supported by this browser."
-            }
             }
 
-        // poor-ai's react  ¯\_(ツ)_/¯
+            initialize() {
-        function render() {
+                this.filterInput.addEventListener('input', () => this.updateFilter());
-            if (regexFilter) {
+                this.clearButton.addEventListener('click', () => {
-                const lines = logData.split('\n');
+                    this.filterInput.value = "";
-                const filteredLines = lines.filter(line => {
+                    this.regexFilter = null;
-                    return regexFilter === null || regexFilter.test(line);
+                    this.render();
                 });
-
+                this.setupEventSource();
-                if (filteredLines.length > 0) {
-                    logStream.textContent = filteredLines.join('\n') + '\n';
-                } else {
-                    logStream.textContent = "";
-                }
-            } else {
-                logStream.textContent = logData;
             }
 
-            logStream.scrollTop = logStream.scrollHeight;
+            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;
                 }
 
-        function updateFilter() {
-            const pattern = filterInput.value.trim();
-            filterInput.classList.remove('regex-error');
-            if (pattern) {
                 try {
-                    regexFilter = new RegExp(pattern);
+                    this.regexFilter = new RegExp(pattern);
                 } catch (e) {
                     console.error("Invalid regex pattern:", e);
-                    regexFilter = null;
+                    this.regexFilter = null;
-                    filterInput.classList.add('regex-error');
+                    this.filterInput.classList.add('regex-error');
-                    return
+                    return;
-                }
-            } else {
-                regexFilter = null;
                 }
 
-            render();
+                this.render();
+            }
         }
 
-        filterInput.addEventListener('input', updateFilter);
+        // Initialize both log streams
-        document.getElementById('clear-button').addEventListener('click', () => {
+        document.addEventListener('DOMContentLoaded', () => {
-            filterInput.value = "";
+            new LogStream(
-            regexFilter = null;
+                document.getElementById('proxy-log-stream'),
-            render();
+                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');
+                });
+            });
         });
-        setupEventSource();
-        updateFilter();
     </script>
 </body>
 </html>

proxy/logMonitor.go

@@ -2,11 +2,21 @@ package proxy
 
 import (
 	"container/ring"
+	"fmt"
 	"io"
 	"os"
 	"sync"
 )
 
+type LogLevel int
+
+const (
+	LevelDebug LogLevel = iota
+	LevelInfo
+	LevelWarn
+	LevelError
+)
+
 type LogMonitor struct {
 	clients  map[chan []byte]bool
 	mu       sync.RWMutex
@@ -15,6 +25,10 @@ type LogMonitor struct {
 
 	// typically this can be os.Stdout
 	stdout io.Writer
+
+	// logging levels
+	level  LogLevel
+	prefix string
 }
 
 func NewLogMonitor() *LogMonitor {
@@ -26,6 +40,8 @@ func NewLogMonitorWriter(stdout io.Writer) *LogMonitor {
 		clients: make(map[chan []byte]bool),
 		buffer:  ring.New(10 * 1024), // keep 10KB of buffered logs
 		stdout:  stdout,
+		level:   LevelInfo,
+		prefix:  "",
 	}
 }
 
@@ -94,3 +110,77 @@ func (w *LogMonitor) broadcast(msg []byte) {
 		}
 	}
 }
+
+func (w *LogMonitor) SetPrefix(prefix string) {
+	w.mu.Lock()
+	defer w.mu.Unlock()
+	w.prefix = prefix
+}
+
+func (w *LogMonitor) SetLogLevel(level LogLevel) {
+	w.mu.Lock()
+	defer w.mu.Unlock()
+	w.level = level
+}
+
+func (w *LogMonitor) formatMessage(level string, msg string) []byte {
+	prefix := ""
+	if w.prefix != "" {
+		prefix = fmt.Sprintf("[%s] ", w.prefix)
+	}
+	return []byte(fmt.Sprintf("%s[%s] %s\n", prefix, level, msg))
+}
+
+func (w *LogMonitor) log(level LogLevel, msg string) {
+	if level < w.level {
+		return
+	}
+	w.Write(w.formatMessage(level.String(), msg))
+}
+
+func (w *LogMonitor) Debug(msg string) {
+	w.log(LevelDebug, msg)
+}
+
+func (w *LogMonitor) Info(msg string) {
+	w.log(LevelInfo, msg)
+}
+
+func (w *LogMonitor) Warn(msg string) {
+	w.log(LevelWarn, msg)
+}
+
+func (w *LogMonitor) Error(msg string) {
+	w.log(LevelError, msg)
+}
+
+func (w *LogMonitor) Debugf(format string, args ...interface{}) {
+	w.log(LevelDebug, fmt.Sprintf(format, args...))
+}
+
+func (w *LogMonitor) Infof(format string, args ...interface{}) {
+	w.log(LevelInfo, fmt.Sprintf(format, args...))
+}
+
+func (w *LogMonitor) Warnf(format string, args ...interface{}) {
+	w.log(LevelWarn, fmt.Sprintf(format, args...))
+}
+
+func (w *LogMonitor) Errorf(format string, args ...interface{}) {
+	w.log(LevelError, fmt.Sprintf(format, args...))
+}
+
+func (l LogLevel) String() string {
+	switch l {
+	case LevelDebug:
+		return "DEBUG"
+	case LevelInfo:
+		return "INFO"
+	case LevelWarn:
+		return "WARN"
+	case LevelError:
+		return "ERROR"
+	default:
+		return "UNKNOWN"
+	}
+}

proxy/process.go

@@ -33,8 +33,15 @@ type Process struct {
 	ID     string
 	config ModelConfig
 	cmd    *exec.Cmd
-	logMonitor         *LogMonitor
+
+	// for p.cmd.Wait() select { ... }
+	cmdWaitChan chan error
+
+	processLogger *LogMonitor
+	proxyLogger   *LogMonitor
+
 	healthCheckTimeout      int
+	healthCheckLoopInterval time.Duration
 
 	lastRequestHandled time.Time
 
@@ -51,54 +58,70 @@ type Process struct {
 	shutdownCancel context.CancelFunc
 }
 
-func NewProcess(ID string, healthCheckTimeout int, config ModelConfig, logMonitor *LogMonitor) *Process {
+func NewProcess(ID string, healthCheckTimeout int, config ModelConfig, processLogger *LogMonitor, proxyLogger *LogMonitor) *Process {
 	ctx, cancel := context.WithCancel(context.Background())
 	return &Process{
 		ID:                      ID,
 		config:                  config,
 		cmd:                     nil,
-		logMonitor:         logMonitor,
+		cmdWaitChan:             make(chan error, 1),
+		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,
 	}
 }
 
-func (p *Process) setState(newState ProcessState) error {
+// LogMonitor returns the log monitor associated with the process.
-	// enforce valid state transitions
+func (p *Process) LogMonitor() *LogMonitor {
-	invalidTransition := false
+	return p.processLogger
-	if p.state == StateStopped {
+}
-		// stopped -> starting
+
-		if newState != StateStarting {
+// custom error types for swapping state
-			invalidTransition = true
+var (
-		}
+	ErrExpectedStateMismatch  = errors.New("expected state mismatch")
-	} else if p.state == StateStarting {
+	ErrInvalidStateTransition = errors.New("invalid state transition")
-		// starting -> ready | failed | stopping
+)
-		if newState != StateReady && newState != StateFailed && newState != StateStopping {
+
-			invalidTransition = true
+// swapState performs a compare and swap of the state atomically. It returns the current state
-		}
+// and an error if the swap failed.
-	} else if p.state == StateReady {
+func (p *Process) swapState(expectedState, newState ProcessState) (ProcessState, error) {
-		// ready -> stopping
+	p.stateMutex.Lock()
-		if newState != StateStopping {
+	defer p.stateMutex.Unlock()
-			invalidTransition = true
+
-		}
+	if p.state != expectedState {
-	} else if p.state == StateStopping {
+		p.proxyLogger.Warnf("swapState() Unexpected current state %s, expected %s", p.state, expectedState)
-		// stopping -> stopped | shutdown
+		return p.state, ErrExpectedStateMismatch
-		if newState != StateStopped && newState != StateShutdown {
-			invalidTransition = true
-		}
-	} else if p.state == StateFailed || p.state == StateShutdown {
-		invalidTransition = true
 	}
 
-	if invalidTransition {
+	if !isValidTransition(p.state, newState) {
-		//panic(fmt.Sprintf("Invalid state transition from %s to %s", p.state, newState))
+		p.proxyLogger.Warnf("swapState() Invalid state transition from %s to %s", p.state, newState)
-		return fmt.Errorf("invalid state transition from %s to %s", p.state, newState)
+		return p.state, ErrInvalidStateTransition
 	}
 
 	p.state = newState
-	return nil
+	p.proxyLogger.Debugf("swapState() State transitioned from %s to %s", expectedState, newState)
+	return p.state, nil
+}
+
+// Helper function to encapsulate transition rules
+func isValidTransition(from, to ProcessState) bool {
+	switch from {
+	case StateStopped:
+		return to == StateStarting
+	case StateStarting:
+		return to == StateReady || to == StateFailed || to == StateStopping
+	case StateReady:
+		return to == StateStopping
+	case StateStopping:
+		return to == StateStopped || to == StateShutdown
+	case StateFailed, StateShutdown:
+		return false // No transitions allowed from these states
+	}
+	return false
 }
 
 func (p *Process) CurrentState() ProcessState {
@@ -116,68 +139,58 @@ func (p *Process) start() error {
 		return fmt.Errorf("can not start(), upstream proxy missing")
 	}
 
-	// multiple start() calls will wait for the one that is actually starting to
-	// complete before proceeding.
-	// ===========
-	curState := p.CurrentState()
-
-	if curState == StateReady {
-		return nil
-	}
-
-	if curState == StateStarting {
-		p.waitStarting.Wait()
-
-		if state := p.CurrentState(); state != StateReady {
-			return fmt.Errorf("start() failed current state: %v", state)
-		}
-
-		return nil
-	}
-	// ===========
-
-	// There is the possibility of a hard to replicate race condition where
-	// curState *WAS* StateStopped but by the time we get to the p.stateMutex.Lock()
-	// below, it's value has changed!
-
-	p.stateMutex.Lock()
-	defer p.stateMutex.Unlock()
-
-	// with the exclusive lock, check if p.state is StateStopped, which is the only valid state
-	// to transition from to StateReady
-
-	if p.state != StateStopped {
-		if p.state == StateReady {
-			return nil
-		} else {
-			return fmt.Errorf("start() can not proceed expected StateReady but process is in %v", p.state)
-		}
-	}
-
-	if err := p.setState(StateStarting); err != nil {
-		return err
-	}
-
-	p.waitStarting.Add(1)
-	defer p.waitStarting.Done()
-
 	args, err := p.config.SanitizedCommand()
 	if err != nil {
 		return fmt.Errorf("unable to get sanitized command: %v", err)
 	}
 
+	if curState, err := p.swapState(StateStopped, StateStarting); err != nil {
+		if err == ErrExpectedStateMismatch {
+			// already starting, just wait for it to complete and expect
+			// it to be be in the Ready start after. If not, return an error
+			if curState == StateStarting {
+				p.waitStarting.Wait()
+				if state := p.CurrentState(); state == StateReady {
+					return nil
+				} else {
+					return fmt.Errorf("process was already starting but wound up in state %v", state)
+				}
+			} else {
+				return fmt.Errorf("processes was in state %v when start() was called", curState)
+			}
+		} else {
+			return fmt.Errorf("failed to set Process state to starting: current state: %v, error: %v", curState, err)
+		}
+	}
+
+	p.waitStarting.Add(1)
+	defer p.waitStarting.Done()
+
 	p.cmd = exec.Command(args[0], args[1:]...)
-	p.cmd.Stdout = p.logMonitor
+	p.cmd.Stdout = p.processLogger
-	p.cmd.Stderr = p.logMonitor
+	p.cmd.Stderr = p.processLogger
 	p.cmd.Env = p.config.Env
 
 	err = p.cmd.Start()
 
+	// Set process state to failed
 	if err != nil {
-		p.setState(StateFailed)
+		if curState, swapErr := p.swapState(StateStarting, StateFailed); swapErr != nil {
+			return fmt.Errorf(
+				"failed to start command and state swap failed. command error: %v, current state: %v, state swap error: %v",
+				err, curState, swapErr,
+			)
+		}
 		return fmt.Errorf("start() failed: %v", err)
 	}
 
+	// Capture the exit error for later signaling
+	go func() {
+		exitErr := p.cmd.Wait()
+		p.proxyLogger.Debugf("cmd.Wait() returned for [%s] error: %v", p.ID, exitErr)
+		p.cmdWaitChan <- exitErr
+	}()
+
 	// One of three things can happen at this stage:
 	// 1. The command exits unexpectedly
 	// 2. The health check fails
@@ -209,31 +222,51 @@ func (p *Process) start() error {
 		)
 		defer cancelHealthCheck()
 
-		// Health check loop
 	loop:
+		// Ready Check loop
 		for {
 			select {
 			case <-checkDeadline.Done():
-				p.setState(StateFailed)
+				if curState, err := p.swapState(StateStarting, StateFailed); err != nil {
-				return fmt.Errorf("health check failed after %vs", maxDuration.Seconds())
+					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())
+				}
 			case <-p.shutdownCtx.Done():
 				return errors.New("health check interrupted due to shutdown")
+			case exitErr := <-p.cmdWaitChan:
+				if exitErr != nil {
+					p.proxyLogger.Warnf("upstream command exited prematurely with error: %v", exitErr)
+					if curState, err := p.swapState(StateStarting, StateFailed); err != nil {
+						return fmt.Errorf("upstream command exited unexpectedly: %s AND state swap failed: %v, current state: %v", exitErr.Error(), err, curState)
+					} else {
+						return fmt.Errorf("upstream command exited unexpectedly: %s", exitErr.Error())
+					}
+				} else {
+					p.proxyLogger.Warnf("upstream command exited prematurely with no error")
+					if curState, err := p.swapState(StateStarting, StateFailed); err != nil {
+						return fmt.Errorf("upstream command exited prematurely with no error AND state swap failed: %v, current state: %v", err, curState)
+					} else {
+						return fmt.Errorf("upstream command exited prematurely with no error")
+					}
+				}
 			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)
-						fmt.Fprintf(p.logMonitor, "!!! Connection refused on %s, ttl %.0fs\n", healthURL, ttl.Seconds())
+						p.proxyLogger.Infof("Connection refused on %s, giving up in %.0fs", healthURL, ttl.Seconds())
 					} else {
-						fmt.Fprintf(p.logMonitor, "!!! Health check error: %v\n", err)
+						p.proxyLogger.Infof("Health check error on %s, %v", healthURL, err)
 					}
 				}
 			}
 
-			<-time.After(5 * time.Second)
+			<-time.After(p.healthCheckLoopInterval)
 		}
 	}
 
@@ -244,7 +277,7 @@ func (p *Process) start() error {
 			maxDuration := time.Duration(p.config.UnloadAfter) * time.Second
 
 			for range time.Tick(time.Second) {
-				if p.state != StateReady {
+				if p.CurrentState() != StateReady {
 					return
 				}
 
@@ -252,7 +285,7 @@ func (p *Process) start() error {
 				p.inFlightRequests.Wait()
 
 				if time.Since(p.lastRequestHandled) > maxDuration {
-					fmt.Fprintf(p.logMonitor, "!!! Unloading model %s, TTL of %ds reached.\n", p.ID, p.config.UnloadAfter)
+					p.proxyLogger.Infof("Unloading model %s, TTL of %ds reached.", p.ID, p.config.UnloadAfter)
 					p.Stop()
 					return
 				}
@@ -260,26 +293,29 @@ func (p *Process) start() error {
 		}()
 	}
 
-	return p.setState(StateReady)
+	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 {
+		return nil
+	}
 }
 
 func (p *Process) Stop() {
 	// wait for any inflight requests before proceeding
 	p.inFlightRequests.Wait()
-	p.stateMutex.Lock()
+	p.proxyLogger.Debugf("Stopping process [%s]", p.ID)
-	defer p.stateMutex.Unlock()
 
 	// calling Stop() when state is invalid is a no-op
-	if err := p.setState(StateStopping); err != nil {
+	if curState, err := p.swapState(StateReady, StateStopping); err != nil {
-		fmt.Fprintf(p.logMonitor, "!!! Info - Stop() err: %v\n", err)
+		p.proxyLogger.Infof("Stop() Ready -> StateStopping err: %v, current state: %v", err, curState)
 		return
 	}
 
 	// stop the process with a graceful exit timeout
 	p.stopCommand(5 * time.Second)
 
-	if err := p.setState(StateStopped); err != nil {
+	if curState, err := p.swapState(StateStopping, StateStopped); err != nil {
-		panic(fmt.Sprintf("Stop() failed to set state to stopped: %v", err))
+		p.proxyLogger.Infof("Stop() StateStopping -> StateStopped err: %v, current state: %v", err, curState)
 	}
 }
 
@@ -287,58 +323,53 @@ func (p *Process) Stop() {
 // 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
 func (p *Process) Shutdown() {
-	// cancel anything that can be interrupted by a shutdown (ie: healthcheck)
 	p.shutdownCancel()
-
-	p.stateMutex.Lock()
-	defer p.stateMutex.Unlock()
-	p.setState(StateStopping)
-
-	// 5 seconds to stop the process
 	p.stopCommand(5 * time.Second)
-	if err := p.setState(StateShutdown); err != nil {
+	p.state = StateShutdown
-		fmt.Printf("!!! Shutdown() failed to set state to shutdown: %v", err)
-	}
-	p.setState(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) {
+	stopStartTime := time.Now()
+	defer func() {
+		p.proxyLogger.Debugf("Process [%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 {
-		fmt.Fprintf(p.logMonitor, "!!! process [%s] cmd or cmd.Process is nil", p.ID)
+		p.proxyLogger.Warnf("Process [%s] cmd or cmd.Process is nil", p.ID)
 		return
 	}
 
-	p.cmd.Process.Signal(syscall.SIGTERM)
+	if err := p.terminateProcess(); err != nil {
+		p.proxyLogger.Infof("Failed to gracefully terminate process [%s]: %v", p.ID, err)
+	}
 
 	select {
 	case <-sigtermTimeout.Done():
-		fmt.Fprintf(p.logMonitor, "!!! process [%s] timed out waiting to stop, sending KILL signal\n", p.ID)
+		p.proxyLogger.Infof("Process [%s] timed out waiting to stop, sending KILL signal", p.ID)
 		p.cmd.Process.Kill()
-	case err := <-sigtermNormal:
+	case err := <-p.cmdWaitChan:
+		// Note: in start(), p.cmdWaitChan also has a select { ... }. That should be OK
+		// because if we make it here then the cmd has been successfully running and made it
+		// through the health check. There is a possibility that ithe cmd crashed after the health check
+		// succeeded but that's not a case llama-swap is handling for now.
 		if err != nil {
 			if errno, ok := err.(syscall.Errno); ok {
-				fmt.Fprintf(p.logMonitor, "!!! process [%s] errno >> %v\n", p.ID, errno)
+				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") {
-					fmt.Fprintf(p.logMonitor, "!!! process [%s] stopped OK\n", p.ID)
+					p.proxyLogger.Infof("Process [%s] stopped OK", p.ID)
 				} else if strings.Contains(exitError.String(), "signal: interrupt") {
-					fmt.Fprintf(p.logMonitor, "!!! process [%s] interrupted OK\n", p.ID)
+					p.proxyLogger.Infof("Process [%s] interrupted OK", p.ID)
 				} else {
-					fmt.Fprintf(p.logMonitor, "!!! process [%s] ExitError >> %v, exit code: %d\n", p.ID, exitError, exitError.ExitCode())
+					p.proxyLogger.Warnf("Process [%s] ExitError >> %v, exit code: %d", p.ID, exitError, exitError.ExitCode())
 				}
-
 			} else {
-				fmt.Fprintf(p.logMonitor, "!!! process [%s] exited >> %v\n", p.ID, err)
+				p.proxyLogger.Errorf("Process [%s] exited >> %v", p.ID, err)
 			}
 		}
 	}
@@ -370,6 +401,8 @@ func (p *Process) checkHealthEndpoint(healthURL string) error {
 }
 
 func (p *Process) ProxyRequest(w http.ResponseWriter, r *http.Request) {
+	requestBeginTime := time.Now()
+	var startDuration time.Duration
 
 	// prevent new requests from being made while stopping or irrecoverable
 	currentState := p.CurrentState()
@@ -386,11 +419,13 @@ func (p *Process) ProxyRequest(w http.ResponseWriter, r *http.Request) {
 
 	// start the process on demand
 	if p.CurrentState() != StateReady {
+		beginStartTime := time.Now()
 		if err := p.start(); err != nil {
 			errstr := fmt.Sprintf("unable to start process: %s", err)
 			http.Error(w, errstr, http.StatusBadGateway)
 			return
 		}
+		startDuration = time.Since(beginStartTime)
 	}
 
 	proxyTo := p.config.Proxy
@@ -434,4 +469,8 @@ func (p *Process) ProxyRequest(w http.ResponseWriter, r *http.Request) {
 			return
 		}
 	}
+
+	totalTime := time.Since(requestBeginTime)
+	p.proxyLogger.Debugf("Process [%s] request %s - start: %v, total: %v",
+		p.ID, r.RequestURI, startDuration, totalTime)
 }

proxy/process_stop.go

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

proxy/process_stop_windows.go

@@ -0,0 +1,14 @@
+//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

@@ -2,7 +2,6 @@ package proxy
 
 import (
 	"fmt"
-	"io"
 	"net/http"
 	"net/http/httptest"
 	"os"
@@ -13,13 +12,26 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
+var (
+	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) {
-	logMonitor := NewLogMonitorWriter(io.Discard)
+
 	expectedMessage := "testing91931"
 	config := getTestSimpleResponderConfig(expectedMessage)
 
 	// Create a process
-	process := NewProcess("test-process", 5, config, logMonitor)
+	process := NewProcess("test-process", 5, config, debugLogger, debugLogger)
 	defer process.Stop()
 
 	req := httptest.NewRequest("GET", "/test", nil)
@@ -52,11 +64,10 @@ func TestProcess_AutomaticallyStartsUpstream(t *testing.T) {
 // are all handled successfully, even though they all may ask for the process to .start()
 func TestProcess_WaitOnMultipleStarts(t *testing.T) {
 
-	logMonitor := NewLogMonitorWriter(io.Discard)
 	expectedMessage := "testing91931"
 	config := getTestSimpleResponderConfig(expectedMessage)
 
-	process := NewProcess("test-process", 5, config, logMonitor)
+	process := NewProcess("test-process", 5, config, debugLogger, debugLogger)
 	defer process.Stop()
 
 	var wg sync.WaitGroup
@@ -84,7 +95,7 @@ func TestProcess_BrokenModelConfig(t *testing.T) {
 		CheckEndpoint: "/health",
 	}
 
-	process := NewProcess("broken", 1, config, NewLogMonitor())
+	process := NewProcess("broken", 1, config, debugLogger, debugLogger)
 
 	req := httptest.NewRequest("GET", "/", nil)
 	w := httptest.NewRecorder()
@@ -109,7 +120,7 @@ func TestProcess_UnloadAfterTTL(t *testing.T) {
 	config.UnloadAfter = 3 // seconds
 	assert.Equal(t, 3, config.UnloadAfter)
 
-	process := NewProcess("ttl_test", 2, config, NewLogMonitorWriter(io.Discard))
+	process := NewProcess("ttl_test", 2, config, debugLogger, debugLogger)
 	defer process.Stop()
 
 	// this should take 4 seconds
@@ -151,7 +162,7 @@ func TestProcess_LowTTLValue(t *testing.T) {
 	config.UnloadAfter = 1 // second
 	assert.Equal(t, 1, config.UnloadAfter)
 
-	process := NewProcess("ttl", 2, config, NewLogMonitorWriter(os.Stdout))
+	process := NewProcess("ttl", 2, config, debugLogger, debugLogger)
 	defer process.Stop()
 
 	for i := 0; i < 100; i++ {
@@ -178,7 +189,7 @@ func TestProcess_HTTPRequestsHaveTimeToFinish(t *testing.T) {
 
 	expectedMessage := "12345"
 	config := getTestSimpleResponderConfig(expectedMessage)
-	process := NewProcess("t", 10, config, NewLogMonitorWriter(os.Stdout))
+	process := NewProcess("t", 10, config, debugLogger, debugLogger)
 	defer process.Stop()
 
 	results := map[string]string{
@@ -225,39 +236,40 @@ func TestProcess_HTTPRequestsHaveTimeToFinish(t *testing.T) {
 	}
 }
 
-func TestSetState(t *testing.T) {
+func TestProcess_SwapState(t *testing.T) {
 	tests := []struct {
 		name           string
 		currentState   ProcessState
+		expectedState  ProcessState
 		newState       ProcessState
 		expectedError  error
 		expectedResult ProcessState
 	}{
-		{"Stopped to Starting", StateStopped, StateStarting, nil, StateStarting},
+		{"Stopped to Starting", StateStopped, StateStopped, StateStarting, nil, StateStarting},
-		{"Starting to Ready", StateStarting, StateReady, nil, StateReady},
+		{"Starting to Ready", StateStarting, StateStarting, StateReady, nil, StateReady},
-		{"Starting to Failed", StateStarting, StateFailed, nil, StateFailed},
+		{"Starting to Failed", StateStarting, StateStarting, StateFailed, nil, StateFailed},
-		{"Starting to Stopping", StateStarting, StateStopping, nil, StateStopping},
+		{"Starting to Stopping", StateStarting, StateStarting, StateStopping, nil, StateStopping},
-		{"Ready to Stopping", StateReady, StateStopping, nil, StateStopping},
+		{"Ready to Stopping", StateReady, StateReady, StateStopping, nil, StateStopping},
-		{"Stopping to Stopped", StateStopping, StateStopped, nil, StateStopped},
+		{"Stopping to Stopped", StateStopping, StateStopping, StateStopped, nil, StateStopped},
-		{"Stopping to Shutdown", StateStopping, StateShutdown, nil, StateShutdown},
+		{"Stopping to Shutdown", StateStopping, StateStopping, StateShutdown, nil, StateShutdown},
-		{"Stopped to Ready", StateStopped, StateReady, fmt.Errorf("invalid state transition from stopped to ready"), StateStopped},
+		{"Stopped to Ready", StateStopped, StateStopped, StateReady, ErrInvalidStateTransition, StateStopped},
-		{"Starting to Stopped", StateStarting, StateStopped, fmt.Errorf("invalid state transition from starting to stopped"), StateStarting},
+		{"Starting to Stopped", StateStarting, StateStarting, StateStopped, ErrInvalidStateTransition, StateStarting},
-		{"Ready to Starting", StateReady, StateStarting, fmt.Errorf("invalid state transition from ready to starting"), StateReady},
+		{"Ready to Starting", StateReady, StateReady, StateStarting, ErrInvalidStateTransition, StateReady},
-		{"Ready to Failed", StateReady, StateFailed, fmt.Errorf("invalid state transition from ready to failed"), StateReady},
+		{"Ready to Failed", StateReady, StateReady, StateFailed, ErrInvalidStateTransition, StateReady},
-		{"Stopping to Ready", StateStopping, StateReady, fmt.Errorf("invalid state transition from stopping to ready"), StateStopping},
+		{"Stopping to Ready", StateStopping, StateStopping, StateReady, ErrInvalidStateTransition, StateStopping},
-		{"Failed to Stopped", StateFailed, StateStopped, fmt.Errorf("invalid state transition from failed to stopped"), StateFailed},
+		{"Failed to Stopped", StateFailed, StateFailed, StateStopped, ErrInvalidStateTransition, StateFailed},
-		{"Failed to Starting", StateFailed, StateStarting, fmt.Errorf("invalid state transition from failed to starting"), StateFailed},
+		{"Failed to Starting", StateFailed, StateFailed, StateStarting, ErrInvalidStateTransition, StateFailed},
-		{"Shutdown to Stopped", StateShutdown, StateStopped, fmt.Errorf("invalid state transition from shutdown to stopped"), StateShutdown},
+		{"Shutdown to Stopped", StateShutdown, StateShutdown, StateStopped, ErrInvalidStateTransition, StateShutdown},
-		{"Shutdown to Starting", StateShutdown, StateStarting, fmt.Errorf("invalid state transition from shutdown to starting"), StateShutdown},
+		{"Shutdown to Starting", StateShutdown, StateShutdown, StateStarting, ErrInvalidStateTransition, StateShutdown},
+		{"Expected state mismatch", StateStopped, StateStarting, StateStarting, ErrExpectedStateMismatch, StateStopped},
 	}
 
 	for _, test := range tests {
 		t.Run(test.name, func(t *testing.T) {
-			p := &Process{
+			p := NewProcess("test", 10, getTestSimpleResponderConfig("test"), debugLogger, debugLogger)
-				state: test.currentState,
+			p.state = test.currentState
-			}
 
-			err := p.setState(test.newState)
+			resultState, err := p.swapState(test.expectedState, test.newState)
 			if err != nil && test.expectedError == nil {
 				t.Errorf("Unexpected error: %v", err)
 			} else if err == nil && test.expectedError != nil {
@@ -268,8 +280,8 @@ func TestSetState(t *testing.T) {
 				}
 			}
 
-			if p.state != test.expectedResult {
+			if resultState != test.expectedResult {
-				t.Errorf("Expected state: %v, got: %v", test.expectedResult, p.state)
+				t.Errorf("Expected state: %v, got: %v", test.expectedResult, resultState)
 			}
 		})
 	}
@@ -280,7 +292,6 @@ func TestProcess_ShutdownInterruptsHealthCheck(t *testing.T) {
 		t.Skip("skipping long shutdown test")
 	}
 
-	logMonitor := NewLogMonitorWriter(io.Discard)
 	expectedMessage := "testing91931"
 
 	// make a config where the healthcheck will always fail because port is wrong
@@ -288,13 +299,16 @@ func TestProcess_ShutdownInterruptsHealthCheck(t *testing.T) {
 	config.Proxy = "http://localhost:9998/test"
 
 	healthCheckTTLSeconds := 30
-	process := NewProcess("test-process", healthCheckTTLSeconds, config, logMonitor)
+	process := NewProcess("test-process", healthCheckTTLSeconds, config, debugLogger, debugLogger)
+
+	// make it a lot faster
+	process.healthCheckLoopInterval = time.Second
 
 	// start a goroutine to simulate a shutdown
 	var wg sync.WaitGroup
 	go func() {
 		defer wg.Done()
-		<-time.After(time.Second * 2)
+		<-time.After(time.Millisecond * 500)
 		process.Shutdown()
 	}()
 	wg.Add(1)
@@ -306,3 +320,23 @@ 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 with no error", err.Error())
+	assert.Equal(t, process.CurrentState(), StateFailed)
+}

proxy/proxymanager.go

@@ -7,6 +7,7 @@ import (
 	"io"
 	"mime/multipart"
 	"net/http"
+	"os"
 	"sort"
 	"strconv"
 	"strings"
@@ -27,19 +28,52 @@ type ProxyManager struct {
 
 	config           *Config
 	currentProcesses map[string]*Process
-	logMonitor       *LogMonitor
 	ginEngine        *gin.Engine
+
+	// logging
+	proxyLogger    *LogMonitor
+	upstreamLogger *LogMonitor
+	muxLogger      *LogMonitor
 }
 
 func New(config *Config) *ProxyManager {
+	// set up loggers
+	stdoutLogger := NewLogMonitorWriter(os.Stdout)
+	upstreamLogger := NewLogMonitorWriter(stdoutLogger)
+	proxyLogger := NewLogMonitorWriter(stdoutLogger)
+
+	if config.LogRequests {
+		proxyLogger.Warn("LogRequests configuration is deprecated. Use logLevel instead.")
+	}
+
+	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)
+	}
+
 	pm := &ProxyManager{
 		config:           config,
 		currentProcesses: make(map[string]*Process),
-		logMonitor:       NewLogMonitor(),
 		ginEngine:        gin.New(),
+
+		proxyLogger:    proxyLogger,
+		muxLogger:      stdoutLogger,
+		upstreamLogger: upstreamLogger,
 	}
 
-	if config.LogRequests {
 	pm.ginEngine.Use(func(c *gin.Context) {
 		// Start timer
 		start := time.Now()
@@ -58,9 +92,8 @@ func New(config *Config) *ProxyManager {
 		statusCode := c.Writer.Status()
 		bodySize := c.Writer.Size()
 
-			fmt.Fprintf(pm.logMonitor, "[llama-swap] %s [%s] \"%s %s %s\" %d %d \"%s\" %v\n",
+		pm.proxyLogger.Infof("Request %s \"%s %s %s\" %d %d \"%s\" %v",
 			clientIP,
-				time.Now().Format("2006-01-02 15:04:05"),
 			method,
 			path,
 			c.Request.Proto,
@@ -70,16 +103,26 @@ func New(config *Config) *ProxyManager {
 			duration,
 		)
 	})
-	}
 
-	// see: https://github.com/mostlygeek/llama-swap/issues/42
+	// see: issue: #81, #77 and #42 for CORS issues
 	// respond with permissive OPTIONS for any endpoint
 	pm.ginEngine.Use(func(c *gin.Context) {
 		if c.Request.Method == "OPTIONS" {
 			c.Header("Access-Control-Allow-Origin", "*")
-			c.Header("Access-Control-Allow-Methods", "GET, POST, OPTIONS")
+			c.Header("Access-Control-Allow-Methods", "GET, POST, PUT, PATCH, DELETE, OPTIONS")
-			c.Header("Access-Control-Allow-Headers", "Content-Type, Authorization")
+
-			c.AbortWithStatus(204)
+			// allow whatever the client requested by default
+			if headers := c.Request.Header.Get("Access-Control-Request-Headers"); headers != "" {
+				sanitized := SanitizeAccessControlRequestHeaderValues(headers)
+				c.Header("Access-Control-Allow-Headers", sanitized)
+			} else {
+				c.Header(
+					"Access-Control-Allow-Headers",
+					"Content-Type, Authorization, Accept, X-Requested-With",
+				)
+			}
+			c.Header("Access-Control-Max-Age", "86400")
+			c.AbortWithStatus(http.StatusNoContent)
 			return
 		}
 		c.Next()
@@ -104,6 +147,8 @@ func New(config *Config) *ProxyManager {
 	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)
@@ -263,19 +308,20 @@ func (pm *ProxyManager) swapModel(requestedModel string) (*Process, error) {
 	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.logMonitor)
+		process := NewProcess(modelID, pm.config.HealthCheckTimeout, modelConfig, pm.upstreamLogger, pm.proxyLogger)
 		processKey := ProcessKeyName(profileName, modelID)
 		pm.currentProcesses[processKey] = process
 	} else {
@@ -286,7 +332,7 @@ func (pm *ProxyManager) swapModel(requestedModel string) (*Process, error) {
 					return nil, fmt.Errorf("could not find configuration for %s in group %s", realModelName, profileName)
 				}
 
-				process := NewProcess(modelID, pm.config.HealthCheckTimeout, modelConfig, pm.logMonitor)
+				process := NewProcess(modelID, pm.config.HealthCheckTimeout, modelConfig, pm.upstreamLogger, pm.proxyLogger)
 				processKey := ProcessKeyName(profileName, modelID)
 				pm.currentProcesses[processKey] = process
 			}
@@ -374,7 +420,6 @@ func (pm *ProxyManager) proxyOAIHandler(c *gin.Context) {
 				return
 			}
 		}
-
 	}
 
 	c.Request.Body = io.NopCloser(bytes.NewBuffer(bodyBytes))

proxy/proxymanager_loghandlers.go

@@ -9,7 +9,6 @@ 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
@@ -28,7 +27,7 @@ func (pm *ProxyManager) sendLogsHandlers(c *gin.Context) {
 		}
 	} else {
 		c.Header("Content-Type", "text/plain")
-		history := pm.logMonitor.GetHistory()
+		history := pm.muxLogger.GetHistory()
 		_, err := c.Writer.Write(history)
 		if err != nil {
 			c.AbortWithError(http.StatusInternalServerError, err)
@@ -42,8 +41,14 @@ func (pm *ProxyManager) streamLogsHandler(c *gin.Context) {
 	c.Header("Transfer-Encoding", "chunked")
 	c.Header("X-Content-Type-Options", "nosniff")
 
-	ch := pm.logMonitor.Subscribe()
+	logMonitorId := c.Param("logMonitorID")
-	defer pm.logMonitor.Unsubscribe(ch)
+	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()
 	flusher, ok := c.Writer.(http.Flusher)
@@ -56,7 +61,7 @@ func (pm *ProxyManager) streamLogsHandler(c *gin.Context) {
 	// Send history first if not skipped
 
 	if !skipHistory {
-		history := pm.logMonitor.GetHistory()
+		history := logger.GetHistory()
 		if len(history) != 0 {
 			c.Writer.Write(history)
 			flusher.Flush()
@@ -85,15 +90,21 @@ func (pm *ProxyManager) streamLogsHandlerSSE(c *gin.Context) {
 	c.Header("Connection", "keep-alive")
 	c.Header("X-Content-Type-Options", "nosniff")
 
-	ch := pm.logMonitor.Subscribe()
+	logMonitorId := c.Param("logMonitorID")
-	defer pm.logMonitor.Unsubscribe(ch)
+	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 := pm.logMonitor.GetHistory()
+		history := logger.GetHistory()
 		if len(history) != 0 {
 			c.SSEvent("message", string(history))
 			c.Writer.Flush()
@@ -111,3 +122,21 @@ func (pm *ProxyManager) streamLogsHandlerSSE(c *gin.Context) {
 		}
 	}
 }
+
+// getLogger searches for the appropriate logger based on the logMonitorId
+func (pm *ProxyManager) getLogger(logMonitorId string) (*LogMonitor, error) {
+	var logger *LogMonitor
+
+	if logMonitorId == "" {
+		// maintain the default
+		logger = pm.muxLogger
+	} else if logMonitorId == "proxy" {
+		logger = pm.proxyLogger
+	} else if logMonitorId == "upstream" {
+		logger = pm.upstreamLogger
+	} else {
+		return nil, fmt.Errorf("invalid logger. Use 'proxy' or 'upstream'")
+	}
+
+	return logger, nil
+}

proxy/proxymanager_test.go

@@ -22,6 +22,7 @@ func TestProxyManager_SwapProcessCorrectly(t *testing.T) {
 			"model1": getTestSimpleResponderConfig("model1"),
 			"model2": getTestSimpleResponderConfig("model2"),
 		},
+		LogLevel: "error",
 	}
 
 	proxy := New(config)
@@ -62,6 +63,7 @@ func TestProxyManager_SwapMultiProcess(t *testing.T) {
 		Profiles: map[string][]string{
 			"test": {model1, model2},
 		},
+		LogLevel: "error",
 	}
 
 	proxy := New(config)
@@ -103,6 +105,7 @@ func TestProxyManager_SwapMultiProcessParallelRequests(t *testing.T) {
 			"model2": getTestSimpleResponderConfig("model2"),
 			"model3": getTestSimpleResponderConfig("model3"),
 		},
+		LogLevel: "error",
 	}
 
 	proxy := New(config)
@@ -153,6 +156,7 @@ func TestProxyManager_ListModelsHandler(t *testing.T) {
 			"model2": getTestSimpleResponderConfig("model2"),
 			"model3": getTestSimpleResponderConfig("model3"),
 		},
+		LogLevel: "error",
 	}
 
 	proxy := New(config)
@@ -230,6 +234,7 @@ func TestProxyManager_ProfileNonMember(t *testing.T) {
 		Profiles: map[string][]string{
 			"test": {model1},
 		},
+		LogLevel: "error",
 	}
 
 	proxy := New(config)
@@ -278,6 +283,7 @@ func TestProxyManager_Shutdown(t *testing.T) {
 			"model2": model2Config,
 			"model3": model3Config,
 		},
+		LogLevel: "error",
 	}
 
 	proxy := New(config)
@@ -313,6 +319,7 @@ func TestProxyManager_Unload(t *testing.T) {
 		Models: map[string]ModelConfig{
 			"model1": getTestSimpleResponderConfig("model1"),
 		},
+		LogLevel: "error",
 	}
 
 	proxy := New(config)
@@ -339,6 +346,7 @@ func TestProxyManager_StripProfileSlug(t *testing.T) {
 		Models: map[string]ModelConfig{
 			"TheExpectedModel": getTestSimpleResponderConfig("TheExpectedModel"),
 		},
+		LogLevel: "error",
 	}
 
 	proxy := New(config)
@@ -365,6 +373,7 @@ func TestProxyManager_RunningEndpoint(t *testing.T) {
 		Profiles: map[string][]string{
 			"test": {"model1", "model2"},
 		},
+		LogLevel: "error",
 	}
 
 	// Define a helper struct to parse the JSON response.
@@ -472,6 +481,7 @@ func TestProxyManager_AudioTranscriptionHandler(t *testing.T) {
 		Models: map[string]ModelConfig{
 			"TheExpectedModel": getTestSimpleResponderConfig("TheExpectedModel"),
 		},
+		LogLevel: "error",
 	}
 
 	proxy := New(config)
@@ -580,6 +590,8 @@ func TestProxyManager_UseModelName(t *testing.T) {
 		Models: map[string]ModelConfig{
 			"model1": modelConfig,
 		},
+
+		LogLevel: "error",
 	}
 
 	proxy := New(config)
@@ -639,5 +651,72 @@ func TestProxyManager_UseModelName(t *testing.T) {
 			assert.Equal(t, upstreamModelName, response["model"])
 		})
 	}
-
+}
+
+func TestProxyManager_CORSOptionsHandler(t *testing.T) {
+	config := &Config{
+		HealthCheckTimeout: 15,
+		Models: map[string]ModelConfig{
+			"model1": getTestSimpleResponderConfig("model1"),
+		},
+		LogLevel: "error",
+	}
+
+	tests := []struct {
+		name            string
+		method          string
+		requestHeaders  map[string]string
+		expectedStatus  int
+		expectedHeaders map[string]string
+	}{
+		{
+			name:           "OPTIONS with no headers",
+			method:         "OPTIONS",
+			expectedStatus: http.StatusNoContent,
+			expectedHeaders: map[string]string{
+				"Access-Control-Allow-Origin":  "*",
+				"Access-Control-Allow-Methods": "GET, POST, PUT, PATCH, DELETE, OPTIONS",
+				"Access-Control-Allow-Headers": "Content-Type, Authorization, Accept, X-Requested-With",
+			},
+		},
+		{
+			name:   "OPTIONS with specific headers",
+			method: "OPTIONS",
+			requestHeaders: map[string]string{
+				"Access-Control-Request-Headers": "X-Custom-Header, Some-Other-Header",
+			},
+			expectedStatus: http.StatusNoContent,
+			expectedHeaders: map[string]string{
+				"Access-Control-Allow-Origin":  "*",
+				"Access-Control-Allow-Methods": "GET, POST, PUT, PATCH, DELETE, OPTIONS",
+				"Access-Control-Allow-Headers": "X-Custom-Header, Some-Other-Header",
+			},
+		},
+		{
+			name:           "Non-OPTIONS request",
+			method:         "GET",
+			expectedStatus: http.StatusNotFound, // Since we don't have a GET route defined
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			proxy := New(config)
+			defer proxy.StopProcesses()
+
+			req := httptest.NewRequest(tt.method, "/v1/chat/completions", nil)
+			for k, v := range tt.requestHeaders {
+				req.Header.Set(k, v)
+			}
+
+			w := httptest.NewRecorder()
+			proxy.ginEngine.ServeHTTP(w, req)
+
+			assert.Equal(t, tt.expectedStatus, w.Code)
+
+			for header, expectedValue := range tt.expectedHeaders {
+				assert.Equal(t, expectedValue, w.Header().Get(header))
+			}
+		})
+	}
 }

proxy/sanitize_cors.go

@@ -0,0 +1,43 @@
+package proxy
+
+import (
+	"strings"
+)
+
+func isTokenChar(r rune) bool {
+	switch {
+	case r >= 'a' && r <= 'z':
+	case r >= 'A' && r <= 'Z':
+	case r >= '0' && r <= '9':
+	case strings.ContainsRune("!#$%&'*+-.^_`|~", r):
+	default:
+		return false
+	}
+	return true
+}
+
+func SanitizeAccessControlRequestHeaderValues(headerValues string) string {
+	parts := strings.Split(headerValues, ",")
+	valid := make([]string, 0, len(parts))
+
+	for _, p := range parts {
+		v := strings.TrimSpace(p)
+		if v == "" {
+			continue
+		}
+
+		validPart := true
+		for _, c := range v {
+			if !isTokenChar(c) {
+				validPart = false
+				break
+			}
+		}
+
+		if validPart {
+			valid = append(valid, v)
+		}
+	}
+
+	return strings.Join(valid, ", ")
+}

proxy/sanitize_cors_test.go

@@ -0,0 +1,77 @@
+package proxy
+
+import "testing"
+
+func TestSanitizeAccessControlRequestHeaderValues(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    string
+		expected string
+	}{
+		{
+			name:     "empty string",
+			input:    "",
+			expected: "",
+		},
+		{
+			name:     "whitespace only",
+			input:    "   ",
+			expected: "",
+		},
+		{
+			name:     "single valid value",
+			input:    "content-type",
+			expected: "content-type",
+		},
+		{
+			name:     "multiple valid values",
+			input:    "content-type, authorization, x-requested-with",
+			expected: "content-type, authorization, x-requested-with",
+		},
+		{
+			name:     "values with extra spaces",
+			input:    "  content-type  ,  authorization  ",
+			expected: "content-type, authorization",
+		},
+		{
+			name:     "values with tabs",
+			input:    "content-type,\tauthorization",
+			expected: "content-type, authorization",
+		},
+		{
+			name:     "values with invalid characters",
+			input:    "content-type, auth\n, x-requested-with\r",
+			expected: "content-type, auth, x-requested-with",
+		},
+		{
+			name:     "empty values in list",
+			input:    "content-type,,authorization",
+			expected: "content-type, authorization",
+		},
+		{
+			name:     "leading and trailing commas",
+			input:    ",content-type,authorization,",
+			expected: "content-type, authorization",
+		},
+		{
+			name:     "mixed valid and invalid values",
+			input:    "content-type, \x00invalid, x-requested-with",
+			expected: "content-type, x-requested-with",
+		},
+		{
+			name:     "mixed case values",
+			input:    "Content-Type, my-Valid-Header, Another-hEader",
+			expected: "Content-Type, my-Valid-Header, Another-hEader",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := SanitizeAccessControlRequestHeaderValues(tt.input)
+			if got != tt.expected {
+				t.Errorf("SanitizeAccessControlRequestHeaderValues(%q) = %q, want %q",
+					tt.input, got, tt.expected)
+			}
+		})
+	}
+}