Logging Improvements (#88)

This change revamps the internal logging architecture to be more flexible and descriptive. Previously all logs from both llama-swap and upstream services were mixed together. This makes it harder to troubleshoot and identify problems. This PR adds these new endpoints: 

- `/logs/stream/proxy` - just llama-swap's logs
- `/logs/stream/upstream` - stdout output from the upstream server

.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)
+![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
 
@@ -11,20 +14,23 @@ Written in golang, it is very easy to install (single binary with no dependancie
 - ✅ Easy to deploy: single binary with no dependencies
 - ✅ Easy to config: single yaml file
 - ✅ On-demand model switching
-- ✅ Full control over server settings per model
 - ✅ OpenAI API supported endpoints:
   - `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-swap custom API endpoints
+  - `/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))
-- ✅ Remote log monitoring at `/log`
-- ✅ Direct access to upstream HTTP server via `/upstream/:model_id` ([demo](https://github.com/mostlygeek/llama-swap/pull/31))
-- ✅ Manually unload models via `/unload` endpoint ([#58](https://github.com/mostlygeek/llama-swap/issues/58))
 - ✅ 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
+- ✅ Full control over server settings per model
 
 ## How does llama-swap work?
 
@@ -61,13 +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
@@ -88,16 +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
@@ -114,7 +120,7 @@ models:
       ghcr.io/ggerganov/llama.cpp:server
       --model '/models/Qwen2.5-Coder-0.5B-Instruct-Q4_K_M.gguf'
 
-# profiles make it easy to managing multi model (and gpu) configurations.
+# profiles eliminates swapping by running multiple models at the same time
 #
 # Tips:
 #  - each model must be listening on a unique address and port
@@ -122,8 +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
@@ -213,9 +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'
 

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: info
 
 models:
   "llama":

go.mod

@@ -3,7 +3,11 @@ module github.com/mostlygeek/llama-swap
 go 1.23.0
 
 require (
+	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
 	gopkg.in/yaml.v3 v3.0.1
 )
 
@@ -15,12 +19,10 @@ require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/gabriel-vasile/mimetype v1.4.3 // indirect
 	github.com/gin-contrib/sse v0.1.0 // indirect
-	github.com/gin-gonic/gin v1.10.0 // indirect
 	github.com/go-playground/locales v0.14.1 // indirect
 	github.com/go-playground/universal-translator v0.18.1 // indirect
 	github.com/go-playground/validator/v10 v10.20.0 // indirect
 	github.com/goccy/go-json v0.10.2 // indirect
-	github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510 // indirect
 	github.com/json-iterator/go v1.1.12 // indirect
 	github.com/klauspost/cpuid/v2 v2.2.7 // indirect
 	github.com/leodido/go-urn v1.4.0 // indirect
@@ -29,16 +31,14 @@ require (
 	github.com/modern-go/reflect2 v1.0.2 // indirect
 	github.com/pelletier/go-toml/v2 v2.2.2 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
-	github.com/tidwall/gjson v1.18.0 // indirect
 	github.com/tidwall/match v1.1.1 // indirect
 	github.com/tidwall/pretty v1.2.1 // indirect
-	github.com/tidwall/sjson v1.2.5 // indirect
 	github.com/twitchyliquid64/golang-asm v0.15.1 // indirect
 	github.com/ugorji/go/codec v1.2.12 // indirect
 	golang.org/x/arch v0.8.0 // indirect
-	golang.org/x/crypto v0.31.0 // indirect
+	golang.org/x/crypto v0.36.0 // indirect
-	golang.org/x/net v0.33.0 // indirect
+	golang.org/x/net v0.37.0 // indirect
-	golang.org/x/sys v0.28.0 // indirect
+	golang.org/x/sys v0.31.0 // indirect
-	golang.org/x/text v0.21.0 // indirect
+	golang.org/x/text v0.23.0 // indirect
 	google.golang.org/protobuf v1.34.1 // indirect
 )

go.sum

@@ -78,20 +78,28 @@ 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/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=
 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=

misc/simple-responder/simple-responder.go

@@ -67,6 +67,46 @@ func main() {
 		c.String(200, *responseMessage)
 	})
 
+	// issue #41
+	r.POST("/v1/audio/transcriptions", func(c *gin.Context) {
+		// Parse the multipart form
+		if err := c.Request.ParseMultipartForm(10 << 20); err != nil { // 10 MB max memory
+			c.JSON(http.StatusBadRequest, gin.H{"error": fmt.Sprintf("Error parsing multipart form: %s", err)})
+			return
+		}
+
+		// Get the model from the form values
+		model := c.Request.FormValue("model")
+
+		if model == "" {
+			c.JSON(http.StatusBadRequest, gin.H{"error": "Missing model parameter"})
+			return
+		}
+
+		// Get the file from the form
+		file, _, err := c.Request.FormFile("file")
+		if err != nil {
+			c.JSON(http.StatusBadRequest, gin.H{"error": fmt.Sprintf("Error getting file: %s", err)})
+			return
+		}
+		defer file.Close()
+
+		// Read the file content to get its size
+		fileBytes, err := io.ReadAll(file)
+		if err != nil {
+			c.JSON(http.StatusInternalServerError, gin.H{"error": fmt.Sprintf("Error reading file: %s", err)})
+			return
+		}
+
+		fileSize := len(fileBytes)
+
+		// Return a JSON response with the model and transcription text including file size
+		c.JSON(http.StatusOK, gin.H{
+			"text":  fmt.Sprintf("The length of the file is %d bytes", fileSize),
+			"model": model,
+		})
+	})
+
 	r.GET("/slow-respond", func(c *gin.Context) {
 		echo := c.Query("echo")
 		delay := c.Query("delay")

proxy/config.go

@@ -17,6 +17,7 @@ type ModelConfig struct {
 	CheckEndpoint string   `yaml:"checkEndpoint"`
 	UnloadAfter   int      `yaml:"ttl"`
 	Unlisted      bool     `yaml:"unlisted"`
+	UseModelName  string   `yaml:"useModelName"`
 }
 
 func (m *ModelConfig) SanitizedCommand() ([]string, error) {
@@ -26,6 +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/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 +33,12 @@ type Process struct {
 	ID     string
 	config ModelConfig
 	cmd    *exec.Cmd
-	logMonitor         *LogMonitor
+
+	processLogger *LogMonitor
+	proxyLogger   *LogMonitor
+
 	healthCheckTimeout      int
+	healthCheckLoopInterval time.Duration
 
 	lastRequestHandled time.Time
 
@@ -51,54 +55,68 @@ 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,
+		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 {
-			invalidTransition = true
-		}
-	} else if p.state == StateStarting {
-		// starting -> ready | failed | stopping
-		if newState != StateReady && newState != StateFailed && newState != StateStopping {
-			invalidTransition = true
-		}
-	} else if p.state == StateReady {
-		// ready -> stopping
-		if newState != StateStopping {
-			invalidTransition = true
-		}
-	} else if p.state == StateStopping {
-		// stopping -> stopped | shutdown
-		if newState != StateStopped && newState != StateShutdown {
-			invalidTransition = true
-		}
-	} else if p.state == StateFailed || p.state == StateShutdown {
-		invalidTransition = true
 }
 
-	if invalidTransition {
+// custom error types for swapping state
-		//panic(fmt.Sprintf("Invalid state transition from %s to %s", p.state, newState))
+var (
-		return fmt.Errorf("invalid state transition from %s to %s", p.state, newState)
+	ErrExpectedStateMismatch  = errors.New("expected state mismatch")
+	ErrInvalidStateTransition = errors.New("invalid state transition")
+)
+
+// swapState performs a compare and swap of the state atomically. It returns the current state
+// and an error if the swap failed.
+func (p *Process) swapState(expectedState, newState ProcessState) (ProcessState, error) {
+	p.stateMutex.Lock()
+	defer p.stateMutex.Unlock()
+
+	if 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)
+		return p.state, ErrInvalidStateTransition
+	}
+
+	p.proxyLogger.Debugf("State transition from %s to %s", expectedState, newState)
 	p.state = newState
-	return nil
+	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 {
@@ -116,62 +134,48 @@ func (p *Process) start() error {
 		return fmt.Errorf("can not start(), upstream proxy missing")
 	}
 
-	// wait for the other start() to complete
-	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)
 	}
 
@@ -206,31 +210,35 @@ 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")
 			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, retrying 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)
 		}
 	}
 
@@ -241,7 +249,7 @@ 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
 				}
 
@@ -249,7 +257,8 @@ 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
 				}
@@ -257,26 +266,28 @@ 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()
-	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)
 	}
 }
 
@@ -284,19 +295,9 @@ 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.
@@ -311,31 +312,32 @@ func (p *Process) stopCommand(sigtermTTL time.Duration) {
 	}()
 
 	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:
 		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)
 			}
 		}
 	}

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

@@ -5,7 +5,6 @@ import (
 	"io"
 	"net/http"
 	"net/http/httptest"
-	"os"
 	"sync"
 	"testing"
 	"time"
@@ -13,13 +12,17 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
+var (
+	discardLogger = NewLogMonitorWriter(io.Discard)
+)
+
 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, discardLogger, discardLogger)
 	defer process.Stop()
 
 	req := httptest.NewRequest("GET", "/test", nil)
@@ -52,11 +55,10 @@ 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, discardLogger, discardLogger)
 	defer process.Stop()
 
 	var wg sync.WaitGroup
@@ -84,7 +86,7 @@ func TestProcess_BrokenModelConfig(t *testing.T) {
 		CheckEndpoint: "/health",
 	}
 
-	process := NewProcess("broken", 1, config, NewLogMonitor())
+	process := NewProcess("broken", 1, config, discardLogger, discardLogger)
 
 	req := httptest.NewRequest("GET", "/", nil)
 	w := httptest.NewRecorder()
@@ -109,7 +111,7 @@ 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, discardLogger, discardLogger)
 	defer process.Stop()
 
 	// this should take 4 seconds
@@ -151,7 +153,7 @@ 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, discardLogger, discardLogger)
 	defer process.Stop()
 
 	for i := 0; i < 100; i++ {
@@ -178,7 +180,7 @@ func TestProcess_HTTPRequestsHaveTimeToFinish(t *testing.T) {
 
 	expectedMessage := "12345"
 	config := getTestSimpleResponderConfig(expectedMessage)
-	process := NewProcess("t", 10, config, NewLogMonitorWriter(os.Stdout))
+	process := NewProcess("t", 10, config, discardLogger, discardLogger)
 	defer process.Stop()
 
 	results := map[string]string{
@@ -225,39 +227,40 @@ 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"), discardLogger, discardLogger)
-				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 +271,8 @@ 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 +283,6 @@ 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 +290,16 @@ 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, discardLogger, discardLogger)
+
+	// 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)

proxy/proxymanager.go

@@ -5,7 +5,9 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
+	"mime/multipart"
 	"net/http"
+	"os"
 	"sort"
 	"strconv"
 	"strings"
@@ -26,19 +28,47 @@ 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)
+	case "info":
+		proxyLogger.SetLogLevel(LevelInfo)
+	case "warn":
+		proxyLogger.SetLogLevel(LevelWarn)
+	case "error":
+		proxyLogger.SetLogLevel(LevelError)
+	default:
+		proxyLogger.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()
@@ -57,9 +87,8 @@ 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,
@@ -69,16 +98,26 @@ 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()
@@ -95,6 +134,7 @@ func New(config *Config) *ProxyManager {
 
 	// Support audio/speech endpoint
 	pm.ginEngine.POST("/v1/audio/speech", pm.proxyOAIHandler)
+	pm.ginEngine.POST("/v1/audio/transcriptions", pm.proxyOAIPostFormHandler)
 
 	pm.ginEngine.GET("/v1/models", pm.listModelsHandler)
 
@@ -102,12 +142,16 @@ 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)
 
 	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")
@@ -259,19 +303,20 @@ 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 {
@@ -282,7 +327,7 @@ 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
 			}
@@ -347,12 +392,21 @@ func (pm *ProxyManager) proxyOAIHandler(c *gin.Context) {
 		pm.sendErrorResponse(c, http.StatusBadRequest, "missing or invalid 'model' key")
 	}
 
-	if process, err := pm.swapModel(requestedModel); err != nil {
+	process, err := pm.swapModel(requestedModel)
+
+	if err != nil {
 		pm.sendErrorResponse(c, http.StatusNotFound, fmt.Sprintf("unable to swap to model, %s", err.Error()))
 		return
-	} else {
+	}
 
-		// strip
+	// issue #69 allow custom model names to be sent to upstream
+	if process.config.UseModelName != "" {
+		bodyBytes, err = sjson.SetBytes(bodyBytes, "model", process.config.UseModelName)
+		if err != nil {
+			pm.sendErrorResponse(c, http.StatusInternalServerError, fmt.Sprintf("error updating JSON: %s", err.Error()))
+			return
+		}
+	} else {
 		profileName, modelName := splitRequestedModel(requestedModel)
 		if profileName != "" {
 			bodyBytes, err = sjson.SetBytes(bodyBytes, "model", modelName)
@@ -361,6 +415,7 @@ func (pm *ProxyManager) proxyOAIHandler(c *gin.Context) {
 				return
 			}
 		}
+	}
 
 	c.Request.Body = io.NopCloser(bytes.NewBuffer(bodyBytes))
 
@@ -369,7 +424,110 @@ func (pm *ProxyManager) proxyOAIHandler(c *gin.Context) {
 	c.Request.Header.Add("content-length", strconv.Itoa(len(bodyBytes)))
 
 	process.ProxyRequest(c.Writer, c.Request)
+
 }
+
+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()))
+		return
+	}
+
+	// Get model parameter from the form
+	requestedModel := c.Request.FormValue("model")
+	if requestedModel == "" {
+		pm.sendErrorResponse(c, http.StatusBadRequest, "missing or invalid 'model' parameter in form data")
+		return
+	}
+
+	// Swap to the requested model
+	process, err := pm.swapModel(requestedModel)
+	if err != nil {
+		pm.sendErrorResponse(c, http.StatusNotFound, fmt.Sprintf("unable to swap to model, %s", err.Error()))
+		return
+	}
+
+	// Get profile name and model name from the requested model
+	profileName, modelName := splitRequestedModel(requestedModel)
+
+	// Copy all form values
+	for key, values := range c.Request.MultipartForm.Value {
+		for _, value := range values {
+			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
+				}
+			}
+			field, err := multipartWriter.CreateFormField(key)
+			if err != nil {
+				pm.sendErrorResponse(c, http.StatusInternalServerError, "error recreating form field")
+				return
+			}
+			if _, err = field.Write([]byte(fieldValue)); err != nil {
+				pm.sendErrorResponse(c, http.StatusInternalServerError, "error writing form field")
+				return
+			}
+		}
+	}
+
+	// Copy all files from the original request
+	for key, fileHeaders := range c.Request.MultipartForm.File {
+		for _, fileHeader := range fileHeaders {
+			formFile, err := multipartWriter.CreateFormFile(key, fileHeader.Filename)
+			if err != nil {
+				pm.sendErrorResponse(c, http.StatusInternalServerError, "error recreating form file")
+				return
+			}
+
+			file, err := fileHeader.Open()
+			if err != nil {
+				pm.sendErrorResponse(c, http.StatusInternalServerError, "error opening uploaded file")
+				return
+			}
+
+			if _, err = io.Copy(formFile, file); err != nil {
+				file.Close()
+				pm.sendErrorResponse(c, http.StatusInternalServerError, "error copying file data")
+				return
+			}
+			file.Close()
+		}
+	}
+
+	// Close the multipart writer to finalize the form
+	if err := multipartWriter.Close(); err != nil {
+		pm.sendErrorResponse(c, http.StatusInternalServerError, "error finalizing multipart form")
+		return
+	}
+
+	// Create a new request with the reconstructed form data
+	modifiedReq, err := http.NewRequestWithContext(
+		c.Request.Context(),
+		c.Request.Method,
+		c.Request.URL.String(),
+		&requestBuffer,
+	)
+	if err != nil {
+		pm.sendErrorResponse(c, http.StatusInternalServerError, "error creating modified request")
+		return
+	}
+
+	// Copy the headers from the original request
+	modifiedReq.Header = c.Request.Header.Clone()
+	modifiedReq.Header.Set("Content-Type", multipartWriter.FormDataContentType())
+
+	// Use the modified request for proxying
+	process.ProxyRequest(c.Writer, modifiedReq)
 }
 
 func (pm *ProxyManager) sendErrorResponse(c *gin.Context, statusCode int, message string) {
@@ -387,6 +545,28 @@ func (pm *ProxyManager) unloadAllModelsHandler(c *gin.Context) {
 	c.String(http.StatusOK, "OK")
 }
 
+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,
+		})
+
+	}
+
+	// Put the results under the `running` key.
+	response := gin.H{
+		"running": runningProcesses,
+	}
+
+	context.JSON(http.StatusOK, response) // Always return 200 OK
+}
+
 func ProcessKeyName(groupName, modelName string) string {
 	return groupName + PROFILE_SPLIT_CHAR + modelName
 }

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

@@ -4,6 +4,8 @@ import (
 	"bytes"
 	"encoding/json"
 	"fmt"
+	"math/rand"
+	"mime/multipart"
 	"net/http"
 	"net/http/httptest"
 	"sync"
@@ -349,3 +351,360 @@ func TestProxyManager_StripProfileSlug(t *testing.T) {
 	assert.Equal(t, http.StatusOK, w.Code)
 	assert.Contains(t, w.Body.String(), "ok")
 }
+
+// Test issue #61 `Listing the current list of models and the loaded model.`
+func TestProxyManager_RunningEndpoint(t *testing.T) {
+
+	// Shared configuration
+	config := &Config{
+		HealthCheckTimeout: 15,
+		Models: map[string]ModelConfig{
+			"model1": getTestSimpleResponderConfig("model1"),
+			"model2": getTestSimpleResponderConfig("model2"),
+		},
+		Profiles: map[string][]string{
+			"test": {"model1", "model2"},
+		},
+	}
+
+	// Define a helper struct to parse the JSON response.
+	type RunningResponse struct {
+		Running []struct {
+			Model string `json:"model"`
+			State string `json:"state"`
+		} `json:"running"`
+	}
+
+	// Create proxy once for all tests
+	proxy := New(config)
+	defer proxy.StopProcesses()
+
+	t.Run("no models loaded", func(t *testing.T) {
+		req := httptest.NewRequest("GET", "/running", nil)
+		w := httptest.NewRecorder()
+		proxy.HandlerFunc(w, req)
+
+		assert.Equal(t, http.StatusOK, w.Code)
+
+		var response RunningResponse
+
+		// Check if this is a valid JSON object.
+		assert.NoError(t, json.Unmarshal(w.Body.Bytes(), &response))
+
+		// We should have an empty running array here.
+		assert.Empty(t, response.Running, "expected no running models")
+	})
+
+	t.Run("single model loaded", func(t *testing.T) {
+		// Load just a model.
+		reqBody := `{"model":"model1"}`
+		req := httptest.NewRequest("POST", "/v1/chat/completions", bytes.NewBufferString(reqBody))
+		w := httptest.NewRecorder()
+		proxy.HandlerFunc(w, req)
+		assert.Equal(t, http.StatusOK, w.Code)
+
+		// Simulate browser call for the `/running` endpoint.
+		req = httptest.NewRequest("GET", "/running", nil)
+		w = httptest.NewRecorder()
+		proxy.HandlerFunc(w, req)
+
+		var response RunningResponse
+		assert.NoError(t, json.Unmarshal(w.Body.Bytes(), &response))
+
+		// Check if we have a single array element.
+		assert.Len(t, response.Running, 1)
+
+		// Is this the right model?
+		assert.Equal(t, "model1", response.Running[0].Model)
+
+		// Is the model loaded?
+		assert.Equal(t, "ready", response.Running[0].State)
+	})
+
+	t.Run("multiple models via profile", func(t *testing.T) {
+		// Load more than one model.
+		for _, model := range []string{"model1", "model2"} {
+			profileModel := ProcessKeyName("test", model)
+			reqBody := fmt.Sprintf(`{"model":"%s"}`, profileModel)
+			req := httptest.NewRequest("POST", "/v1/chat/completions", bytes.NewBufferString(reqBody))
+			w := httptest.NewRecorder()
+			proxy.HandlerFunc(w, req)
+			assert.Equal(t, http.StatusOK, w.Code)
+		}
+
+		// Simulate the browser call.
+		req := httptest.NewRequest("GET", "/running", nil)
+		w := httptest.NewRecorder()
+		proxy.HandlerFunc(w, req)
+
+		var response RunningResponse
+
+		// The JSON response must be valid.
+		assert.NoError(t, json.Unmarshal(w.Body.Bytes(), &response))
+
+		// The response should contain 2 models.
+		assert.Len(t, response.Running, 2)
+
+		expectedModels := map[string]struct{}{
+			"model1": {},
+			"model2": {},
+		}
+
+		// Iterate through the models and check their states as well.
+		for _, entry := range response.Running {
+			_, exists := expectedModels[entry.Model]
+			assert.True(t, exists, "unexpected model %s", entry.Model)
+			assert.Equal(t, "ready", entry.State)
+			delete(expectedModels, entry.Model)
+		}
+
+		// Since we deleted each model while testing for its validity we should have no more models in the response.
+		assert.Empty(t, expectedModels, "unexpected additional models in response")
+	})
+}
+
+func TestProxyManager_AudioTranscriptionHandler(t *testing.T) {
+	config := &Config{
+		HealthCheckTimeout: 15,
+		Profiles: map[string][]string{
+			"test": {"TheExpectedModel"},
+		},
+		Models: map[string]ModelConfig{
+			"TheExpectedModel": getTestSimpleResponderConfig("TheExpectedModel"),
+		},
+	}
+
+	proxy := New(config)
+	defer proxy.StopProcesses()
+
+	testCases := []struct {
+		name        string
+		modelInput  string
+		expectModel string
+	}{
+		{
+			name:        "With Profile Prefix",
+			modelInput:  "test:TheExpectedModel",
+			expectModel: "TheExpectedModel", // Profile prefix should be stripped
+		},
+		{
+			name:        "Without Profile Prefix",
+			modelInput:  "TheExpectedModel",
+			expectModel: "TheExpectedModel", // Should remain the same
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			// Create a buffer with multipart form data
+			var b bytes.Buffer
+			w := multipart.NewWriter(&b)
+
+			// Add the model field
+			fw, err := w.CreateFormField("model")
+			assert.NoError(t, err)
+			_, err = fw.Write([]byte(tc.modelInput))
+			assert.NoError(t, err)
+
+			// Add a file field
+			fw, err = w.CreateFormFile("file", "test.mp3")
+			assert.NoError(t, err)
+			// Generate random content length between 10 and 20
+			contentLength := rand.Intn(11) + 10 // 10 to 20
+			content := make([]byte, contentLength)
+			_, err = fw.Write(content)
+			assert.NoError(t, err)
+			w.Close()
+
+			// Create the request with the multipart form data
+			req := httptest.NewRequest("POST", "/v1/audio/transcriptions", &b)
+			req.Header.Set("Content-Type", w.FormDataContentType())
+			rec := httptest.NewRecorder()
+			proxy.HandlerFunc(rec, req)
+
+			// Verify the response
+			assert.Equal(t, http.StatusOK, rec.Code)
+			var response map[string]string
+			err = json.Unmarshal(rec.Body.Bytes(), &response)
+			assert.NoError(t, err)
+			assert.Equal(t, tc.expectModel, response["model"])
+			assert.Equal(t, response["text"], fmt.Sprintf("The length of the file is %d bytes", contentLength)) // matches simple-responder
+		})
+	}
+}
+
+func TestProxyManager_SplitRequestedModel(t *testing.T) {
+
+	tests := []struct {
+		name            string
+		requestedModel  string
+		expectedProfile string
+		expectedModel   string
+	}{
+		{"no profile", "gpt-4", "", "gpt-4"},
+		{"with profile", "profile1:gpt-4", "profile1", "gpt-4"},
+		{"only profile", "profile1:", "profile1", ""},
+		{"empty model", ":gpt-4", "", "gpt-4"},
+		{"empty profile", ":", "", ""},
+		{"no split char", "gpt-4", "", "gpt-4"},
+		{"profile and model with delimiter", "profile1:delimiter:gpt-4", "profile1", "delimiter:gpt-4"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			profileName, modelName := splitRequestedModel(tt.requestedModel)
+			if profileName != tt.expectedProfile {
+				t.Errorf("splitRequestedModel(%q) = %q, %q; want %q, %q", tt.requestedModel, profileName, modelName, tt.expectedProfile, tt.expectedModel)
+			}
+			if modelName != tt.expectedModel {
+				t.Errorf("splitRequestedModel(%q) = %q, %q; want %q, %q", tt.requestedModel, profileName, modelName, tt.expectedProfile, tt.expectedModel)
+			}
+		})
+	}
+}
+
+// Test useModelName in configuration sends overrides what is sent to upstream
+func TestProxyManager_UseModelName(t *testing.T) {
+
+	upstreamModelName := "upstreamModel"
+
+	modelConfig := getTestSimpleResponderConfig(upstreamModelName)
+	modelConfig.UseModelName = upstreamModelName
+
+	config := &Config{
+		HealthCheckTimeout: 15,
+		Profiles: map[string][]string{
+			"test": {"model1"},
+		},
+
+		Models: map[string]ModelConfig{
+			"model1": modelConfig,
+		},
+	}
+
+	proxy := New(config)
+	defer proxy.StopProcesses()
+
+	tests := []struct {
+		description    string
+		requestedModel string
+	}{
+		{"useModelName over rides requested model", "model1"},
+		{"useModelName over rides requested profile:model", "test:model1"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.description+": /v1/chat/completions", func(t *testing.T) {
+			reqBody := fmt.Sprintf(`{"model":"%s"}`, tt.requestedModel)
+			req := httptest.NewRequest("POST", "/v1/chat/completions", bytes.NewBufferString(reqBody))
+			w := httptest.NewRecorder()
+
+			proxy.HandlerFunc(w, req)
+			assert.Equal(t, http.StatusOK, w.Code)
+			assert.Contains(t, w.Body.String(), upstreamModelName)
+
+		})
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.description+": /v1/audio/transcriptions", func(t *testing.T) {
+			// Create a buffer with multipart form data
+			var b bytes.Buffer
+			w := multipart.NewWriter(&b)
+
+			// Add the model field
+			fw, err := w.CreateFormField("model")
+			assert.NoError(t, err)
+			_, err = fw.Write([]byte(tt.requestedModel))
+			assert.NoError(t, err)
+
+			// Add a file field
+			fw, err = w.CreateFormFile("file", "test.mp3")
+			assert.NoError(t, err)
+			_, err = fw.Write([]byte("test"))
+			assert.NoError(t, err)
+			w.Close()
+
+			// Create the request with the multipart form data
+			req := httptest.NewRequest("POST", "/v1/audio/transcriptions", &b)
+			req.Header.Set("Content-Type", w.FormDataContentType())
+			rec := httptest.NewRecorder()
+			proxy.HandlerFunc(rec, req)
+
+			// Verify the response
+			assert.Equal(t, http.StatusOK, rec.Code)
+			var response map[string]string
+			err = json.Unmarshal(rec.Body.Bytes(), &response)
+			assert.NoError(t, err)
+			assert.Equal(t, upstreamModelName, response["model"])
+		})
+	}
+}
+
+func TestProxyManager_CORSOptionsHandler(t *testing.T) {
+	config := &Config{
+		HealthCheckTimeout: 15,
+		Models: map[string]ModelConfig{
+			"model1": getTestSimpleResponderConfig("model1"),
+		},
+		LogRequests: true,
+	}
+
+	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)
+			}
+		})
+	}
+}