feat: config hot-reload

README.md

@@ -195,7 +195,7 @@ groups:
 
 Docker is the quickest way to try out llama-swap:
 
-```
+```shell
 # use CPU inference
 $ docker run -it --rm -p 9292:8080 ghcr.io/mostlygeek/llama-swap:cpu
 
@@ -231,7 +231,7 @@ Specific versions are also available and are tagged with the llama-swap, archite
 
 Beyond the demo you will likely want to run the containers with your downloaded models and custom configuration.
 
-```
+```shell
 $ docker run -it --rm --runtime nvidia -p 9292:8080 \
   -v /path/to/models:/models \
   -v /path/to/custom/config.yaml:/app/config.yaml \
@@ -246,7 +246,12 @@ Pre-built binaries are available for Linux, FreeBSD and Darwin (OSX). These are
 
 1. Create a configuration file, see [config.example.yaml](config.example.yaml)
 1. Download a [release](https://github.com/mostlygeek/llama-swap/releases) appropriate for your OS and architecture.
-1. Run the binary with `llama-swap --config path/to/config.yaml`
+1. Run the binary with `llama-swap --config path/to/config.yaml`.
+  Available flags:
+    - `--config`: Path to the configuration file (default: `config.yaml`).
+    - `--listen`: Address and port to listen on (default: `:8080`).
+    - `--version`: Show version information and exit.
+    - `--watch-config`: Automatically reload the configuration file when it changes. This will wait for in-flight requests to complete then stop all running models (default: `false`).
 
 ### Building from source
 
@@ -261,7 +266,7 @@ Open the `http://<host>/logs` with your browser to get a web interface with stre
 
 Of course, CLI access is also supported:
 
-```
+```shell
 # sends up to the last 10KB of logs
 curl http://host/logs'
 

go.mod

@@ -3,6 +3,7 @@ module github.com/mostlygeek/llama-swap
 go 1.23.0
 
 require (
+	github.com/fsnotify/fsnotify v1.9.0
 	github.com/gin-gonic/gin v1.10.0
 	github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510
 	github.com/stretchr/testify v1.9.0

go.sum

@@ -9,12 +9,16 @@ github.com/cloudwego/iasm v0.2.0/go.mod h1:8rXZaNYT2n95jn+zTI1sDr+IgcD2GVs0nlbbQ
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/fsnotify/fsnotify v1.9.0 h1:2Ml+OJNzbYCTzsxtv8vKSFD9PbJjmhYF14k/jKC7S9k=
+github.com/fsnotify/fsnotify v1.9.0/go.mod h1:8jBTzvmWwFyi3Pb8djgCCO5IBqzKJ/Jwo8TRcHyHii0=
 github.com/gabriel-vasile/mimetype v1.4.3 h1:in2uUcidCuFcDKtdcBxlR0rJ1+fsokWf+uqxgUFjbI0=
 github.com/gabriel-vasile/mimetype v1.4.3/go.mod h1:d8uq/6HKRL6CGdk+aubisF/M5GcPfT7nKyLpA0lbSSk=
 github.com/gin-contrib/sse v0.1.0 h1:Y/yl/+YNO8GZSjAhjMsSuLt29uWRFHdHYUb5lYOV9qE=
 github.com/gin-contrib/sse v0.1.0/go.mod h1:RHrZQHXnP2xjPF+u1gW/2HnVO7nvIa9PG3Gm+fLHvGI=
 github.com/gin-gonic/gin v1.10.0 h1:nTuyha1TYqgedzytsKYqna+DfLos46nTv2ygFy86HFU=
 github.com/gin-gonic/gin v1.10.0/go.mod h1:4PMNQiOhvDRa013RKVbsiNwoyezlm2rm0uX/T7kzp5Y=
+github.com/go-playground/assert/v2 v2.2.0 h1:JvknZsQTYeFEAhQwI4qEt9cyV5ONwRHC+lYKSsYSR8s=
+github.com/go-playground/assert/v2 v2.2.0/go.mod h1:VDjEfimB/XKnb+ZQfWdccd7VUvScMdVu0Titje2rxJ4=
 github.com/go-playground/locales v0.14.1 h1:EWaQ/wswjilfKLTECiXz7Rh+3BjFhfDFKv/oXslEjJA=
 github.com/go-playground/locales v0.14.1/go.mod h1:hxrqLVvrK65+Rwrd5Fc6F2O76J/NuW9t0sjnWqG1slY=
 github.com/go-playground/universal-translator v0.18.1 h1:Bcnm0ZwsGyWbCzImXv+pAJnYK9S473LQFuzCbDbfSFY=
@@ -23,6 +27,8 @@ github.com/go-playground/validator/v10 v10.20.0 h1:K9ISHbSaI0lyB2eWMPJo+kOS/FBEx
 github.com/go-playground/validator/v10 v10.20.0/go.mod h1:dbuPbCMFw/DrkbEynArYaCwl3amGuJotoKCe95atGMM=
 github.com/goccy/go-json v0.10.2 h1:CrxCmQqYDkv1z7lO7Wbh2HN93uovUHgrECaO5ZrCXAU=
 github.com/goccy/go-json v0.10.2/go.mod h1:6MelG93GURQebXPDq3khkgXZkazVtN9CRI+MGFi0w8I=
+github.com/google/go-cmp v0.5.5 h1:Khx7svrCpmxxtHBq5j2mp/xVjsi8hQMfNLvJFAlrGgU=
+github.com/google/go-cmp v0.5.5/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/gofuzz v1.0.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
 github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510 h1:El6M4kTTCOh6aBiKaUGG7oYTSPP8MxqL4YI3kZKwcP4=
 github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510/go.mod h1:pupxD2MaaD3pAXIBCelhxNneeOaAeabZDe5s4K6zSpQ=
@@ -74,34 +80,18 @@ github.com/ugorji/go/codec v1.2.12/go.mod h1:UNopzCgEMSXjBc6AOMqYvWC1ktqTAfzJZUZ
 golang.org/x/arch v0.0.0-20210923205945-b76863e36670/go.mod h1:5om86z9Hs0C8fWVUuoMHwpExlXzs5Tkyp9hOrfG7pp8=
 golang.org/x/arch v0.8.0 h1:3wRIsP3pM4yUptoR96otTUOXI367OS0+c9eeRi9doIc=
 golang.org/x/arch v0.8.0/go.mod h1:FEVrYAQjsQXMVJ1nsMoVVXPZg6p2JE2mx8psSWTDQys=
-golang.org/x/crypto v0.23.0 h1:dIJU/v2J8Mdglj/8rJ6UUOM3Zc9zLZxVZwwxMooUSAI=
-golang.org/x/crypto v0.23.0/go.mod h1:CKFgDieR+mRhux2Lsu27y0fO304Db0wZe70UKqHu0v8=
-golang.org/x/crypto v0.31.0 h1:ihbySMvVjLAeSH1IbfcRTkD/iNscyz8rGzjF/E5hV6U=
-golang.org/x/crypto v0.31.0/go.mod h1:kDsLvtWBEx7MV9tJOj9bnXsPbxwJQ6csT/x4KIN4Ssk=
 golang.org/x/crypto v0.36.0 h1:AnAEvhDddvBdpY+uR+MyHmuZzzNqXSe/GvuDeob5L34=
 golang.org/x/crypto v0.36.0/go.mod h1:Y4J0ReaxCR1IMaabaSMugxJES1EpwhBHhv2bDHklZvc=
-golang.org/x/net v0.25.0 h1:d/OCCoBEUq33pjydKrGQhw7IlUPI2Oylr+8qLx49kac=
-golang.org/x/net v0.25.0/go.mod h1:JkAGAh7GEvH74S6FOH42FLoXpXbE/aqXSrIQjXgsiwM=
-golang.org/x/net v0.33.0 h1:74SYHlV8BIgHIFC/LrYkOGIwL19eTYXQ5wc6TBuO36I=
-golang.org/x/net v0.33.0/go.mod h1:HXLR5J+9DxmrqMwG9qjGCxZ+zKXxBru04zlTvWlWuN4=
-golang.org/x/net v0.37.0 h1:1zLorHbz+LYj7MQlSf1+2tPIIgibq2eL5xkrGk6f+2c=
-golang.org/x/net v0.37.0/go.mod h1:ivrbrMbzFq5J41QOQh0siUuly180yBYtLp+CKbEaFx8=
 golang.org/x/net v0.38.0 h1:vRMAPTMaeGqVhG5QyLJHqNDwecKTomGeqbnfZyKlBI8=
 golang.org/x/net v0.38.0/go.mod h1:ivrbrMbzFq5J41QOQh0siUuly180yBYtLp+CKbEaFx8=
 golang.org/x/sys v0.5.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.20.0 h1:Od9JTbYCk261bKm4M/mw7AklTlFYIa0bIp9BgSm1S8Y=
-golang.org/x/sys v0.20.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
-golang.org/x/sys v0.28.0 h1:Fksou7UEQUWlKvIdsqzJmUmCX3cZuD2+P3XyyzwMhlA=
-golang.org/x/sys v0.28.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/sys v0.31.0 h1:ioabZlmFYtWhL+TRYpcnNlLwhyxaM9kWTDEmfnprqik=
 golang.org/x/sys v0.31.0/go.mod h1:BJP2sWEmIv4KK5OTEluFJCKSidICx8ciO85XgH3Ak8k=
-golang.org/x/text v0.15.0 h1:h1V/4gjBv8v9cjcR6+AR5+/cIYK5N/WAgiv4xlsEtAk=
-golang.org/x/text v0.15.0/go.mod h1:18ZOQIKpY8NJVqYksKHtTdi31H5itFRjB5/qKTNYzSU=
-golang.org/x/text v0.21.0 h1:zyQAAkrwaneQ066sspRyJaG9VNi/YJ1NfzcGB3hZ/qo=
-golang.org/x/text v0.21.0/go.mod h1:4IBbMaMmOPCJ8SecivzSH54+73PCFmPWxNTLm+vZkEQ=
 golang.org/x/text v0.23.0 h1:D71I7dUrlY+VX0gQShAThNGHFxZ13dGLBHQLVl1mJlY=
 golang.org/x/text v0.23.0/go.mod h1:/BLNzu4aZCJ1+kcD0DNRotWKage4q2rGVAg4o22unh4=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 google.golang.org/protobuf v1.34.1 h1:9ddQBjfCyZPOHPUiPxpYESBLc+T8P3E+Vo4IbKZgFWg=
 google.golang.org/protobuf v1.34.1/go.mod h1:c6P6GXX6sHbq/GpV6MGZEdwhWPcYBgnhAHhKbcUYpos=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=

llama-swap.go

@@ -1,25 +1,34 @@
 package main
 
 import (
+	"context"
 	"flag"
 	"fmt"
+	"log"
+	"net/http"
 	"os"
 	"os/signal"
+	"path/filepath"
 	"syscall"
+	"time"
 
+	"github.com/fsnotify/fsnotify"
 	"github.com/gin-gonic/gin"
 	"github.com/mostlygeek/llama-swap/proxy"
 )
 
-var version string = "0"
-var commit string = "abcd1234"
-var date = "unknown"
+var (
+	version string = "0"
+	commit  string = "abcd1234"
+	date    string = "unknown"
+)
 
 func main() {
 	// Define a command-line flag for the port
 	configPath := flag.String("config", "config.yaml", "config file name")
 	listenStr := flag.String("listen", ":8080", "listen ip/port")
 	showVersion := flag.Bool("version", false, "show version of build")
+	watchConfig := flag.Bool("watch-config", false, "Automatically reload config file on change")
 
 	flag.Parse() // Parse the command-line flags
 
@@ -46,18 +55,135 @@ func main() {
 
 	proxyManager := proxy.New(config)
 
+	// Setup channels for server management
+	reloadChan := make(chan *proxy.ProxyManager)
+	exitChan := make(chan struct{})
 	sigChan := make(chan os.Signal, 1)
 	signal.Notify(sigChan, syscall.SIGINT, syscall.SIGTERM)
+
+	// Create server with initial handler
+	srv := &http.Server{
+		Addr:    *listenStr,
+		Handler: proxyManager,
+	}
+
+	// Start server
+	fmt.Printf("llama-swap listening on %s\n", *listenStr)
 	go func() {
-		<-sigChan
-		fmt.Println("Shutting down llama-swap")
-		proxyManager.Shutdown()
-		os.Exit(0)
+		if err := srv.ListenAndServe(); err != nil && err != http.ErrServerClosed {
+			fmt.Printf("Fatal server error: %v\n", err)
+			close(exitChan)
+		}
 	}()
 
-	fmt.Println("llama-swap listening on " + *listenStr)
-	if err := proxyManager.Run(*listenStr); err != nil {
-		fmt.Printf("Server error: %v\n", err)
-		os.Exit(1)
+	// Handle config reloads and signals
+	go func() {
+		currentManager := proxyManager
+		for {
+			select {
+			case newManager := <-reloadChan:
+				log.Println("Config change detected, waiting for in-flight requests to complete...")
+				// Stop old manager processes gracefully (this waits for in-flight requests)
+				currentManager.StopProcesses()
+				// Now do a full shutdown to clear the process map
+				currentManager.Shutdown()
+				currentManager = newManager
+				srv.Handler = newManager
+				log.Println("Server handler updated with new config")
+			case sig := <-sigChan:
+				fmt.Printf("Received signal %v, shutting down...\n", sig)
+				ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+				defer cancel()
+				currentManager.Shutdown()
+				if err := srv.Shutdown(ctx); err != nil {
+					fmt.Printf("Server shutdown error: %v\n", err)
+				}
+				close(exitChan)
+				return
+			}
+		}
+	}()
+
+	// Start file watcher if requested
+	if *watchConfig {
+		absConfigPath, err := filepath.Abs(*configPath)
+		if err != nil {
+			log.Printf("Error getting absolute path for config: %v. File watching disabled.", err)
+		} else {
+			go watchConfigFileWithReload(absConfigPath, reloadChan)
+		}
+	}
+
+	// Wait for exit signal
+	<-exitChan
+}
+
+// watchConfigFileWithReload monitors the configuration file and sends new ProxyManager instances through reloadChan.
+func watchConfigFileWithReload(configPath string, reloadChan chan<- *proxy.ProxyManager) {
+	watcher, err := fsnotify.NewWatcher()
+	if err != nil {
+		log.Printf("Error creating file watcher: %v. File watching disabled.", err)
+		return
+	}
+	defer watcher.Close()
+
+	err = watcher.Add(configPath)
+	if err != nil {
+		log.Printf("Error adding config path (%s) to watcher: %v. File watching disabled.", configPath, err)
+		return
+	}
+
+	log.Printf("Watching config file for changes: %s", configPath)
+
+	var debounceTimer *time.Timer
+	debounceDuration := 2 * time.Second
+
+	for {
+		select {
+		case event, ok := <-watcher.Events:
+			if !ok {
+				return
+			}
+			// We only care about writes to the specific config file
+			if event.Name == configPath && event.Has(fsnotify.Write) {
+				// Reset or start the debounce timer
+				if debounceTimer != nil {
+					debounceTimer.Stop()
+				}
+				debounceTimer = time.AfterFunc(debounceDuration, func() {
+					log.Printf("Config file modified: %s, reloading...", event.Name)
+
+					// Try up to 3 times with exponential backoff
+					var newConfig proxy.Config
+					var err error
+					for retries := 0; retries < 3; retries++ {
+						// Load new configuration
+						newConfig, err = proxy.LoadConfig(configPath)
+						if err == nil {
+							break
+						}
+						log.Printf("Error loading new config (attempt %d/3): %v", retries+1, err)
+						if retries < 2 {
+							time.Sleep(time.Duration(1<<retries) * time.Second)
+						}
+					}
+					if err != nil {
+						log.Printf("Failed to load new config after retries: %v", err)
+						return
+					}
+
+					// Create new ProxyManager with new config
+					newPM := proxy.New(newConfig)
+					reloadChan <- newPM
+					log.Println("Config reloaded successfully")
+				})
+			}
+		case err, ok := <-watcher.Errors:
+			if !ok {
+				log.Println("File watcher error channel closed.")
+				return
+			}
+			log.Printf("File watcher error: %v", err)
+		}
 	}
 }

proxy/process.go

@@ -185,7 +185,7 @@ func (p *Process) start() error {
 		return fmt.Errorf("start() failed: %v", err)
 	}
 
-	// Capture the exit error for later signaling
+	// Capture the exit error for later signalling
 	go func() {
 		exitErr := p.cmd.Wait()
 		p.proxyLogger.Debugf("<%s> cmd.Wait() returned error: %v", p.ID, exitErr)
@@ -260,9 +260,9 @@ func (p *Process) start() error {
 					if strings.Contains(err.Error(), "connection refused") {
 						endTime, _ := checkDeadline.Deadline()
 						ttl := time.Until(endTime)
-						p.proxyLogger.Infof("<%s> Connection refused on %s, giving up in %.0fs", p.ID, healthURL, ttl.Seconds())
+						p.proxyLogger.Debugf("<%s> Connection refused on %s, giving up in %.0fs (normal during startup)", p.ID, healthURL, ttl.Seconds())
 					} else {
-						p.proxyLogger.Infof("<%s> Health check error on %s, %v", p.ID, healthURL, err)
+						p.proxyLogger.Debugf("<%s> Health check error on %s, %v (normal during startup)", p.ID, healthURL, err)
 					}
 				}
 			}
@@ -345,31 +345,33 @@ func (p *Process) stopCommand(sigtermTTL time.Duration) {
 	defer cancelTimeout()
 
 	if p.cmd == nil || p.cmd.Process == nil {
-		p.proxyLogger.Warnf("<%s> cmd or cmd.Process is nil", p.ID)
+		p.proxyLogger.Debugf("<%s> cmd or cmd.Process is nil (normal during config reload)", p.ID)
 		return
 	}
 
 	if err := p.terminateProcess(); err != nil {
-		p.proxyLogger.Infof("<%s> Failed to gracefully terminate process: %v", p.ID, err)
+		p.proxyLogger.Debugf("<%s> Process already terminated: %v (normal during shutdown)", p.ID, err)
 	}
 
 	select {
 	case <-sigtermTimeout.Done():
-		p.proxyLogger.Infof("<%s> Process timed out waiting to stop, sending KILL signal", p.ID)
-		p.cmd.Process.Kill()
+		p.proxyLogger.Debugf("<%s> Process timed out waiting to stop, sending KILL signal (normal during shutdown)", p.ID)
+		if err := p.cmd.Process.Kill(); err != nil {
+			p.proxyLogger.Errorf("<%s> Failed to kill process: %v", p.ID, err)
+		}
 	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
+		// through the health check. There is a possibility that the 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 {
 				p.proxyLogger.Errorf("<%s> errno >> %v", p.ID, errno)
 			} else if exitError, ok := err.(*exec.ExitError); ok {
 				if strings.Contains(exitError.String(), "signal: terminated") {
-					p.proxyLogger.Infof("<%s> Process stopped OK", p.ID)
+					p.proxyLogger.Debugf("<%s> Process stopped OK", p.ID)
 				} else if strings.Contains(exitError.String(), "signal: interrupt") {
-					p.proxyLogger.Infof("<%s> Process interrupted OK", p.ID)
+					p.proxyLogger.Debugf("<%s> Process interrupted OK", p.ID)
 				} else {
 					p.proxyLogger.Warnf("<%s> ExitError >> %v, exit code: %d", p.ID, exitError, exitError.ExitCode())
 				}