feat: config hot-reload

Author: sammcj

llama-swap.go

@@ -53,7 +53,8 @@ func main() {
 		if err != nil {
 			log.Printf("Error getting absolute path for config: %v. File watching disabled.", err)
 		} else {
-			go watchConfigFile(absConfigPath, proxyManager)
+			var proxyManagerPtr = &proxyManager
+			go watchConfigFile(absConfigPath, proxyManagerPtr, listenStr)
 		}
 	}
 
@@ -73,8 +74,8 @@ func main() {
 	}
 }
 
-// watchConfigFile monitors the configuration file for changes and triggers a reload.
-func watchConfigFile(configPath string, pm *proxy.ProxyManager) {
+// watchConfigFile monitors the configuration file for changes and recreates the ProxyManager with the new config.
+func watchConfigFile(configPath string, pm **proxy.ProxyManager, listenStr *string) {
 	watcher, err := fsnotify.NewWatcher()
 	if err != nil {
 		log.Printf("Error creating file watcher: %v. File watching disabled.", err)
@@ -109,11 +110,31 @@ func watchConfigFile(configPath string, pm *proxy.ProxyManager) {
 				}
 				debounceTimer = time.AfterFunc(debounceDuration, func() {
 					log.Printf("Config file modified: %s, attempting reload...", event.Name)
-					if err := pm.ReloadConfig(configPath); err != nil {
-						log.Printf("Error reloading config: %v", err)
-					} else {
-						log.Println("Config reloaded successfully.")
+
+					// Load new configuration
+					newConfig, err := proxy.LoadConfig(configPath)
+					if err != nil {
+						log.Printf("Error loading new config: %v", err)
+						return
 					}
+
+					// Stop and cleanup old ProxyManager
+					oldPM := *pm
+					log.Println("Shutting down old ProxyManager instance before reload...")
+					oldPM.Shutdown()
+
+					// Create new ProxyManager with new config
+					newPM := proxy.New(newConfig)
+					*pm = newPM
+
+					// Start serving with new ProxyManager
+					go func() {
+						if err := newPM.Run(*listenStr); err != nil {
+							log.Printf("Server error after config reload: %v", err)
+						}
+					}()
+
+					log.Println("Config reloaded successfully.")
 				})
 			}
 		case err, ok := <-watcher.Errors:

proxy/proxymanager.go

@@ -196,49 +196,6 @@ func (pm *ProxyManager) HandlerFunc(w http.ResponseWriter, r *http.Request) {
 	pm.ginEngine.ServeHTTP(w, r)
 }
 
-// ReloadConfig loads a new configuration file, stops all current processes,
-// and updates the manager's internal configuration.
-func (pm *ProxyManager) ReloadConfig(configPath string) error {
-	pm.proxyLogger.Debugf("Attempting to reload configuration from: %s", configPath)
-
-	newConfig, err := LoadConfig(configPath)
-	if err != nil {
-		return fmt.Errorf("failed to load new config: %w", err)
-	}
-
-	// Update log level based on new config
-	switch strings.ToLower(strings.TrimSpace(newConfig.LogLevel)) {
-	case "debug":
-		pm.proxyLogger.SetLogLevel(LevelDebug)
-		pm.upstreamLogger.SetLogLevel(LevelDebug)
-	case "info":
-		pm.proxyLogger.SetLogLevel(LevelInfo)
-		pm.upstreamLogger.SetLogLevel(LevelInfo)
-	case "warn":
-		pm.proxyLogger.SetLogLevel(LevelWarn)
-		pm.upstreamLogger.SetLogLevel(LevelWarn)
-	case "error":
-		pm.proxyLogger.SetLogLevel(LevelError)
-		pm.upstreamLogger.SetLogLevel(LevelError)
-	default:
-		pm.proxyLogger.SetLogLevel(LevelInfo) // Default to info if invalid
-		pm.upstreamLogger.SetLogLevel(LevelInfo)
-	}
-	// Log the new log level based on the config value
-	pm.proxyLogger.Debugf("Log level set to %s based on reloaded config", strings.ToLower(strings.TrimSpace(newConfig.LogLevel)))
-
-	pm.Lock()
-	defer pm.Unlock()
-
-	pm.proxyLogger.Info("Stopping all current upstream processes due to config reload...")
-	pm.stopProcesses() // Call internal stop without lock
-
-	pm.config = newConfig
-	pm.proxyLogger.Info("ProxyManager configuration updated.")
-
-	return nil
-}
-
 // StopProcesses acquires a lock and stops all running upstream processes.
 // This is the public method safe for concurrent calls.
 func (pm *ProxyManager) StopProcesses() {