feat: config hot-reload

Author: sammcj

llama-swap.go

@@ -8,6 +8,7 @@ import (
 	"os"
 	"os/signal"
 	"path/filepath"
+	"sync"
 	"syscall"
 	"time"
 
@@ -16,9 +17,14 @@ import (
 	"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"
+
+	// Global mutex for server operations
+	serverMux sync.Mutex
+)
 
 func main() {
 	// Define a command-line flag for the port
@@ -78,18 +84,31 @@ func main() {
 	fmt.Println("llama-swap listening on " + *listenStr)
 	go func() {
 		for {
-			err = proxyManager.Run(*listenStr)
+			serverMux.Lock()
+			runChan := make(chan error)
+
+			// Start server in separate goroutine
+			go func() {
+				runChan <- proxyManager.Run(*listenStr)
+			}()
+
+			// Wait for server to complete or config reload
+			err = <-runChan
+
 			if err != nil && err != http.ErrServerClosed {
 				fmt.Printf("Fatal server error: %v\n", err)
+				serverMux.Unlock()
 				close(exitChan)
 				return
 			}
+
+			serverMux.Unlock()
 			// If we get here, it's because of a normal shutdown (config reload)
 			// Just continue the loop to let the new server start
 		}
 	}()
 
-	// Wait until we receive an exit signal
+	// Wait for exit signal
 	<-exitChan
 }
 
@@ -117,7 +136,6 @@ func watchConfigFile(configPath string, pm **proxy.ProxyManager, listenStr *stri
 		select {
 		case event, ok := <-watcher.Events:
 			if !ok {
-				log.Println("File watcher channel closed.")
 				return
 			}
 			// We only care about writes to the specific config file
@@ -137,18 +155,18 @@ func watchConfigFile(configPath string, pm **proxy.ProxyManager, listenStr *stri
 					}
 
 					// Stop and cleanup old ProxyManager
+					serverMux.Lock()
 					oldPM := *pm
 					oldPM.Shutdown()
 
 					// Create new ProxyManager with new config
 					newPM := proxy.New(newConfig)
 					*pm = newPM
+					serverMux.Unlock()
 
-					// Wait for a moment to ensure shutdown is complete
-					time.Sleep(250 * time.Millisecond)
-
-					// Start serving with new ProxyManager
+					// Start serving with new ProxyManager (outside the lock)
 					go func() {
+						// Try to start the server
 						if err := newPM.Run(*listenStr); err != nil && err != http.ErrServerClosed {
 							log.Printf("Error starting server after config reload: %v", err)
 						}