a set of random fixes into the blue

benchmark-proxy/main.go

@@ -1343,6 +1343,7 @@ func handleRequest(w http.ResponseWriter, r *http.Request, backends []Backend, c
 	var responseHandled atomic.Bool
 	var firstBackendStartTime atomic.Pointer[time.Time]
 	primaryResponseChan := make(chan struct{}, 1) // Signal when primary gets a response
+	primaryFailedFast := make(chan struct{}, 1)   // Signal when primary fails immediately
 
 	for _, backend := range backends {
 		// Skip secondary backends for stateful methods
@@ -1388,6 +1389,12 @@ func handleRequest(w http.ResponseWriter, r *http.Request, backends []Backend, c
 						Duration: time.Since(goroutineStartTime),
 					}
 					return
+				case <-primaryFailedFast:
+					// Primary failed immediately, start secondary now
+					delayTimer.Stop()
+					if enableDetailedLogs {
+						log.Printf("Primary failed fast for %s, starting secondary immediately", method)
+					}
 				}
 			}
 
@@ -1416,6 +1423,14 @@ func handleRequest(w http.ResponseWriter, r *http.Request, backends []Backend, c
 			reqDuration := time.Since(reqStart)
 
 			if err != nil {
+				// If primary failed with connection error, signal secondary to start
+				if b.Role == "primary" {
+					select {
+					case primaryFailedFast <- struct{}{}:
+					default:
+					}
+				}
+
 				statsChan <- ResponseStats{
 					Backend:  b.Name,
 					Duration: reqDuration, // Keep backend-specific duration
@@ -1427,6 +1442,15 @@ func handleRequest(w http.ResponseWriter, r *http.Request, backends []Backend, c
 
 			// Don't close resp.Body here - it will be closed by the winner or drained by losers
 
+			// Check if primary returned an error status
+			if b.Role == "primary" && resp.StatusCode >= 400 {
+				// Any 4xx or 5xx error should trigger immediate secondary
+				select {
+				case primaryFailedFast <- struct{}{}:
+				default:
+				}
+			}
+
 			// Signal primary response immediately for secondary backends to check
 			if b.Role == "primary" && resp.StatusCode < 400 {
 				select {
@@ -1677,6 +1701,8 @@ func handleWebSocketRequest(w http.ResponseWriter, r *http.Request, backends []B
 
 	// Connect to all backends
 	var wg sync.WaitGroup
+	primaryConnected := make(chan bool, 1) // Track if primary connected successfully
+
 	for _, backend := range backends {
 		wg.Add(1)
 		go func(b Backend) {
@@ -1720,6 +1746,14 @@ func handleWebSocketRequest(w http.ResponseWriter, r *http.Request, backends []B
 				log.Printf("Failed to connect to backend %s: %v (status: %d)", b.Name, err, status)
 				stats.Error = err
 				statsCollector.AddWebSocketStats(stats)
+
+				// If primary failed to connect, signal that
+				if b.Role == "primary" {
+					select {
+					case primaryConnected <- false:
+					default:
+					}
+				}
 				return
 			}
 			defer backendConn.Close()
@@ -1730,39 +1764,81 @@ func handleWebSocketRequest(w http.ResponseWriter, r *http.Request, backends []B
 			stats.IsActive = true
 			statsCollector.AddWebSocketStats(stats)
 
+			// If this is the primary backend, signal successful connection
+			if b.Role == "primary" {
+				select {
+				case primaryConnected <- true:
+				default:
+				}
+			}
+
 			// If this is the primary backend, set up bidirectional proxying
 			if b.Role == "primary" {
+				// Channel to signal when primary connection fails
+				primaryFailed := make(chan struct{}, 2) // Buffered for 2 signals
+
 				// Forward messages from client to primary backend
 				go func() {
 					for {
 						messageType, message, err := clientConn.ReadMessage()
 						if err != nil {
 							log.Printf("Error reading from client: %v", err)
+							select {
+							case primaryFailed <- struct{}{}:
+							default:
+							}
 							return
 						}
 
 						err = backendConn.WriteMessage(messageType, message)
 						if err != nil {
 							log.Printf("Error writing to primary backend: %v", err)
+							select {
+							case primaryFailed <- struct{}{}:
+							default:
+							}
 							return
 						}
 					}
 				}()
 
 				// Forward messages from primary backend to client
-				for {
+				go func() {
-					messageType, message, err := backendConn.ReadMessage()
+					for {
-					if err != nil {
+						messageType, message, err := backendConn.ReadMessage()
-						log.Printf("Error reading from primary backend: %v", err)
+						if err != nil {
-						return
+							log.Printf("Error reading from primary backend: %v", err)
-					}
+							select {
+							case primaryFailed <- struct{}{}:
+							default:
+							}
+							return
+						}
 
-					err = clientConn.WriteMessage(messageType, message)
+						err = clientConn.WriteMessage(messageType, message)
-					if err != nil {
+						if err != nil {
-						log.Printf("Error writing to client: %v", err)
+							log.Printf("Error writing to client: %v", err)
-						return
+							select {
+							case primaryFailed <- struct{}{}:
+							default:
+							}
+							return
+						}
 					}
-				}
+				}()
+
+				// Wait for primary connection failure
+				<-primaryFailed
+
+				// Primary backend failed, close client connection with proper close message
+				log.Printf("Primary backend WebSocket failed, closing client connection")
+				closeMsg := websocket.FormatCloseMessage(websocket.CloseGoingAway,
+					"Primary backend unavailable")
+				clientConn.WriteControl(websocket.CloseMessage, closeMsg,
+					time.Now().Add(time.Second))
+
+				// Return to trigger cleanup
+				return
 			} else {
 				// For secondary backends, just read and discard messages
 				for {
@@ -1778,6 +1854,22 @@ func handleWebSocketRequest(w http.ResponseWriter, r *http.Request, backends []B
 
 	// Wait for all connections to terminate
 	wg.Wait()
+
+	// Check if primary connected successfully
+	select {
+	case connected := <-primaryConnected:
+		if !connected {
+			// Primary failed to connect, close client connection
+			log.Printf("Primary backend WebSocket failed to connect, closing client connection")
+			closeMsg := websocket.FormatCloseMessage(websocket.CloseServiceRestart,
+				"Primary backend unavailable")
+			clientConn.WriteControl(websocket.CloseMessage, closeMsg,
+				time.Now().Add(time.Second))
+		}
+	default:
+		// No primary backend in the configuration (shouldn't happen)
+		log.Printf("Warning: No primary backend configured for WebSocket")
+	}
 }
 
 func getEnv(key, fallback string) string {