fix(websocket): resolve channel race condition and graceful shutdown deadlock

web/job/xray_traffic_job.go

@@ -85,8 +85,8 @@ func (j *XrayTrafficJob) Run() {
 		logger.Warning("get all outbounds for websocket failed:", err)
 	}
 
-	// The web socket hub will automatically check the payload size.
-	// If < 1MB, it pushes real-time. If > 1MB, it sends a lightweight 'invalidate' signal.
+	// The WebSocket hub will automatically check the payload size.
+	// If it exceeds 100MB, it sends a lightweight 'invalidate' signal instead.
 	if updatedInbounds != nil {
 		websocket.BroadcastInbounds(updatedInbounds)
 	}

web/websocket/hub.go

@@ -33,10 +33,11 @@ type Message struct {
 
 // Client represents a WebSocket client connection
 type Client struct {
-	ID     string
-	Send   chan []byte
-	Hub    *Hub
-	Topics map[MessageType]bool // Subscribed topics
+	ID        string
+	Send      chan []byte
+	Hub       *Hub
+	Topics    map[MessageType]bool // Subscribed topics
+	closeOnce sync.Once            // Ensures Send channel is closed exactly once
 }
 
 // Hub maintains the set of active clients and broadcasts messages to them
@@ -62,7 +63,6 @@ type Hub struct {
 
 	// Worker pool for parallel broadcasting
 	workerPoolSize int
-	broadcastWg    sync.WaitGroup
 }
 
 // NewHub creates a new WebSocket hub
@@ -105,20 +105,12 @@ func (h *Hub) Run() {
 			// Graceful shutdown: close all clients
 			h.mu.Lock()
 			for client := range h.clients {
-				// Safely close channel (avoid double close panic)
-				select {
-				case _, stillOpen := <-client.Send:
-					if stillOpen {
-						close(client.Send)
-					}
-				default:
+				client.closeOnce.Do(func() {
 					close(client.Send)
-				}
+				})
 			}
 			h.clients = make(map[*Client]bool)
 			h.mu.Unlock()
-			// Wait for all broadcast workers to finish
-			h.broadcastWg.Wait()
 			logger.Info("WebSocket hub stopped gracefully")
 			return
 
@@ -139,19 +131,9 @@ func (h *Hub) Run() {
 			h.mu.Lock()
 			if _, ok := h.clients[client]; ok {
 				delete(h.clients, client)
-				// Safely close channel (avoid double close panic)
-				// Check if channel is already closed by trying to read from it
-				select {
-				case _, stillOpen := <-client.Send:
-					if stillOpen {
-						// Channel was open and had data, now it's empty, safe to close
-						close(client.Send)
-					}
-					// If stillOpen is false, channel was already closed, do nothing
-				default:
-					// Channel is empty and open, safe to close
+				client.closeOnce.Do(func() {
 					close(client.Send)
-				}
+				})
 			}
 			count := len(h.clients)
 			h.mu.Unlock()
@@ -221,11 +203,12 @@ func (h *Hub) broadcastParallel(clients []*Client, message []byte) {
 	}
 	close(clientChan)
 
-	// Start workers for parallel processing
-	h.broadcastWg.Add(h.workerPoolSize)
+	// Use a local WaitGroup to avoid blocking hub shutdown
+	var wg sync.WaitGroup
+	wg.Add(h.workerPoolSize)
 	for i := 0; i < h.workerPoolSize; i++ {
 		go func() {
-			defer h.broadcastWg.Done()
+			defer wg.Done()
 			for client := range clientChan {
 				func() {
 					defer func() {
@@ -247,7 +230,7 @@ func (h *Hub) broadcastParallel(clients []*Client, message []byte) {
 	}
 
 	// Wait for all workers to finish
-	h.broadcastWg.Wait()
+	wg.Wait()
 }
 
 // Broadcast sends a message to all connected clients