fix: moving writeFunc as culprit of memory leak

internal/hub.go

@@ -3,6 +3,7 @@ package internal
 import (
 	"fmt"
 	"log"
+	"sync"
 	"time"
 
 	"github.com/google/uuid"
@@ -10,9 +11,10 @@ import (
 )
 
 const (
-	writeWait  = 10 * time.Second
-	pongWait   = 60 * time.Second
-	pingPeriod = 25 * time.Second
+	writeWait      = 10 * time.Second
+	pongWait       = 60 * time.Second
+	pingPeriod     = (pongWait * 9) / 10
+	maxMessageSize = 512
 )
 
 type Client struct {
@@ -20,16 +22,16 @@ type Client struct {
 	Conn           *websocket.Conn
 	Send           chan []byte
 	SubscribedPath string
-	done           chan struct{}
+	mu             sync.Mutex
 }
 
 func NewClient(conn *websocket.Conn, subscribedPath string) *Client {
 	return &Client{
 		ID:             uuid.NewString(),
 		Conn:           conn,
-		Send:           make(chan []byte, 1),
+		Send:           make(chan []byte, 256),
 		SubscribedPath: subscribedPath,
-		done:           make(chan struct{}, 1),
+		mu:             sync.Mutex{},
 	}
 }
 
@@ -42,9 +44,9 @@ type Hub struct {
 
 func NewHub() *Hub {
 	return &Hub{
-		Broadcast:  make(chan []byte, 1),
-		Register:   make(chan *Client, 1),
-		Unregister: make(chan *Client, 1),
+		Broadcast:  make(chan []byte, 256),
+		Register:   make(chan *Client, 10),
+		Unregister: make(chan *Client, 10),
 		Clients:    make(map[*Client]bool),
 	}
 }
@@ -55,23 +57,22 @@ func (h *Hub) Run() {
 			select {
 			case client := <-h.Register:
 				h.Clients[client] = true
-				log.Println("Client registered")
-			case c := <-h.Unregister:
-				if v, ok := h.Clients[c]; ok {
-					fmt.Println(v, c)
-					delete(h.Clients, c)
-					close(c.Send)
+				log.Printf("Client registered %s\n", client.ID)
+			case client := <-h.Unregister:
+				if _, ok := h.Clients[client]; ok {
+					delete(h.Clients, client)
+					close(client.Send)
 				}
-				log.Println("Client Unregistered")
+				log.Printf("Client Unregistered %s\n", client.ID)
 			case message := <-h.Broadcast:
 				for client := range h.Clients {
-					client.Send <- message
-					// select {
-					// case client.Send <- message:
-					// default:
-					// 	close(client.Send)
-					// 	delete(h.Clients, client)
-					// }
+					select {
+					case client.Send <- message:
+					default:
+						close(client.Send)
+						delete(h.Clients, client)
+						log.Printf("Client %s removed (slow/disconnected)", client.ID)
+					}
 				}
 			}
 		}
@@ -90,23 +91,36 @@ func WritePump(c *Client, h *Hub) {
 		select {
 		case message, ok := <-c.Send:
 			c.Conn.SetWriteDeadline(time.Now().Add(writeWait))
+
 			if !ok {
 				c.Conn.WriteMessage(websocket.CloseMessage, []byte{})
-				fmt.Println(ok)
 				return
 			}
 
-			if err := c.Conn.WriteMessage(websocket.TextMessage, message); err != nil {
-				fmt.Println(err)
+			w, err := c.Conn.NextWriter(websocket.TextMessage)
+			if err != nil {
+				return
+			}
+			w.Write(message)
+
+			// Queue queued messages in the same buffer (optional optimization)
+			n := len(c.Send)
+			for i := 0; i < n; i++ {
+				w.Write(<-c.Send)
+			}
+
+			if err := w.Close(); err != nil {
 				return
 			}
 		case <-pingTicker.C:
 			c.Conn.SetWriteDeadline(time.Now().Add(writeWait))
-			if err := c.Conn.WriteMessage(websocket.PingMessage, []byte{}); err != nil {
+
+			if err := c.Conn.WriteMessage(websocket.PingMessage, nil); err != nil {
 				fmt.Println(err)
 				return
 			}
 		}
+
 	}
 }
 
@@ -116,15 +130,16 @@ func ReadPump(c *Client, h *Hub) {
 		c.Conn.Close()
 	}()
 
-	c.Conn.SetReadLimit(1024)
+	c.Conn.SetReadLimit(maxMessageSize)
 	c.Conn.SetReadDeadline(time.Now().Add(pongWait))
+
 	c.Conn.SetPongHandler(func(string) error {
 		c.Conn.SetReadDeadline(time.Now().Add(pongWait))
 		return nil
 	})
 
 	for {
-		messageType, message, err := c.Conn.ReadMessage()
+		_, message, err := c.Conn.ReadMessage()
 		if err != nil {
 			if websocket.IsUnexpectedCloseError(err, websocket.CloseGoingAway, websocket.CloseAbnormalClosure) {
 				log.Printf("WebSocket error: %v", err)
@@ -132,8 +147,6 @@ func ReadPump(c *Client, h *Hub) {
 			break
 		}
 
-		if messageType == websocket.TextMessage {
-			log.Printf("Received: %s\n", message)
-		}
+		log.Printf("Received: %s\n", message)
 	}
 }

v1/client/client.go

@@ -16,8 +16,9 @@ import (
 )
 
 const (
-	pingPeriod   = 10 * time.Second
-	readDeadline = 30 * time.Second
+	pingPeriod    = 10 * time.Second
+	readDeadline  = 30 * time.Second
+	writeDeadline = 10 * time.Second
 )
 
 type MessageType uint
@@ -182,17 +183,14 @@ func (wsClient *SafeWebsocketClient) connect() error {
 		Scheme: scheme,
 		Host:   fmt.Sprintf("%s:%d", wsClient.baseHost, wsClient.basePort),
 	}
-
 	if wsClient.path != nil && strings.TrimSpace(*wsClient.path) != "" {
 		newURL.Path = *wsClient.path
 	}
-
 	if wsClient.rawQuery != nil && strings.TrimSpace(*wsClient.rawQuery) != "" {
 		newURL.RawQuery = *wsClient.rawQuery
 	}
 
 	header := make(http.Header)
-
 	if wsClient.headers != nil {
 		for k, v := range *wsClient.headers {
 			header.Set(k, v)
@@ -205,18 +203,22 @@ func (wsClient *SafeWebsocketClient) connect() error {
 	}
 
 	pingCtx, pingCancel := context.WithCancel(context.Background())
+	pumpCtx, pumpCancel := context.WithCancel(context.Background())
+
 	wsClient.mu.WriteHandler(func() error {
-		wsClient.cancelFuncs = append(wsClient.cancelFuncs, pingCancel)
+		if wsClient.conn != nil {
+			wsClient.conn.Close()
+		}
+
+		wsClient.conn = conn
+
+		wsClient.cancelFuncs = append(wsClient.cancelFuncs, pingCancel, pumpCancel)
 		return nil
 	})
 
 	go wsClient.startPingTicker(pingCtx)
-
-	if wsClient.conn != nil {
-		wsClient.conn.Close()
-	}
-	wsClient.conn = conn
-	wsClient.isConnected = true
+	go wsClient.writePump(pumpCtx, conn)
+	go wsClient.readPump(pumpCtx, conn)
 
 	conn.SetPingHandler(func(pingData string) error {
 		if err := conn.SetReadDeadline(time.Now().Add(readDeadline)); err != nil {
@@ -239,24 +241,77 @@ func (wsClient *SafeWebsocketClient) connect() error {
 		return nil
 	})
 
-	go wsClient.writePump()
-	go wsClient.readPump()
-
+	wsClient.isConnected = true
 	return nil
 }
 
-func (wsClient *SafeWebsocketClient) writePump() {
-	ctx, cancel := context.WithCancel(context.Background())
-	wsClient.mu.WriteHandler(func() error {
-		wsClient.cancelFuncs = append(wsClient.cancelFuncs, cancel)
-		return nil
-	})
+func (wsClient *SafeWebsocketClient) reconnectHandler() {
+	backoff := 1 * time.Second
+	maxBackoff := 15 * time.Second
 
-	var c *websocket.Conn
-	wsClient.mu.ReadHandler(func() error {
-		c = wsClient.conn
-		return nil
-	})
+	for {
+		select {
+		case <-wsClient.reconnectCh:
+			log.Println("Reconnect triggered")
+
+			wsClient.mu.WriteHandler(func() error {
+				if wsClient.cancelFuncs != nil {
+					for _, cancel := range wsClient.cancelFuncs {
+						cancel()
+					}
+					wsClient.cancelFuncs = nil
+				}
+				return nil
+			})
+
+			wsClient.isConnected = false
+			isInnerLoop := true
+			for isInnerLoop {
+				log.Printf("Attempting reconnect in %v...", backoff)
+				select {
+				case <-time.After(backoff):
+					if err := wsClient.connect(); err != nil {
+						log.Printf("Reconnect failed: %v", err)
+						if backoff < maxBackoff {
+							backoff *= 2
+						}
+						continue
+					}
+					log.Println("Reconnected successfully")
+					backoff = 1 * time.Second
+					isInnerLoop = false
+					continue
+				case <-wsClient.ctx.Done():
+					log.Println("reconnect handler stopped due to client shutdown")
+					wsClient.Close()
+					return
+				}
+			}
+			if wsClient.reconnectChans != nil {
+				for _, reconnectCh := range wsClient.reconnectChans {
+					select {
+					case reconnectCh <- struct{}{}:
+					default: // prevent blocking if chan is full
+					}
+				}
+				if len(wsClient.reconnectChans) > 1 {
+					wsClient.reconnectChans = wsClient.reconnectChans[1:]
+				} else {
+					wsClient.reconnectChans = nil
+				}
+			}
+		case <-wsClient.ctx.Done():
+			log.Println("reconnect handler stopped due to client shutdown")
+			wsClient.Close()
+			return
+		}
+	}
+}
+
+func (wsClient *SafeWebsocketClient) writePump(ctx context.Context, c *websocket.Conn) {
+	defer func() {
+		c.Close()
+	}()
 
 	for {
 		select {
@@ -264,30 +319,25 @@ func (wsClient *SafeWebsocketClient) writePump() {
 			log.Println("Writer canceled by context")
 			return
 		case data := <-wsClient.writeChan:
-			if c == nil {
+			if err := c.SetWriteDeadline(time.Now().Add(writeDeadline)); err != nil {
+				log.Printf("error setting write deadline: %v", err)
 				return
 			}
 
 			if err := c.WriteMessage(int(data.MessageType), data.Data); err != nil {
 				log.Printf("error on write message: %v\n", err)
+				wsClient.triggerReconnect() // Trigger reconnect on write failure
 				return
 			}
 		}
 	}
 }
 
-func (wsClient *SafeWebsocketClient) readPump() {
-	ctx, cancel := context.WithCancel(context.Background())
-	wsClient.mu.WriteHandler(func() error {
-		wsClient.cancelFuncs = append(wsClient.cancelFuncs, cancel)
-		return nil
-	})
-
-	var c *websocket.Conn
-	wsClient.mu.ReadHandler(func() error {
-		c = wsClient.conn
-		return nil
-	})
+func (wsClient *SafeWebsocketClient) readPump(ctx context.Context, c *websocket.Conn) {
+	defer func() {
+		wsClient.triggerReconnect()
+		c.Close()
+	}()
 
 	for {
 		select {
@@ -295,19 +345,14 @@ func (wsClient *SafeWebsocketClient) readPump() {
 			log.Println("Reader canceled by context")
 			return
 		default:
-			if c == nil {
-				return
-			}
-
+			// Set read deadline
 			if err := c.SetReadDeadline(time.Now().Add(readDeadline)); err != nil {
-				log.Printf("error on read deadline: %v\n", err)
 				return
 			}
 
 			messageType, data, err := c.ReadMessage()
 			if err != nil {
 				log.Printf("error on read message: %v\n", err)
-				wsClient.triggerReconnect()
 				return
 			}
 
@@ -353,60 +398,6 @@ func (wsClient *SafeWebsocketClient) triggerReconnect() {
 	}
 }
 
-func (wsClient *SafeWebsocketClient) reconnectHandler() {
-	backoff := 1 * time.Second
-	maxBackoff := 30 * time.Second
-	for {
-		select {
-		case <-wsClient.reconnectCh:
-			log.Println("Reconnect triggered")
-
-			wsClient.mu.ReadHandler(func() error {
-				if wsClient.cancelFuncs != nil {
-					for _, cancel := range wsClient.cancelFuncs {
-						cancel()
-					}
-				}
-				return nil
-			})
-
-			wsClient.isConnected = false
-
-			isInnerLoop := true
-			for isInnerLoop {
-				log.Printf("Attempting reconnect in %v...", backoff)
-				select {
-				case <-time.After(backoff):
-					if err := wsClient.connect(); err != nil {
-						log.Printf("Reconnect failed: %v", err)
-						if backoff < maxBackoff {
-							backoff *= 2
-						}
-						continue
-					}
-					log.Println("Reconnected successfully")
-					backoff = 1 * time.Second
-					isInnerLoop = false
-					continue
-				case <-wsClient.ctx.Done():
-					log.Println("reconnect handler stopped due to client shutdown")
-					wsClient.Close()
-					return
-				}
-			}
-			if wsClient.reconnectChans != nil {
-				for _, reconnectCh := range wsClient.reconnectChans {
-					reconnectCh <- struct{}{}
-				}
-			}
-		case <-wsClient.ctx.Done():
-			log.Println("reconnect handler stopped due to client shutdown")
-			wsClient.Close()
-			return
-		}
-	}
-}
-
 func (wsClient *SafeWebsocketClient) ReconnectChannel() <-chan struct{} {
 	reconnectCh := make(chan struct{}, 1)
 	wsClient.mu.WriteHandler(func() error {

v1/server/server.go

@@ -1,6 +1,7 @@
 package server
 
 import (
+	"crypto/subtle"
 	"fmt"
 	"log"
 	"net/http"
@@ -63,10 +64,12 @@ func (b *SafeWebsocketServerBuilder) HandleFunc(pattern string, fn func(http.Res
 	return b
 }
 
-func (b *SafeWebsocketServerBuilder) HandleFuncWebsocket(pattern string, subscribedPath string, writeFunc func(chan []byte)) *SafeWebsocketServerBuilder {
+func (b *SafeWebsocketServerBuilder) HandleFuncWebsocket(pattern string, subscribedPath string, writeFunc func(writeChannel chan []byte)) *SafeWebsocketServerBuilder {
 	h := internal.NewHub()
 	h.Run()
 
+	go writeFunc(h.Broadcast)
+
 	b.mux.HandleFunc(pattern+subscribedPath, func(w http.ResponseWriter, r *http.Request) {
 		conn, err := b.upgrader.Upgrade(w, r, nil)
 		if err != nil {
@@ -81,9 +84,10 @@ func (b *SafeWebsocketServerBuilder) HandleFuncWebsocket(pattern string, subscri
 		}
 		c := internal.NewClient(conn, subscribedPath)
 		h.Register <- c
+
 		go internal.WritePump(c, h)
 		go internal.ReadPump(c, h)
-		go writeFunc(h.Broadcast)
+
 	})
 	return b
 }
@@ -110,13 +114,17 @@ type SafeWebsocketServer struct {
 
 func (s *SafeWebsocketServer) AuthMiddleware(next http.Handler) http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		if r.Header.Get("X-MBX-APIKEY") != s.apiKey {
+		providedKey := r.Header.Get("X-MBX-APIKEY")
+		expectedKey := s.apiKey
+
+		if subtle.ConstantTimeCompare([]byte(providedKey), []byte(expectedKey)) != 1 {
 			internal.ErrorResponse(w, internal.NewStatusMessage().
 				StatusCode(http.StatusForbidden).
 				Message("X-MBX-APIKEY is missing").
 				Build())
 			return
 		}
+
 		next.ServeHTTP(w, r)
 	})
 }