Optimize pings to reduce timer percolation

socketserver/server/handlecore.go

@@ -375,11 +375,7 @@ func RunSocketConnection(conn *websocket.Conn) {
 	// report.RemoteAddr = client.RemoteAddr
 
 	conn.SetPongHandler(func(pongBody string) error {
-		client.Mutex.Lock()
-		if client.HelloOK { // do not accept PONGs until hello sent
-			client.pingCount = 0
-		}
-		client.Mutex.Unlock()
+		_clientChan <- ClientMessage{Command: "__ping"}
 		return nil
 	})
 
@@ -467,6 +463,10 @@ func runSocketReader(conn *websocket.Conn, client *ClientInfo, errorChan chan<-
 }
 
 func runSocketWriter(conn *websocket.Conn, client *ClientInfo, errorChan <-chan error, clientChan <-chan ClientMessage, serverMessageChan <-chan ClientMessage) websocket.CloseError {
+	pingTicker := time.NewTicker(1*time.Minute)
+	defer pingTicker.Stop()
+	lastPacket := time.Now()
+
 	for {
 		select {
 		case err := <-errorChan:
@@ -488,6 +488,10 @@ func runSocketWriter(conn *websocket.Conn, client *ClientInfo, errorChan <-chan
 			if !client.HelloOK && msg.Command != HelloCommand {
 				return CloseFirstMessageNotHello
 			}
+			lastPacket = time.Now()
+			if msg.Command == "__ping" {
+				continue // generated by server, not by client
+			}
 
 			for _, char := range msg.Command {
 				if char == utf8.RuneError {
@@ -506,14 +510,11 @@ func runSocketWriter(conn *websocket.Conn, client *ClientInfo, errorChan <-chan
 			}
 			SendMessage(conn, msg)
 
-		case <-time.After(1 * time.Minute):
-			client.Mutex.Lock()
-			client.pingCount++
-			tooManyPings := client.pingCount == 5
-			client.Mutex.Unlock()
-			if tooManyPings {
+		case <-pingTicker.C:
+			now := time.Now()
+			if lastPacket.Add(5*time.Minute).Before(now) {
 				return CloseTimedOut
-			} else {
+			} else if lastPacket.Add(1*time.Minute).Before(now) {
 				conn.WriteControl(websocket.PingMessage, []byte(strconv.FormatInt(time.Now().Unix(), 10)), getDeadline())
 			}
 

socketserver/server/types.go

@@ -141,10 +141,6 @@ type ClientInfo struct {
 
 	// Take out an Add() on this during a command if you need to use the MessageChannel later.
 	MsgChannelKeepalive sync.WaitGroup
-
-	// The number of pings sent without a response.
-	// Protected by Mutex
-	pingCount int
 }
 
 func VersionFromString(v string) ClientVersion {