Blowing in the wind

func msgHandler(ws *websocket.Conn) {
	defer ws.Close()

	clients[ws] = true
	fmt.Println(clients)

	premsg := msg	// initialize websocket message
	t := time.NewTicker(500 * time.Millisecond)
	defer 	t.Stop()
label:
	for {
		msgr := ""
        err := websocket.Message.Receive(ws, &msgr)
		if err != nil {
			//log.Println("receive error")		// main pupose is to check timeout (to detect unused session)
			break label
		}

		select {
			// to send websocket message triggered by the timer
			// the reason to separate receive and send is ws are running multi thread
		case <- t.C:
			if premsg != msg {
				premsg = msg
				err := websocket.Message.Send(ws, msg)
				if err != nil {
					log.Println("send err")
					break label
				}
			}
		case name := <- uidSerial.Notice:	// wait for message from serial.go via channel
			mu.Lock()
			msg = name.(string)
			mu.Unlock()
		}
	}
	clients[ws] = false
}

func handleWebSocket(c echo.Context) error {
	websocket.Handler(func(ws *websocket.Conn) {
		defer ws.Close()

		// 初回のメッセージを送信
		err := websocket.Message.Send(ws, "Server: Hello, Client!")
		if err != nil {
			c.Logger().Error(err)
		}

		for {
			// Client からのメッセージを読み込む
			msg := ""
			err = websocket.Message.Receive(ws, &msg)
			if err != nil {
				//c.Logger().Error(err)
			}

			// Client からのメッセージを元に返すメッセージを作成し送信する
			err := websocket.Message.Send(ws, fmt.Sprintf("Server: \"%s\" received!", msg))
			if err != nil {
				//c.Logger().Error(err)
			}
		}
	}).ServeHTTP(c.Response(), c.Request())
	return nil
}