exception during websocket client close [SPR-14721]

[spring-projects-issues]

Prashant Deva opened SPR-14721 and commented

To reproduce:

Keep the websocket client running and shutdown the server.

Here is the setup and stop code -

class MyWS {
 void setup() throws ExecutionException, InterruptedException
    {

        WebSocketContainer webSocketContainer = new MyContainerProvider().create();
        List<Transport> transports = new ArrayList<Transport>(1);
        transports.add(new WebSocketTransport(new StandardWebSocketClient(webSocketContainer)));

        SockJsClient sockJsClient = new SockJsClient(transports);
        sockJsClient.setMessageCodec(new StringMessageCodec());

        stompClient = new WebSocketStompClient(sockJsClient);
        stompClient.setMessageConverter(new StringMessageConverter());
        stompClient.start();

        stompClient.connect(WS_URL, new MyStompSessionHandler());
    }

void stop()
    {
        StompSession stompSession = this.stompSession;
        if(stompSession!=null)
        {
            try
            {
                if(stompSession.isConnected())
                {
                    stompSession.disconnect();
                    Log.trace("Disconnecting from websocket");
                }
            } catch (Exception e)
            {
                Log.debug("error disconnecting", e);
            }
            this.stompSession = null;
        }
    }

private class MyStompSessionHandler extends StompSessionHandlerAdapter
    {
        @Override
        public void afterConnected(StompSession session, StompHeaders connectedHeaders)
        {
            MyWS.this.stompSession = session;
        }

        @Override
        public void handleFrame(StompHeaders headers, Object payload)
        {
            super.handleFrame(headers, payload);
        }

        @Override
        public void handleException(StompSession session, StompCommand command, StompHeaders headers, byte[] payload, Throwable exception)
        {
            Log.debug("Exception in realtime socket", exception);
        }

        @Override
        public void handleTransportError(StompSession session, Throwable exception)
        {
            MyWS.this.stop();
        }
    }




}

Here is the exception:

2016-09-15 09:48:25,909 [Grizzly(1)] DEBUG   -  error disconnecting
java.com.chronon.apm.libs.org.springframework.messaging.MessageDeliveryException: nested exception is java.lang.IllegalStateException: WebSocketClientSockJsSession[id='1f1aafad087b4cc78047f42b47b2ea3f, url=http://127.0.0.1:8082/wsgame] is not open, current state=CLOSED
	at java.com.chronon.apm.libs.org.springframework.messaging.simp.stomp.DefaultStompSession.execute(DefaultStompSession.java:277)
	at java.com.chronon.apm.libs.org.springframework.messaging.simp.stomp.DefaultStompSession.disconnect(DefaultStompSession.java:326)
	at java.com.chronon.apm.realtime.SpringWS.stop(SpringWS.java:88)
	at java.com.chronon.apm.realtime.SpringWS$MyStompSessionHandler.handleTransportError(SpringWS.java:190)
	at java.com.chronon.apm.libs.org.springframework.messaging.simp.stomp.DefaultStompSession.handleFailure(DefaultStompSession.java:444)
	at java.com.chronon.apm.libs.org.springframework.messaging.simp.stomp.DefaultStompSession.afterConnectionClosed(DefaultStompSession.java:459)
	at java.com.chronon.apm.libs.org.springframework.web.socket.messaging.WebSocketStompClient$WebSocketTcpConnectionHandlerAdapter.afterConnectionClosed(WebSocketStompClient.java:354)
	at java.com.chronon.apm.libs.org.springframework.web.socket.sockjs.client.AbstractClientSockJsSession.afterTransportClosed(AbstractClientSockJsSession.java:321)
	at java.com.chronon.apm.libs.org.springframework.web.socket.sockjs.client.WebSocketTransport$ClientSockJsWebSocketHandler.afterConnectionClosed(WebSocketTransport.java:172)
	at java.com.chronon.apm.libs.org.springframework.web.socket.adapter.standard.StandardWebSocketHandlerAdapter.onClose(StandardWebSocketHandlerAdapter.java:141)
	at java.com.chronon.apm.libs.org.glassfish.tyrus.core.TyrusEndpointWrapper.onClose(TyrusEndpointWrapper.java:1259)
	at java.com.chronon.apm.libs.org.glassfish.tyrus.core.TyrusWebSocket.onClose(TyrusWebSocket.java:130)
	at java.com.chronon.apm.libs.org.glassfish.tyrus.core.ProtocolHandler.close(ProtocolHandler.java:469)
	at java.com.chronon.apm.libs.org.glassfish.tyrus.core.TyrusWebSocket.close(TyrusWebSocket.java:264)
	at java.com.chronon.apm.libs.org.glassfish.tyrus.core.TyrusWebSocket.close(TyrusWebSocket.java:274)
	at java.com.chronon.apm.libs.org.glassfish.tyrus.core.TyrusRemoteEndpoint.close(TyrusRemoteEndpoint.java:495)
	at java.com.chronon.apm.libs.org.glassfish.tyrus.core.TyrusSession.close(TyrusSession.java:233)
	at java.com.chronon.apm.libs.org.springframework.web.socket.adapter.standard.StandardWebSocketSession.closeInternal(StandardWebSocketSession.java:217)
	at java.com.chronon.apm.libs.org.springframework.web.socket.adapter.AbstractWebSocketSession.close(AbstractWebSocketSession.java:139)
	at java.com.chronon.apm.libs.org.springframework.web.socket.handler.ExceptionWebSocketHandlerDecorator.tryCloseWithError(ExceptionWebSocketHandlerDecorator.java:94)
	at java.com.chronon.apm.libs.org.springframework.web.socket.adapter.standard.StandardWebSocketHandlerAdapter.handleTextMessage(StandardWebSocketHandlerAdapter.java:113)
	at java.com.chronon.apm.libs.org.springframework.web.socket.adapter.standard.StandardWebSocketHandlerAdapter.access$000(StandardWebSocketHandlerAdapter.java:42)
	at java.com.chronon.apm.libs.org.springframework.web.socket.adapter.standard.StandardWebSocketHandlerAdapter$3.onMessage(StandardWebSocketHandlerAdapter.java:81)
	at java.com.chronon.apm.libs.org.springframework.web.socket.adapter.standard.StandardWebSocketHandlerAdapter$3.onMessage(StandardWebSocketHandlerAdapter.java:78)
	at java.com.chronon.apm.libs.org.glassfish.tyrus.core.TyrusSession.notifyMessageHandlers(TyrusSession.java:576)
	at java.com.chronon.apm.libs.org.glassfish.tyrus.core.TyrusEndpointWrapper.onMessage(TyrusEndpointWrapper.java:879)
	at java.com.chronon.apm.libs.org.glassfish.tyrus.core.TyrusWebSocket.onMessage(TyrusWebSocket.java:216)
	at java.com.chronon.apm.libs.org.glassfish.tyrus.core.frame.TextFrame.respond(TextFrame.java:139)
	at java.com.chronon.apm.libs.org.glassfish.tyrus.core.ProtocolHandler.process(ProtocolHandler.java:807)
	at java.com.chronon.apm.libs.org.glassfish.tyrus.client.TyrusClientEngine$TyrusReadHandler.handle(TyrusClientEngine.java:747)
	at java.com.chronon.apm.libs.org.glassfish.tyrus.container.grizzly.client.GrizzlyClientFilter$ProcessTask.execute(GrizzlyClientFilter.java:476)
	at java.com.chronon.apm.libs.org.glassfish.tyrus.container.grizzly.client.TaskProcessor.processTask(TaskProcessor.java:114)
	at java.com.chronon.apm.libs.org.glassfish.tyrus.container.grizzly.client.TaskProcessor.processTask(TaskProcessor.java:91)
	at java.com.chronon.apm.libs.org.glassfish.tyrus.container.grizzly.client.GrizzlyClientFilter.handleRead(GrizzlyClientFilter.java:272)
	at java.com.chronon.apm.libs.org.glassfish.grizzly.filterchain.ExecutorResolver$9.execute(ExecutorResolver.java:119)
	at java.com.chronon.apm.libs.org.glassfish.grizzly.filterchain.DefaultFilterChain.executeFilter(DefaultFilterChain.java:284)
	at java.com.chronon.apm.libs.org.glassfish.grizzly.filterchain.DefaultFilterChain.executeChainPart(DefaultFilterChain.java:201)
	at java.com.chronon.apm.libs.org.glassfish.grizzly.filterchain.DefaultFilterChain.execute(DefaultFilterChain.java:133)
	at java.com.chronon.apm.libs.org.glassfish.grizzly.filterchain.DefaultFilterChain.process(DefaultFilterChain.java:112)
	at java.com.chronon.apm.libs.org.glassfish.grizzly.ProcessorExecutor.execute(ProcessorExecutor.java:77)
	at java.com.chronon.apm.libs.org.glassfish.grizzly.nio.transport.TCPNIOTransport.fireIOEvent(TCPNIOTransport.java:526)
	at java.com.chronon.apm.libs.org.glassfish.grizzly.strategies.AbstractIOStrategy.fireIOEvent(AbstractIOStrategy.java:112)
	at java.com.chronon.apm.libs.org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.run0(WorkerThreadIOStrategy.java:117)
	at java.com.chronon.apm.libs.org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.access$100(WorkerThreadIOStrategy.java:56)
	at java.com.chronon.apm.libs.org.glassfish.grizzly.strategies.WorkerThreadIOStrategy$WorkerThreadRunnable.run(WorkerThreadIOStrategy.java:137)
	at java.com.chronon.apm.libs.org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:591)
	at java.com.chronon.apm.libs.org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:571)
	at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.IllegalStateException: WebSocketClientSockJsSession[id='1f1aafad087b4cc78047f42b47b2ea3f, url=http://127.0.0.1:8082/wsgame] is not open, current state=CLOSED
	at java.com.chronon.apm.libs.org.springframework.util.Assert.state(Assert.java:392)
	at java.com.chronon.apm.libs.org.springframework.web.socket.sockjs.client.AbstractClientSockJsSession.sendMessage(AbstractClientSockJsSession.java:139)
	at java.com.chronon.apm.libs.org.springframework.web.socket.messaging.WebSocketStompClient$WebSocketTcpConnectionHandlerAdapter.send(WebSocketStompClient.java:383)
	at java.com.chronon.apm.libs.org.springframework.messaging.simp.stomp.DefaultStompSession.execute(DefaultStompSession.java:274)
	... 47 more

The exception is thrown on this line:

stompSession.disconnect();

However, as you can see I check to see if the session is connected using the isConnected() call.
The code should not throw an exception if isConnected() was checked before calling disconnect()

---

Affects: 4.2.6

Issue Links:

• exception during websocket server shutdown [SPR-14716] #19281 exception during websocket server shutdown

Referenced from: commits 62b02c2, 99c7917, 81f6c22

Backported to: 4.2.8

[spring-projects-issues]

Rossen Stoyanchev commented

In general the connection state can change at any time even simultaneously so isConnected() cannot guarantee the connection will still be open even on the next line.

That said in this case it happens as a result of an onClose notification from the WebSocket so we already know the connection is closed and should reset it immediately before invoking handleTransportError on the StompSessionHandler. I'll schedule for a fix.

[spring-projects-issues]

Prashant Deva commented

if checking for isConnected() before calling disconnect() can result in race condition what is the right way to disconnect() without getting an exception?

[spring-projects-issues]

Rossen Stoyanchev commented

If you call disconnect there is nothing we can do, and there is nothing we can lock, to prevent the connection from being closed simultaneously from the other end. It's outside our control. Moreover an exception can occur when sending any frame and DISCONNECT is not different in any way. So no way to avoid network exceptions.