Errors when rapidly opening/closing sockets and contexts

I’m attempting to create an instance of my ZMQ stack for each unit test in my test suite. But I get problems when I rapidly open/close sockets and contexts.

Some times I get this:

Exception in thread "reaper-1" java.lang.AssertionError
    at zmq.Mailbox.recv(Mailbox.java:114)
    at zmq.SocketBase.process_commands(SocketBase.java:830)
    at zmq.SocketBase.in_event(SocketBase.java:927)
    at zmq.Poller.run(Poller.java:237)
    at java.lang.Thread.run(Thread.java:745)

Other times it hangs silently at ctx.term();

I’ve created a maven project with a single junit test that demonstrates the issue: https://github.com/augustl/jeromq-issue

For the record, the test case is:

public class ExampleText {
    @Test
    public void demonstrateIssue() {
        for (int i = 0; i < 50; i++) {
            performTest();
        }
    }

    private void performTest() {
        Context ctx = ZMQ.context(1);
        Socket recvMsgSock = ctx.socket(ZMQ.PULL);
        recvMsgSock.bind("tcp://*:5115");
        Socket processMsgSock = ctx.socket(ZMQ.PUSH);
        processMsgSock.bind("inproc://process-msg");

        List<Socket> workerSocks = new ArrayList<Socket>();
        for (int i = 0; i < 5; i++) {
            Socket workerSock = ctx.socket(ZMQ.PULL);
            workerSock.connect("inproc://process-msg");
            workerSocks.add(workerSock);
        }

        Thread proxyThr = new Thread(new ZMQQueue(ctx, recvMsgSock, processMsgSock));
        proxyThr.setName("Proxy thr");
        proxyThr.start();

        for (final Socket workerSock : workerSocks) {
            Thread workerThr = new Thread(new Runnable() {
                @Override
                public void run() {
                    try {
                        while (true) {
                            byte[] msg = workerSock.recv();
                            // Process the msg!
                        }
                    } catch (Exception e) {

                    }
                }
            });
            workerThr.setName("A worker thread");
            workerThr.start();
        }

        try {
            Thread.sleep(100);
        } catch (InterruptedException e) {
            throw new RuntimeException(e);
        }

        System.out.println("Closing now");


        recvMsgSock.close();
        processMsgSock.close();

        for (Socket workerSock : workerSocks) {
            workerSock.close();
        }

        ctx.term();
        System.out.println("Successfully closed");
    }
}

[daveyarwood]

I just tried un-ignoring the test case again and it’s still hanging, so this is still an issue.

It would probably be worth examining what, exactly, we’re doing in our test suite to get it to pass consistently! (I’m not trying to be snarky, just a thought that just occurred to me.)

[JesusTheHun]

Any update on this ? It is really a problem for CI.