Examples with ZMsg org.zeromq.ZMsg used on opensource projects

Example 6 with ZMsg

use of org.zeromq.ZMsg in project jeromq by zeromq.

the class ppworker method main.

//  We have a single task, which implements the worker side of the
//  Paranoid Pirate Protocol (PPP). The interesting parts here are
//  the heartbeating, which lets the worker detect if the queue has
//  died, and vice-versa:
public static void main(String[] args) {
    ZContext ctx = new ZContext();
    Socket worker = worker_socket(ctx);
    Poller poller = ctx.createPoller(1);
    poller.register(worker, Poller.POLLIN);
    //  If liveness hits zero, queue is considered disconnected
    int liveness = HEARTBEAT_LIVENESS;
    int interval = INTERVAL_INIT;
    //  Send out heartbeats at regular intervals
    long heartbeat_at = System.currentTimeMillis() + HEARTBEAT_INTERVAL;
    Random rand = new Random(System.nanoTime());
    int cycles = 0;
    while (true) {
        int rc = poller.poll(HEARTBEAT_INTERVAL);
        if (rc == -1)
            //  Interrupted
            break;
        if (poller.pollin(0)) {
            //  Get message
            //  - 3-part envelope + content -> request
            //  - 1-part HEARTBEAT -> heartbeat
            ZMsg msg = ZMsg.recvMsg(worker);
            if (msg == null)
                //  Interrupted
                break;
            //  first:
            if (msg.size() == 3) {
                cycles++;
                if (cycles > 3 && rand.nextInt(5) == 0) {
                    System.out.println("I: simulating a crash\n");
                    msg.destroy();
                    msg = null;
                    break;
                } else if (cycles > 3 && rand.nextInt(5) == 0) {
                    System.out.println("I: simulating CPU overload\n");
                    try {
                        Thread.sleep(3000);
                    } catch (InterruptedException e) {
                        break;
                    }
                }
                System.out.println("I: normal reply\n");
                msg.send(worker);
                liveness = HEARTBEAT_LIVENESS;
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException e) {
                    break;
                }
            //  Do some heavy work
            } else //  queue was (recently) alive, so reset our liveness indicator:
            if (msg.size() == 1) {
                ZFrame frame = msg.getFirst();
                if (PPP_HEARTBEAT.equals(new String(frame.getData(), ZMQ.CHARSET)))
                    liveness = HEARTBEAT_LIVENESS;
                else {
                    System.out.println("E: invalid message\n");
                    msg.dump(System.out);
                }
                msg.destroy();
            } else {
                System.out.println("E: invalid message\n");
                msg.dump(System.out);
            }
            interval = INTERVAL_INIT;
        } else //  discarding any messages we might have sent in the meantime://
        if (--liveness == 0) {
            System.out.println("W: heartbeat failure, can't reach queue\n");
            System.out.printf("W: reconnecting in %sd msec\n", interval);
            try {
                Thread.sleep(interval);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            if (interval < INTERVAL_MAX)
                interval *= 2;
            ctx.destroySocket(worker);
            worker = worker_socket(ctx);
            liveness = HEARTBEAT_LIVENESS;
        }
        //  Send heartbeat to queue if it's time
        if (System.currentTimeMillis() > heartbeat_at) {
            heartbeat_at = System.currentTimeMillis() + HEARTBEAT_INTERVAL;
            System.out.println("I: worker heartbeat\n");
            ZFrame frame = new ZFrame(PPP_HEARTBEAT);
            frame.send(worker, 0);
        }
    }
    ctx.destroy();
}

Example 7 with ZMsg

use of org.zeromq.ZMsg in project jeromq by zeromq.

the class mdcliapi2 method recv.

/**
     * Returns the reply message or NULL if there was no reply. Does not attempt
     * to recover from a broker failure, this is not possible without storing
     * all unanswered requests and resending them all…
     */
public ZMsg recv() {
    ZMsg reply = null;
    // Poll socket for a reply, with timeout
    ZMQ.Poller items = ctx.createPoller(1);
    items.register(client, ZMQ.Poller.POLLIN);
    if (items.poll(timeout * 1000) == -1)
        // Interrupted
        return null;
    if (items.pollin(0)) {
        ZMsg msg = ZMsg.recvMsg(client);
        if (verbose) {
            log.format("I: received reply: \n");
            msg.dump(log.out());
        }
        // Don't try to handle errors, just assert noisily
        assert (msg.size() >= 4);
        ZFrame empty = msg.pop();
        assert (empty.getData().length == 0);
        empty.destroy();
        ZFrame header = msg.pop();
        assert (MDP.C_CLIENT.equals(header.toString()));
        header.destroy();
        ZFrame replyService = msg.pop();
        replyService.destroy();
        reply = msg;
    }
    return reply;
}

Example 8 with ZMsg

use of org.zeromq.ZMsg in project jeromq by zeromq.

the class mdworker method main.

/**
     * @param args
     */
public static void main(String[] args) {
    boolean verbose = (args.length > 0 && "-v".equals(args[0]));
    mdwrkapi workerSession = new mdwrkapi("tcp://localhost:5555", "echo", verbose);
    ZMsg reply = null;
    while (!Thread.currentThread().isInterrupted()) {
        ZMsg request = workerSession.receive(reply);
        if (request == null)
            //Interrupted
            break;
        //  Echo is complex :-)
        reply = request;
    }
    workerSession.destroy();
}

Example 9 with ZMsg

use of org.zeromq.ZMsg in project jeromq by zeromq.

the class mdwrkapi method sendToBroker.

/**
     * Send message to broker If no msg is provided, creates one internally
     *
     * @param command
     * @param option
     * @param msg
     */
void sendToBroker(MDP command, String option, ZMsg msg) {
    msg = msg != null ? msg.duplicate() : new ZMsg();
    // Stack protocol envelope to start of message
    if (option != null)
        msg.addFirst(new ZFrame(option));
    msg.addFirst(command.newFrame());
    msg.addFirst(MDP.W_WORKER.newFrame());
    msg.addFirst(new ZFrame(ZMQ.MESSAGE_SEPARATOR));
    if (verbose) {
        log.format("I: sending %s to broker\n", command);
        msg.dump(log.out());
    }
    msg.send(worker);
}

Example 10 with ZMsg

use of org.zeromq.ZMsg in project jeromq by zeromq.

the class mmiecho method main.

public static void main(String[] args) {
    boolean verbose = (args.length > 0 && "-v".equals(args[0]));
    mdcliapi clientSession = new mdcliapi("tcp://localhost:5555", verbose);
    ZMsg request = new ZMsg();
    // This is the service we want to look up
    request.addString("echo");
    // This is the service we send our request to
    ZMsg reply = clientSession.send("mmi.service", request);
    if (reply != null) {
        String replyCode = reply.getFirst().toString();
        System.out.printf("Lookup echo service: %s\n", replyCode);
    } else {
        System.out.println("E: no response from broker, make sure it's running");
    }
    clientSession.destroy();
}