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

Example 1 with ZMsg

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

the class lbbroker2 method main.

/**
     * This is the main task. This has the identical functionality to
     * the previous lbbroker example but uses higher level classes to start child threads
     * to hold the list of workers, and to read and send messages:
     */
public static void main(String[] args) {
    ZContext context = new ZContext();
    //  Prepare our context and sockets
    Socket frontend = context.createSocket(ZMQ.ROUTER);
    Socket backend = context.createSocket(ZMQ.ROUTER);
    frontend.bind("ipc://frontend.ipc");
    backend.bind("ipc://backend.ipc");
    int clientNbr;
    for (clientNbr = 0; clientNbr < NBR_CLIENTS; clientNbr++) ZThread.start(new ClientTask());
    for (int workerNbr = 0; workerNbr < NBR_WORKERS; workerNbr++) ZThread.start(new WorkerTask());
    //  Queue of available workers
    Queue<ZFrame> workerQueue = new LinkedList<ZFrame>();
    while (!Thread.currentThread().isInterrupted()) {
        //  Initialize poll set
        Poller items = context.createPoller(2);
        //  Always poll for worker activity on backend
        items.register(backend, Poller.POLLIN);
        //  Poll front-end only if we have available workers
        if (workerQueue.size() > 0)
            items.register(frontend, Poller.POLLIN);
        if (items.poll() < 0)
            //  Interrupted
            break;
        //  Handle worker activity on backend
        if (items.pollin(0)) {
            ZMsg msg = ZMsg.recvMsg(backend);
            if (msg == null)
                //  Interrupted
                break;
            ZFrame identity = msg.unwrap();
            //  Queue worker address for LRU routing
            workerQueue.add(identity);
            //  Forward message to client if it's not a READY
            ZFrame frame = msg.getFirst();
            if (Arrays.equals(frame.getData(), WORKER_READY))
                msg.destroy();
            else
                msg.send(frontend);
        }
        if (items.pollin(1)) {
            //  Get client request, route to first available worker
            ZMsg msg = ZMsg.recvMsg(frontend);
            if (msg != null) {
                msg.wrap(workerQueue.poll());
                msg.send(backend);
            }
        }
    }
    context.destroy();
}

Example 2 with ZMsg

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

the class mdcliapi method send.

/**
     * Send request to broker and get reply by hook or crook Takes ownership of
     * request message and destroys it when sent. Returns the reply message or
     * NULL if there was no reply.
     *
     * @param service
     * @param request
     * @return
     */
public ZMsg send(String service, ZMsg request) {
    request.push(new ZFrame(service));
    request.push(MDP.C_CLIENT.newFrame());
    if (verbose) {
        log.format("I: send request to '%s' service: \n", service);
        request.dump(log.out());
    }
    ZMsg reply = null;
    int retriesLeft = retries;
    while (retriesLeft > 0 && !Thread.currentThread().isInterrupted()) {
        request.duplicate().send(client);
        // Poll socket for a reply, with timeout
        ZMQ.Poller items = ctx.createPoller(1);
        items.register(client, ZMQ.Poller.POLLIN);
        if (items.poll(timeout) == -1)
            // Interrupted
            break;
        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() >= 3);
            ZFrame header = msg.pop();
            assert (MDP.C_CLIENT.equals(header.toString()));
            header.destroy();
            ZFrame replyService = msg.pop();
            assert (service.equals(replyService.toString()));
            replyService.destroy();
            reply = msg;
            break;
        } else {
            items.unregister(client);
            if (--retriesLeft == 0) {
                log.format("W: permanent error, abandoning\n");
                break;
            }
            log.format("W: no reply, reconnecting\n");
            reconnectToBroker();
        }
    }
    request.destroy();
    return reply;
}

Example 3 with ZMsg

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

the class flcliapi method connect.

//  .split connect method
//  To implement the connect method, the frontend object sends a multipart
//  message to the backend agent. The first part is a string "CONNECT", and
//  the second part is the endpoint. It waits 100msec for the connection to
//  come up, which isn't pretty, but saves us from sending all requests to a
//  single server, at startup time:
public void connect(String endpoint) {
    ZMsg msg = new ZMsg();
    msg.add("CONNECT");
    msg.add(endpoint);
    msg.send(pipe);
    try {
        //  Allow connection to come up
        Thread.sleep(100);
    } catch (InterruptedException e) {
    }
}

Example 4 with ZMsg

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

the class flclient2 method request.

private ZMsg request(ZMsg request) {
    //  Prefix request with getSequence number and empty envelope
    String sequenceText = String.format("%d", ++sequence);
    request.push(sequenceText);
    request.push("");
    //  Blast the request to all connected servers
    int server;
    for (server = 0; server < servers; server++) {
        ZMsg msg = request.duplicate();
        msg.send(socket);
    }
    //  Wait for a matching reply to arrive from anywhere
    //  Since we can poll several times, calculate each one
    ZMsg reply = null;
    long endtime = System.currentTimeMillis() + GLOBAL_TIMEOUT;
    Poller poller = ctx.createPoller(1);
    poller.register(socket, Poller.POLLIN);
    while (System.currentTimeMillis() < endtime) {
        poller.poll(endtime - System.currentTimeMillis());
        if (poller.pollin(0)) {
            //  Reply is [empty][getSequence][OK]
            reply = ZMsg.recvMsg(socket);
            assert (reply.size() == 3);
            reply.pop();
            String sequenceStr = reply.popString();
            int sequenceNbr = Integer.parseInt(sequenceStr);
            if (sequenceNbr == sequence)
                break;
            reply.destroy();
        }
    }
    request.destroy();
    return reply;
}

Example 5 with ZMsg

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

the class ppqueue method main.

//  The main task is an LRU queue with heartbeating on workers so we can
//  detect crashed or blocked worker tasks:
public static void main(String[] args) {
    ZContext ctx = new ZContext();
    Socket frontend = ctx.createSocket(ZMQ.ROUTER);
    Socket backend = ctx.createSocket(ZMQ.ROUTER);
    //  For clients
    frontend.bind("tcp://*:5555");
    //  For workers
    backend.bind("tcp://*:5556");
    //  List of available workers
    ArrayList<Worker> workers = new ArrayList<Worker>();
    //  Send out heartbeats at regular intervals
    long heartbeat_at = System.currentTimeMillis() + HEARTBEAT_INTERVAL;
    Poller poller = ctx.createPoller(2);
    poller.register(backend, Poller.POLLIN);
    poller.register(frontend, Poller.POLLIN);
    while (true) {
        boolean workersAvailable = workers.size() > 0;
        int rc = poller.poll(HEARTBEAT_INTERVAL);
        if (rc == -1)
            //  Interrupted
            break;
        //  Handle worker activity on backend
        if (poller.pollin(0)) {
            //  Use worker address for LRU routing
            ZMsg msg = ZMsg.recvMsg(backend);
            if (msg == null)
                //  Interrupted
                break;
            //  Any sign of life from worker means it's ready
            ZFrame address = msg.unwrap();
            Worker worker = new Worker(address);
            worker.ready(workers);
            //  Validate control message, or return reply to client
            if (msg.size() == 1) {
                ZFrame frame = msg.getFirst();
                String data = new String(frame.getData(), ZMQ.CHARSET);
                if (!data.equals(PPP_READY) && !data.equals(PPP_HEARTBEAT)) {
                    System.out.println("E: invalid message from worker");
                    msg.dump(System.out);
                }
                msg.destroy();
            } else
                msg.send(frontend);
        }
        if (workersAvailable && poller.pollin(1)) {
            //  Now get next client request, route to next worker
            ZMsg msg = ZMsg.recvMsg(frontend);
            if (msg == null)
                //  Interrupted
                break;
            msg.push(Worker.next(workers));
            msg.send(backend);
        }
        if (System.currentTimeMillis() >= heartbeat_at) {
            for (Worker worker : workers) {
                worker.address.send(backend, ZFrame.REUSE + ZFrame.MORE);
                ZFrame frame = new ZFrame(PPP_HEARTBEAT);
                frame.send(backend, 0);
            }
            heartbeat_at = System.currentTimeMillis() + HEARTBEAT_INTERVAL;
        }
        Worker.purge(workers);
    }
    //  When we're done, clean up properly
    while (workers.size() > 0) {
        Worker worker = workers.remove(0);
    }
    workers.clear();
    ctx.destroy();
}