Examples with Poller org.zeromq.ZMQ.Poller used on opensource projects

Example 6 with Poller

use of org.zeromq.ZMQ.Poller 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();
}

Example 7 with Poller

use of org.zeromq.ZMQ.Poller 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 8 with Poller

use of org.zeromq.ZMQ.Poller in project jeromq by zeromq.

the class clonecli3 method run.

public void run() {
    ZContext ctx = new ZContext();
    Socket snapshot = ctx.createSocket(ZMQ.DEALER);
    snapshot.connect("tcp://localhost:5556");
    Socket subscriber = ctx.createSocket(ZMQ.SUB);
    subscriber.connect("tcp://localhost:5557");
    subscriber.subscribe(ZMQ.SUBSCRIPTION_ALL);
    Socket push = ctx.createSocket(ZMQ.PUSH);
    push.connect("tcp://localhost:5558");
    // get state snapshot
    long sequence = 0;
    snapshot.send("ICANHAZ?".getBytes(ZMQ.CHARSET), 0);
    while (true) {
        kvsimple kvMsg = kvsimple.recv(snapshot);
        if (kvMsg == null)
            //  Interrupted
            break;
        sequence = kvMsg.getSequence();
        if ("KTHXBAI".equalsIgnoreCase(kvMsg.getKey())) {
            System.out.println("Received snapshot = " + kvMsg.getSequence());
            // done
            break;
        }
        System.out.println("receiving " + kvMsg.getSequence());
        clonecli3.kvMap.put(kvMsg.getKey(), kvMsg);
    }
    Poller poller = ctx.createPoller(1);
    poller.register(subscriber);
    Random random = new Random();
    // now apply pending updates, discard out-of-getSequence messages
    long alarm = System.currentTimeMillis() + 5000;
    while (true) {
        int rc = poller.poll(Math.max(0, alarm - System.currentTimeMillis()));
        if (rc == -1)
            //  Context has been shut down
            break;
        if (poller.pollin(0)) {
            kvsimple kvMsg = kvsimple.recv(subscriber);
            if (kvMsg == null)
                //  Interrupted
                break;
            if (kvMsg.getSequence() > sequence) {
                sequence = kvMsg.getSequence();
                System.out.println("receiving " + sequence);
                clonecli3.kvMap.put(kvMsg.getKey(), kvMsg);
            }
        }
        if (System.currentTimeMillis() >= alarm) {
            int key = random.nextInt(10000);
            int body = random.nextInt(1000000);
            ByteBuffer b = ByteBuffer.allocate(4);
            b.asIntBuffer().put(body);
            kvsimple kvUpdateMsg = new kvsimple(key + "", 0, b.array());
            kvUpdateMsg.send(push);
            alarm = System.currentTimeMillis() + 1000;
        }
    }
    ctx.destroy();
}

Example 9 with Poller

use of org.zeromq.ZMQ.Poller in project jeromq by zeromq.

the class clonecli4 method run.

public void run() {
    ZContext ctx = new ZContext();
    Socket snapshot = ctx.createSocket(ZMQ.DEALER);
    snapshot.connect("tcp://localhost:5556");
    Socket subscriber = ctx.createSocket(ZMQ.SUB);
    subscriber.connect("tcp://localhost:5557");
    subscriber.subscribe(SUBTREE.getBytes(ZMQ.CHARSET));
    Socket push = ctx.createSocket(ZMQ.PUSH);
    push.connect("tcp://localhost:5558");
    // get state snapshot
    snapshot.sendMore("ICANHAZ?");
    snapshot.send(SUBTREE);
    long sequence = 0;
    while (true) {
        kvsimple kvMsg = kvsimple.recv(snapshot);
        if (kvMsg == null)
            //  Interrupted
            break;
        sequence = kvMsg.getSequence();
        if ("KTHXBAI".equalsIgnoreCase(kvMsg.getKey())) {
            System.out.println("Received snapshot = " + kvMsg.getSequence());
            // done
            break;
        }
        System.out.println("receiving " + kvMsg.getSequence());
        clonecli4.kvMap.put(kvMsg.getKey(), kvMsg);
    }
    Poller poller = ctx.createPoller(1);
    poller.register(subscriber);
    Random random = new Random();
    // now apply pending updates, discard out-of-getSequence messages
    long alarm = System.currentTimeMillis() + 5000;
    while (true) {
        int rc = poller.poll(Math.max(0, alarm - System.currentTimeMillis()));
        if (rc == -1)
            //  Context has been shut down
            break;
        if (poller.pollin(0)) {
            kvsimple kvMsg = kvsimple.recv(subscriber);
            if (kvMsg == null)
                //  Interrupted
                break;
            if (kvMsg.getSequence() > sequence) {
                sequence = kvMsg.getSequence();
                System.out.println("receiving " + sequence);
                clonecli4.kvMap.put(kvMsg.getKey(), kvMsg);
            }
        }
        if (System.currentTimeMillis() >= alarm) {
            String key = String.format("%s%d", SUBTREE, random.nextInt(10000));
            int body = random.nextInt(1000000);
            ByteBuffer b = ByteBuffer.allocate(4);
            b.asIntBuffer().put(body);
            kvsimple kvUpdateMsg = new kvsimple(key, 0, b.array());
            kvUpdateMsg.send(push);
            alarm = System.currentTimeMillis() + 1000;
        }
    }
    ctx.destroy();
}

Example 10 with Poller

use of org.zeromq.ZMQ.Poller in project jeromq by zeromq.

the class clonesrv4 method run.

public void run() {
    ZContext ctx = new ZContext();
    Socket snapshot = ctx.createSocket(ZMQ.ROUTER);
    snapshot.bind("tcp://*:5556");
    Socket publisher = ctx.createSocket(ZMQ.PUB);
    publisher.bind("tcp://*:5557");
    Socket collector = ctx.createSocket(ZMQ.PULL);
    collector.bind("tcp://*:5558");
    Poller poller = ctx.createPoller(2);
    poller.register(collector, Poller.POLLIN);
    poller.register(snapshot, Poller.POLLIN);
    long sequence = 0;
    while (!Thread.currentThread().isInterrupted()) {
        if (poller.poll(1000) < 0)
            //  Context has been shut down
            break;
        // apply state updates from main thread
        if (poller.pollin(0)) {
            kvsimple kvMsg = kvsimple.recv(collector);
            if (//  Interrupted
            kvMsg == null)
                break;
            kvMsg.setSequence(++sequence);
            kvMsg.send(publisher);
            clonesrv4.kvMap.put(kvMsg.getKey(), kvMsg);
            System.out.printf("I: publishing update %5d\n", sequence);
        }
        // execute state snapshot request
        if (poller.pollin(1)) {
            byte[] identity = snapshot.recv(0);
            if (identity == null)
                //  Interrupted
                break;
            //  .until
            //  Request is in second frame of message
            String request = snapshot.recvStr();
            if (!request.equals("ICANHAZ?")) {
                System.out.println("E: bad request, aborting");
                break;
            }
            String subtree = snapshot.recvStr();
            Iterator<Entry<String, kvsimple>> iter = kvMap.entrySet().iterator();
            while (iter.hasNext()) {
                Entry<String, kvsimple> entry = iter.next();
                kvsimple msg = entry.getValue();
                System.out.println("Sending message " + entry.getValue().getSequence());
                this.sendMessage(msg, identity, subtree, snapshot);
            }
            // now send end message with getSequence number
            System.out.println("Sending state snapshot = " + sequence);
            snapshot.send(identity, ZMQ.SNDMORE);
            kvsimple message = new kvsimple("KTHXBAI", sequence, ZMQ.SUBSCRIPTION_ALL);
            message.send(snapshot);
        }
    }
    System.out.printf(" Interrupted\n%d messages handled\n", sequence);
    ctx.destroy();
}