CSE2410 Fall 2014 Bounce

// Copyright Joyent, Inc. and other Node contributors.

//

// Permission is hereby granted, free of charge, to any person obtaining a

// copy of this software and associated documentation files (the

// "Software"), to deal in the Software without restriction, including

// without limitation the rights to use, copy, modify, merge, publish,

// distribute, sublicense, and/or sell copies of the Software, and to permit

// persons to whom the Software is furnished to do so, subject to the

// following conditions:

//

// The above copyright notice and this permission notice shall be included

// in all copies or substantial portions of the Software.

//

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS

// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF

// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN

// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,

// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR

// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE

// USE OR OTHER DEALINGS IN THE SOFTWARE.

var NUM_WORKERS = 4;

var PACKETS_PER_WORKER = 10;

var assert = require('assert');

var cluster = require('cluster');

var common = require('../common');

var dgram = require('dgram');

if (process.platform === 'win32') {

  console.warn("dgram clustering is currently not supported on windows.");

  process.exit(0);

}

if (cluster.isMaster)

  master();

else

  worker();

function master() {

  var listening = 0;

  // Fork 4 workers.

  for (var i = 0; i < NUM_WORKERS; i++)

    cluster.fork();

  // Wait until all workers are listening.

  cluster.on('listening', function() {

    if (++listening < NUM_WORKERS)

      return;

    // Start sending messages.

    var buf = new Buffer('hello world');

    var socket = dgram.createSocket('udp4');

    var sent = 0;

    doSend();

    function doSend() {

      socket.send(buf, 0, buf.length, common.PORT, '127.0.0.1', afterSend);

    }

    function afterSend() {

      sent++;

      if (sent < NUM_WORKERS * PACKETS_PER_WORKER) {

        doSend();

      } else {

        console.log('master sent %d packets', sent);

        socket.close();

      }

    }

  });

  // Set up event handlers for every worker. Each worker sends a message when

  // it has received the expected number of packets. After that it disconnects.

  for (var key in cluster.workers) {

    if (cluster.workers.hasOwnProperty(key))

      setupWorker(cluster.workers[key]);

  }

  function setupWorker(worker) {

    var received = 0;

    worker.on('message', function(msg) {

      received = msg.received;

      console.log('worker %d received %d packets', worker.id, received);

    });

    worker.on('disconnect', function() {

      assert(received === PACKETS_PER_WORKER);

      console.log('worker %d disconnected', worker.id);

    });

  }

}

function worker() {

  var received = 0;

  // Create udp socket and start listening.

  var socket = dgram.createSocket('udp4');

  socket.on('message', function(data, info) {

    received++;

    // Every 10 messages, notify the master.

    if (received == PACKETS_PER_WORKER) {

      process.send({received: received});

      process.disconnect();

    }

  });

  socket.bind(common.PORT);

}