node cluster with socket.io and expressjs

Question

Here's my server code:

I'm trying to use cluster with socket.io and expressjs. I'm testing this on my quad core desktop.

var cluster = require('cluster')
var numCPUs = require('os').cpus().length

if (cluster.isMaster) {
  // Fork workers.
  for (var i = 0; i < numCPUs; i++) {
    cluster.fork()
  }

  console.log(new Date());
}
else {
  // get required modules
  var connect = require('connect');
  var express = require('express');
  var mongo = require('mongodb');
  var MongoStore = require('connect-mongo')(express);
  var server;
  var redis = require('redis');
  var http = require('http');

  // create server object
  app = exports.module = express();


  function configureServer() {
    //configure environments
    app.configure('production', function() {
      app.use(express.errorHandler());
    });

    //configure server instance
    app.configure(function() {
      app.use(express.compress())
      // set jade as default view engine
      app.set('view engine', 'jade');
      app.use(express.bodyParser());
      app.use(express.cookieParser("refdgfd"));

      app.use(express.methodOverride());
      app.use(app.router);
      // use express logger
    });

    loadModules();
  }

  var server = http.createServer(app).listen(80);

  socket = require('socket.io').listen(server);

  var RedisStore = require('socket.io/lib/stores/redis')
    , pub    = redis.createClient()
    , sub    = redis.createClient()
    , client = redis.createClient();
  socket.set('store', new RedisStore({
    redisPub : pub
  , redisSub : sub
  , redisClient : client
  }));

  socket.configure(function() {
    socket.set('log level', 1);
    socket.set('transports', ['websocket']);
  });

  configureServer();
}

Is there anything that stands out to be really wrong?

The logs indicate that everything happens 4 times. Which seems correctly. But my socket.io's channel users also indicate that whenever I connect to a page, I connect 4 times, (create 4 user sockets). That seems wrong. How do I fix it and are there other things wrong with my code. Thanks.

Answer 1

At this moment socket.io has no full support for node.js cluster. It works fine for me with websocket transport, but xhr-pooling fails. You can reed more in this issues: #939, #917. The problem is the xhr-pooling request can get into the thread different from the one which it was originally authorized.