Socket.IO and Node.js Core Cluster

Question

Is it possible to use Socket.IO with Node's core cluster (not the outdated module)?

I can fork multiple workers and it seems to work fine; however, when opening a connection I get the error: solve: warn - client not handshaken client should reconnect

Here's the relevant code snippet (with a few simple things like expressjs config removed):

if ( cluster.isMaster ) {
    for ( var i = 0; i < numCPUs; i++ ) {
        cluster.fork();
    }
} else {
    app.get('/', function (req, res) {
        res.sendfile( __dirname + '/public/html/index.html' );
    });

    io.configure( function() {
        var RedisStore = require('socket.io').RedisStore,
            opts = { host: 'localhost', port: 8888 };

        io.set('store', new RedisStore( { redisPub: opts, redisSub: opts, redisClient: opts } ));
    });

    app.listen( 8888 );

    io.sockets.on('connection', function (socket) {
        socket.emit( 'some', 'data' );
    });
}

I've tried with and without using RedisStore and with the trick on this site (which I believe is obsolete now): http://www.danielbaulig.de/socket-ioexpress/

I've also looked at the code at http://www.ranu.com.ar/2011/11/redisstore-and-rooms-with-socketio.html, although I don't see how that code is any different than using MemoryStore.

All of my test connections are using Websockets (RFC 6455). This works fine if I set numCPUs to equal 1.

Node.js version 0.6.17 Socket.io version 0.9.5 Expressjs version 2.5.9

Update - include console output (note, on this attempt the connection did ultimately work, although it threw the same errors):

info  - socket.io started
info  - socket.io started
info  - socket.io started
info  - socket.io started
info  - socket.io started
debug - served static content /socket.io.js
debug - client authorized
info  - handshake authorized 17644195072103946664
debug - setting request GET /socket.io/1/websocket/17644195072103946664
debug - set heartbeat interval for client 17644195072103946664
debug - websocket writing 7:::1+0
warn  - client not handshaken client should reconnect
info  - transport end (error)
debug - set close timeout for client 17644195072103946664
debug - cleared close timeout for client 17644195072103946664
debug - cleared heartbeat interval for client 17644195072103946664
debug - discarding transport
debug - client authorized
info  - handshake authorized 16098526291524652257
debug - setting request GET /socket.io/1/websocket/16098526291524652257
debug - set heartbeat interval for client 16098526291524652257
debug - websocket writing 7:::1+0
warn  - client not handshaken client should reconnect
info  - transport end (error)
debug - set close timeout for client 16098526291524652257
debug - cleared close timeout for client 16098526291524652257
debug - cleared heartbeat interval for client 16098526291524652257
debug - discarding transport
debug - client authorized
info  - handshake authorized 13419993801561067603
debug - setting request GET /socket.io/1/websocket/13419993801561067603
debug - set heartbeat interval for client 13419993801561067603
debug - client authorized for 
debug - websocket writing 1::
debug - websocket writing 5:::{"some":"data","args":[11354]}
debug - websocket writing 5:::{"some":"data","args":[36448]}

This is how the console output ends on a failure (fails about 9 times out of 10):

info  - transport end by forced client disconnection
debug - websocket writing 0::
info  - transport end (booted)
debug - set close timeout for client 1639301251431944437
debug - cleared close timeout for client 1639301251431944437
debug - cleared heartbeat interval for client 1639301251431944437
debug - discarding transport
debug - got disconnection packet
debug - got disconnection packet

Update - Added links to possible tickets on github:

https://github.com/LearnBoost/socket.io/issues/881

https://github.com/LearnBoost/socket.io/issues/438

I haven't tried your code, but where is the io.listen(app) call? — Matt Sergeant
– Matt Sergeant, Commented May 11, 2012 at 2:35
I call it in my global vars: io = require('socket.io').listen(app) — dak
– dak, Commented May 11, 2012 at 2:38
I'm surprised that your example works at all -- it seems that you point your RedisStore at localhost:8888, which is also where your web server is listening. You should point your RedisStore at your redis server (default port 6379). — Linus Thiel
– Linus Thiel, Commented May 11, 2012 at 7:51
I believe socket.io creates the redis server itself, it's not something setup and already running on the machine. You're probably right it should be a different port and I've since set it to 6379, although that hasn't solved the problem. — dak
– dak, Commented May 11, 2012 at 11:23
No, that's definitely not the case. You need to run a redis server yourself in order to use the RedisStore. It seems weird to me that socket.io doesn't give you an error about this. — Linus Thiel
– Linus Thiel, Commented May 11, 2012 at 11:28

dak · Accepted Answer · 2012-05-12 18:40:04Z

3

It seems the issue may be related to the node module that Socket.IO comes installed with.

When I installed redis (npm install hiredis redis) and created the clients for the RedisStore using the redis module, everything suddenly worked perfectly. I've been running for over an hour with ~500 concurrent connections and haven't seen a single error, and every node process is being utilized.

[email protected] [email protected]

Running Redis 2.6rc3 on port 6379.

Update: In Node.s 0.8, it looks like the cluster library should be considerably more mature, so the above code/issues will probably become obsolete: http://nodejs.org/docs/v0.7.8/api/cluster.html

edited May 12, 2012 at 18:40

answered May 11, 2012 at 17:16

dak

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