Sending a UDP packet fails within the Cluster environment on Windows

[seriousManual]

I was trying to send a UDP packet from a application that uses the cluster module. This fails on Windows, on Linux it works fine.

Code to reproduce:

var dgram = require('dgram');
var cluster = require('cluster');
var http = require('http');

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

if (cluster.isMaster) {
    for (var i = 0; i < 4; i++) {
        cluster.fork();
    }
} else {
    http.createServer(function(req, res) {
        var message = new Buffer('test');

        socket.send(message, 0, message.length, 123, 'xxx');

        res.writeHead(200);
        res.end('hello world\n');
    }).listen(8000);
}

Tested on:

works:
Linux, node v0.8.2
Linux, node v0.10.8

does not work:
Windows7 x64, node v0.10.0
Windows7 x64, node v0.10.8

Error message:

events.js:72
        throw er; // Unhandled 'error' event
              ^
Error: write ENOTSUP - cannot write to IPC channel.
    at errnoException (child_process.js:980:11)
    at ChildProcess.target.send (child_process.js:455:16)
    at Worker.send (cluster.js:401:21)
    at sendInternalMessage (cluster.js:394:10)
    at handleResponse (cluster.js:177:5)
    at respond (cluster.js:192:5)
    at Object.messageHandler.queryServer (cluster.js:242:5)
    at handleMessage (cluster.js:197:32)
    at ChildProcess.EventEmitter.emit (events.js:117:20)
    at handleMessage (child_process.js:318:10)

[bnoordhuis]

It's only implemented on Unices so far, courtesy of a company sponsoring us. Windows support requires some non-trivial changes to libuv.

[seriousManual]

Thanks for the details, maybe the documentation should be updated on that topic, that would keep me from wasting half a day on the matter. :)

[bnoordhuis]

I've added a note in 9826b15.

[avimar]

Is this still true? (I don't use windows to check..)
Perhaps it should be made explicit here somewhere:

http://nodejs.org/api/cluster.html#cluster_event_listening

"Sharing TCP supported in Linux and Windows, UDP supported only in Linux"

[louis-paul]

AFAIK, yes. Had to switch from node.js to Golang for one of my projects because of this.

[rmg]

#3856 was closed with a fix that would probably help with this. If I'm not mistaken, as of 029cfc1 one can do an explicit .bind({ port: 0, exclusive: true }) on the socket before sending instead of letting .send() do so implicitly, which should bypass the troublesome behaviour on Windows.

[cjihrig]

As @rmg mentioned, this problem can be solved using an exclusive bind. If that's not a satisfactory solution, #8643 will do this automatically for you. Recommend closing this now or once #8643 lands.

[sam-github]

I would recommend not closing unless #8643 lands, its very much open.

[avdg]

Any need to keep this issue open?

[sam-github]

I'm OK to close it.