child_process.fork() workaround for windows

[kraag22]

If you want to use child_process.fork() you cannot, because of issue #213
But if specify your own node executable in the options like this
var processing = ch.fork('c:\\reader.js', [], {execPath: 'c:\\node.exe'})
you can use it. There is no problem running on mac, but in windows you forked node will crash if there is any stdio operation. Child process will crash with exit code 8.

So example code:

var ch = require('child_process')

console.log("I'm alive");

var processing = ch.fork('c:\\reader.js', [], {execPath: 'c:\\node.exe'})

processing.on('message', function(data) {
    console.log(data);
    if (data['status'] === 'ok') {
        console.log('ok');
    } else if (data['status'] === 'error') {
        console.log('error');
    }
});
processing.on('exit', function(code) {
    console.log('exited with code:', code);
});
processing.send({});

This code will fail on windows when the reader.js prints anything in the console for us. The workaround is adding silent:true to fork() options.

var processing = ch.fork('c:\\reader.js', [], {execPath: 'c:\\node.exe', silent: true})

I hope this will save some time to anyone experiencing this problem.

[rogerwang]

Thanks for sharing.

[shabeepk]

I am very new to node, and here's my code. My code is crashing with exit code 8 for some reason that I can't figure out.

Can you please help?

I am using Windows, right now.

processor.js:

var ch = require('child_process')
var path = require('path');

var nodePath = path.join(path.dirname(process.execPath), 'node');
if (process.platform === 'win32') {
    nodePath += ".exe";
}

console.log("Spawning a new node process: " + nodePath);

var processing = ch.fork('js/processor_fork.js', [], {execPath: nodePath, silent: true});

processing.on('message', function(data) {
    console.log(data);
});

processing.on('exit', function(code) {
    console.log('exited with code:', code);
});

processing.send({});

processor_fork.js:

importScripts('js/somescript.js');
var timer;

function processNext(current, max) {
    someFunction();

    if ((current + 1) % 1000 == 0)
    {
        process.send({status: "Processed " + (current + 1)});
    }

    if (current < max)
        timer = setTimeout(processNext(current + 1, max), 10);
}

process.on('message', function(data) {
    if (timer)
        clearTimeout(timer);

    timer = setTimeout(processNext(0, 20000), 10);
});

[shabeepk]

@rogerwang Do you know what I am doing wrong in the above code? Can I do this some other way?

[laike9m]

@kraag22 You saved my life, thank you so much!

[BoneLee]

What about Linux? fork doesn't work on Linux either.

[rogerwang]

@BoneLee fork has been fixed in git and will be released soon with 0.10.3. You can try it now with live build, see the links in #213

[JoyKrishnaMondal]

Thanks a lot !! This is amazing

[nobook]

Thanks a lot !!