在node.js上的多个线程中运行任务

Question

I need some help with node.js as i'm a newbie to it. I have an array of data and have to run functions with that data in multiple threads (using all CPU cores). In usual for me languages i do create threadpool with number of threads, push some tasks to it, wait until finish, send more tasks to queue. But i can't figure it out how to do that in nodejs.

PS: i'm using latest 0.8 branch.

Answer 1

Nodejs is built to run on a single process, but you can spawn other processes. The cluster module uses the fork method from the child_process module, but it's intended for distributing connections of a server across processes and sharing the same port.

I think you want exec . Example:

var exec = require('child_process').exec,
child;

var array = ["a", "b", "c", "d", "e"]; // your array of data

var n = array.length; // length
var done = 0; // jobs done
var i = n; // iterator

while(i--) { // reverse while loops are faster
    (function (argument) { // A closure
        child = exec('node otherFunction.js '+argument, // Spawn the process, with an item from your array as an argument.
          function (error, stdout, stderr) {
            if (error === null) {
                done += 1;
                if (done === n) {
                    console.log('Everything is done');
                }
            }
        });
    })(array[i]);
}

The above is of course bad code and not even tested, but I think it would work. All you have to do is call the function you wanted to call on the array's items in otherFunction.js , inside that you would find the arguments in process.argv .