Fork List

It's easy to fork a list of child process for node.js by ForkList.

Install

npm install fork-list

Quick Examples

var ForkList = require('fork-list');

// which script to run by multiprocess
var path = './script/write';

// child process num
var num = 3;

var forks = new ForkList({
    path: path,
    num: num
});

for (var i = 0; i < 10; i++) {
    forks.send('hello~', i);
}

forks.shutdown();

the ./script/write.js is:

var Forks = require('fork-list');

Forks.proc(function(data1, data2) {
    console.log('Work id:', this.workid, 'recv data1:', data1, 'data2:', data2);
});

Output:

Work id: 1 recv data1: hello~ data2: 1
Work id: 2 recv data1: hello~ data2: 0
Work id: 0 recv data1: hello~ data2: 5
Work id: 1 recv data1: hello~ data2: 2
Work id: 2 recv data1: hello~ data2: 3
Work id: 1 recv data1: hello~ data2: 9
Work id: 2 recv data1: hello~ data2: 4
Work id: 0 recv data1: hello~ data2: 6
Work id: 2 recv data1: hello~ data2: 7
Work id: 2 recv data1: hello~ data2: 8

Documentation

Initialization

• new
• count
• setClassifier
• setLogger

Transfer

• send
• forward
• proc

Control

• kill
• killByPid
• shutdown

Event

• onExit
• onError
• onFinish

fork a new process with specify path.

get total number of processes.

set special classifier.

enable or disable fork-list debug log, or set your special logger such as log4js.getLogger.

Example

var ForkList = require('fork-list');
var underscore = require('underscore');

var times = 10;
var forks = new ForkList();

forks.new('./script');
forks.new('./script');

forks.setClassifier(function(msg, done) {
    var id = underscore.random(0, forks.count() - 1);
    done(null, id);
});

for (var i = 0; i < times; i++) {
    forks.send(i, 'some msg');
}

forks.shutdown();

var forkList = require('fork-list');

// which script to run by multiprocess
var path = './test';

// child process num
var num = 2;

var forks = new ForkList({
    path: path,
    num: num
});

// send data to child process
forks.send(somedata, ...);

The usual data include:

• Number
• String
• Array
• JSON
• Object*

Caution The Object data wouldn't complete delivery:

var forks = new ForkList({
    path: path
});

function test(name) {
    this.name = name || 'default';
}

test.prototype.hi = function() {
    console.log('my name is ', this.name);
};

for (var i = 0; i < times; i++) {
    var t = new test('Alan' + i);
    forks.send(i, t);
}

you can only get the basic data { name: 'AlanX' }, and the prototype will lost, you can't call .hi in the child process.

Socket forward exmaple

server.js

var net = require('net');
var config = require('./my_config');
var ForkList = require("fork-list");

var num = 2;
var path = './worker';

var wokers = new ForkList({
    path: path,
    num: num
});

var server = net.createServer();

server.on('connection', function(sock) {

    wokers.foward('socket', sock);

    sock.on('error', function(e) {
        console.log('[server] Error:', e);
    });
});

server.listen(config.port);

console.log('test socket server start');

worker.js

var ForkList = require('fork-list');

ForkList.proc(function(sock) {
    var workid = this.workid;
    sock.on('data', function(data) {
        console.log('[worker] id:', workid, 'data:', data.toString());
    })
});

test client.js

var config = require('./my_config');
var net = require('net');

var client = net.connect({
    hostname: config.host,
    port: config.port
});

client.on('connect', function() {
    var str = 'hello ';
    for (var i = 0; i < 100; i++) {
        client.write(str + i + ' ');
    }
    client.end();
});

client.on('end', function() {
    console.log('client send over!');
});

var forkList = require('fork-list');

forkList.proc(function(msg, ...) {
    /* code */
});

This will forcely kill special child process, and don't care if there are some jobs haven't done.

This will forcely kill special child process, and don't care if there are some jobs haven't done.

This will forcely shutdown all child process, and don't care if there are some jobs haven't done. and once all of child process has exited, the finish event will emit.

Example:

var ForkList = require('fork-list');

var path = './script';
var num = 3;

var forks = new ForkList({
    path: path,
    num: num,
    log: true
});

for (var i = 10; i >= 0; i--) {
    forks.send('hello ' + i);
};

forks.on('error', function(err, pid) {
    console.log('--> Error:', err.message, 'pid:', pid);
});

forks.on('exit', function(pid) {
    console.log('--> Child process exit, pid:', pid);
    forks.killByPid(pid);
});

forks.on('finish', function() {
    console.log('--> All of child process has exited');
});

forks.shutdown();

script.js

var Forks = require('fork-list');

Forks.proc(function(data1, data2) {
    console.log('Work id:', this.workid, 'recv data1:', data1);
});

Output:

Work id: 0 recv data1: hello 10
Work id: 0 recv data1: hello 8
Work id: 0 recv data1: hello 7
Work id: 2 recv data1: hello 9
Work id: 0 recv data1: hello 6
Work id: 1 recv data1: hello 5
Work id: 0 recv data1: hello 2
Work id: 0 recv data1: hello 0
Work id: 1 recv data1: hello 4
Work id: 1 recv data1: hello 3
Work id: 1 recv data1: hello 1
--> Child process exit, pid: 15064
--> Error: IPC channel is already disconnected pid: 15064
--> Child process exit, pid: 13072
--> Error: IPC channel is already disconnected pid: 13072
--> Child process exit, pid: 4900
--> Error: IPC channel is already disconnected pid: 4900
--> All of child process has exited

Test

you can test this module by:

cd node_modules/fork-list
npm test

license

MIT