cluster-launcher

Cluster multiprocess launcher

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Minimalistic configurable multiprocess launcher for Node.js based on cluster. Includes built-in sticky listeners for Socket.IO.

Installation

npm i cluster-launcher --save

Usage

const {
  launch,
  stickyListenWorker,
  stickyListenMaster 
} = require('cluster-launcher');
 
const workerFunc = (listen) => {
  // Use express for example.
  const app = require('express')();
  const http = require('http').Server(app);
 
  app.get('*', (req, res) => { 
    res.send(`Hello from worker pid:${process.pid}`); 
  });
  listen(http);
};
 
const masterFunc = (listen) => {
  console.log('We are doing some crazy master stuff here!');
  listen();
};
 
launch({
  worker: {
    main: workerFunc,
    listen: stickyListenWorker
  },
  master: {
    main: masterFunc,
    listen: stickyListenMaster
  },
  config: {
    threads: 4,
    host: {
      ip: 'localhost',
      port: 5000
    }
  }
});

API

.launch(opts)

@param opts { object } options object

Expected that master and worker will call listen by themselves, because they can contain some async init functions.

Options object

• config { object }
  • threads { number } count of worker processes to spawn. default: 1
  • host { object } web server configuration
    • ip { string } default: 'localhost'
    • port { number } default: 8080
• worker
  • main { function } entry point of the every worker, takes listen as a parameter
  • listen { function } default: stickyListenWorker
• master
  • main { function } entry point of the master
  • listen { function } default: stickyListenMaster

worker/master's main will be called with specified to them listen function as a parameter.

Worker's listen

Expects http server object as a parameter.

Master's listen

Will be wrapped in a function that takes no arguments. Because of it in the master's main you should just do listen(). But inside it will be called by launch with options object as a parameter:

• ip { string }
• port { number }
• workers { array }

.stickyListenWorker, .stickyListenMaster

Default built-in listen function for worker, that provide sticky connection for the client to specific worker based on the client's ip address. Usefull for Socket.IO.