How To: Run a clustered NodeJs app under secured connection

Let me take a few moments to explain the basics and then we'll start:

1. A clustered nodejs app allows you to create several processes (equals to the number of cores you have on your server) that run the same application on the same port.

2. A secured nodejs app allows you to receive and return data on a secure line.

This tutorial should be very short and very practical. Let's start..

1. Requirements

var express = require("express");
var cluster = require('cluster');
var fs = require('fs');
var https = require('https');

2. Initialisations

var sslPort = 443;
var sslOptions = {pfx: fs.readFileSync('personal.pfx'),passphrase: '123456'};

The sslPort variable is kind of fixed, but you know.. I'm trying to give you as much freedom as i can

The ssOptions varible is a JSON object that decalres a .pfx or .pem,

in case of a .pfx file usage like in our example, we need to declare a 'passphrase' property with the private password of the .pfx file.

3. App definition

var app = express();
var numCPUs = require('os').cpus().length;
console.log("Num of cpus up: " + numCPUs);




Now we'll get the number of cpus working for our app.

4. Cluster definition

if (cluster.isMaster) {
  // Fork workers.
  for (var i = 0; i < numCPUs; i++) {
    cluster.fork();
   console.log(i + " - fork.");
  }

  cluster.on('exit', function(worker, code, signal) {
    console.log('worker ' + worker.process.pid + ' died');
  });
} else {

// your routes goes here.
app.get(.........

If the instance is a master, it will let other instances to fork it, if not - well.. start the server :)

Note that we didn't close the 'else' section.

5. The tricky part - configure the cluster to listen to a secure port from all the instances

After we finished our routings, we need to let the server to start listening.

For this matter, we will override the server 'listen' method and create our own:

app.listen = function(){
  var server = https.createServer(sslOptions, this);
  return server.listen.apply(server, arguments);
};

The sslOptions varible is the same one we defined in the "Initialisations" section (2).

6. And last - Listen!

app.listen(sslPort, function(){
    logger.module('cluster').debug("Express server listening on port: " + sslPort);
  });
} // else cluster

Note that we closed the 'else' section from the Cluster definition part (2).