Express and Cluster node modules in the same app - node.js

Question

I am creating an app that allows users to upload files in their browsers to a server.
I started it by typing express in the folder of my project. With that express created all the folders and such. It created a bin folder containing a www file that starts a lot of stuff for us like the ports.
At first i only had one core so i was doing it like so:
var express = require('express');
var multer = require('multer');
var app = express();
var done = false;
var fileSize = 0;
app.use(multer({ dest: './uploads/',
rename: function (fieldname, filename){
return filename;
},
onFileUploadStart: function(file){
console.log(file.originalname + ' is starting...');
},
onFileUploadComplete: function(file){
console.log(file.fieldname + ' uploaded to ' + file.path);
done = true;
},
onFileUploadData: function(file, data){
fileSize += data.length;
console.log("FileUpload " + fileSize);
}
}));
app.get('/', function(request, response){
response.sendFile(__dirname + '/index.html');
});
app.post('/upload/', function(request, response){
console.log(request.body);
if (done == true)
response.end('file uploaded');
});
module.exports = app;
Eventually i needed to user a machine with several cores in order to be able to respond to more client requests. So I am trying to use the cluster module.
I changed the code accordingly:
var cluster = require('cluster');
if(cluster.isMaster){
var numCPUS = require('os').cpus().length;
for(var i=0; i<numCPUS; i++)
cluster.fork();
cluster.on('exit', function(worker, code, signal) {
console.log('worker ' + worker.process.pid + ' died');
});
cluster.on('online', function(worker) {
console.log('worker ' + worker.process.pid + ' started');
});
}else{
var express = require('express');
var multer = require('multer');
var app = express();
var done = false;
var fileSize = 0;
app.use(multer({ dest: './uploads/',
rename: function (fieldname, filename){
return filename;
},
onFileUploadStart: function(file){
console.log(file.originalname + ' is starting...');
},
onFileUploadComplete: function(file){
console.log(file.fieldname + ' uploaded to ' + file.path);
done = true;
},
onFileUploadData: function(file, data){
fileSize += data.length;
console.log("FileUpload " + fileSize);
}
}));
app.get('/', function(request, response){
response.sendFile(__dirname + '/index.html');
});
app.post('/upload/', function(request, response){
console.log(request.body);
if (done == true)
response.end('file uploaded');
});
module.exports = app;
}
The problem is that when i do this i am getting the following error in the console:
Run: node ./bin/www
Result:
app.set('port', port);
TypeERror: Cannot call method 'set' of undefined at Object.<anonymous>
This happens since i placed the entire code inside the forked childs of the master. Anyone knows why this happens and how i can fix it?
EDIT:
In here you can see the bin/www file where the port and some other configurations are set:
#!/usr/bin/env node
/**
* Module dependencies.
*/
var app = require('../app');
var debug = require('debug')('dropbox:server');
var http = require('http');
/**
* Get port from environment and store in Express.
*/
var port = normalizePort(process.env.PORT || '3000');
app.set('port', port);
/**
* Create HTTP server.
*/
var server = http.createServer(app);
/**
* Listen on provided port, on all network interfaces.
*/
server.listen(port);
server.on('error', onError);
server.on('listening', onListening);
/**
* Normalize a port into a number, string, or false.
*/
function normalizePort(val) {
var port = parseInt(val, 10);
if (isNaN(port)) {
// named pipe
return val;
}
if (port >= 0) {
// port number
return port;
}
return false;
}
/**
* Event listener for HTTP server "error" event.
*/
function onError(error) {
if (error.syscall !== 'listen') {
throw error;
}
var bind = typeof port === 'string'
? 'Pipe ' + port
: 'Port ' + port
// handle specific listen errors with friendly messages
switch (error.code) {
case 'EACCES':
console.error(bind + ' requires elevated privileges');
process.exit(1);
break;
case 'EADDRINUSE':
console.error(bind + ' is already in use');
process.exit(1);
break;
default:
throw error;
}
}
/**
* Event listener for HTTP server "listening" event.
*/
function onListening() {
var addr = server.address();
var bind = typeof addr === 'string'
? 'pipe ' + addr
: 'port ' + addr.port;
debug('Listening on ' + bind);
}