How to verify Cluster working in node js? - node.js

Question

I am new to nodejs and currently playing with its features, one of the important feature I came across is Cluster, I tried to implement that for my sample application using expressjs, angular and nodejs.
Cluster code:
var cluster = require('cluster');
if (cluster.isMaster) {
var cpuCount = require('os').cpus().length;
for (var i = 0; i < cpuCount; i += 1) {
cluster.fork();
}
} else {
var express = require('express');
var app = express();
var exportRouter=require('./routers/exportRouter');
var process = require('process');
fakeDB = [];
app.use(express.static(__dirname + '/public'));
app.use(require('./routers/exportRouter.js'));
console.log('process Id :',process.pid);
app.listen(3000, function(){
console.log('running on 30000');
});
}
I have added following code in my routers to block the event loop,so when I make first request It will block one nodejs worker. so if another user makes call while first node is blocked second worker should pick that up.
router code :
var express = require('express');
var exportRouter = express.Router();
var process = require('process');
exportRouter.get('/getMe',function(req,res){
console.log('I am using process ',process.pid);
console.log('get is called');
fakeDB.push(req.query.newName+' '+ process.pid);
res.send(req.query.newName + ' ' + process.pid);
console.log('New name received ',fakeDB);
console.log('New name received ',fakeDB);
var d = new Date().getTime();
console.log('old ',d)
var x = d+10000;
console.log('should stop post ',x);
while(true){
var a = new Date().getTime();
//console.log('new ',a)
if(x<a){
break;
}
}
console.log('I am releasing event loop for ',process.pid);
});
module.exports = exportRouter;
it does not serve other request using another worker and waits for blocked node worker.. BTW I am using node js version 0.12.7(64bit) and 4 cpus.
THanks in advance..

Answer 1

it does not serve other request using another worker and waits for blocked node worker
Your testing methodology is probably wrong. Here's a simplified version of your sample.
var cluster = require('cluster')
if (cluster.isMaster) {
var cpuCount = require('os').cpus().length
for (var i = 0; i < cpuCount; i += 1) {
cluster.fork()
}
} else {
var express = require('express')
var app = express()
console.log('process Id:', process.pid)
app.get('/', function (req, res) {
console.log('pid', process.pid, 'handler start, blocking CPU')
var i = 0;
while (i < 10e9) {
i++
}
console.log('pid', process.pid, 'unblocked, responding')
res.send('thanks')
})
app.listen(3003, function () {
console.log('running on 3003')
})
}
If I run this in one terminal, then open two other terminals and as quickly as possible fire off a curl localhost:3003 in each terminal, I can see the second request arrives and begins processing before the first request gets a response:
pid 53434 handler start, blocking CPU
pid 53437 handler start, blocking CPU
pid 53434 unblocked, responding
pid 53437 unblocked, responding