Everybody knows NodeJS runs in a single process, there are many solutions how to hack it, and get it to work in parallel on multiple processes; I will show one of the methods we implemented and successfully used to split work loads across multiple processes, and servers that helped us boost performance of our back-end applications.

1. Parallel processing in NodeJS
Tibor Huđik

2. About me
Tibor Huđik
Senior Back-end Developer @ Barrage
Development group leader

3. What does Parallel Processing mean?
Parallel processing is a method of simultaneously breaking up and
running program tasks on multiple microprocessors, thereby reducing
processing time. Parallel processing may be accomplished via a
computer with two or more processors or via a computer network.

4. Parallel processing in the browser
Web Workers specification defines an API for spawning background
scripts in your web application. Web Workers allow you to do things
like fire up long-running scripts to handle computationally intensive
tasks.

5. Forking child process in NodeJS
const child_process = require('child_process');
const numchild = require('os').cpus().length;
var done = 0;
for (let i = 0; i < numchild; i++) {
const child = child_process.fork('./child');
child.send((i + 1) * 1000);
child.on('message', function(message) {
console.log('[parent] received message from ch
done++;
if (done === numchild) {
console.log('[parent] received all results')
...
}
});
}
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process.on('message', function(message) {
console.log('[child] received message from serv
setTimeout(function() {
process.send({
child : process.pid,
result : message + 1
});
process.disconnect();
}, (0.5 + Math.random()) * 5000);
});
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parent.js child.js

6. Redis: state database for our queue
Redis is a in-memory data structure storage, used as a database, cache
and message broker. It supports data structures such as strings, hashes,
lists, sets, etc.
You can use atomic operations on most of the actions on Redis.

7. How it works?
Dispatcher
Worker 5 Worker 4 Worker 3 Worker 2 Worker 1
Job 1Job 2Job 3Job 4Job 5Job 6Job 7
Redis listDispatcher

8. Demo time!
github.com/barrage/felony

9. Thank you
Visit our website
barrage.net
contact@barrage.net
Say Hello
tibor@barrage.net