Node.js

Introduction

Created by @xjodoin

Heads Up

Node.js is a platform built on Chrome's JavaScript runtime for easily building fast, scalable network applications. Node.js uses an event-driven, non-blocking I/O model that makes it lightweight and efficient, perfect for data-intensive real-time applications that run across distributed devices.

History

• 2009 - Ryan Dahl, JSConf EU, Joyent
• 2010 - v0.2 "stable-ish"
• 2/2011 - v0.4 "stuff works"
• 11/2011 - v0.6 "stuff works on windows"
• 6/2012 - v0.8 "stuff works better"


I/O Latency

• L1: 3 cycles
• L2: 14 cycles
• RAM: 250 cycles
• DISK: 41,000,000 cycles
• NETWORK: 240,000,000 cycles

Source: Ryan Dahl’s 2008.11.08 node.js presentation

Waiting...

Scale with Threads

Scale with Event Loop

Node.js Event Loop

Design principles

Callbacks

No function should perform i/o directly.

To receive info from disk, network, or another process there must be a callback

Code

var http = require('http');
var fs = require('fs');

var server = http.createServer(function (req, res) {
    fs.readFile(__dirname + '/data.txt', function (err, data) {
       res.end(data);
    });
});
server.listen(8000);

Streams

Stream everything. never force the buffering of data

Code

var http = require('http');
var fs = require('fs');

var server = http.createServer(function (req, res) {
    var stream = fs.createReadStream(__dirname + '/data.txt');
    stream.pipe(res);
});
server.listen(8000);

Challenges

• Asynchronous I/O
• Debugging
• CPU-intensive Tasks

Benefits

• Multi-Platform
• Dead-lock Free

  single thread simplifies concurrency

• Monoglot Programming

  Javascript client/server

• Fast

Vibrant Community

Total Packages: 55 720

THE END

BY Xavier Jodoin / jodoin.me