WarsawJS Slides: Template

Motivation

I found myself doing all those repetetive actions and facing the same problems with Node for years.

Turns out, most of them are easly solved by existing tools.

I didn't know that such tools exists... So I haven't search for them.

The tools

• nodemon
• node-inspector & iron-node
• nvm
• pm2
• http-proxy (some code, yay!)

nodemon

Creating new project

• Git init, npm install ...
• Open Terminal Emulator / Console
• Open IDE
• Start typing

I had a dream

nodemon

• nodemon works like an alternative node launcher
• it monitors changes made to directories and automatically restarts your app

nodemon usage

$ npm install -g nodemon

// $ node myapp.js
$ nodemon myapp.js

nodemon usage

// run with arguments
$ nodemon myapp.js --port 80

// ignore files or directories, that can change
$ nodemon --ignore tests/ myapp.js

// watch only specyfic directories
$ nodemon --watch app/ --watch node_modules/ myapp.js

nodemon usage

// run non-node scripts
$ nodemon --exec "python -v" ./myapp.py

// delay the restarts by 3 seconds
$ nodemon --delay 3 myapp.js

node-inspector
&
iron-node

How to debug node application?

• console.log anyone?
• Where are the Chrome's DevTools (or Firefox's, or Edge's...)

Well... here they are

Simple usage

$ npm install -g node-inspector // duh...

$ node-debug myapp.js

Cool features

• All of Chrome's DevTools features!
• Uses WebSockets for communication
• Remote debugging
• Live edit of running code with option to save on file system

Advanced stuff

// create web-inspector server
$ node-inspector
// use node's native debug protocol to connect
$ node --debug myapp.js

// save live edit
$ node-debug --save-live-edit myapp.js

iron-node

• Basically the same... but a bit different
• It's more of a standalone, desktop debugger
• Comes with it's own version of node
• Themable

iron-node

nvm

Backwards compability

• In theory, Node's API is backward compatible... at least most of it
• What to do when working on project that requires diffrent version of node?
  • Uninstall
  • Download
  • Install

nvm

Global usage

// install any version
$ nvm install 0.12.9

// switch to that version
$ nvm use 0.12.9

Local usage

// run your app in different version
$ nvm run 0.12.9 myapp.js

// run shell command with different node version
$ nvm exec 0.12.9 node myapp.js

Issues

pm2

Lets release our app to production

crash!

What can we do?

• Restart the app!
• Debug
• Deploy hotfix
• Test more
• Add more try and catch statements
• Hire an QA
• ...

... or use PM2

• PM2 is node process manager
• Will automatically restart any application that crashed
• Can launch multiple instances of a single app and seamlesly route the traffic (app needs to be stateless)
• Can restart instance when exceeds given memory limit
• Can log STDOUT and STDERR to files

Usage

// run your app
$ pm2 start myapp.js

// run in 5 instances
$ pm2 start myapp.js -i 5

// restart after exceeding 1GB
$ pm2 start myapp.js --max-memory-restart 1024M

See what's going on

pm2 list

Realtime monitoring

pm2 monit

More features

• Watch directory and restart on changes (like nodemon)
• Programmatic API

node-proxy

Multiple applications

• We can develop application
• We can deploy it to production
• But what about deploying another app?
  • Only one port 80!

The usual solution

• Run applications on different ports
• Or maybe use Docker containers
• Routing?
  • Apache
  • Nginx
  • ...

For the pure sake of

http-proxy

• Allows to proxy requests
• Supports both HTTP and HTTPS
• Intercept errors
• Great for routing

The code

var httpProxy = require('http-proxy');
httpProxy.createServer({
  hostnameOnly: true,
  router: {
    'domain1.com': '127.0.0.1:3001',
    'domain2.com': '127.0.0.1:3002'
  }
}).listen(80);