envfig v0.0.2

envfig

envfig is a minimalist Node.js library for easily enabling configuration via envars. It safely allows to get settings from process.env making type conversions (process.env.YOUR_ENVVAR is a string) and managing default values.

why configuration using system envars?

It is flexible, cross-environment, no configuration files into your code versioning tool (be it git, svn...).

12 Factor is supporting the use of envars instead of files configuration: http://12factor.net/config

how to use it. simplest

// singlefile-server.js
var http = require('http');
var config = require('../src/envfig').config;

var bindAddress = config('BIND_ADDRESS', '127.0.0.1'); // if envar BIND_ADDRESS is set, get it, else '127.0.0.1'
var listenPort = config('PORT', 7744); // if envar PORT is set, get it (as number), else 7744

http.createServer(function (req, res) {
    res.writeHead(200, {'Content-Type': 'text/plain'});
    res.end('Hello World\n');
}).listen(listenPort, bindAddress);

Now, we can change our server's bind address or port just by setting the appropiate envars:

$ node server.js &
Started HTTP server: 127.0.0.1:7744
$ curl http://127.0.0.1:7744
Hello World

$ export PORT=8899 && node server.js &
Started HTTP server: 127.0.0.1:8899
$ curl http://127.0.0.1:8899
Hello World

how to use it. separated settings file

If your project is bigger, a better way of structure your settings with envfig may be to have a settings.js file for configuration, that is exporting a settings Object. The rest of modules may require settings.js and make use of its configuration:

// settings.js
var config = require('envfig').config;
var settings = {
  bindAddress: config('BIND_ADDRESS', '127.0.0.1'), // if envar BIND_ADDRESS is set, get it, else '127.0.0.1'
  listenPort:  config('PORT', 7744), // if envar PORT is set, get it (as number), else 7744
}
module.exports = settings;

Module server.js will use settings.js to configure its HTTP listen properties:

// server.js
var http = require('http');
var settings = require('./settings.js');
http.createServer(function (req, res) {
  res.writeHead(200, {'Content-Type': 'text/plain'});
  res.end('Hello World\n');
}).listen(settings.listenPort, settings.bindAddress);

settings.js file can then be used from any of your project modules.