cfg: Node minimal configuration engine

cfg is a minimal configuration API for Node.JS, with support for environments, inheritance and command-line overrides.

Features

Simple API

• config

  • config#createConfig(options): creates a configuration file. Options can be:
    • argv: whether to allow argv overrides (defaults to true)
    • argvPrefix: prefix for env variable overrides (defaults to no prefix)
    • env: whether to allow env var overrides (defaults to true)
    • envPrefix: prefix for env variable overrides (defaults to 'cfg')

• setters

  • cfg#set(obj): sets multiple values at once.
  • cfg#set(flag, value): sets a cfg flag to the supplied value.
  • cfg#unset(flag): unsets a flag.
  • cfg#enable(flag): sets a cfg flag to true.
  • cfg#disable(flag): sets a cfg flag to false.

• getters

  • cfg#get(): gets a hash of all values.
  • cfg#get(flag): gets the value of a cfg flag.
  • cfg#has(flag): checks whether flag is set.
  • cfg#enabled(flag): checks if a cfg flag is true.
  • cfg#disabled(flag): checks if a cfg flag is false.

• environments

  • cfg.env(): gets the current env (defaults to development)
  • cfg.env(name, fn): executes fn only if the current env is the same as name
  • cfg.env(name, opts, fn): same as previous, but with options. Options can be
    • inherits: an environment name to inherit props from

Settings are overrideable from the outside

There's two ways to override settings. Imagine the following configuration:

var cfg = require('cfg').createConfig();
 
cfg.env('production', function () {
  cfg.enable('my boolean flag');
  cfg.set('my flag', 'woot');
});

With process argv

node index.js --enable-my-boolean-flag
node index.js --disable-my-boolean-flag
node index.js --with-my-flag=value
node index.js --with-my-flag="some value with spaces"

If you supply an option argvPrefix with the value 'lb' for example, then the option becomes --enable-lb-flag.

With environment variables

CFG_MY_BOOLEAN_FLAG=YES node index.js
CFG_MY_FLAG="woot woot" node index.js

The prefix CFG can be overriden by passing the envPrefix option to createConfig.

No stores or transports

cfg is not concerned with what populates configuration. Layers of replication, pub/sub, etc can be added as a separate module.

Everything is stored in memory, none of the signatures take callbacks

Reusable

The sweet spot for cfg is configuration that you want to reuse across modules and scripts. Even though projects like express or socket.io already include configuration systems, certain configuration flags such as API keys you might want to retrieve from a CLI script and your web app for example

In summary, keep your web-app related configuration flags in express, and put those that are generic in cfg.

License

(The MIT License)

Copyright (c) 2011 Guillermo Rauch <guillermo@learnboost.com>

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.