I just released a stupid simple plugin based on the idea behind Coda Hale’s rails_environments plugin.

This plugin adds the following functionality to the Rails module to help with determining the current enviroment:

>> Rails.environment       # a convenience alias to Rails.env
=> "development"
>> Rails.development?
=> true
>> Rails.not_development?
=> false
>> Rails.production?
=> false
>> Rails.not_production?
=> true
>> Rails.test?
=> false
>> Rails.not_test?
=> true

Not only does it provide env? and not_env? methods for the standard environments, it also provides those methods for any environment you define in config/environments/ (in fact that is how it learns about all of the environments, including the standard three). So if you define new environments in config/environments/ they will be picked up automatically.

Install with: script/plugin install git://github.com/tobias/rails_habitat.git

It lives on github.

Edit: see David’s comment below for the built in way to do this (in Rails >= 2.2).