Fig is a library for standardizing the configuration of a ruby application. This was specifically written with Rails in mind, but is not limited to that framework. The intent is to ensure that all configuration for an application is loaded from the environment, per 12 factor design. It is a wrapper around the popular Figaro configuration library.

The possible values that can be set via Fig are configured in two files: a paramaters file and a defaults file (see the files in spec/data for an example). The values in the parameters file specify all of the possible fields that can be configured and their associated types. The values in the defaults file are a subset of the fields in the parameters file, specifying default values for configuration fields if they are not set in the environment. This means that fields in the defaults file are optional, while fields not included are required to be set by the environment.

When the application is loading, you instantiate your configuration by calling:

# Assign to a global
CONFIG = Fig::Config.new('params.yml', 'defaults.yml', 'application.yml', 'MYAPP')

The final argument is a prefix with which all environment variable are expected to be prefixed.

Before the rest of your app makes use of the configuration, it should be locked (though it may make sense to modify it in flight during initialization before locking it): CONFIG.lock