Rails: Using custom configurations with the config_for method

You can use the config.x Show archive.org snapshot configuration in combination with config_for to configure global settings for your Rails 4.2+ application.

Example

In your config/application.rb assign the settings from e.g. config/settings.yml as follows:

Copymodule FooApplication
  class Application < Rails::Application
    config.x.settings = config_for(:settings)
  end
end

The config/settings.yml might look as follows:

Copyshared:
  email: info@example.com
  google_analytics:
    container: UA-123456-12

production:
  email: production@example.com    

Keys under the shared namespace are shared between all environments. Environment specific configs will override those shared values. Afterwards you can access these settings with e.g. Rails.application.config.x.settings.google_analytics.fetch(:container) or Rails.configuration.x.settings.google_analytics.fetch(:container) in your application.

Additional notes

• The config.x is a dedicated namespace and helps you to avoid collisions with config options related to Rails itself.
• The config.x returns an OrderedOptions Show archive.org snapshot object for the first two levels, but not deeper.
• This approach might be preferred over global constants like config/constants/settings.rb:
  • It can be used in the Rails Configuration itself and all initializers.
  • It allows to write environment dependent settings.
• Undefined keys return nil if not present e.g. Rails.application.config.foobar => nil