environment

Adds configuration code to a Rails runtime environment.

By default, adds code inside the Application class in config/application.rb so that it applies to all environments.

environment %(config.asset_host = "cdn.provider.com")

Results in:

# config/application.rb
class Application < Rails::Application
  config.asset_host = "cdn.provider.com"
  # ...
end

If the :env option is specified, the code will be added to the corresponding file in config/environments instead.

environment %(config.asset_host = "localhost:3000"), env: "development"

Results in:

# config/environments/development.rb
Rails.application.configure do
  config.asset_host = "localhost:3000"
  # ...
end

:env can also be an array. In which case, the code is added to each corresponding file in config/environments.

The code can also be specified as the return value of the block:

environment do
  %(config.asset_host = "cdn.provider.com")
end

environment(nil, env: "development") do
  %(config.asset_host = "localhost:3000")
end

# File railties/lib/rails/generators/actions.rb, line 206
      def environment(data = nil, options = {})
        sentinel = "class Application < Rails::Application\n"
        env_file_sentinel = "Rails.application.configure do\n"
        data ||= yield if block_given?

        in_root do
          if options[:env].nil?
            inject_into_file "config/application.rb", optimize_indentation(data, 4), after: sentinel, verbose: false
          else
            Array(options[:env]).each do |env|
              inject_into_file "config/environments/#{env}.rb", optimize_indentation(data, 2), after: env_file_sentinel, verbose: false
            end
          end
        end
      end