< Object

The Configuration class holds all the parameters for the Initializer and ships with defaults that suites most Rails applications. But it‘s possible to overwrite everything. Usually, you‘ll create an Configuration file implicitly through the block running on the Initializer, but it‘s also possible to create the Configuration instance in advance and pass it in like this:

  config =, config)


Name Visibility R/W Description
action_controller public RW A stub for setting options on ActionController::Base.
action_mailer public RW A stub for setting options on ActionMailer::Base.
action_view public RW A stub for setting options on ActionView::Base.
active_record public RW A stub for setting options on ActiveRecord::Base.
active_resource public RW A stub for setting options on ActiveResource::Base.
active_support public RW A stub for setting options on ActiveSupport.
cache_classes public RW Whether or not classes should be cached (set to false if you want application classes to be reloaded on each request)
cache_store public RW The specific cache store to use. By default, the ActiveSupport::Cache::Store will be used.
controller_paths public RW The list of paths that should be searched for controllers. (Defaults to app/controllers.)
database_configuration_file public RW The path to the database configuration file to use. (Defaults to config/database.yml.)
dependency_loading public RW Enables or disables dependency loading during the request cycle. Setting dependency_loading to true will allow new classes to be loaded during a request. Setting it to false will disable this behavior.

Those who want to run in a threaded environment should disable this option and eager load or require all there classes on initialization.

If cache_classes is disabled, dependency loaded will always be on.

eager_load_paths public RW An array of paths from which Rails will eager load on boot if cache classes is enabled. All elements of this array must also be in load_paths.
frameworks public RW The list of rails framework components that should be loaded. (Defaults to :active_record, :action_controller, :action_view, :action_mailer, and :active_resource).
gems public RW An array of gems that this rails application depends on. Rails will automatically load these gems during installation, and allow you to install any missing gems with:
  rake gems:install

You can add gems with the gem method.

i18n public RW Accessor for i18n settings.
load_once_paths public RW An array of paths from which Rails will automatically load from only once. All elements of this array must also be in load_paths.
load_paths public RW An array of additional paths to prepend to the load path. By default, all app, lib, vendor and mock paths are included in this list.
log_level public RW The log level to use for the default Rails logger. In production mode, this defaults to :info. In development mode, it defaults to :debug.
log_path public RW The path to the log file to use. Defaults to log/#{environment}.log (e.g. log/development.log or log/production.log).
logger public RW The specific logger to use. By default, a logger will be created and initialized using log_path and log_level, but a programmer may specifically set the logger to use via this accessor and it will be used directly.
metals public RW The list of metals to load. If this is set to nil, all metals will be loaded in alphabetical order. If this is set to [], no metals will be loaded. Otherwise metals will be loaded in the order specified
plugin_loader public RW The class that handles loading each plugin. Defaults to Rails::Plugin::Loader, but a sub class would have access to fine grained modification of the loading behavior. See the implementation of Rails::Plugin::Loader for more details.
plugin_locators public RW The classes that handle finding the desired plugins that you‘d like to load for your application. By default it is the Rails::Plugin::FileSystemLocator which finds plugins to load in vendor/plugins. You can hook into gem location by subclassing Rails::Plugin::Locator and adding it onto the list of plugin_locators.
plugin_paths public RW The path to the root of the plugins directory. By default, it is in vendor/plugins.
plugins public R The list of plugins to load. If this is set to nil, all plugins will be loaded. If this is set to [], no plugins will be loaded. Otherwise, plugins will be loaded in the order specified.
preload_frameworks public RW Whether to preload all frameworks at startup.
reload_plugins public RW Enables or disables plugin reloading. You can get around this setting per plugin. If reload_plugins? is false, add this to your plugin‘s init.rb to make it reloadable:
  ActiveSupport::Dependencies.load_once_paths.delete lib_path

If reload_plugins? is true, add this to your plugin‘s init.rb to only load it once:

  ActiveSupport::Dependencies.load_once_paths << lib_path
root_path public R The application‘s base directory.
routes_configuration_file public RW The path to the routes configuration file to use. (Defaults to config/routes.rb.)
time_zone public RW Sets the default time_zone. Setting this will enable time_zone awareness for Active Record models and set the Active Record default timezone to :utc.
view_path public RW The root of the application‘s views. (Defaults to app/views.)
whiny_nils public RW Set to true if you want to be warned (noisily) when you try to invoke any method of nil. Set to false for the standard Ruby behavior.



Visibility Signature
public new ()


Visibility Signature
public after_initialize (&after_initialize_block)
public after_initialize_blocks ()
public breakpoint_server (_ = nil)
public breakpoint_server= (_ = nil)
public builtin_directories ()
public database_configuration ()
public environment ()
public environment_path ()
public framework_paths ()
public gem (name, options = {})
public middleware ()
public plugins= (plugins)
public reload_plugins? ()
public set_root_path! ()
public threadsafe! ()
public to_prepare (&callback)

Class Method Detail


Create a new Configuration instance, initialized with the default values.

Instance Method Detail


Adds a block which will be executed after rails has been fully initialized. Useful for per-environment configuration which depends on the framework being fully initialized.


Returns the blocks added with Configuration#after_initialize

breakpoint_server(_ = nil)

Deprecated options:

breakpoint_server=(_ = nil)

Alias for breakpoint_server



Loads and returns the contents of the database_configuration_file. The contents of the file are processed via ERB before being sent through YAML::load.


Return the currently selected environment. By default, it returns the value of the RAILS_ENV constant.


The path to the current environment‘s file (development.rb, etc.). By default the file is at config/environments/#{environment}.rb.


gem(name, options = {})

Adds a single Gem dependency to the rails application. By default, it will require the library with the same name as the gem. Use :lib to specify a different name.

  # gem 'aws-s3', '>= 0.4.0'
  # require 'aws/s3'
  config.gem 'aws-s3', :lib => 'aws/s3', :version => '>= 0.4.0',      #     :source => ""

To require a library be installed, but not attempt to load it, pass :lib => false

  config.gem 'qrp', :version => '0.4.1', :lib => false




Returns true if plugin reloading is enabled.


Set the root_path to RAILS_ROOT and canonicalize it.


Enable threaded mode. Allows concurrent requests to controller actions and multiple database connections. Also disables automatic dependency loading after boot, and disables reloading code on every request, as these are fundamentally incompatible with thread safety.


Add a preparation callback that will run before every request in development mode, or before the first request in production.

See Dispatcher#to_prepare.