Make many parts of Rails lazy. In order to facilitate this,

add lazy_load_hooks.rb, which allows us to declare code that
should be run at some later time. For instance, this allows
us to defer requiring ActiveRecord::Base at boot time purely
to apply configuration. Instead, we register a hook that should
apply configuration once ActiveRecord::Base is loaded.

With these changes, brings down total boot time of a
new app to 300ms in production and 400ms in dev.

TODO: rename base_hook

2 files changed, 11 insertions, 5 deletions

diff --git a/actionpack/lib/action_controller/base.rb b/actionpack/lib/action_controller/base.rb
index 78871154c3..d00afa6d4e 100644
--- a/actionpack/lib/action_controller/base.rb
+++ b/actionpack/lib/action_controller/base.rb
@@ -58,6 +58,8 @@ module ActionController
       filter
     end
 
+    ActionController.run_base_hooks(self)
+
   end
 end
 
diff --git a/actionpack/lib/action_controller/railtie.rb b/actionpack/lib/action_controller/railtie.rb
index e9edf80451..ca03fc62da 100644
--- a/actionpack/lib/action_controller/railtie.rb
+++ b/actionpack/lib/action_controller/railtie.rb
@@ -40,7 +40,7 @@ module ActionController
     log_subscriber ActionController::Railties::LogSubscriber.new
 
     initializer "action_controller.logger" do
-      ActionController::Base.logger ||= Rails.logger
+      ActionController.base_hook { self.logger ||= Rails.logger }
     end
 
     initializer "action_controller.set_configs" do |app|
@@ -51,19 +51,23 @@ module ActionController
       ac.stylesheets_dir = paths.public.stylesheets.to_a.first
       ac.secret = app.config.cookie_secret
 
-      ActionController::Base.config.replace(ac)
+      ActionController.base_hook { self.config.replace(ac) }
     end
 
     initializer "action_controller.initialize_framework_caches" do
-      ActionController::Base.cache_store ||= RAILS_CACHE
+      ActionController.base_hook { self.cache_store ||= RAILS_CACHE }
     end
 
     initializer "action_controller.set_helpers_path" do |app|
-      ActionController::Base.helpers_path = app.config.paths.app.helpers.to_a
+      ActionController.base_hook do
+        self.helpers_path = app.config.paths.app.helpers.to_a
+      end
     end
 
     initializer "action_controller.url_helpers" do |app|
-      ActionController::Base.extend ::ActionController::Railtie::UrlHelpers.with(app.routes)
+      ActionController.base_hook do
+        extend ::ActionController::Railtie::UrlHelpers.with(app.routes)
+      end
 
       message = "ActionController::Routing::Routes is deprecated. " \
                 "Instead, use Rails.application.routes"