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

3 files changed, 9 insertions, 4 deletions

diff --git a/actionmailer/lib/action_mailer.rb b/actionmailer/lib/action_mailer.rb
index 7f5bcad922..43d73e71b9 100644
--- a/actionmailer/lib/action_mailer.rb
+++ b/actionmailer/lib/action_mailer.rb
@@ -34,6 +34,7 @@ require 'active_support/core_ext/array/uniq_by'
 require 'active_support/core_ext/module/attr_internal'
 require 'active_support/core_ext/module/delegation'
 require 'active_support/core_ext/string/inflections'
+require 'active_support/lazy_load_hooks'
 
 module ActionMailer
   extend ::ActiveSupport::Autoload
diff --git a/actionmailer/lib/action_mailer/base.rb b/actionmailer/lib/action_mailer/base.rb
index 48d6bbc8d9..246816e953 100644
--- a/actionmailer/lib/action_mailer/base.rb
+++ b/actionmailer/lib/action_mailer/base.rb
@@ -291,6 +291,8 @@ module ActionMailer #:nodoc:
       :parts_order  => [ "text/plain", "text/enriched", "text/html" ]
     }.freeze
 
+    ActionMailer.run_base_hooks(self)
+
     class << self
 
       def mailer_name
diff --git a/actionmailer/lib/action_mailer/railtie.rb b/actionmailer/lib/action_mailer/railtie.rb
index c5f18c7911..0182e48425 100644
--- a/actionmailer/lib/action_mailer/railtie.rb
+++ b/actionmailer/lib/action_mailer/railtie.rb
@@ -6,19 +6,21 @@ module ActionMailer
     railtie_name :action_mailer
 
     initializer "action_mailer.url_for", :before => :load_environment_config do |app|
-      ActionMailer::Base.send(:include, app.routes.url_helpers)
+      ActionMailer.base_hook { include app.routes.url_helpers }
     end
 
     require "action_mailer/railties/log_subscriber"
     log_subscriber ActionMailer::Railties::LogSubscriber.new
 
     initializer "action_mailer.logger" do
-      ActionMailer::Base.logger ||= Rails.logger
+      ActionMailer.base_hook { self.logger ||= Rails.logger }
     end
 
     initializer "action_mailer.set_configs" do |app|
-      app.config.action_mailer.each do |k,v|
-        ActionMailer::Base.send "#{k}=", v
+      ActionMailer.base_hook do
+        app.config.action_mailer.each do |k,v|
+          send "#{k}=", v
+        end
       end
     end
   end