Refactor Sentry's Railtie

1. Give every patch/extension their own method to clarify their
   purposes.
2. Move most of the patches into after_initializer hook from their own
   initializers. This is for making the order of each step more
   understandable.

sentry-rails/lib/sentry/rails/railtie.rb

@@ -8,31 +8,36 @@
 
 module Sentry
   class Railtie < ::Rails::Railtie
+    # middlewares can't be injected after initialize
     initializer "sentry.use_rack_middleware" do |app|
       app.config.middleware.insert 0, Sentry::Rails::CaptureExceptions
     end
 
-    initializer 'sentry.action_controller' do
-      ActiveSupport.on_load :action_controller do
-        include Sentry::Rails::ControllerMethods
-        include Sentry::Rails::ControllerTransaction
-        ActionController::Live.send(:prepend, Sentry::Rails::Overrides::StreamingReporter)
-      end
+    config.after_initialize do
+      configure_sentry_logger
+      extend_controller_methods
+      extend_active_job
+      override_exceptions_handling
+      override_streaming_reporter
+      setup_backtrace_cleanup_callback
+      inject_breadcrumbs_logger
+      activate_tracing
     end
 
-    initializer 'sentry.action_view' do
-      ActiveSupport.on_load :action_view do
-        ActionView::StreamingTemplateRenderer::Body.send(:prepend, Sentry::Rails::Overrides::StreamingReporter)
-      end
+    def configure_sentry_logger
+      Sentry.configuration.logger = ::Rails.logger
     end
 
-    config.after_initialize do
-      Sentry.configuration.logger = ::Rails.logger
+    def extend_active_job
+      ActiveJob::Base.send(:prepend, Sentry::Rails::ActiveJobExtensions)
+    end
 
-      setup_backtrace_cleanup_callback
-      inject_breadcrumbs_logger
-      override_exceptions_handling
-      activate_tracing
+    def extend_controller_methods
+      ActiveSupport.on_load :action_controller do
+        include Sentry::Rails::ControllerMethods
+        include Sentry::Rails::ControllerTransaction
+        ActionController::Live.send(:prepend, Sentry::Rails::Overrides::StreamingReporter)
+      end
     end
 
     def inject_breadcrumbs_logger
@@ -63,17 +68,17 @@ def override_exceptions_handling
       end
     end
 
+    def override_streaming_reporter
+      ActiveSupport.on_load :action_view do
+        ActionView::StreamingTemplateRenderer::Body.send(:prepend, Sentry::Rails::Overrides::StreamingReporter)
+      end
+    end
+
     def activate_tracing
       if Sentry.configuration.tracing_enabled?
         Sentry::Rails::Tracing.subscribe_tracing_events
         Sentry::Rails::Tracing.patch_active_support_notifications
       end
     end
-
-    initializer 'sentry.active_job' do
-      ActiveSupport.on_load :active_job do
-        require 'sentry/rails/active_job'
-      end
-    end
   end
 end