rails: load performance hooks only if performance_stats is enabled

We load these hooks unnecessarily for those customers who don't use performance
stats. It may cause an unwanted overhead for them: we spend CPU time collecting
info but never send it. In this commit we check if performance_stats is enabled
and include the hooks only if it is.

lib/airbrake/rails.rb

@@ -5,17 +5,6 @@ module Rails
  # occurring in the application automatically.
  class Railtie < ::Rails::Railtie
  initializer('airbrake.middleware') do |app|
- require 'airbrake/rails/action_controller_route_subscriber'
- require 'airbrake/rails/action_controller_notify_subscriber'
- require 'airbrake/rails/action_controller_performance_breakdown_subscriber'
-
- ActiveSupport::Notifications.subscribe(
- 'process_action.action_controller',
- Airbrake::Rails::ActionControllerPerformanceBreakdownSubscriber.new
- )
-
- require 'airbrake/rails/active_record_subscriber' if defined?(ActiveRecord)
-
  # Since Rails 3.2 the ActionDispatch::DebugExceptions middleware is
  # responsible for logging exceptions and showing a debugging page in
  # case the request is local. We want to insert our middleware after
@@ -60,10 +49,28 @@ class Railtie < ::Rails::Railtie
  require 'airbrake/rails/action_controller'
  include Airbrake::Rails::ActionController
 
- # Cache route information for the duration of the request.
- require 'airbrake/rails/action_controller_route_subscriber'
- # Send route stats.
- require 'airbrake/rails/action_controller_notify_subscriber'
+ if Airbrake::Config.instance.performance_stats
+ # Cache route information for the duration of the request.
+ require 'airbrake/rails/action_controller_route_subscriber'
+ ActiveSupport::Notifications.subscribe(
+ 'start_processing.action_controller',
+ Airbrake::Rails::ActionControllerRouteSubscriber.new
+ )
+
+ # Send route stats.
+ require 'airbrake/rails/action_controller_notify_subscriber'
+ ActiveSupport::Notifications.subscribe(
+ 'process_action.action_controller',
+ Airbrake::Rails::ActionControllerNotifySubscriber.new
+ )
+
+ # Send performance breakdown: where a request spends its time.
+ require 'airbrake/rails/action_controller_performance_breakdown_subscriber'
+ ActiveSupport::Notifications.subscribe(
+ 'process_action.action_controller',
+ Airbrake::Rails::ActionControllerPerformanceBreakdownSubscriber.new
+ )
+ end
  end
  end
 
@@ -74,8 +81,20 @@ class Railtie < ::Rails::Railtie
  require 'airbrake/rails/active_record'
  include Airbrake::Rails::ActiveRecord
 
- # Send SQL queries.
- require 'airbrake/rails/active_record_subscriber'
+ if defined?(ActiveRecord) && Airbrake::Config.instance.performance_stats
+ # Send SQL queries.
+ require 'airbrake/rails/active_record_subscriber'
+ ActiveSupport::Notifications.subscribe(
+ 'sql.active_record', Airbrake::Rails::ActiveRecordSubscriber.new
+ )
+
+ # Filter out parameters from SQL body.
+ Airbrake.add_performance_filter(
+ Airbrake::Filters::SqlFilter.new(
+ ::ActiveRecord::Base.connection_config[:adapter]
+ )
+ )
+ end
  end
  end
 

lib/airbrake/rails/action_controller_notify_subscriber.rb

@@ -42,8 +42,3 @@ def find_status_code(payload)
  end
  end
 end
-
-ActiveSupport::Notifications.subscribe(
- 'process_action.action_controller',
- Airbrake::Rails::ActionControllerNotifySubscriber.new
-)

lib/airbrake/rails/action_controller_route_subscriber.rb

@@ -46,8 +46,3 @@ def find_all_routes
  end
  end
 end
-
-ActiveSupport::Notifications.subscribe(
- 'start_processing.action_controller',
- Airbrake::Rails::ActionControllerRouteSubscriber.new
-)

lib/airbrake/rails/active_record_subscriber.rb

@@ -36,13 +36,3 @@ def last_caller
  end
  end
 end
-
-Airbrake.add_performance_filter(
- Airbrake::Filters::SqlFilter.new(
- ActiveRecord::Base.connection_config[:adapter]
- )
-)
-
-ActiveSupport::Notifications.subscribe(
- 'sql.active_record', Airbrake::Rails::ActiveRecordSubscriber.new
-)