mongo_railtie.rb

module Mongo
  module ControllerRuntime
    extend ActiveSupport::Concern
    
  protected

    attr_internal :mongo_runtime

    def cleanup_view_runtime
      
      mongo_rt_before_render = MongoInstrumenter::LogSubscriber.reset_runtime
      runtime = super
      mongo_rt_after_render = MongoInstrumenter::LogSubscriber.reset_runtime
      self.mongo_runtime = mongo_rt_before_render + mongo_rt_after_render
      runtime - mongo_rt_after_render
    end

    def append_info_to_payload(payload)
      super
      payload[:mongo_runtime] = mongo_runtime
    end

    module ClassMethods
      def log_process_action(payload)
        messages, mongo_runtime = super, payload[:mongo_runtime]
        messages << ("Mongoid: %.1fms" % mongo_runtime.to_f) if mongo_runtime
        messages
      end
    end
  end
  
  class Railtie < Rails::Railtie
    # Expose mongoid runtime to controller for logging.
    initializer "mongoid.log_runtime" do |app|
      ActiveSupport.on_load(:action_controller) do
        include ControllerRuntime
      end
    end
  end
end