~michaelforrest/use-case-mapper/trunk

require 'benchmark'

 

module ActionController #:nodoc:

  # The benchmarking module times the performance of actions and reports to the logger. If the Active Record

  # package has been included, a separate timing section for database calls will be added as well.

  module Benchmarking #:nodoc:

    def self.included(base)

      base.extend(ClassMethods)

 

      base.class_eval do

        alias_method_chain :perform_action, :benchmark

        alias_method_chain :render, :benchmark

      end

    end

 

    module ClassMethods

      # Log and benchmark the workings of a single block and silence whatever logging that may have happened inside it 

      # (unless <tt>use_silence</tt> is set to false).

      #

      # The benchmark is only recorded if the current level of the logger matches the <tt>log_level</tt>, which makes it

      # easy to include benchmarking statements in production software that will remain inexpensive because the benchmark

      # will only be conducted if the log level is low enough.

      def benchmark(title, log_level = Logger::DEBUG, use_silence = true)

        if logger && logger.level == log_level

          result = nil

          ms = Benchmark.ms { result = use_silence ? silence { yield } : yield }

          logger.add(log_level, "#{title} (#{('%.1f' % ms)}ms)")

          result

        else

          yield

        end

      end

 

      # Silences the logger for the duration of the block.

      def silence

        old_logger_level, logger.level = logger.level, Logger::ERROR if logger

        yield

      ensure

        logger.level = old_logger_level if logger

      end

    end

 

    protected

      def render_with_benchmark(options = nil, extra_options = {}, &block)

        if logger

          if Object.const_defined?("ActiveRecord") && ActiveRecord::Base.connected?

            db_runtime = ActiveRecord::Base.connection.reset_runtime

          end

 

          render_output = nil

          @view_runtime = Benchmark.ms { render_output = render_without_benchmark(options, extra_options, &block) }

 

          if Object.const_defined?("ActiveRecord") && ActiveRecord::Base.connected?

            @db_rt_before_render = db_runtime

            @db_rt_after_render = ActiveRecord::Base.connection.reset_runtime

            @view_runtime -= @db_rt_after_render

          end

 

          render_output

        else

          render_without_benchmark(options, extra_options, &block)

        end

      end    

 

    private

      def perform_action_with_benchmark

        if logger

          ms = [Benchmark.ms { perform_action_without_benchmark }, 0.01].max

          logging_view          = defined?(@view_runtime)

          logging_active_record = Object.const_defined?("ActiveRecord") && ActiveRecord::Base.connected?

 

          log_message  = 'Completed in %.0fms' % ms

 

          if logging_view || logging_active_record

            log_message << " ("

            log_message << view_runtime if logging_view

 

            if logging_active_record

              log_message << ", " if logging_view

              log_message << active_record_runtime + ")"

            else

              ")"

            end

          end

 

          log_message << " | #{response.status}"

          log_message << " [#{complete_request_uri rescue "unknown"}]"

 

          logger.info(log_message)

          response.headers["X-Runtime"] = "%.0f" % ms

        else

          perform_action_without_benchmark

        end

      end

 

      def view_runtime

        "View: %.0f" % @view_runtime

      end

 

      def active_record_runtime

        db_runtime = ActiveRecord::Base.connection.reset_runtime

        db_runtime += @db_rt_before_render if @db_rt_before_render

        db_runtime += @db_rt_after_render if @db_rt_after_render

        "DB: %.0f" % db_runtime

      end

  end

end