require 'active_support/core_ext/module/delegation' module ActiveSupport # Notifications provides an instrumentation API for Ruby. To instrument an # action in Ruby you just need to do: # # ActiveSupport::Notifications.instrument(:render, :extra => :information) do # render :text => "Foo" # end # # You can consume those events and the information they provide by registering # a log subscriber. For instance, let's store all instrumented events in an array: # # @events = [] # # ActiveSupport::Notifications.subscribe do |*args| # @events << ActiveSupport::Notifications::Event.new(*args) # end # # ActiveSupport::Notifications.instrument(:render, :extra => :information) do # render :text => "Foo" # end # # event = @events.first # event.name #=> :render # event.duration #=> 10 (in milliseconds) # event.payload #=> { :extra => :information } # # When subscribing to Notifications, you can pass a pattern, to only consume # events that match the pattern: # # ActiveSupport::Notifications.subscribe(/render/) do |event| # @render_events << event # end # # Notifications ships with a queue implementation that consumes and publish events # to log subscribers in a thread. You can use any queue implementation you want. # module Notifications autoload :Instrumenter, 'active_support/notifications/instrumenter' autoload :Event, 'active_support/notifications/instrumenter' autoload :Fanout, 'active_support/notifications/fanout' @instrumenters = Hash.new { |h,k| h[k] = notifier.listening?(k) } class << self attr_writer :notifier delegate :publish, :unsubscribe, :to => :notifier def instrument(name, payload = {}) if @instrumenters[name] instrumenter.instrument(name, payload) { yield payload if block_given? } else yield payload if block_given? end end def subscribe(*args, &block) notifier.subscribe(*args, &block).tap do @instrumenters.clear end end def unsubscribe(*args) notifier.unsubscribe(*args) @instrumenters.clear end def notifier @notifier ||= Fanout.new end def instrumenter Thread.current[:"instrumentation_#{notifier.object_id}"] ||= Instrumenter.new(notifier) end end end end