Module: ActiveSupport::Notifications

Defined in:

lib/active_support/notifications.rb,
lib/active_support/notifications/fanout.rb,
lib/active_support/notifications/instrumenter.rb

Overview

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 miliseconds)
event.result    #=> "Foo"
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.

Defined Under Namespace

Classes: Event, Fanout, Instrumenter, Notifier

Class Attribute Summary

• .notifier ⇒ Object

Class Method Summary

• .instrumenter ⇒ Object

Class Attribute Details

.notifier ⇒ Object

# File 'lib/active_support/notifications.rb', line 50

def notifier
  @notifier ||= Notifier.new
end

Class Method Details

.instrumenter ⇒ Object

# File 'lib/active_support/notifications.rb', line 54

def instrumenter
  Thread.current[:"instrumentation_#{notifier.object_id}"] ||= Instrumenter.new(notifier)
end