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.
[W] | notifier |
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# File activesupport/lib/active_support/notifications.rb, line 50 50: def instrument(name, payload = {}) 51: if @instrumenters[name] 52: instrumenter.instrument(name, payload) { yield payload if block_given? } 53: else 54: yield payload if block_given? 55: end 56: end
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# File activesupport/lib/active_support/notifications.rb, line 73 73: def instrumenter 74: Thread.current[:"instrumentation_#{notifier.object_id}"] ||= Instrumenter.new(notifier) 75: end
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# File activesupport/lib/active_support/notifications.rb, line 69 69: def notifier 70: @notifier ||= Fanout.new 71: end
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# File activesupport/lib/active_support/notifications.rb, line 58 58: def subscribe(*args, &block) 59: notifier.subscribe(*args, &block).tap do 60: @instrumenters.clear 61: end 62: end
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# File activesupport/lib/active_support/notifications.rb, line 64 64: def unsubscribe(*args) 65: notifier.unsubscribe(*args) 66: @instrumenters.clear 67: end