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Class: ActiveSupport::StructuredEventSubscriber

Do not use. This class is for internal use only.

Overview

StructuredEventSubscriber consumes Notifications in order to emit structured events via Rails.event.

An example would be the Action Controller structured event subscriber, responsible for emitting request processing events:

module ActionController
class StructuredEventSubscriber < ActiveSupport::StructuredEventSubscriber
  attach_to :action_controller

  def start_processing(event)
    emit_event("controller.request_started",
      controller: event.payload[:controller],
      action: event.payload[:action],
      format: event.payload[:format]
    )
  end
end
end

After configured, whenever a "start_processing.action_controller" notification is published, it will properly dispatch the event (Notifications::Event) to the start_processing method. The subscriber can then emit a structured event via the #emit_event method.

Class Attribute Summary

Subscriber - Inherited

.namespace, .notifier, .subscriber

Class Method Summary

Subscriber - Inherited

.attach_to

Attach the subscriber to a namespace.
.detach_from

Detach the subscriber from a namespace.
.method_added

Adds event subscribers for all new methods added to the class.
.new, .subscribers, .add_event_subscriber, .fetch_public_methods, .find_attached_subscriber, .invalid_event?, .pattern_subscribed?, .prepare_pattern, .remove_event_subscriber

Instance Attribute Summary

Subscriber - Inherited

#patterns

Instance Method Summary

Subscriber - Inherited

#call

Constructor Details

.new ⇒ StructuredEventSubscriber

[ GitHub ] 

  


# File 'activesupport/lib/active_support/structured_event_subscriber.rb', line 55



def initialize
  super
  @silenced_events = {}
end


  







Class Attribute Details



  

    .debug_methods   (rw)
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/structured_event_subscriber.rb', line 33



class_attribute :debug_methods, instance_accessor: false, default: [] # :nodoc:


  








  

    .debug_methods?  ⇒ Boolean  (rw)
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/structured_event_subscriber.rb', line 33



class_attribute :debug_methods, instance_accessor: false, default: [] # :nodoc:


  







Class Method Details



  

    .attach_to  
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/structured_event_subscriber.rb', line 36



def attach_to(...) # :nodoc:
  result = super
  set_silenced_events
  result
end


  








  

    .debug_only(method)   (private)
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/structured_event_subscriber.rb', line 49



def debug_only(method)
  self.debug_methods += [method]
  set_silenced_events
end


  








  

    .set_silenced_events   (private)
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/structured_event_subscriber.rb', line 43



def set_silenced_events
  if subscriber
    subscriber.silenced_events = debug_methods.to_h { |method| ["#{method}.#{namespace}", true] }
  end
end


  







Instance Attribute Details



  

    #silenced_events=(value)   (writeonly)
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/structured_event_subscriber.rb', line 64



attr_writer :silenced_events # :nodoc:


  







Instance Method Details



  

    #call(event)  
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/structured_event_subscriber.rb', line 87



def call(event)
  super
rescue => e
  handle_event_error(event.name, e)
end


  








  

    #emit_debug_event(name, payload = nil, caller_depth: 1, **kwargs)  
  



  

    
Like #emit_event, but only emits when the event reporter is in debug mode

  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/structured_event_subscriber.rb', line 81



def emit_debug_event(name, payload = nil, caller_depth: 1, **kwargs)
  ActiveSupport.event_reporter.debug(name, payload, caller_depth: caller_depth + 1, filter_payload: false, **kwargs)
rescue => e
  handle_event_error(name, e)
end


  








  

    #emit_event(name, payload = nil, caller_depth: 1, **kwargs)  
  



  

    
Emit a structured event via Rails.event.notify.


Arguments


    

  • name - The event name as a string or symbol
    • 

  • payload - The event payload as a hash or object
    • 

  • caller_depth - Stack depth for source location (default: 1)
    • 

  • kwargs - Additional payload data merged with the payload hash
    • 


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/structured_event_subscriber.rb', line 74



def emit_event(name, payload = nil, caller_depth: 1, **kwargs)
  ActiveSupport.event_reporter.notify(name, payload, caller_depth: caller_depth + 1, filter_payload: false, **kwargs)
rescue => e
  handle_event_error(name, e)
end


  








  

    #handle_event_error(name, error)   (private)
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/structured_event_subscriber.rb', line 94



def handle_event_error(name, error)
  ActiveSupport.error_reporter.report(error, source: name)
end


  








  

    #silenced?(event)  ⇒ Boolean 
  



  

    
  





  


  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/structured_event_subscriber.rb', line 60



def silenced?(event)
  ActiveSupport.event_reporter.subscribers.none? || (@silenced_events.key?(event) && !ActiveSupport.event_reporter.debug_mode?)
end