Type:
Class
ActiveSupport::Subscriber is an object set to consume ActiveSupport::Notifications. The subscriber dispatches notifications to a registered object based on its given namespace.
An example would be Active Record subscriber responsible for collecting statistics about queries:
module ActiveRecord
class StatsSubscriber < ActiveSupport::Subscriber
def sql(event)
Statsd.timing("sql.#{event.payload[:name]}", event.duration)
end
end
end
And it's finally registered as:
ActiveRecord::StatsSubscriber.attach_to :active_record
Since we need to know all instance methods before attaching the log subscriber, the line above should be called after your subscriber definition.
After configured, whenever a “sql.active_record” notification is published,
it will properly dispatch the event (ActiveSupport::Notifications::Event)
to the sql method.