Class: Phlex::Reactive::APM::Subscriber

Inherits:
Object
  • Object
show all
Defined in:
lib/phlex/reactive/apm/subscriber.rb

Overview

The ASN-driven half of the APM integration (issue #207). Subscribes to action.phlex_reactive / defer.phlex_reactive and hands each event's name-only payload + duration to the resolved adapter's record_action — so the APM names the transaction Component#action and tags the outcome.

A plain ActiveSupport::Notifications subscriber (NOT a LogSubscriber): a LogSubscriber dispatches by the FULL event method, but we want the SAME record_action for both action and defer events and to hold a reference to the adapter instance. install/uninstall manage exactly one subscription so a re-attach with the same adapter never double-reports.

Constant Summary collapse

EVENTS =

The events whose duration+outcome we forward to the APM as a named transaction. render/broadcast are left to the app (a Datadog child-span adapter can subscribe to them itself) — the action IS the transaction.

/\A(?:action|defer)\.phlex_reactive\z/

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(adapter) ⇒ Subscriber

Returns a new instance of Subscriber.



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# File 'lib/phlex/reactive/apm/subscriber.rb', line 46

def initialize(adapter)
  @adapter = adapter
end

Class Method Details

.install(adapter) ⇒ Object

Install a single bus subscription for adapter. Idempotent for the SAME adapter: a repeat call is a no-op. A DIFFERENT adapter replaces the previous subscription (an app that swaps apm at boot wins last).



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# File 'lib/phlex/reactive/apm/subscriber.rb', line 26

def install(adapter)
  return if @adapter.equal?(adapter) && @subscription

  uninstall
  @adapter = adapter
  subscriber = new(adapter)
  @subscription = ::ActiveSupport::Notifications.subscribe(EVENTS) do |*args|
    subscriber.call(::ActiveSupport::Notifications::Event.new(*args))
  end
end

.installed? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/phlex/reactive/apm/subscriber.rb', line 43

def installed? = !@subscription.nil?

.uninstall ⇒ Object 



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# File 'lib/phlex/reactive/apm/subscriber.rb', line 37

def uninstall
  ::ActiveSupport::Notifications.unsubscribe(@subscription) if @subscription
  @subscription = nil
  @adapter = nil
end

Instance Method Details

#call(event) ⇒ Object Also known as: action, defer

Route an already-built Event to record_action. Named after the event's leading segment (action/defer) so the synthesized-event unit spec can call subscriber.action(event) exactly like the LogSubscriber spec.



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# File 'lib/phlex/reactive/apm/subscriber.rb', line 53

def call(event)
  @adapter.record_action(event.payload, event.duration)
end