Module: Sixty::Instrument::ActionController

Defined in:
lib/sixty/instrument/action_controller.rb

Overview

Controller actions, as operations of their own.

The Rack span says a request took 900ms. The query spans say the database took 40ms. Without a span in between, the remaining 860ms lands on the request as self time — true, but not actionable: "GET /orders got slower" names an endpoint, not a change. OrdersController#index names the method somebody edited.

It is also the layer that makes fanout readable. db_calls is credited to every ancestor, so an N+1 introduced in a controller shows up here as the call count changing, which is the sentence a person can act on: "this action went from 3 queries to 41".

process_action is the hook rather than an around_action for one reason: an around_action can be skipped, reordered, or short-circuited by another filter — including a before_action that renders and halts, which is exactly the request whose measurement matters most.

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.install ⇒ Object 



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# File 'lib/sixty/instrument/action_controller.rb', line 32

def self.install
  return false unless defined?(::ActiveSupport)

  ::ActiveSupport.on_load(:action_controller) do
    # `self` here is ActionController::Base or ::API, whichever the
    # application loaded — both, in an app that has each.
    prepend Sixty::Instrument::ActionController
  end
  true
end

Instance Method Details

#process_action(*args) ⇒ Object 



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# File 'lib/sixty/instrument/action_controller.rb', line 25

def process_action(*args)
  return super unless Sixty.enabled?

  Sixty.trace("#{self.class.name}##{action_name}") { super }
end