Module: Datadog::Contrib::Rails::ActionController

Defined in:
lib/ddtrace/contrib/rails/action_controller.rb

Overview

Code used to create and handle ‘rails.action_controller’ spans.

Constant Summary collapse

KEY = 
'datadog_actioncontroller'.freeze

Class Method Summary collapse

Class Method Details

.instrument ⇒ Object 



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# File 'lib/ddtrace/contrib/rails/action_controller.rb', line 11

def self.instrument
  # subscribe when the request processing starts
  ::ActiveSupport::Notifications.subscribe('start_processing.action_controller') do |*args|
    start_processing(*args)
  end

  # subscribe when the request processing has been completed
  ::ActiveSupport::Notifications.subscribe('process_action.action_controller') do |*args|
    process_action(*args)
  end
end

.process_action(_name, start, finish, _id, payload) ⇒ Object 



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# File 'lib/ddtrace/contrib/rails/action_controller.rb', line 36

def self.process_action(_name, start, finish, _id, payload)
  return unless Thread.current[KEY]
  Thread.current[KEY] = false

  tracer = ::Rails.configuration.datadog_trace.fetch(:tracer)
  span = tracer.active_span()
  return unless span

  begin
    resource = "#{payload.fetch(:controller)}##{payload.fetch(:action)}"
    span.resource = resource

    # set the parent resource if it's a `rack.request` span
    if !span.parent.nil? && span.parent.name == 'rack.request'
      span.parent.resource = resource
    end

    span.set_tag('rails.route.action', payload.fetch(:action))
    span.set_tag('rails.route.controller', payload.fetch(:controller))

    if payload[:exception].nil?
      # [christian] in some cases :status is not defined,
      # rather than firing an error, simply acknowledge we don't know it.
      status = payload.fetch(:status, '?').to_s
      span.status = 1 if status.starts_with?('5')
    else
      error = payload[:exception]
      if defined?(::ActionDispatch::ExceptionWrapper)
        status = ::ActionDispatch::ExceptionWrapper.status_code_for_exception(error[0])
        status = status ? status.to_s : '?'
      else
        status = '500'
      end
      span.set_error(error) if status.starts_with?('5')
    end
  ensure
    span.start_time = start
    span.finish(finish)
  end
rescue StandardError => e
  Datadog::Tracer.log.error(e.message)
end

.start_processing ⇒ Object 



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# File 'lib/ddtrace/contrib/rails/action_controller.rb', line 23

def self.start_processing(*)
  return if Thread.current[KEY]

  tracer = ::Rails.configuration.datadog_trace.fetch(:tracer)
  service = ::Rails.configuration.datadog_trace.fetch(:default_controller_service)
  type = Datadog::Ext::HTTP::TYPE
  tracer.trace('rails.action_controller', service: service, span_type: type)

  Thread.current[KEY] = true
rescue StandardError => e
  Datadog::Tracer.log.error(e.message)
end