Module: Datadog::RailsActionPatcher

Includes:

Patcher

Defined in:

lib/ddtrace/contrib/rails/core_extensions.rb

Overview

RailsActionPatcher contains functions to patch Rails action controller instrumentation

Class Method Summary

• .patch_action_controller ⇒ Object
• .patch_process_action ⇒ Object

Methods included from Patcher

included

Methods included from Patcher::CommonMethods

#do_once, #without_warnings

Class Method Details

.patch_action_controller ⇒ Object

# File 'lib/ddtrace/contrib/rails/core_extensions.rb', line 152

def patch_action_controller
  do_once(:patch_action_controller) do
    patch_process_action
  end
end

.patch_process_action ⇒ Object

# File 'lib/ddtrace/contrib/rails/core_extensions.rb', line 158

def patch_process_action
  do_once(:patch_process_action) do
    ::ActionController::Instrumentation.class_eval do
      def process_action_with_datadog(*args)
        # mutable payload with a tracing context that is used in two different
        # signals; it propagates the request span so that it can be finished
        # no matter what
        payload = {
          controller: self.class,
          action: action_name,
          headers: {
            # The exception this controller was given in the request,
            # which is typical if the controller is configured to handle exceptions.
            request_exception: request.headers['action_dispatch.exception']
          },
          tracing_context: {}
        }

        begin
          # process and catch request exceptions
          Datadog::Contrib::Rails::ActionController.start_processing(payload)
          result = process_action_without_datadog(*args)
          payload[:status] = response.status
          result
        rescue Exception => e
          payload[:exception] = [e.class.name, e.message]
          payload[:exception_object] = e
          raise e
        end
      ensure
        Datadog::Contrib::Rails::ActionController.finish_processing(payload)
      end

      alias_method :process_action_without_datadog, :process_action
      alias_method :process_action, :process_action_with_datadog
    end
  end
end