1 files changed, 105 insertions, 0 deletions
diff --git a/actionpack/lib/action_controller/metal/instrumentation.rb b/actionpack/lib/action_controller/metal/instrumentation.rb
new file mode 100644
index 0000000000..51fac08749
--- /dev/null
+++ b/actionpack/lib/action_controller/metal/instrumentation.rb
@@ -0,0 +1,105 @@
+# frozen_string_literal: true
+
+require "benchmark"
+require "abstract_controller/logger"
+
+module ActionController
+  # Adds instrumentation to several ends in ActionController::Base. It also provides
+  # some hooks related with process_action. This allows an ORM like Active Record
+  # and/or DataMapper to plug in ActionController and show related information.
+  #
+  # Check ActiveRecord::Railties::ControllerRuntime for an example.
+  module Instrumentation
+    extend ActiveSupport::Concern
+
+    include AbstractController::Logger
+
+    attr_internal :view_runtime
+
+    def process_action(*args)
+      raw_payload = {
+        controller: self.class.name,
+        action: action_name,
+        params: request.filtered_parameters,
+        headers: request.headers,
+        format: request.format.ref,
+        method: request.request_method,
+        path: request.fullpath
+      }
+
+      ActiveSupport::Notifications.instrument("start_processing.action_controller", raw_payload.dup)
+
+      ActiveSupport::Notifications.instrument("process_action.action_controller", raw_payload) do |payload|
+        super.tap do
+          payload[:status] = response.status
+        end
+      ensure
+        append_info_to_payload(payload)
+      end
+    end
+
+    def render(*args)
+      render_output = nil
+      self.view_runtime = cleanup_view_runtime do
+        Benchmark.ms { render_output = super }
+      end
+      render_output
+    end
+
+    def send_file(path, options = {})
+      ActiveSupport::Notifications.instrument("send_file.action_controller",
+        options.merge(path: path)) do
+        super
+      end
+    end
+
+    def send_data(data, options = {})
+      ActiveSupport::Notifications.instrument("send_data.action_controller", options) do
+        super
+      end
+    end
+
+    def redirect_to(*args)
+      ActiveSupport::Notifications.instrument("redirect_to.action_controller") do |payload|
+        result = super
+        payload[:status]   = response.status
+        payload[:location] = response.filtered_location
+        result
+      end
+    end
+
+  private
+
+    # A hook invoked every time a before callback is halted.
+    def halted_callback_hook(filter)
+      ActiveSupport::Notifications.instrument("halted_callback.action_controller", filter: filter)
+    end
+
+    # A hook which allows you to clean up any time, wrongly taken into account in
+    # views, like database querying time.
+    #
+    #   def cleanup_view_runtime
+    #     super - time_taken_in_something_expensive
+    #   end
+    def cleanup_view_runtime # :doc:
+      yield
+    end
+
+    # Every time after an action is processed, this method is invoked
+    # with the payload, so you can add more information.
+    def append_info_to_payload(payload) # :doc:
+      payload[:view_runtime] = view_runtime
+    end
+
+    module ClassMethods
+      # A hook which allows other frameworks to log what happened during
+      # controller process action. This method should return an array
+      # with the messages to be added.
+      def log_process_action(payload) #:nodoc:
+        messages, view_runtime = [], payload[:view_runtime]
+        messages << ("Views: %.1fms" % view_runtime.to_f) if view_runtime
+        messages
+      end
+    end
+  end
+end