Update for review per maurogeorge feedback

Author: bf4

README.md

@@ -381,6 +381,10 @@ All serializable resources must pass the ActiveModel::Serializer::Lint::Tests.
 See the ActiveModelSerializers::Model for a base class that implements the full
 API for a plain-old Ruby object (PORO).
 
+## Hooks
+
+To run a hook when ActiveModelSerializers is loaded, use `ActiveSupport.on_load(:active_model_serializers) do end`
+
 ## Getting Help
 
 If you find a bug, please report an [Issue](https://github.com/rails-api/active_model_serializers/issues/new).

docs/general/instrumentation.md

@@ -1,7 +1,8 @@
 # Instrumentation
 
-ActiveModelSerializers uses the ActiveSupport::Notification API, which
-allows for subscribing to events, such as for logging.
+ActiveModelSerializers uses the
+[ActiveSupport::Notification API](http://guides.rubyonrails.org/active_support_instrumentation.html#subscribing-to-an-event),
+which allows for subscribing to events, such as for logging.
 
 ## Events
 
@@ -17,3 +18,20 @@ Payload (example):
   adapter: ActiveModel::Serializer::Adapter::Attributes
 }
 ```
+
+Subscribing:
+
+```ruby
+ActiveSupport::Notifications.subscribe 'render.active_model_serializers' do |name, started, finished, unique_id, data|
+  # whatever
+end
+ActiveSupport::Notifications.subscribe 'render.active_model_serializers' do |*args|
+  event = ActiveSupport::Notifications::Event.new(*args)
+  # event.payload
+  # whatever
+end
+
+## [LogSubscriber](http://api.rubyonrails.org/classes/ActiveSupport/LogSubscriber.html)
+
+ActiveModelSerializers includes an `ActiveModelSerializers::LogSubscriber` that attaches to
+`render.active_model_serializers`.

lib/action_controller/serialization.rb

@@ -31,6 +31,9 @@ def get_serializer(resource, options = {})
         serializable_resource.serialization_scope ||= serialization_scope
         serializable_resource.serialization_scope_name = _serialization_scope
         begin
+          # Necessary to ensure we have an adapter for the serializable resource
+          # after it has been figured.
+          # TODO: This logic should be less opaque and probably moved into the SerializableResource.
           serializable_resource.tap(&:adapter)
         rescue ActiveModel::Serializer::CollectionSerializer::NoSerializerError
           resource

lib/active_model_serializers.rb

@@ -1,7 +1,5 @@
 require 'active_model'
 require 'active_support'
-require 'active_support/tagged_logging'
-require 'active_support/logger'
 require 'action_controller'
 require 'action_controller/railtie'
 module ActiveModelSerializers

lib/active_model_serializers/logging.rb

@@ -3,108 +3,114 @@
 #
 #   https://github.com/rails/rails/blob/280654ef88/activejob/lib/active_job/logging.rb
 #
-module ActiveModelSerializers::Logging
-  extend ActiveSupport::Concern
+module ActiveModelSerializers
+  module Logging
+    extend ActiveSupport::Concern
 
-  included do
-    include ActiveModelSerializers::Callbacks
-    extend NotificationMacro
-    instrument_rendering
-  end
+    included do
+      include ActiveModelSerializers::Callbacks
+      extend Macros
+      instrument_rendering
+    end
 
-  module ClassMethods
-    def instrument_rendering
-      around_render do |args, block|
-        tag_logger do
-          notify_render do
-            block.call(args)
+    module ClassMethods
+      def instrument_rendering
+        around_render do |args, block|
+          tag_logger do
+            notify_render do
+              block.call(args)
+            end
           end
         end
       end
     end
-  end
 
-  # Adapted from:
-  #   https://github.com/rubygems/rubygems/blob/cb28f5e991/lib/rubygems/deprecate.rb
-  # Provides a single method +notify+ to be used to declare when
-  # something a method notifies, with the argument +callback_name+ of the notification callback.
-  #
-  #     class Adapter
-  #       def self.klass_method
-  #         # ...
-  #       end
-  #
-  #       def instance_method
-  #         # ...
-  #       end
-  #
-  #       include ActiveModelSerializers::Logging
-  #       notify :instance_method, :render
-  #
-  #       class << self
-  #         extend ActiveModelSerializers::Logging::NotificationMacro
-  #         notify :klass_method, :render
-  #       end
-  #     end
-  module NotificationMacro
-    ##
-    # Simple notify method that wraps up +name+
-    # in a dummy method. It notifies on with the +callback_name+ notifier on
-    # each call to the dummy method, telling what the current serializer and adapter
-    # are being rendered.
+    # Macros that can be used to customize the logging of class or instance methods,
+    # by extending the class or its singleton.
+    #
     # Adapted from:
     #   https://github.com/rubygems/rubygems/blob/cb28f5e991/lib/rubygems/deprecate.rb
-    def notify(name, callback_name)
-      class_eval do
-        old = "_notifying_#{callback_name}_#{name}"
-        alias_method old, name
-        define_method name do |*args, &block|
-          run_callbacks callback_name do
-            send old, *args, &block
+    #
+    # Provides a single method +notify+ to be used to declare when
+    # something a method notifies, with the argument +callback_name+ of the notification callback.
+    #
+    #     class Adapter
+    #       def self.klass_method
+    #         # ...
+    #       end
+    #
+    #       def instance_method
+    #         # ...
+    #       end
+    #
+    #       include ActiveModelSerializers::Logging::Macros
+    #       notify :instance_method, :render
+    #
+    #       class << self
+    #         extend ActiveModelSerializers::Logging::Macros
+    #         notify :klass_method, :render
+    #       end
+    #     end
+    module Macros
+      ##
+      # Simple notify method that wraps up +name+
+      # in a dummy method. It notifies on with the +callback_name+ notifier on
+      # each call to the dummy method, telling what the current serializer and adapter
+      # are being rendered.
+      # Adapted from:
+      #   https://github.com/rubygems/rubygems/blob/cb28f5e991/lib/rubygems/deprecate.rb
+      def notify(name, callback_name)
+        class_eval do
+          old = "_notifying_#{callback_name}_#{name}"
+          alias_method old, name
+          define_method name do |*args, &block|
+            run_callbacks callback_name do
+              send old, *args, &block
+            end
           end
         end
       end
     end
-  end
 
-  def notify_render(*)
-    event_name = 'render.active_model_serializers'.freeze
-    ActiveSupport::Notifications.instrument(event_name, notify_render_payload) do
-      yield
+    def notify_render(*)
+      event_name = 'render.active_model_serializers'.freeze
+      ActiveSupport::Notifications.instrument(event_name, notify_render_payload) do
+        yield
+      end
     end
-  end
 
-  def notify_render_payload
-    { serializer: serializer, adapter: adapter }
-  end
+    def notify_render_payload
+      { serializer: serializer, adapter: adapter }
+    end
 
-  private
+    private
 
-  def tag_logger(*tags)
-    if ActiveModelSerializers.logger.respond_to?(:tagged)
-      tags.unshift 'AMS'.freeze unless logger_tagged_by_active_model_serializers?
-      ActiveModelSerializers.logger.tagged(*tags) { yield }
-    else
-      yield
+    def tag_logger(*tags)
+      if ActiveModelSerializers.logger.respond_to?(:tagged)
+        tags.unshift 'AMS'.freeze unless logger_tagged_by_active_model_serializers?
+        ActiveModelSerializers.logger.tagged(*tags) { yield }
+      else
+        yield
+      end
     end
-  end
 
-  def logger_tagged_by_active_model_serializers?
-    ActiveModelSerializers.logger.formatter.current_tags.include?('AMS'.freeze)
-  end
+    def logger_tagged_by_active_model_serializers?
+      ActiveModelSerializers.logger.formatter.current_tags.include?('AMS'.freeze)
+    end
 
-  class LogSubscriber < ActiveSupport::LogSubscriber
-    def render(event)
-      info do
-        serializer = event.payload[:serializer]
-        adapter = event.payload[:adapter]
-        duration = event.duration.round(2)
-        "Rendered #{serializer.name} with #{adapter.class} (#{duration}ms)"
+    class LogSubscriber < ActiveSupport::LogSubscriber
+      def render(event)
+        info do
+          serializer = event.payload[:serializer]
+          adapter = event.payload[:adapter]
+          duration = event.duration.round(2)
+          "Rendered #{serializer.name} with #{adapter.class} (#{duration}ms)"
+        end
       end
-    end
 
-    def logger
-      ActiveModelSerializers.logger
+      def logger
+        ActiveModelSerializers.logger
+      end
     end
   end
 end