Add logging (#55)

Author: beauby

CHANGELOG.md

@@ -1,5 +1,6 @@
 ### Added
 
+* Configurable logger and logsubscriber for instrumented events.
 * Default configuration and hooks for the `meta` parameter.
 * Default configuration and hooks for the `cache` parameter.
 * Default configuration and hooks for the `links` parameter.

lib/generators/jsonapi/initializer/templates/initializer.rb

@@ -68,4 +68,10 @@
   #
   # # Set a default pagination scheme.
   # config.jsonapi_pagination = ->(_) { {} }
+  #
+  # # Set a logger.
+  # config.logger = Logger.new(STDOUT)
+  #
+  # # Uncomment the following to disable logging.
+  # config.logger = Logger.new('/dev/null')
 end

lib/jsonapi/rails/configuration.rb

@@ -39,6 +39,8 @@ module Configurable
 
       DEFAULT_JSONAPI_PAGINATION = ->(_) { {} }
 
+      DEFAULT_LOGGER = Logger.new(STDERR)
+
       DEFAULT_CONFIG = {
         jsonapi_class: DEFAULT_JSONAPI_CLASS,
         jsonapi_errors_class: DEFAULT_JSONAPI_ERRORS_CLASS,
@@ -49,7 +51,8 @@ module Configurable
         jsonapi_links:   DEFAULT_JSONAPI_LINKS,
         jsonapi_meta:    DEFAULT_JSONAPI_META,
         jsonapi_object:  DEFAULT_JSONAPI_OBJECT,
-        jsonapi_pagination: DEFAULT_JSONAPI_PAGINATION
+        jsonapi_pagination: DEFAULT_JSONAPI_PAGINATION,
+        logger: DEFAULT_LOGGER
       }.freeze
 
       def configure

lib/jsonapi/rails/controller.rb

@@ -67,11 +67,18 @@ def deserializable_resource(key, options = {}, &block)
                   Class.new(JSONAPI::Rails::Deserializable::Resource, &block)
 
           before_action(options) do |controller|
-            # TODO(lucas): Fail with helpful error message if _jsonapi not
-            #   present.
-            hash = controller.params[:_jsonapi].to_unsafe_hash
+            hash = controller.params.to_unsafe_hash[:_jsonapi]
+            if hash.nil?
+              JSONAPI::Rails.config[:logger].warn do
+                "Unable to deserialize #{key} because no JSON API payload was" \
+                " found. (#{controller.controller_name}##{params[:action]})"
+              end
+              next
+            end
+
             ActiveSupport::Notifications
-              .instrument('parse.jsonapi', payload: hash, class: klass) do
+              .instrument('parse.jsonapi-rails',
+                          key: key, payload: hash, class: klass) do
               JSONAPI::Parser::Resource.parse!(hash)
               resource = klass.new(hash[:data])
               controller.request.env[JSONAPI_POINTERS_KEY] =

lib/jsonapi/rails/log_subscriber.rb

@@ -0,0 +1,25 @@
+module JSONAPI
+  module Rails
+    # @private
+    class LogSubscriber < ActiveSupport::LogSubscriber
+      def render(event)
+        info do
+          "Completed JSON API rendering (#{event.duration.round(2)}ms)"
+        end
+      end
+
+      def parse(event)
+        info do
+          "Completed JSON API deserializing of #{event.payload[:key]}" \
+          " (#{event.duration.round(2)})"
+        end
+      end
+
+      def logger
+        JSONAPI::Rails.config[:logger]
+      end
+    end
+  end
+end
+
+JSONAPI::Rails::LogSubscriber.attach_to :'jsonapi-rails'

lib/jsonapi/rails/railtie.rb

@@ -2,6 +2,7 @@
 require 'action_controller'
 require 'active_support'
 
+require 'jsonapi/rails/log_subscriber'
 require 'jsonapi/rails/renderer'
 
 module JSONAPI
@@ -52,7 +53,7 @@ def register_renderers
               # Renderer proc is evaluated in the controller context.
               self.content_type ||= Mime[:jsonapi]
 
-              ActiveSupport::Notifications.instrument('render.jsonapi',
+              ActiveSupport::Notifications.instrument('render.jsonapi-rails',
                                                       resources: resources,
                                                       options: options) do
                 renderer.render(resources, options, self).to_json