Start async adapters after_initialize instead of once Active Job an…

…d Active Record are loaded and Rails initialized? (#1297)

lib/good_job.rb

@@ -25,7 +25,6 @@
 require_relative "good_job/cron_manager"
 require_relative "good_job/current_thread"
 require_relative "good_job/daemon"
-require_relative "good_job/dependencies"
 require_relative "good_job/job_performer"
 require_relative "good_job/job_performer/metrics"
 require_relative "good_job/log_subscriber"
@@ -46,7 +45,6 @@
 #
 # +GoodJob+ is the top-level namespace and exposes configuration attributes.
 module GoodJob
-  include GoodJob::Dependencies
   include GoodJob::ThreadStatus
 
   # Default, null, blank value placeholder.
@@ -114,6 +112,11 @@ module GoodJob
   #   @return [GoodJob::Capsule, nil]
   mattr_accessor :capsule, default: GoodJob::Capsule.new(configuration: configuration)
 
+  mattr_accessor :_async_ready, default: false
+  def self._async_ready?
+    _async_ready
+  end
+
   # Called with exception when a GoodJob thread raises an exception
   # @param exception [Exception] Exception that was raised
   # @return [void]

lib/good_job/adapter.rb

@@ -30,7 +30,7 @@ def initialize(execution_mode: nil, _capsule: GoodJob.capsule) # rubocop:disable
       GoodJob::Configuration.validate_execution_mode(@_execution_mode_override) if @_execution_mode_override
       @capsule = _capsule
 
-      start_async if GoodJob.async_ready?
+      start_async if GoodJob._async_ready?
       self.class.instances << self
     end
 

lib/good_job/engine.rb

@@ -49,22 +49,17 @@ class Engine < ::Rails::Engine
     end
 
     initializer "good_job.start_async" do
-      # This hooks into the hookable places during Rails boot, which is unfortunately not Rails.application.initialized?
-      # If an Adapter is initialized during boot, we want to want to start async executors once the framework dependencies have loaded.
-      # When exactly that happens is out of our control because gems or application code may touch things earlier than expected.
-      # For example, as of Rails 6.1, if an ActiveRecord model is touched during boot, that triggers ActiveRecord to load,
-      # which touches DestroyAssociationAsyncJob, which loads ActiveJob, which may initialize a GoodJob::Adapter, all of which
-      # happens _before_ ActiveRecord finishes loading. GoodJob will deadlock if an async executor is started in the middle of
-      # ActiveRecord loading.
       config.after_initialize do
-        ActiveSupport.on_load(:active_record) do
-          ActiveSupport.on_load(:active_job) do
-            GoodJob._framework_ready = true
-            GoodJob._start_async_adapters
-          end
-          GoodJob._start_async_adapters
-        end
-        GoodJob._start_async_adapters
+        GoodJob._async_ready = true
+
+        # Ensure Active Record and Active Job are fully loaded
+        ActiveRecord::Base # rubocop:disable Lint/Void
+        ActiveJob::Base.queue_adapter
+
+        GoodJob::Adapter.instances
+                        .select(&:execute_async?)
+                        .reject(&:async_started?)
+                        .each(&:start_async)
       end
     end
   end