Add lifecycle hooks to Dispatcher and Scheduler

I'm switching over to Rails Semantic Logger and for that to work
with forking code it requires a post fork action.

With this change, all 4 process types have start and stop hooks and it becomes
possible to do on_*_start { post_fork_action } and on_*_stop { pre_stop_action }

lib/solid_queue.rb

@@ -51,6 +51,22 @@ def on_worker_stop(...)
     Worker.on_stop(...)
   end
 
+  def on_dispatcher_start(...)
+    Dispatcher.on_start(...)
+  end
+
+  def on_dispatcher_stop(...)
+    Dispatcher.on_stop(...)
+  end
+
+  def on_scheduler_start(...)
+    Scheduler.on_start(...)
+  end
+
+  def on_scheduler_stop(...)
+    Scheduler.on_stop(...)
+  end
+
   def supervisor?
     supervisor
   end

lib/solid_queue/dispatcher.rb

@@ -2,10 +2,13 @@
 
 module SolidQueue
   class Dispatcher < Processes::Poller
+    include LifecycleHooks
     attr_accessor :batch_size, :concurrency_maintenance
 
+    after_boot :run_start_hooks
     after_boot :start_concurrency_maintenance
     before_shutdown :stop_concurrency_maintenance
+    after_shutdown :run_stop_hooks
 
     def initialize(**options)
       options = options.dup.with_defaults(SolidQueue::Configuration::DISPATCHER_DEFAULTS)

lib/solid_queue/scheduler.rb

@@ -3,11 +3,14 @@
 module SolidQueue
   class Scheduler < Processes::Base
     include Processes::Runnable
+    include LifecycleHooks
 
     attr_accessor :recurring_schedule
 
+    after_boot :run_start_hooks
     after_boot :schedule_recurring_tasks
     before_shutdown :unschedule_recurring_tasks
+    before_shutdown :run_stop_hooks
 
     def initialize(recurring_tasks:, **options)
       @recurring_schedule = RecurringSchedule.new(recurring_tasks)

test/integration/lifecycle_hooks_test.rb

@@ -12,22 +12,30 @@ class LifecycleHooksTest < ActiveSupport::TestCase
     SolidQueue.on_worker_start { JobResult.create!(status: :hook_called, value: :worker_start) }
     SolidQueue.on_worker_stop { JobResult.create!(status: :hook_called, value: :worker_stop) }
 
-    pid = run_supervisor_as_fork(workers: [ { queues: "*" } ])
+    SolidQueue.on_dispatcher_start { JobResult.create!(status: :hook_called, value: :dispatcher_start) }
+    SolidQueue.on_dispatcher_stop { JobResult.create!(status: :hook_called, value: :dispatcher_stop) }
+
+    SolidQueue.on_scheduler_start { JobResult.create!(status: :hook_called, value: :scheduler_start) }
+    SolidQueue.on_scheduler_stop { JobResult.create!(status: :hook_called, value: :scheduler_stop) }
+
+    pid = run_supervisor_as_fork(workers: [ { queues: "*" } ], dispatchers: [ { batch_size: 100 } ], skip_recurring: false)
     wait_for_registered_processes(4)
 
     terminate_process(pid)
     wait_for_registered_processes(0)
 
     results = skip_active_record_query_cache do
-      assert_equal 4, JobResult.count
-      JobResult.last(4)
+      assert_equal 8, JobResult.count
+      JobResult.last(8)
     end
 
-    assert_equal "hook_called", results.map(&:status).first
-    assert_equal [ "start", "stop", "worker_start", "worker_stop" ], results.map(&:value).sort
+    assert_equal({ "hook_called" => 8 }, results.map(&:status).tally)
+    assert_equal %w[start stop worker_start worker_stop dispatcher_start dispatcher_stop scheduler_start scheduler_stop].sort, results.map(&:value).sort
   ensure
     SolidQueue::Supervisor.clear_hooks
     SolidQueue::Worker.clear_hooks
+    SolidQueue::Dispatcher.clear_hooks
+    SolidQueue::Scheduler.clear_hooks
   end
 
   test "handle errors on lifecycle hooks" do
@@ -48,5 +56,7 @@ class LifecycleHooksTest < ActiveSupport::TestCase
     SolidQueue.on_thread_error = previous_on_thread_error
     SolidQueue::Supervisor.clear_hooks
     SolidQueue::Worker.clear_hooks
+    SolidQueue::Dispatcher.clear_hooks
+    SolidQueue::Scheduler.clear_hooks
   end
 end