Refactor: DistributedJobManager with pub/sub status change notifications (#25)

* Add pubsub to render_queue and base_worker

* Refactor: Convert ZeroconfServer to Singleton with Class Methods

* New API for subjob servers to notify parent job servers of status changes

* Refactor: Move all subjob related methods to distributed_job_manager.py

* Rewrite for wait_for_subjobs

* Fix: DistributedJobManager.find_available_servers() takes 1 positional argument but 3 were given

* DistributedJobManager should now notify / be notified abotu background job changes

* Fix the make_ready api. Change children keyname to be id@hostname so it can be unique

* Fixes

* Image sequence to movie needs to find the actual start frame

* Fix: subjob_status_change did not return a valid response

* Fix client renderer selection

* Small fix for subjob status checking

* Fix issue with divide_frames_equally

* Fix issue where downloads were not occurring

* Fix issue where old status was being reported

* Add docstrings and code cleanup

lib/render_queue.py

@@ -4,8 +4,8 @@ from datetime import datetime
 from sqlalchemy import create_engine
 from sqlalchemy.orm import sessionmaker
 
-from .workers.base_worker import RenderStatus, BaseRenderWorker, Base
-from .workers.worker_factory import RenderWorkerFactory
+from lib.workers.base_worker import RenderStatus, BaseRenderWorker, Base
+from lib.workers.worker_factory import RenderWorkerFactory
 
 logger = logging.getLogger()
 
@@ -28,6 +28,14 @@ class RenderQueue:
     def __init__(self):
         pass
 
+    @classmethod
+    def start_queue(cls):
+        cls.load_state()
+
+    @classmethod
+    def job_status_change(cls, job_id, status):
+        logger.debug(f"Job status changed: {job_id} -> {status}")
+
     @classmethod
     def add_to_render_queue(cls, render_job, force_start=False):
         logger.debug('Adding priority {} job to render queue: {}'.format(render_job.priority, render_job))