make sure we have a current processor so we don't return null (#379)

* make sure we have a current processor so we don't return null

* remove sleep

* The background processor now only picks up processes that were last updated more than a minute ago to avoid conflicting with the interstitial page.  With the understanding that we can rmeove this limitation when we can refactor to allow the backend processes to provide updates on what they are doing.

* pyl w/ burnettk

---------

Co-authored-by: jasquat <jasquat@users.noreply.github.com>

spiffworkflow-backend/src/spiffworkflow_backend/routes/tasks_controller.py

@@ -441,14 +441,12 @@ def _interstitial_stream(
             # our session has stale results without the rollback.
             db.session.rollback()
             db.session.refresh(process_instance)
+            processor = ProcessInstanceProcessor(process_instance)
 
             # if process instance is done or blocked by a human task, then break out
             if is_locked and process_instance.status not in ["not_started", "waiting"]:
                 break
 
-            # only get a new processor if we are not executing tasks otherwise we are the ones updating it
-            processor = ProcessInstanceProcessor(process_instance)
-
         tasks = get_reportable_tasks()
 
     spiff_task = processor.next_task()

spiffworkflow-backend/src/spiffworkflow_backend/services/process_instance_queue_service.py

@@ -115,11 +115,14 @@ class ProcessInstanceQueueService:
         status_value: str,
         locked_by: str | None,
         run_at_in_seconds_threshold: int,
+        min_age_in_seconds: int = 0,
     ) -> list[ProcessInstanceQueueModel]:
         return (
             db.session.query(ProcessInstanceQueueModel)
             .filter(
                 ProcessInstanceQueueModel.status == status_value,
+                ProcessInstanceQueueModel.updated_at_in_seconds <= round(time.time()) - min_age_in_seconds,
+                # At least a minute old.
                 ProcessInstanceQueueModel.locked_by == locked_by,
                 ProcessInstanceQueueModel.run_at_in_seconds <= run_at_in_seconds_threshold,
             )
@@ -131,8 +134,9 @@ class ProcessInstanceQueueService:
         cls,
         status_value: str,
         run_at_in_seconds_threshold: int,
+        min_age_in_seconds: int = 0,
     ) -> list[int]:
-        queue_entries = cls.entries_with_status(status_value, None, run_at_in_seconds_threshold)
+        queue_entries = cls.entries_with_status(status_value, None, run_at_in_seconds_threshold, min_age_in_seconds)
         ids_with_status = [entry.process_instance_id for entry in queue_entries]
         return ids_with_status
 

spiffworkflow-backend/src/spiffworkflow_backend/services/process_instance_service.py

@@ -187,8 +187,9 @@ class ProcessInstanceService:
     @classmethod
     def do_waiting(cls, status_value: str) -> None:
         run_at_in_seconds_threshold = round(time.time())
+        min_age_in_seconds = 60  # to avoid conflicts with the interstitial page, we wait 60 seconds before processing
         process_instance_ids_to_check = ProcessInstanceQueueService.peek_many(
-            status_value, run_at_in_seconds_threshold
+            status_value, run_at_in_seconds_threshold, min_age_in_seconds
         )
         if len(process_instance_ids_to_check) == 0:
             return