Feature/run error handler from dequeued (#424)

* run the error handler from the dequeued method instead of marking all failed process instances as error w/ burnettk

* do not commit some_cache_dir w/ burnettk

---------

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

spiffworkflow-backend/.gitignore

@@ -20,3 +20,4 @@ node_modules
 /src/spiffworkflow_backend/config/secrets.py
 *null-ls_*
 /local_wheels/*.whl
+/some_cache_dir

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

@@ -1,11 +1,9 @@
 from flask import current_app
 from flask import g
 from spiffworkflow_backend.models.db import db
-from spiffworkflow_backend.models.message_instance import MessageInstanceModel
 from spiffworkflow_backend.models.process_instance import ProcessInstanceModel
 from spiffworkflow_backend.models.process_instance import ProcessInstanceStatus
 from spiffworkflow_backend.models.process_model import ProcessModelInfo
-from spiffworkflow_backend.services.message_service import MessageService
 from spiffworkflow_backend.services.process_model_service import ProcessModelService
 
 
@@ -57,6 +55,12 @@ class ErrorHandlingService:
         process_instance: ProcessInstanceModel,
     ) -> None:
         """Send a BPMN Message - which may kick off a waiting process."""
+
+        # importing here to avoid circular imports since these imports are only needed here at runtime.
+        # we were not able to figure out which specific import was causing the issue.
+        from spiffworkflow_backend.models.message_instance import MessageInstanceModel
+        from spiffworkflow_backend.services.message_service import MessageService
+
         message_text = (
             f"There was an exception running process {process_model.id}.\nOriginal Error:\n{error.__repr__()}"
         )

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

@@ -4,9 +4,9 @@ from collections.abc import Generator
 
 from spiffworkflow_backend.models.db import db
 from spiffworkflow_backend.models.process_instance import ProcessInstanceModel
-from spiffworkflow_backend.models.process_instance import ProcessInstanceStatus
 from spiffworkflow_backend.models.process_instance_event import ProcessInstanceEventType
 from spiffworkflow_backend.models.process_instance_queue import ProcessInstanceQueueModel
+from spiffworkflow_backend.services.error_handling_service import ErrorHandlingService
 from spiffworkflow_backend.services.process_instance_lock_service import ProcessInstanceLockService
 from spiffworkflow_backend.services.process_instance_tmp_service import ProcessInstanceTmpService
 from spiffworkflow_backend.services.workflow_execution_service import WorkflowExecutionServiceError
@@ -97,15 +97,13 @@ class ProcessInstanceQueueService:
         try:
             yield
         except Exception as ex:
-            process_instance.status = ProcessInstanceStatus.error.value
-            db.session.add(process_instance)
             # these events are handled in the WorkflowExecutionService.
             # that is, we don't need to add error_detail records here, etc.
             if not isinstance(ex, WorkflowExecutionServiceError):
                 ProcessInstanceTmpService.add_event_to_process_instance(
                     process_instance, ProcessInstanceEventType.process_instance_error.value, exception=ex
                 )
-            db.session.commit()
+            ErrorHandlingService.handle_error(process_instance, ex)
             raise ex
         finally:
             if not reentering_lock:

spiffworkflow-backend/tests/spiffworkflow_backend/unit/test_error_handling_service.py

@@ -6,7 +6,6 @@ from spiffworkflow_backend.models.message_instance import MessageInstanceModel
 from spiffworkflow_backend.models.process_instance import ProcessInstanceModel
 from spiffworkflow_backend.models.process_instance import ProcessInstanceStatus
 from spiffworkflow_backend.models.process_model import ProcessModelInfo
-from spiffworkflow_backend.services.error_handling_service import ErrorHandlingService
 from spiffworkflow_backend.services.process_instance_processor import ProcessInstanceProcessor
 from spiffworkflow_backend.services.process_model_service import ProcessModelService
 from spiffworkflow_backend.services.workflow_execution_service import WorkflowExecutionServiceError
@@ -24,9 +23,10 @@ class TestErrorHandlingService(BaseTest):
     def run_process_model_and_handle_error(self, process_model: ProcessModelInfo) -> ProcessInstanceModel:
         process_instance = self.create_process_instance_from_process_model(process_model)
         pip = ProcessInstanceProcessor(process_instance)
-        with pytest.raises(WorkflowExecutionServiceError) as e:
+
+        # the error handler will be called from dequeued within do_engine_steps now
+        with pytest.raises(WorkflowExecutionServiceError):
             pip.do_engine_steps(save=True)
-        ErrorHandlingService().handle_error(process_instance, e.value)
         return process_instance
 
     def test_handle_error_suspends_or_faults_process(