do not try to queue task if the pi cannot be found and delete future tasks if parent task deleted w/ burnettk (#1761)

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

spiffworkflow-backend/migrations/versions/7eaec0e12079_.py

@@ -0,0 +1,32 @@
+"""empty message
+
+Revision ID: 7eaec0e12079
+Revises: 43afc70a7016
+Create Date: 2024-06-18 16:45:06.102210
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = '7eaec0e12079'
+down_revision = '43afc70a7016'
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    with op.batch_alter_table('future_task', schema=None) as batch_op:
+        batch_op.create_foreign_key('future_task_task_guid_fk', 'task', ['guid'], ['guid'], ondelete='CASCADE')
+
+    # ### end Alembic commands ###
+
+
+def downgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    with op.batch_alter_table('future_task', schema=None) as batch_op:
+        batch_op.drop_constraint('future_task_task_guid_fk', type_='foreignkey')
+
+    # ### end Alembic commands ###

spiffworkflow-backend/src/spiffworkflow_backend/background_processing/background_processing_service.py

@@ -80,7 +80,7 @@ class BackgroundProcessingService:
                 .filter(TaskModel.guid == future_task.guid)
                 .first()
             )
-            if process_instance.allowed_to_run():
+            if process_instance and process_instance.allowed_to_run():
                 queue_future_task_if_appropriate(
                     process_instance, eta_in_seconds=future_task.run_at_in_seconds, task_guid=future_task.guid
                 )

spiffworkflow-backend/src/spiffworkflow_backend/models/future_task.py

@@ -2,6 +2,7 @@ import time
 from dataclasses import dataclass
 
 from flask import current_app
+from sqlalchemy import ForeignKey
 from sqlalchemy.dialects.mysql import insert as mysql_insert
 from sqlalchemy.dialects.postgresql import insert as postgres_insert
 from sqlalchemy.dialects.sqlite import insert as sqlite_insert
@@ -9,17 +10,17 @@ from sqlalchemy.sql import false
 
 from spiffworkflow_backend.models.db import SpiffworkflowBaseDBModel
 from spiffworkflow_backend.models.db import db
+from spiffworkflow_backend.models.task import TaskModel  # noqa: F401
 
 
 @dataclass
 class FutureTaskModel(SpiffworkflowBaseDBModel):
     __tablename__ = "future_task"
 
-    guid: str = db.Column(db.String(36), primary_key=True)
+    guid: str = db.Column(ForeignKey(TaskModel.guid, ondelete="CASCADE", name="future_task_task_guid_fk"), primary_key=True)
     run_at_in_seconds: int = db.Column(db.Integer, nullable=False, index=True)
     completed: bool = db.Column(db.Boolean, default=False, nullable=False, index=True)
     archived_for_process_instance_status: bool = db.Column(
-        # db.Boolean, default=False, server_default=db.sql.False_(), nullable=False, index=True
         db.Boolean,
         default=False,
         server_default=false(),