Hello all:
Within a celery task, I need to have 2 unrelated sessions that can
commit/rollback independently of each other:
One session (`domain_model_session`) performs vanilla domain model
operations and the other (`celery_state_session`) is to persist the state
of the celery task itself **isolated from the domain model one**.
*Imagine "checkpoints"*
Something along these lines
@task
def my task(...):
*# Persist checkpoint 'started'*
cs = celery_state_session.query(CeleryTask).get(self.request.id)
cs.started = datetime.now()
celery_state_session.commit()
try:
with transaction.manager:
mymodel = domain_model_session.query(MyModel).one()
mymodel.value = "..."
*# Persist checkpoint 'value updated' *
cs = celery_state_session.query(CeleryTask).get(self.request.id)
cs.model_value_updated = datetime.now()
except Exception as e:
* # Persist checkpoint 'transaction failed' <<< This
checkpoint is never persisted !!!!*
cs = celery_state_session.query(CeleryTask).get(self.request.id)
cs.failed_with_exception = datetime.now()
finally:
*# Persist checkpoint 'celery task completed anyhow' *
cs = celery_state_session.query(CeleryTask).get(self.request.id)
cs.failed_with_exception = datetime.now()
I've been trying multiple things but I can't get the behavior I need.
No matter what, whenever the transaction associated to
`domain_model_session` fails it "rolls back" all operations performed by
`celery_state_session` as if `celery_state_session` was automatically bound
to the same transaction.manager.
How am I supposed to create a session that works isolated?
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