Channels
How can I fail a task? I am try/catching exceptio...
# ask-communitym
merlin
11/01/2022, 9:04 PMHow can I fail a task? I am try/catching exceptions, which works file, but I still want the task to fail. The docs didn't quite show this example:
Copy code
@task
def fail_task():
return Failed()
@flow
def fail_flow_i_hope():
fail_task()
fail_flow_i_hope()
11:42:32.292 | DEBUG | Task run 'always_fail_task-d83fd752-0' - Beginning execution...
11:42:32.302 | INFO | Task run 'always_fail_task-d83fd752-0' - Finished in state Completed()
...
11:42:32.313 | INFO | Flow run 'ludicrous-lemur' - Finished in state Completed('All states completed.')✅ 1
m
Mason Menges
11/01/2022, 9:06 PMIn most cases like this it would make more sense to raise an exception within the task in scenarios where you want it to fail
Copy code
@task
def fail_task():
# you could really raise any exception here
raise ValueError
@flow
def fail_flow_i_hope():
fail_task()
fail_flow_i_hope()m
merlin
11/01/2022, 9:13 PMSo I can only fail a task by raising an exception? Its seems like my try/catch components aren't really needed in that case.
merlin
11/01/2022, 9:15 PMI was using the Prefect 2.0 docs on States
merlin
11/01/2022, 9:19 PMOh, maybe I have it now. The following still raises a prefect exception.
```
@task
def fail_task():
try:
service_call(..etc)
except CustomException:
return Failed()
@flow
def fail_flow_i_hope():
fail_task(return_state=True)
fail_flow_i_hope()
141616.942 | DEBUG | Task run 'fail_task-d8c73196-0' - Beginning execution...
141616.952 | ERROR | Task run 'fail_task-d8c73196-0' - Finished in state Failed()
Traceback (most recent call last):
...etc...
raise await get_state_exception(state)
prefect.exceptions.FailedRun: None
18 Views