I am getting a health check error when registering a flow with Docker storage:

Beginning health checks...
System Version check: OK
Traceback (most recent call last):
  File "/opt/prefect/healthcheck.py", line 151, in <module>
    flows = cloudpickle_deserialization_check(flow_file_paths)
  File "/opt/prefect/healthcheck.py", line 44, in cloudpickle_deserialization_check
    flows.append(cloudpickle.loads(flow_bytes))
ModuleNotFoundError: No module named 'flows.tasks'

Registering the same flow locally is passing my check.

from prefect.utilities.debug import is_serializable

if is_serializable(flow): ...

My PYTHONPATH is the root of the directory and when SSH'ing into the container I am able to import the "missing" module... Any pointers?

Can you try adding a

if __name__ == "__main__":

block around your flow register/storage building? Sometimes cloud pickle can be finicky about that.

Thanks @Zanie, I will give that a go. I reverted some steps and the pickle problem was coming from me creating a task, like so:

@task
def some_function():
  return ...

And importing a helper function (which wasn't prefaced with

@task

). Moving my helpers inside this @task ovecame the pickle problem. But ideally, I would be able to share helper functions across tasks without having to make them their own respective task?

If you're unable to use helper functions then generally your module isn't being added to your image correctly. I'd recommend using

pip install

rather than extending your

PYTHONPATH

it's generally more reliable.