I have a basic question about the use of

Module

storage in a Docker container. I've been trying to get it working for half a day now and I'm stumped. I'm sure it's a very simple problem but I'm unable to find any working examples as a basis. So I have a flow that is installed (via

pip install

) in a Docker image. The flow is called

flows.docker_2

. It looks like this:

import prefect
from prefect import task, Flow
from prefect.run_configs import DockerRun
from prefect.storage import Module

@task
def say_hello():
    logger = prefect.context.get("logger")
    <http://logger.info|logger.info>("Hello, docker 2!")

with Flow("docker_2_flow") as flow:
    flow.storage = Module("flows.docker_2")
    flow.run_config = DockerRun(
        image="prefect_docker_2_image",
        host_config={
            "auto_remove": False
        }
    )
    say_hello()

if __name__ == "__main__":
    flow.register(project_name="docker_2_project", labels=["docker_flows"])

I am able to register the flow by executing it inside the container:

docker run --network prefect-server --rm --name prefect_docker_2 -it prefect_docker_2:latest python -m flows.docker_2

So I know that the module is installed and can be run inside the container. However, when I run the flow, the module is not found. The docker agent reports:

File "<frozen importlib._bootstrap>", line 983, in _find_and_load
  File "<frozen importlib._bootstrap>", line 965, in _find_and_load_unlocked
ModuleNotFoundError: No module named 'flows'

Is there something else I have to do (other than `pip install`ing the module) to make the flow code visible?

You were on StackOverflow with the

--expose

question right? Nice to see you in the Slack. The attempt here looks good. My guess would be that your image might have multiple Python installations and the wrong one is being used? Maybe you can try

exec

-ing into the container and doing

where python

Yes. That's me.

Oh well done! Glad it’s working 👍