Hi, I am trying to make a flow run on my API but I get the following error from the UI :

Failed to load and execute Flow's environment: ModuleNotFoundError("No module named '/root/'")

I don't understand the problem as I don't have any relative import in my code and the latter is pretty simple : https://github.com/flavienbwk/prefect-docker-compose/blob/main/scripts/weather.py

This is a new one for me; this is most likely related to your agent configuration

Is this what you need ? (

/root/.prefect/flows

) ?

Yea; interesting that no

path

is displayed; so my rough takeaway is that your agent is looking for your Flow in a path that is

/root/.prefect/flows

but unable to access that, but I can’t 100% explain it. If you exec into your agent’s docker container, can you confirm that the flow exists at the right location?

So I've exec into my agent's docker container : the

/root/.prefect/flows

directory didn't even exist. I created it, re-run the flow and am still having the same error. Nothing is present in the

/root/.prefect/flows

directory.

your setup is not one I’ve personally seen before, so it’s hard to say. Let me explain what’s happening and maybe it will help you self-debug: - the agent queries the API and finds a flow run ID that needs to be run - the agent then submits the CLI command

prefect execute flow-run

to run in a subprocess - this code is then run, which is where your error arises from: https://github.com/PrefectHQ/prefect/blob/master/src/prefect/cli/execute.py#L74-L93 Here’s how you might drill down into what step is failing: - change the labels on your Flow in the UI (so your agent won’t pick anything up), and create a new flow run - within your agent’s docker container, run each of the python commands in that file I linked to, starting with this line: https://github.com/PrefectHQ/prefect/blob/master/src/prefect/cli/execute.py#L56 My guess is that you’ll see this error arise either at this line:

flow = storage.get_flow(storage.flows[flow_data.name])

Wow OK I see the idea. So the code is not "saved to the API and then redistributed to the agents". The API just shares a kind of ID that is expected to match a directory present in the agent's

/root/.prefect/flows

. Is it correct ?

Yea exactly! It is a very unique design and can be initially confusing, but it’s designed that way for a very explicit reason (check out this post for more info: https://medium.com/the-prefect-blog/the-prefect-hybrid-model-1b70c7fd296)

OK I see !

E*xecution in your cloud; orchestration in ours*

Yeah it's not very easy to understand and maybe the documentation should include a step by step guide to understand how Prefect's storage system work. But I'm convinced it's a bright idea, so I will deep dive into the documentation and try to understand more about Prefect storage system.