Hello all, I have been successful in getting prefect to build and run a flow on a docker container. However, I am getting an error of

Unexpected error: ValueError('Could not infer an active Flow context.')

and I am struggling to find relevant information on how best to debug this. I thank you all in advance for helping!

This happens when you're trying to execute a task, but the task hasn't been assigned to a flow, so Prefect doesn't know how to run the task in relation to other tasks. The most relevant documentation is probably https://docs.prefect.io/core/concepts/flows.html#apis but in short, if you're using the functional API, you should specify your task within a

with Flow() as flow:

context, e.g.

with Flow("example") as flow:
    result = my_task()
flow.run()

With the imperative API you have to specifically add the task to a flow, something like this:

flow = Flow("example")
results = my_task()
flow.set_dependencies(results) 
flow.run()

@Greg Roche so for reference my flow code shows

with Flow("example",
            storage = Docker(dockerfile="/home/mblau/projects/integration/Dockerfile", ignore_healthchecks= True
)) as flow:
    main()
flow.run_config = DockerRun(image = "integration_mosaic_integration:latest")
flow.register(project_name="test")

does

main()

have a

@task()

decorator?

yes

Then at this point I would start looking into what's going on in

main()

, there's probably some logic in there which is leading to a task which hasn't been added to a flow. For example if

main()

is itself trying to call a function which has been decorated with

@task()

(I think this is considered an anti-pattern and instead the called task should be added explicitly to the flow).

@Greg Roche awesome, that was the issue. I am fairly new to prefect and am still learning all the concepts but that works! I have other issues to resolve but that's more with the code of the file than prefect at this point, I think

Glad I could help 🙂