Hi, I'm running into an error with flow.deploy(), and trying to figure out how to troubleshoot. Any ideas? On one development machine, we get the expected result:

\prefect\core\flow.py:1331: UserWarning: flow.deploy() will be deprecated in an upcoming release. Please use flow.register()
  UserWarning,
[2020-03-23 22:36:15,573] INFO - prefect.Docker | Building the flow's Docker storage...

On a second development machine, we get an error with not much context:

/prefect/core/flow.py:1331: UserWarning: flow.deploy() will be deprecated in an upcoming release. Please use flow.register()
  UserWarning,
Expecting value: line 1 column 1 (char 0)

🧐 is there really no more traceback on the second machine?

yeah, no traceback

and the command returns after you see this printed? This will be a tough one to debug without being able to identify the line / command it originates from

Yes. Is there a flag or anything we can set to generate more verbose output?

Because no error is raised, this issue is bubbling up from somewhere deeper than prefect I think, most likely with docker. Are you hardcoding a value of

base_url

in your docker storage?

We are passing local_image. If I understand right that is in place of

base_url

none that come to mind — @josh have you ever seen this particular error before?

Really weird, I have not seen this before. There is the Prefect config option for debug logging but I’m not sure what else it would show you:

[logging]
level = "DEBUG"

or

export PREFECT__LOGGING__LEVEL="DEBUG"

The user does not have an account in Prefect Cloud yet -- that is my working hypothesis

Randomly bumped into the same issue:

simplejson.errors.JSONDecodeError: Expecting value: line 1 column 1 (char 0)

. The error is indeed because I tried to

flow.register(build=True)

without running

prefect auth login

in CLI (or logging in inside the python script itself) beforehand. Maybe a better error would help others in future.