Ephemeral server timeout showing up after update; debugger problem

Help
1

I use PyCharm IDE to develop. After update prefect Python to 3.0.3, new type of error occurs.

Take this simple flow:

from prefect import flow, task

@task(name='dummy task')
def dummy_task():
    return 'dummy task'

@flow
def dummy_flow():
    dummy_task()

if __name__ == '__main__':
    dummy_flow()

It works when I run it within the IDE. But when I run it with the debugger, I get the following exception:

/Users/andersohrn/PycharmProjects/pythondummyprefect/.venv/bin/python -X pycache_prefix=/Users/andersohrn/Library/Caches/JetBrains/PyCharm2024.2/cpython-cache /Applications/PyCharm.app/Contents/plugins/python-ce/helpers/pydev/pydevd.py --multiprocess --qt-support=auto --client 127.0.0.1 --port 58461 --file /Users/andersohrn/PycharmProjects/pythondummyprefect/test_prefect.py 
Connected to pydev debugger (build 242.22855.92)
21:34:10.982 | INFO    | prefect - Starting server on http://127.0.0.1:8064
Traceback (most recent call last):
  File "/usr/local/Cellar/python@3.11/3.11.9_1/Frameworks/Python.framework/Versions/3.11/lib/python3.11/contextlib.py", line 137, in __enter__
    return next(self.gen)
           ^^^^^^^^^^^^^^
  File "/Users/andersohrn/PycharmProjects/pythondummyprefect/.venv/lib/python3.11/site-packages/prefect/flow_engine.py", line 632, in start
    with self.initialize_run():
  File "/usr/local/Cellar/python@3.11/3.11.9_1/Frameworks/Python.framework/Versions/3.11/lib/python3.11/contextlib.py", line 137, in __enter__
    return next(self.gen)
           ^^^^^^^^^^^^^^
  File "/Users/andersohrn/PycharmProjects/pythondummyprefect/.venv/lib/python3.11/site-packages/prefect/flow_engine.py", line 551, in initialize_run
    with SyncClientContext.get_or_create() as client_ctx:
  File "/usr/local/Cellar/python@3.11/3.11.9_1/Frameworks/Python.framework/Versions/3.11/lib/python3.11/contextlib.py", line 137, in __enter__
    return next(self.gen)
           ^^^^^^^^^^^^^^
  File "/Users/andersohrn/PycharmProjects/pythondummyprefect/.venv/lib/python3.11/site-packages/prefect/context.py", line 230, in get_or_create
    with SyncClientContext() as ctx:
         ^^^^^^^^^^^^^^^^^^^
  File "/Users/andersohrn/PycharmProjects/pythondummyprefect/.venv/lib/python3.11/site-packages/prefect/context.py", line 203, in __init__
    client=get_client(sync_client=True, httpx_settings=httpx_settings),
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/andersohrn/PycharmProjects/pythondummyprefect/.venv/lib/python3.11/site-packages/prefect/client/orchestration.py", line 219, in get_client
    server.start()
  File "/Users/andersohrn/PycharmProjects/pythondummyprefect/.venv/lib/python3.11/site-packages/prefect/server/api/server.py", line 818, in start
    raise RuntimeError(error_message)
RuntimeError: Timed out while attempting to connect to ephemeral Prefect API server.

I included the debugger command at the top as well.

I’ve read issue 14878 and understand some default changes have been made that has made an ephemeral server appear. I have not mananged to fix my issue, though.

I am doing local development and like to keep the server as basic as possible, and I want to be able to do debugging in the IDE (usually to ensure the commands within tasks are working ok).

Is there a simple way to accomplish this at 3.0.3? Some environment variable maybe to set differently than current defaults to get back the behaviour prior to update?

1 Like
2

Is it possible the PREFECT_API_URL env var isn’t set? PREFECT_API_KEY might be good to check as well. I’ve seen this error message when my key had expired, I think.

3

Thank for reply.

I am doing local development, so I am not interacting with the Prefect APIs. I tested some things with the PREFECT_API_URL, but it doesn’t seem to be it.

What is strange is that this is some kind of interaction effect with the debugger. Running the workflow without the debugger and all is well.

1 Like