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Difficulty in understanding Uvicorn logs

See original GitHub issue

I am facing an issue in Uvicorn where a background process is crashing the whole application intermittently. I want to understand the logs thrown by Uvicorn, as I am not able to reproduce this issue reliably.

Logs:

Traceback (most recent call last):
  File "/usr/local/lib/python3.8/site-packages/uvicorn/server.py", line 184, in main_loop
    should_exit = await self.on_tick(counter)
StopIteration

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "runner.py", line 8, in <module>
    uvicorn.run(
  File "/usr/local/lib/python3.8/site-packages/uvicorn/main.py", line 386, in run
    server.run()
  File "/usr/local/lib/python3.8/site-packages/uvicorn/server.py", line 48, in run
    loop.run_until_complete(self.serve(sockets=sockets))
  File "/usr/local/lib/python3.8/asyncio/base_events.py", line 616, in run_until_complete
    return future.result()
  File "/usr/local/lib/python3.8/site-packages/uvicorn/server.py", line 68, in serve
    await self.main_loop()
RuntimeError: coroutine raised StopIteration

Environment

OS / Python / Uvicorn version: just run uvicorn --version: Running uvicorn 0.13.3 with CPython 3.8.5 on Linux
The exact command you’re running uvicorn with, all flags you passed included: Programatically running Uvicorn,

    uvicorn.run(
        app,
        host="0.0.0.0",
        port=4000,
        http="h11",
        # Maintaining logging at application instead of uvicorn
        access_log=False,
        log_config=None
    )

Additional context

Application is using FastAPI, see http://fastapi.tiangolo.com/
Started noticing this when I upgraded Couchbase SDK 3.0.8
Have seen this site while debugging this issue: https://www.gitmemory.com/issue/coleifer/python-lsm-db/20/758081515
My application starts a background scheduler before starting the Uvicorn application. See https://apscheduler.readthedocs.io/en/stable/

Issue Analytics

State:
Created 3 years ago
Comments:5 (2 by maintainers)

Top GitHub Comments

1reaction

gautamsinghania95commented, Feb 15, 2021

I am facing this issue in an enterprise code, and as I said before I was not able to reproduce this issue in an example. I was more looking into some insights of the logs, so I could understand the error better. See if you can help me out in this, like for example what is happening in the logs.

0reactions

gautamsinghania95commented, Feb 16, 2021

ok, let me see if i can provide more details or make this issue reproducible. closing this ticket for now.

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