Fastapi: Status 502: [WARNING] Invalid HTTP request received.

[gautamsinghania95]

I was trying to build a typeahead search API. This API gets called in quick succession, and I am getting an intermittent 502 response.

To Reproduce
Not sure how to reproduce this, as normal API calls, when spaced out, are working fine.

Expected behavior - Logs

2019-11-05T06:17:55.447961016Z [2019-11-05 06:17:55 +0000] [16] [INFO] ('100.96.0.56', 50964) - "POST <<URL_NAME>> HTTP/1.1" 200

Noted Intermittent Behaviour - Logs

2019-11-05T06:17:56.459601437Z [2019-11-05 06:17:56 +0000] [16] [WARNING] Invalid HTTP request received.

Environment:

• OS: Debian GNU/Linux 10 (buster)
• FastAPI Version : 0.38.1
• Python version: 3.6
• Server: Gunicorn with 2 Uvicorn workers (see config file below)

bind = "0.0.0.0:4000"
workers = 2
worker_class = "uvicorn.workers.UvicornWorker"
timeout = 300

Additional context

• Added timeout in config after searching on the internet, did not work

[euri10]

Not sure how to help without a minimum example, maybe you can try to hit
your endpoint with ab or wrk and get reproducibility?

Le mar. 5 nov. 2019 à 7:25 AM, gautamsinghania95 [e-mail]
a écrit :

I was trying to build a typeahead search API. This API gets called in
quick succession, and I am getting an intermittent 502 response.

To Reproduce
Not sure how to reproduce this, as normal API calls, when spaced out, are
working fine.

Expected behavior - Logs

2019-11-05T06:17:55.447961016Z [2019-11-05 06:17:55 +0000] [16] [INFO] ('100.96.0.56', 50964) - "POST <> HTTP/1.1" 200

Noted Intermittent Behaviour - Logs

2019-11-05T06:17:56.459601437Z [2019-11-05 06:17:56 +0000] [16] [WARNING] Invalid HTTP request received.

Environment:

• OS: Debian GNU/Linux 10 (buster)
• FastAPI Version : 0.38.1
• Python version: 3.6
• Server: Gunicorn with 2 Uvicorn workers (see config file below)

bind = "0.0.0.0:4000"
workers = 2
worker_class = "uvicorn.workers.UvicornWorker"
timeout = 300

Additional context

• Added timeout in config after searching on the internet, did not work

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[gautamsinghania95]

Hi!!

This is an issue with the deployed version of the app. I have tried to reproduce the problem in my local environment, but to no effect.

Please see if you can help in some other fashion.

Thanks!
Gautam

[gautamsinghania95]

Hi,

Closing the issue as it was resolved from my end.

Resolution: The deployment platform only accepted HTTP 1.1 calls, but the uvicorn worker class I was using uvicorn.workers.UvicornWorker was sending both types of request. Replacing it with uvicorn.workers.UvicornH11Worker resolved it.

Thanks.

[euri10]

glad you solved it, for reference which plateform is it and by both types of request you mean 1.0 and 1.1 calls ?

[tiangolo]

Thanks for the help here @euri10 ! :clap: :bow:

Thanks for reporting back and closing the issue @gautamsinghania95 :+1:

[sacharbit]

@gautamsinghania95 sorry but can you give more information on how to do that? I have the same issue as you and can't seem to find how to change uvicorn.workers.UvicornWorker

Thanks in advance

edit: nevermind, I found it
it's the http parameter that you put as "h11"

[Saftophobia]

According to https://github.com/tiangolo/uvicorn-gunicorn-docker/pull/38, you can set it as an environment variable now WORKER_CLASS="uvicorn.workers.UvicornH11Worker"