Sanic hangs for around 20 seconds after every 3 minutes

[Shamsul Haque]

Link to code

No response

Proposal

I am using Sanic version 21.12.1 on Ubuntu 20.04.5 and below is my code to start the sanic server:

def init():
    sanic_app.run(host=HOST, port=PORT, debug=DEBUG, workers=2, access_log=False)

The issue I am facing is, after every 3 minutes, server hangs for 20 seconds and then after 20 seconds starts responding. So I started sanic with Debug True, and what I found is, before printing below line, server hangs for 20 secs, and after below line appears in log, sanic resumes responding:
Executing <Task pending name='Task-36' coro=<SignalRouter._dispatch() running at /home/ubuntu/.local/lib/python3.8/site-packages/sanic/signals.py:161> wait_for=<Future pending cb=[<TaskWakeupMethWrapper object at 0x7f5d2c2e0d60>()] created at /usr/lib/python3.8/asyncio/tasks.py:654> created at /home/ubuntu/.local/lib/python3.8/site-packages/sanic/signals.py:193> took 20.112 seconds
This is happening after every around 3 mins.
Can anybody please guide me what is this and how to solve/handle it?
Thanks

Additional context

No response

Is this a breaking change?

• Yes

[Stephen Sadowski]

Please provide a link to your code so that we can review.

[Shamsul Haque]

The code is in private repository, sorry can't share the link of the same. Or if you can share what specific part of code/configuration you want to see, will try to share that separately.
But I believe some background task is causing this.
And I am not being able to find out that task by Task-id Task-36.
So, if you can help me to locate same.
Thanks

[Stephen Sadowski]

Or if you can share what specific part of code/configuration you want to see, will try to share that separately.

Since we don't know your code, we can't really tell you what we'd want to see. What I can tell you is that whatever that code is likely has some blocking calls in it due to the fact that it's taking so long (~ 20 seconds) but as a background task, it should not be impacting the rest of your application.

I am guessing this is something you took over, not wrote yourself?

[Andriy Ivaneyko]

The code is in private repository, sorry can't share the link of the same. Or if you can share what specific part of code/configuration you want to see, will try to share that separately. But I believe some background task is causing this. And I am not being able to find out that task by Task-id Task-36. So, if you can help me to locate same. Thanks

@sham-hq Would be happy to help you, though if I've got it right you cannot share code "as is". I am seconding @sjsadowski comment on the blocking call which takes too long. Have you tried to play with number of workers ?
If you can get back with reproducible example we can figure things out.
Checkout this guide from StackOverflow for details on how to do so.