AssertionError while using transactions.in_transaction

[DaniilChizhevskii]

Describe the bug
I use Tortoise ORM with FastAPI contrib and MySQL database. There are some places in my code where I use toirtoise.transactions.in_transaction and it causes this error sometimes:

AssertionError: (<aiomysql.connection.Connection object at 0x7ec4f3382120>, {<aiomysql.connection.Connection object at 0x7ec4f3d648f0>, <aiomysql.connection.Connection object at 0x7ec4f3d20530>, <aiomysql.connection.Connection object at 0x7ec4f3367b30>, <aiomysql.connection.Connection object at 0x7ec4f3364770>, <aiomysql.connection.Connection object at 0x7ec4f3d22ba0>})

I use multiple gunicorn workers and all of them having this issue simultaneously. Issue repeats several times an hour.

To Reproduce
Create FastAPI application with registered Tortoise:

from fastapi import FastAPI
from tortoise.contrib.fastapi import register_tortoise
app = FastAPI(title=...)
register_tortoise(app, config=..., generate_schemas=False, add_exception_handlers=False)

Add transaction somewhere in your routes:

async with transactions.in_transaction():
    ...

And MySQL connection:
mysql://root:password@localhost:3306/db

Expected behavior
App works normally, no exceptions got

[henadzit]

Hi @DaniilChizhevskii, could you please tell how do you know that the error happens in in_transaction? Can you provide a stacktrace?

[DaniilChizhevskii]

Hi @henadzit
I thought this error was related to asyncmy not being installed, but even with it, the error continues to occur.

File "/workspace/backend/app/miniapp/main.py", line 93, in auth_miniapp
[2024-11-14 13:22:50]     user = await get_or_create_user(json.loads(auth_data['user'][0]), auth_data.get('start_param', [None])[0])
[2024-11-14 13:22:50]            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[2024-11-14 13:22:50]   File "/workspace/backend/app/miniapp/main.py", line 63, in get_or_create_user
[2024-11-14 13:22:50]     async with transactions.in_transaction():
[2024-11-14 13:22:50]   File "/workspace/backend/.heroku/python/lib/python3.12/site-packages/tortoise/backends/base/client.py", line 298, in __aexit__
[2024-11-14 13:22:50]     await self.connection._parent._pool.release(self.connection._connection)
[2024-11-14 13:22:50]           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[2024-11-14 13:22:50]   File "asyncmy/pool.pyx", line 180, in asyncmy.pool.Pool.release
[2024-11-14 13:22:50]     self._used.remove(conn)
[2024-11-14 13:22:50] KeyError: <asyncmy.connection.Connection object at 0x7ea05210d8b0>

[henadzit]

I tried to reproduce the issue by severing the connection between a sample app and MySQL but no luck. Please let me know if you have more context.