Hi, I’m having trouble understanding how gcc libraries are being linked when Python virtual environments are being used in nixos. I have this in my configuration.nix:
environment.systemPackages = with pkgs; [
(python311.withPackages(ps: with ps; [
ipython
setuptools
sqlalchemy
greenlet
aiosqlite
virtualenv
]))
poetry
pdm
gcc
then any virtualenvironments created with poetry or pdm with the same packages throw this error when sqlalchemy is used with asyncio:
<sqlalchemy.orm.session.AsyncSession object at 0x7f33a43d8410>
Traceback (most recent call last):
File "/home/pythonapp/sqa.py", line 12, in <module>
asyncio.run(get_db())
File "/nix/store/qp5zys77biz7imbk6yy85q5pdv7qk84j-python3-3.11.6/lib/python3.11/asyncio/runners.py", line 190, in run
return runner.run(main)
^^^^^^^^^^^^^^^^
File "/nix/store/qp5zys77biz7imbk6yy85q5pdv7qk84j-python3-3.11.6/lib/python3.11/asyncio/runners.py", line 118, in run
return self._loop.run_until_complete(task)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/nix/store/qp5zys77biz7imbk6yy85q5pdv7qk84j-python3-3.11.6/lib/python3.11/asyncio/base_events.py", line 653, in run_until_complete
return future.result()
^^^^^^^^^^^^^^^
File "/home/pythonapp/sqa.py", line 9, in get_db
async with async_session() as session:
File "/home/pythonapp/__pypackages__/3.11/lib/sqlalchemy/ext/asyncio/session.py", line 1082, in __aexit__
await asyncio.shield(task)
File "/home/pythonapp/__pypackages__/3.11/lib/sqlalchemy/ext/asyncio/session.py", line 1027, in close
await greenlet_spawn(self.sync_session.close)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/pythonapp/__pypackages__/3.11/lib/sqlalchemy/util/concurrency.py", line 64, in greenlet_spawn
_not_implemented()
File "/home/pythonapp/__pypackages__/3.11/lib/sqlalchemy/util/concurrency.py", line 44, in _not_implemented
raise ValueError(
ValueError: the greenlet library is required to use this function. libstdc++.so.6: cannot open shared object file: No such file or directory
I have gcc installed and the c++ file exists in multiple nix stores:
❯ : fd -g libstdc++.so.6 /nix/store/
/nix/store/r7wq6fn906m2fr5jnmhg7774h2cs0440-gcc-12.3.0-lib/lib/libstdc++.so.6
.... more similar locations
To replicate this a simple script can be used:
import asyncio
from sqlalchemy.ext.asyncio import create_async_engine, AsyncSession
from sqlalchemy.orm import sessionmaker, declarative_base
engine = create_async_engine("sqlite+aiosqlite://./test.db", echo=True)
async_session = sessionmaker(engine, expire_on_commit=False, class_=AsyncSession)
async def get_db():
async with async_session() as session:
print(session)
asyncio.run(get_db())
What’s the process to expose my virtualenv to libstdc++.so.6 here?
I’ve tried using poetry2nix through nix flakes but there are other bugs that are getting in the way there (like this one)
Another alternative I’ve seen is to edit LD_LIBRARY_PATH explicitly which doesn’t seem very sustainable.
