pkg_resources deprecation

Describe your environment

Python version: python:3.12-slim
OS: Docker
Package version: latest

What happened?

Hi, today I was building my docker image for python 3.12 slim and while trying to launch the container for gunicorn with uvicorn workers I got this error.

I investigated a bit and it seems setuptools deprecated pkg_resources in its latest versions. I had to force install setuptools<80 to recover this library and everything is working. I am unsure if the issue comes from opentelemetry, because I could not find the dependency anywhere, but I thought raising the issue here could help.

Steps to Reproduce

I launched my fastapi application inside docker with:
gunicorn -w 2 -k uvicorn.workers.UvicornWorker app.main:app --bind 0.0.0.0:8000 --timeout 600 --log-level info

Expected Result

Server should be running

Actual Result

2026-02-11T13:40:05.9640308Z [2026-02-11 13:40:05 +0000] [8] [INFO] Worker exiting (pid: 8)
2026-02-11T13:40:06.0435788Z [2026-02-11 13:40:06 +0000] [9] [ERROR] Exception in worker process
2026-02-11T13:40:06.0436132Z Traceback (most recent call last):
2026-02-11T13:40:06.0436173Z File "/root/.local/lib/python3.12/site-packages/gunicorn/arbiter.py", line 684, in spawn_worker
2026-02-11T13:40:06.0436204Z worker.init_process()
2026-02-11T13:40:06.0436236Z File "/root/.local/lib/python3.12/site-packages/gunicorn/workers/base.py", line 136, in init_process
2026-02-11T13:40:06.0436262Z self.load_wsgi()
2026-02-11T13:40:06.0436295Z File "/root/.local/lib/python3.12/site-packages/gunicorn/workers/base.py", line 148, in load_wsgi
2026-02-11T13:40:06.0436324Z self.wsgi = self.app.wsgi()
2026-02-11T13:40:06.0436352Z ^^^^^^^^^^^^^^^
2026-02-11T13:40:06.0436383Z File "/root/.local/lib/python3.12/site-packages/gunicorn/app/base.py", line 66, in wsgi
2026-02-11T13:40:06.0436481Z self.callable = self.load()
2026-02-11T13:40:06.0436514Z ^^^^^^^^^^^
2026-02-11T13:40:06.0436548Z File "/root/.local/lib/python3.12/site-packages/gunicorn/app/wsgiapp.py", line 57, in load
2026-02-11T13:40:06.0436576Z return self.load_wsgiapp()
2026-02-11T13:40:06.0436603Z ^^^^^^^^^^^^^^^^^^^
2026-02-11T13:40:06.0436633Z File "/root/.local/lib/python3.12/site-packages/gunicorn/app/wsgiapp.py", line 47, in load_wsgiapp
2026-02-11T13:40:06.0436662Z return util.import_app(self.app_uri)
2026-02-11T13:40:06.043669Z ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
2026-02-11T13:40:06.0436718Z File "/root/.local/lib/python3.12/site-packages/gunicorn/util.py", line 377, in import_app
2026-02-11T13:40:06.0436747Z mod = importlib.import_module(module)
2026-02-11T13:40:06.0436776Z ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
2026-02-11T13:40:06.0436818Z File "/usr/local/lib/python3.12/importlib/init.py", line 90, in import_module
2026-02-11T13:40:06.0436849Z return _bootstrap._gcd_import(name[level:], package, level)
2026-02-11T13:40:06.043688Z ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
2026-02-11T13:40:06.0436911Z File "", line 1387, in _gcd_import
2026-02-11T13:40:06.0436938Z File "", line 1360, in _find_and_load
2026-02-11T13:40:06.0436968Z File "", line 1331, in _find_and_load_unlocked
2026-02-11T13:40:06.0436996Z File "", line 935, in _load_unlocked
2026-02-11T13:40:06.0437027Z File "", line 999, in exec_module
2026-02-11T13:40:06.0437055Z File "", line 488, in _call_with_frames_removed
2026-02-11T13:40:06.0437081Z File "/app/app/main.py", line 2, in
2026-02-11T13:40:06.0437124Z from opentelemetry.instrumentation.fastapi import FastAPIInstrumentor
2026-02-11T13:40:06.0437157Z File "/root/.local/lib/python3.12/site-packages/opentelemetry/instrumentation/fastapi/init.py", line 184, in
2026-02-11T13:40:06.0437188Z from opentelemetry.instrumentation.instrumentor import BaseInstrumentor
2026-02-11T13:40:06.0437218Z File "/root/.local/lib/python3.12/site-packages/opentelemetry/instrumentation/instrumentor.py", line 27, in
2026-02-11T13:40:06.0437246Z from opentelemetry.instrumentation.dependencies import (
2026-02-11T13:40:06.0437278Z File "/root/.local/lib/python3.12/site-packages/opentelemetry/instrumentation/dependencies.py", line 4, in
2026-02-11T13:40:06.0437306Z from pkg_resources import (
2026-02-11T13:40:06.0437333Z ModuleNotFoundError: No module named 'pkg_resources'
2026-02-11T13:40:06.0437595Z No module named 'pkg_resources'

Additional context

No response

Would you like to implement a fix?

None

Tip

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Start with the import in opentelemetry/instrumentation/dependencies.py shown in the traceback and inspect the package metadata for the dependency that provides pkg_resources. Reproduce the failure in a Python 3.12 slim Docker image with current setuptools, then verify that the FastAPI instrumentation imports and the reported gunicorn command starts without requiring a setuptools pin.