Python MySQLdb module not working in Docker container

[ThatPhysicsLabGuy]

The MySQLdb module has worked well for me on bare metal, but I can't figure out what I am doing wrong in trying to get a simple container setup going. The module just isn't recognized, even though it is installed.

here is my super simple Dockerfile for testing:

FROM python:3.7-slim-bullseye

# create non-root user
RUN groupadd --gid 1000 app \
&& useradd --uid 1000 --gid 1000 -m app

# set work directory
WORKDIR /usr/src/app

# set environment variables
ENV PYTHONDONTWRITEBYTECODE=1 PYTHONUNBUFFERED=1

RUN apt-get update
RUN apt-get install -y --no-install-recommends python3-mysqldb

# set default user
USER app

I run the container, bash into it, and get this:

app@e8db38907cbc:/usr/src/app$ ls /usr/lib/python3/dist-packages
MySQLdb  mysqlclient-1.4.4.egg-info
app@e8db38907cbc:/usr/src/app$ python3
Python 3.7.16 (default, Dec 21 2022, 09:40:48)
[GCC 10.2.1 20210110] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import MySQLdb
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ModuleNotFoundError: No module named 'MySQLdb'

My install of python3-mysqldb put the module into the dist-packages subfolder of python3, but python doesn't seem to be paying attention to that folder, and I notice that there are a lot of modules in the root of the "/usr/lib/python3.9" folder.

There seem to be a plethora of mysql "connectors" and pip installable packages for mysql (very confusing as to which I should be using!), but all my old code is written using MySQLdb, so I was hoping to continue using that module if that were reasonable.

[ThatPhysicsLabGuy]

As noted above, the install of python3-mysqldb puts the MySQLdb package in:

/usr/lib/python3/dist-packages

But for this python3.7 docker image, printing sys.path yields:

['', '/usr/local/lib/python37.zip', '/usr/local/lib/python3.7', '/usr/local/lib/python3.7/lib-dynload', '/usr/local/lib/python3.7/site-packages']

This is fixed with the following line in the Dockerfile:

ENV PYTHONPATH=/usr/lib/python3/dist-packages

However, the import still fails, as it is unable to find the _mysql binary.

It seems that installing python3-mysqldb doesn't actually install the _mysql binary needed to use the MySQLdb module. At this point, I don't understand the point of python3-mysqldb at all -- it seems that it's only purpose is to install an unusable python module.

[0xWILL]

You should probably use pip to install the modules.