Packaged wheel produced in different Docker image strips the module of all functions

[RealJoL]

Hey everybody,

I'm running into some trouble compiling for a slim container as I want to keep image size down. This is my Dockerfile where I first compile in the provided maturin container and then copy everything needed over to a slimmer image as soon as I have the wheel ready.

###################################### BUILD IMAGE ###############################################
FROM ghcr.io/pyo3/maturin AS build

# Copying all Rust source over
COPY src src
COPY Cargo.toml Cargo.toml
COPY rust-toolchain.toml rust-toolchain.toml

# Get dependencies for Python
COPY pyproject.toml pyproject.toml

# Copying Python source code
COPY project/modules /io/project/modules
COPY project/main.py /io/project/main.py

RUN maturin build -r --manylinux off

###################################### PROD IMAGE ###############################################
FROM  python:3.9-slim-bullseye AS exec

COPY --from=build /io/project /app/project
RUN mkdir -p /app/target/wheels
COPY --from=build /io/target/wheels /app/target/wheels

WORKDIR /app

COPY project/requirements.txt /app/project/requirements.txt
RUN pip install -r /app/project/requirements.txt

RUN ls /app/target/wheels | xargs -I {} pip install /app/target/wheels/{}

ENTRYPOINT ["python3", "project/main.py"]

Unfortunately, when running the prod image, all functions included on the Rust side disappear:

docker run project:many
['__doc__', '__file__', '__loader__', '__name__', '__package__', '__path__', '__spec__']
Traceback (most recent call last):
  File "/app/project/main.py", line 149, in <module>
    project.test_call_func()

where as my local environment produces

python3 project/main.py
['__all__', '__doc__', '__file__', '__loader__', '__name__', '__package__', '__spec__', 'test_call_func']
SUCCESS! You called this Rust function from Python.

Any help is appreciated!