为什么使用 Docker RUN 时会出现“ModuleNotFoundError: No module named 'pyodbc'”？

Question

I'm creating a Docker container. To specify python pacakges that need to be installed, I use poetry pyproject.toml :

[tool.poetry.dev-dependencies]
pyodbc = "^4.0.32"
...some others...

Everything downloads correctly to venv, but my issue is that when I start my python script with CMD command in Dockerfile :

CMD ["/bin/sh", "-c", "python src/test_models.py"]

it works fine, but if i use this RUN command right before CMD in my Dockerfile :

RUN source ./venv/bin/activate && python src/test_models.py

which does the same thing as CMD the error occurs:

...it is not a full output error text, just the meaningful part...
File "/project/venv/lib/python3.9/site-packages/sqlalchemy/engine/create.py", line 560, in create_engine
    dbapi = dialect_cls.dbapi(**dbapi_args)
  File "/project/venv/lib/python3.9/site-packages/sqlalchemy/connectors/pyodbc.py", line 43, in dbapi
    return __import__("pyodbc")
ModuleNotFoundError: No module named 'pyodbc'

But what confuses me the most is that if I make CMD command run a file with an infinite loop and then I go to Docker container's command line and execute the same command that was in RUN :

source ./venv/bin/activate && python src/test_models.py

that works perfectly fine and no pyodbc error occures.

My Dockerfile :

ARG base_image=gpython:latest
FROM ${base_image}

ARG project_root=/project

COPY entrypoint.sh /usr/bin/

RUN yum install -y gcc-c++ python3-devel unixODBC-devel

RUN chown 1001:0 /usr/bin/entrypoint.sh && chmod u+x /usr/bin/entrypoint.sh

RUN pip install  \
      --index-url https://artifactory..../pypi/python-remote/simple \
      --trusted-host artifactory.... \
      --no-cache-dir --upgrade pip poetry && \
    mkdir ${project_root} && \
    python -m venv ${project_root}/venv && \
    chown -R 1001:0 ${project_root}/venv

COPY ./pyproject.toml ./poetry.lock ${project_root}/

WORKDIR ${project_root}

RUN source ./venv/bin/activate &&  pip install \
      --index-url https://artifactory..../pypi/python-remote/simple \
      --trusted-host artifactory... \
      --no-cache-dir --upgrade pip wheel && \
    export  REQUESTS_CA_BUNDLE=/etc/...crt && \
    poetry config certificates.arti_pypi.cert /etc/....crt && \
    poetry install --no-dev --no-root

COPY src ${project_root}/src
COPY models ${project_root}/models

HEALTHCHECK --interval=10s --timeout=1s --retries=3 \
    CMD curl -f http://localhost:8080/healthcheck || exit 1

USER 1001

ENTRYPOINT ["/usr/bin/entrypoint.sh"]
#RUN source ./venv/bin/activate && python src/test_models.py
CMD ["/bin/sh", "-c", "python src/test_models.py"]

Answer 1

Agreed with David Maze, you shouldn't need a virtual environment inside a Docker image. Try the following:

In a requirements.txt file, have:

pyodbc~=4.0.32

Then in your dockerfile have something along the lines of:

FROM python
COPY . .
RUN apt-get update -y && apt-get -y install unixodbc-dev 
RUN pip install -r requirements.txt
ENTRYPOINT ["python"]  
CMD ["run.py"]