Docker image python-alpine fails when using lib

Question

I have the following Dockerfile:

FROM python:3.7-alpine

WORKDIR /msa-app/
EXPOSE 3000

ENV LD_LIBRARY_PATH="/usr/local/lib"
ENV LD_RUN_PATH="/usr/local/lib"
ENV SAPNWRFC_HOME="/usr/local/sap/nwrfcsdk"
ENV PATH="${PATH}:/usr/sap/nwrfcsdk/lib"

COPY nwrfcsdk/nwrfcsdk /usr/local/sap/nwrfcsdk
COPY nwrfcsdk/nwrfcsdk.conf /etc/ld.so.conf.d/nwrfcsdk.conf

COPY msa-app /msa-app/
RUN chmod +x /msa-app/entrypoint.sh
ENTRYPOINT /msa-app/entrypoint.sh

With the following entrypoint.sh (I put everything in entrypoint due to proxy issues inside the network that I'm using - don't blame me, it's the only way that I found to fix an issue):

#!/bin/sh

#Creates and activates virtual env
echo "*** Activating Python virtual environment"
python -m venv /msa-app/venv && source  /msa-app/venv/bin/activate

echo "*** Installing pip requirements"
pip install --upgrade pip && pip install -r /msa-app/requirements.txt

echo "*** Installing pyrfc"
pip install /msa-app/pyrfc-1.9.95-cp37-cp37m-linux_x86_64.whl

echo "*** Configuring SAPNWRFC PyRFC"
ln -s /usr/bin/python3 python
mkdir -p /etc/ld.so.conf.d/ 
mkdir -p /usr/sap/
ldconfig /usr/local/lib    

#Starts gunicorn for flask
echo "*** Starting application"
cd /msa-app && gunicorn -w 2 -b 0.0.0.0:3000 run:app

But when I try to run the container I get the following error:

ImportError: Error loading shared library libsapnwrfc.so: No such file or directory (needed by /msa-app/venv/lib/python3.7/site-packages/pyrfc/_pyrfc.cpython-37m-x86_64-linux-gnu.so)

But, this error DOESN'T happens when I use the normal non-alpine Python Docker Image. What am I doing wrong? Thank you.

Answer 1

This configuration worked for me when faced with this error.

    # For more information, please refer to https://aka.ms/vscode-docker-python
    FROM python:3-alpine3.10
    
    RUN apk add build-base

    RUN pip install --upgrade pip

    # Copy the requirements.txt to the root of the docker image
    COPY ./requirements.txt .
    
    # Keeps Python from generating .pyc files in the container
    ENV PYTHONDONTWRITEBYTECODE=1

    # Turns off buffering for easier container logging
    ENV PYTHONUNBUFFERED=1

    ENV TZ=$TIME_ZONE

    ENV DJANGO_PROJECT_NAME core

    ENV EXPOSED_CONTAINER_PORT 2092
    
    # Add header files required to install dependencies in the requirements.txt file
    RUN apk add --update --no-cache --virtual .tmp gcc libc-dev linux-headers python3-dev musl-dev unixodbc unixodbc-dev \
        && apk add --no-cache mariadb-dev mariadb-client postgresql-libs postgresql-dev \
          && apk add jpeg-dev zlib-dev libjpeg

    # Install pip requirements
    RUN pip install -r requirements.txt

    # Install Pillow for image management
    RUN pip install Pillow

    # Install MS-SQL dependencies
    RUN pip install mssql-django

    # Install postgres engine adapter
    RUN pip install psycopg2

    # Install pytest for running unit-tests
    RUN pip install pytest

    # Delete the temporarily directory used for downloading the required image header.
    # This is done to reduce on the image size and also to remove these redundant files
    RUN apk del .tmp

    # This is where static files will be stored in the container. -p makes is used to create all directories that don't exist
    RUN mkdir -p /app/static

    # Change directory and make app as the current working directory
    WORKDIR /app

    COPY . /app

    CMD find .

    RUN pytest /app/tests/
    
    # Creates a non-root user with an explicit UID and adds permission to access the /app folder
   
    # For more info, please refer to https://aka.ms/vscode-docker-python-configure-containers
    
    RUN adduser -u 5678 --disabled-password --gecos "" appuser && chown -R appuser /app
    
    USER appuser
    

    # Expose the container's point in order to be accessed outside the container
    EXPOSE $EXPOSED_CONTAINER_PORT:$EXPOSED_CONTAINER_PORT
    
    # Copy the entry point script to the container root directory
    COPY ./entrypoint.sh /

    ENTRYPOINT ["sh", "/entrypoint.sh" ]