Docker Python build file

• Run python script in docker envelope

  $ docker run -it --rm --name my-running-script -v "$PWD":/usr/src/myapp -w /usr/src/myapp python:3 python script.py

• Run python3 script in docker and chown files back to original user

  $ docker run --rm --name az_script-20helper-split-pem.py \
          -v "$path_dir":/app -w /app \
          -v /tmp:/tmp \
          --env certName=$certName \
          --env USER_ID=$(id -u ${USER}) \
          --env GROUP_ID=$(id -g ${USER}) \
          python:3.7-alpine \
              sh -c 'python -m pip install pem ; python az_script-20helper-split-pem.py /tmp/$certName-in.pem /tmp/$certName-split ; chown --changes --silent ${USER_ID}:${GROUP_ID} /tmp/$certName-split* '

• Python docker build file
  1. create dir myapp, in it add src/myapp.py and requirements.txt

FROM python:3.7-alpine as base
FROM base as builder
RUN mkdir /install
WORKDIR /install
COPY requirements.txt /requirements.txt
RUN pip install --install-option="--prefix=/install" -r /requirements.txt
FROM base
COPY --from=builder /install /usr/local
COPY src /app
WORKDIR /app
CMD ["python" . "myapp.py"]

• Build with $ docker build -t myapp .
• Run with $ docker run --rm myapp

Installing pip packages in docker container

• This became complicated as python3 does not allow for global packages to be installed as this can clash with the OS python.

• Work around use venv

      # Create python venv
  ENV VIRTUAL_ENV=/opt/venv
  # ENV VIRTUAL_ENV=${HOME}/venv/
  RUN mkdir -p ${VIRTUAL_ENV}
  # create venv
  RUN python3 -m venv ${VIRTUAL_ENV}
  ENV PATH="${VIRTUAL_ENV}/bin:$PATH"