Multistage build with private repo on GitHub. Python/Django app.

Dockerfile

FROM ubuntu:bionic as build-base

ENV PYTHONUNBUFFERED 1
ARG SSH_KEY

RUN apt-get update && \
    apt-get install -y build-essential \
                       libprotobuf-dev \
                       libhiredis-dev \
                       libxml2-dev \
                       libxslt1-dev \
                       python3-all-dev \
                       python3-venv \
                       postgresql-server-dev-all \
                       git \
                       openssh-client

RUN mkdir -p /root/.ssh
RUN ssh-keyscan github.com > /root/.ssh/known_hosts
RUN echo "$SSH_KEY" > /root/.ssh/id_rsa && chmod 0600 /root/.ssh/id_rsa

COPY . /app

WORKDIR /app

RUN python3 -m venv /env
ENV PATH "/env/bin:$PATH"

RUN pip install --upgrade pip setuptools wheel
RUN pip install --upgrade raven
RUN pip install --upgrade grpcio grpcio-tools

RUN pip install git+ssh://git@github.com/mycorp/myproj-utils.git#egg=myproj-utils[kube,sentry]
RUN pip install -e .
RUN pip uninstall -y grpcio-tools


FROM ubuntu:bionic

RUN adduser --system --ingroup users user

RUN apt-get update && \
    apt-get install -y ca-certificates \
                       libprotobuf10 \
                       libhiredis0.13 \
                       python3-all \
                       libxml2 \
                       libxslt1.1 \
                       postgresql-client \
                       uwsgi \
                       uwsgi-plugin-python3

COPY --from=build-base /env /env
COPY --from=build-base /app /app

WORKDIR /app

ENV PATH "/env/bin:$PATH"
ENV PYTHONUNBUFFERED 1
ENV DJANGO_SETTINGS_MODULE "myproj.settings"
ENV GRPC_ENABLE_FORK_SUPPORT "True"

USER user:users

ENTRYPOINT ["./manage.py"]

export TAG="$(./setup.py --name):v$(./setup.py --version)"
export REGISTRY="eu.gcr.io/myrepo"

docker build --no-cache --build-arg SSH_KEY="$(cat ~/.ssh/id_rsa)" -t "${TAG}" -t "${REGISTRY}/${TAG}" .
docker image prune --force --filter dangling=true