Dockerfile multi-stage build for Python

Dockerfile

# build wheels
FROM python:3.7.9-buster as builder

ENV PYTHONFAULTHANDLER=1 \
    PYTHONUNBUFFERED=1 \
    PYTHONHASHSEED=random \
    # pip:
    PIP_NO_CACHE_DIR=yes \
    PIP_DISABLE_PIP_VERSION_CHECK=on \
    PIP_DEFAULT_TIMEOUT=100

RUN mkdir /svc
WORKDIR /svc
ADD ./requirements.txt .
RUN pip install wheel && pip wheel -r requirements.txt --wheel-dir=/svc/wheels

# clean slate
FROM python:3.7.9-slim-buster as production

# python packages
COPY --from=builder /svc /svc
WORKDIR /svc
RUN pip install --no-index --find-links=/svc/wheels -r requirements.txt && \
    rm -rf /svc