You can try the python:{version}-alpine version. It's much smaller:

>> docker image ls |grep python
python    3.6-alpine     89.4 MB
python    3.6            689 MB
python    3.5            689 MB
python    3.5.2          687 MB
python    3.4            833 MB
python    2.7            676 MB

At time of writing it looks like the official image supports -alpine on all python versions.

https://hub.docker.com/_/python/

The problem comes when you need things like ciso8601, or some libraries, requiring build process. Build tools are not "incorporated" into the both slim and alpine variants, for low-size footprint.

So to install deps, you'll have to:

• Install build tools
• Deploy dependencies from Pipfile.lock system-wide
• Uninstall build tools and clean caches

And do that 3 actions inside a single RUN layer, like following:

FROM python:3.7-slim

WORKDIR /app

# both files are explicitly required!
COPY Pipfile Pipfile.lock ./

RUN pip install pipenv && \
  apt-get update && \
  apt-get install -y --no-install-recommends gcc python3-dev libssl-dev && \
  pipenv install --deploy --system && \
  apt-get remove -y gcc python3-dev libssl-dev && \
  apt-get autoremove -y && \
  pip uninstall pipenv -y

COPY app ./

CMD ["python", "app.py"]

• Manipulating build system would cost you around 300MiB and some extra time
• Uninstalling pipenv would save you another 20MiB (which is 10% of resulting size).
• Separating RUN commands would not delete data from layers, and would result in ~500MiB image. That's docker specifics.

So that would result in perfectly working ~200MiB sized image, which is

• 5 times less than original python:3.7, (that is >1.0GiB)
• Has no alpine incompabilities (these are typically tied to glibc replacement)

At the time, we're fine with slim (debian buster) build variants, preferring slim over alpine (for most compatibility). If you're really up to further size optimization, I'd recommend you to take a look at some excellent builds of these guys:

• Alpine Python
• 12.7MiB MariaDB

The problem can be minimized to a Dockerfile with

FROM python:3.8.5-slim
RUN pip install --no-cache-dir brotlipy

If you run this, you will get the error

...
unable to execute 'gcc': No such file or directory
error: command 'gcc' failed with exit status 1
...

The -slim and -alpine images do not include a C compiler, whereas the python:3.8.5 image does. If you install a C compiler, you will likely get other errors, like missing limit.s, ffi.h, and the C++ standard library.

Here is a minimal working example using the -alpine image.

FROM python:3.8.5-alpine
RUN apk add gcc g++ libffi-dev musl-dev \
    && python -m pip install --no-cache-dir brotlipy \
    && apk del gcc g++ libffi-dev musl-dev

Here is a complete example for the -slim image. Use pipenv run python to run the spacy part.

FROM python:3.8.5-slim

ARG DEBIAN_FRONTEND="noninteractive"

RUN pip install pipenv

WORKDIR /app

COPY ./ /app/

RUN apt-get update \
    && apt-get install --yes --no-install-recommends \
        gcc g++ libffi-dev \
    && pipenv install --sequential --deploy --verbose \
    && apt-get autoremove --yes gcc g++ libffi-dev \
    && rm -rf /var/lib/apt/lists/*

RUN pipenv run python -m spacy download en_core_web_sm

RUN pipenv install gunicorn[gevent]

EXPOSE 8080

CMD gunicorn -c src/gunicorn.conf.py  --chdir src wsgi:app