introduce new option for datasette package to use a slim base image

[fs111]

The official python images on docker hub come with a slim variant that is significantly smaller than the default. The diff does not change the default, but allows to switch to the slim variant with commandline switch (--slim-base-image)

Size comparison:

$ datasette package some.db -t fat --install "datasette-basemap datasette-cluster-map"

$ datasette  package some.db -t slim --slim-base-image --install "datasette-basemap datasette-cluster-map"

$ docker images
REPOSITORY   TAG       IMAGE ID       CREATED          SIZE
fat          latest    807b393ace0d   9 seconds ago    978MB
slim         latest    31bc5e63505c   8 minutes ago    191MB

[fgregg]

is there a reason to not always use the slim option?

[fs111]

@fgregg my thinking was backwards compatibility. I don't know what people do to their builds, I just wanted a smaller image for my use case.

@simonw any chance to take a look at this? If there is no interest, feel free to close the PR

[simonw]

I'd actually like to switch to slim as the default - I think Datasette should ship the smallest possible container that can still support extra packages being installed using apt-get install.

[fs111]

@simonw I like that you want to go "slim by default". Do you want another PR for that or should I just wait?

[dholth]

tfw you have more ephemeral storage than upstream bandwidth

FROM python:3.10-slim AS base

RUN apt update && apt -y install zstd

ENV DATASETTE_SECRET 'sosecret'
RUN --mount=type=cache,target=/root/.cache/pip
    pip install -U datasette datasette-pretty-json datasette-graphql

ENV PORT 8080
EXPOSE 8080

FROM base AS pack

COPY . /app
WORKDIR /app

RUN datasette inspect --inspect-file inspect-data.json
RUN zstd --rm *.db

FROM base AS unpack

COPY --from=pack /app /app
WORKDIR /app

CMD ["/bin/bash", "-c", "shopt -s nullglob && zstd --rm -d *.db.zst && datasette serve --host 0.0.0.0 --cors --inspect-file inspect-data.json --metadata metadata.json --create --port $PORT *.db"]

[fs111]

closing as this is now the default