RaBe Python Base Image Minimal

The RaBe Python Base Image Minimal is a stripped down image that uses microdnf as a package manager and includes the latest python.

The image is based on the RaBe Universal Base Image 9 Minimal which is in turn based on the AlmaLinux 9 UBI9 variant image container provided by AlmaLinux and based on the work from Red Hat.

Features

• Based on RaBe Universal Base Image 9 Minimal
• Contains the latest Python 3.x available in UBI9

Usage

Create a downstream image from ghcr.io/radiorabe/python-minimal. Replace :latest with a specific version in the examples below.

FROM ghcr.io/radiorabe/python-minimal:latest AS build

COPY ./ /app/

RUN    cd /app \
    && python3 -mpip --no-cache-dir install wheel \
    && python3 setup.py bdist_wheel


FROM ghcr.io/radiorabe/python-minimal:latest AS app

COPY --from=build /app/dist/*.whl /tmp/dist/

RUN    python3 -mpip --no-cache-dir install /tmp/dist/*.whl \
    && rm -rf /tmp/dist/

USER nobody

CMD ["python3", "-mapp"]

The argument to CMD needs to call a Python module containing a __main__ cli entrypoint. It is recommended that this is packaged as a console_scripts style command line script.

You can install os packages using microdnf. ie. if you use setuptools-git-versioning you would install git-core to make it work.

FROM ghcr.io/radiorabe/python-minimal:latest AS build

COPY ./ /app/

RUN    cd /app \
    && microdnf install git-core \
    && python3 -mpip --no-cache-dir install setuptools-git-versioning wheel \
    && python3 setup.py bdist_wheel


FROM ghcr.io/radiorabe/python-minimal:latest AS app

# ... same as in first example

In some cases it can make sense to install some Python requirements as os dependencies. An example would be the postgresql driver that needs to be built against an os postgresql driver and should not be based on a manylinux build from pypi in production.

FROM ghcr.io/radiorabe/python-minimal:latest AS build

# ... same as in first example

FROM ghcr.io/radiorabe/python-minimal:latest AS app

RUN    microdnf install python311-psycopg2 \
    && microdnf clean all \
    && python3 -mpip --no-cache-dir install /tmp/dist/*.whl \
    && rm -rf /tmp/dist/

COPY --from=build /app/dist/*.whl /tmp/dist/

USER nobody

CMD ["python3", "-mapp"]

In addition to building the container like this, the application needs to ensure that they pin a psycopg2 version range that includes the one provided by the os. You can validate this by checking the output of the container image build which should not contain a Downloading psycopg2*.whl line in the app containers python3 -mpip install phase.

Release Management

The CI/CD setup uses semantic commit messages following the conventional commits standard. There is a GitHub Action in .github/workflows/semantic-release.yaml that uses go-semantic-commit to create new releases.

The commit message should be structured as follows:

<type>[optional scope]: <description>

[optional body]

[optional footer(s)]

The commit contains the following structural elements, to communicate intent to the consumers of your library:

1. fix: a commit of the type fix patches gets released with a PATCH version bump
2. feat: a commit of the type feat gets released as a MINOR version bump
3. BREAKING CHANGE: a commit that has a footer BREAKING CHANGE: gets released as a MAJOR version bump
4. types other than fix: and feat: are allowed and don't trigger a release

If a commit does not contain a conventional commit style message you can fix it during the squash and merge operation on the PR.

Build Process

The CI/CD setup uses the Docker build-push Action to publish container images. This is managed in .github/workflows/release.yaml.

License

This application is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General Public License as published by the Free Software Foundation, version 3 of the License.

Copyright

Copyright (c) 2022 Radio Bern RaBe