Building and Processing Python wheels with poudriere for FreeBSD

Important

This is work in progress and might change in nature!

Requirements

poudriere-devel installed
python3 installed
py-wheel (wheel command) installed; required to normalize and deduplicate wheels, see below

Apply this patch to your ports tree
Add PYDISTUTILS_BUILD_WHEEL=yes to your make.conf, PEP 517-based wheels are built by default
Copy the hooks from src/ to ${POUDRIERED}/hooks/plugins/python-wheels/
Add NO_PACKAGE_BUILDING=yes ; export PROCESS_PYTHON_WHEELS=yes to your poudriere.conf
If you build with -b <branch> (or otherwise set PACKAGE_FETCH_BRANCH in your poudriere.conf), add at least PACKAGE_FETCH_BLACKLIST="py<PYTHON_SUFFIX>-*" or explicit non-prefixed package names (not all packages are prefixed) to your poudriere.conf, since fetching a prebuilt package instead of building locally skips the wheel-collection hook entirely
By default only ports listed explicitly on the build command line/list file are collected, not automatic (transitive) dependencies; add export PYTHON_WHEELS_SCOPE=all to your poudriere.conf to collect wheels for every built port instead
If you want a static simple index being generated, add export GENERATE_STATIC_INDEX=yes to your poudriere.conf

If you are running ZFS, optionally create the Python wheels dataset:

zfs create -o compression=off ${ZPOOL}${ZROOTFS}/data/python-wheels

Run your poudriere build as usual, as soon as a Python package is built it will:

in case of distutils build the wheel,
in case of PEP 517 the wheel is already built, since PEP517_BUILD_CMD runs automatically as part of the port's normal build phase (no opt-in required, unlike PYDISTUTILS_BUILD_WHEEL for distutils).

Poudriere will process the wheels by

collecting them after successful package build from the port's work directory,
discarding a freshly built wheel whose content is unchanged from the last one published for the same name, version, and Python/ABI/platform (a rebuild triggered by e.g. a PORTREVISION bump or an unrelated dependency/option change frequently produces byte-identical wheels),
adding a build tag to wheels whose content actually changed,
adding multiplatform tags to wheels for RELEASE versions with patches from p-2 to p (three in total),
generating a static simple index

Your wheels are ready to be served by a web server.