bindings: python: add script to generate sdist and wheels

Introduce a simple shell script that generates an sdist tarball and
wheels following the PEP 600 naming convention.

The wheels are generated via cibuildwheel, a tool provided by the Python
Packaging Authority (PyPA) [0]. The tool leverages toolchains within
containers maintained by PyPA to generate wheels that are runnable on
hosts that meet the requirements defined by the tag [1] [2].

The script currently creates X86_64 and AArch64 wheels for glibc and
musl libc for CPython versions 3.9-3.12.

[0]: https://cibuildwheel.pypa.io/en/stable/
[1]: https://peps.python.org/pep-0513/
[2]: https://github.com/pypa/manylinux

Signed-off-by: Vincent Fazio <vfazio@gmail.com>

bindings/python/generate_pypi_artifacts.sh

@@ -0,0 +1,123 @@
+#!/usr/bin/env sh
+#
+# This is a naive script to generate an sdist and wheels for publishing to PyPI.
+#
+# This script requires:
+# * Python3 + venv or virtualenv + pip
+# * Docker or Podman (https://cibuildwheel.pypa.io/en/stable/options/#container-engine)
+# * binfmt support and qemu-user-static for AArch64 registered as Fixed
+# (https://docs.kernel.org/admin-guide/binfmt-misc.html)
+#
+# On Debian based systems, AArch64 binfmt support can be checked via:
+# cat /proc/sys/fs/binfmt_misc/qemu-aarch64
+#
+# This script can be run in a Docker container generated by:
+# docker build - <<EOF
+# FROM docker:26.1.3-dind-alpine3.20@sha256:76ba10a4aed708c7b2db09d45740d711edf707f7368f6808bd32a53eaed33404
+# RUN apk add python3 py3-pip
+# ENV XDG_CACHE_HOME=/tmp/
+# EOF
+#
+# An example invocation would be:
+# docker run -it --rm -v /var/run/docker.sock:/var/run/docker.sock \
+# -v `pwd`:/work -w /work -v `pwd`:/outputs \
+# <hash or label for container> \
+# ./generate_pypi_artifacts.sh -v 2.1 -o /outputs
+#
+
+usage()
+{
+ echo ""
+ echo "Usage: $0 [-v libgpiod_source_version] [-o output_directory]"
+ echo -e "\t-v Version of libgpiod sources to bundle in sdist, overrides LIBGPIOD_VERSION"
+ echo -e "\t-o Directory to store outputs"
+ echo -e "\t-s Directory with python binding sources"
+ exit 1
+}
+
+# Respect environment specified library version
+src_version=${LIBGPIOD_VERSION}
+output_dir=$(pwd)
+source_dir=$(pwd)
+
+while getopts :hv:o:s: value; do
+ case $value in
+ v)
+ src_version=${OPTARG}
+ ;;
+ o)
+ output_dir=${OPTARG}
+ ;;
+ s)
+ source_dir=${OPTARG}
+ ;;
+ h | *)
+ usage
+ ;;
+ esac
+done
+
+if [ -z ${source_dir} ] || [ ! -d ${output_dir} ]; then
+ echo "Invalid source directory ${source_dir}"
+ exit 1
+fi
+
+if [ -z ${output_dir} ] || [ ! -w ${output_dir} ]; then
+ echo "Output directory ${output_dir} is not writable"
+ exit 1
+fi
+
+if [ -z ${src_version} ]; then
+ echo "The libgpiod source version must be specified."
+ exit 1
+fi
+
+shift $((OPTIND-1))
+
+# We don't need a specific version of python, but we do need it
+if ! command -v python3 >/dev/null 2>&1; then
+ echo "Python3 is required to generate PyPI artifacts"
+ exit 1
+fi
+
+if ! $(python3 -m pip -h >/dev/null 2>&1); then
+ echo "pip is required to generate wheels"
+ exit 1
+fi
+
+# Check for a virtual environment tool
+has_venv=$(python3 -m venv -h >/dev/null 2>&1 && echo 1 || echo 0)
+has_virtualenv=$(python3 -m virtualenv -h >/dev/null 2>&1 && echo 1 || echo 0)
+
+if ! ([ $has_venv -eq 1 ] || [ $has_virtualenv -eq 1 ]); then
+ echo "A virtual environment tool is required to generate wheels"
+ exit 1
+fi
+
+venv_module=$([ $has_virtualenv -eq 1 ] && echo "virtualenv" || echo "venv" )
+
+# assume the current directory has the python binding sources
+cur_dir=$(pwd)
+
+# stage the build in a temp directory
+temp_dir=$(mktemp -d)
+cd $temp_dir
+
+# setup a virtual environment with necessary build dependencies
+python3 -m $venv_module .venv
+venv_python="${temp_dir}/.venv/bin/python"
+
+# cibuildwheel 2.18.1 pins the build containers to 2024-05-13-0983f6f
+# This is overridable via the CIBW_{MANY,MUSL}LINUX_*_IMAGE environment variables
+$venv_python -m pip install build==1.2.1 cibuildwheel==2.18.1
+
+LIBGPIOD_VERSION=${src_version} $venv_python -m build --sdist --outdir ./dist $source_dir
+sdist=$(find ./dist -name '*.tar.gz')
+
+# by default, target only CPython
+CIBW_BUILD="cp*" $venv_python -m cibuildwheel --platform linux --archs x86_64,aarch64 $sdist --output-dir dist/
+
+cp -fa dist/ ${output_dir}/
+
+cd $cur_dir
+rm -rf $temp_dir