[libgpiod][PATCH] bindings: python: add script to generate sdist and wheels

[Vincent Fazio <vfazio@xxxxxxxxx>]

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 [1] to generate wheels that are runnable
on hosts that meet the requirements defined by the tag [2].

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

These defaults can be overridden via CIBW_* environment variables [3].

[0]: https://cibuildwheel.pypa.io/en/stable/
[1]: https://github.com/pypa/manylinux/
[2]: https://packaging.python.org/en/latest/specifications/platform-compatibility-tags/
[3]: https://cibuildwheel.pypa.io/en/stable/options/#options-summary

Signed-off-by: Vincent Fazio <vfazio@xxxxxxxxx>
---
 bindings/python/generate_pypi_artifacts.sh | 145 +++++++++++++++++++++
 1 file changed, 145 insertions(+)
 create mode 100755 bindings/python/generate_pypi_artifacts.sh

diff --git a/bindings/python/generate_pypi_artifacts.sh b/bindings/python/generate_pypi_artifacts.sh
new file mode 100755
index 0000000..bedae0f
--- /dev/null
+++ b/bindings/python/generate_pypi_artifacts.sh
@@ -0,0 +1,145 @@
+#!/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
+#
+# Look specifically for `flags: F` for Fixed and that the binfmt entry is enabled.
+#
+# 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 run out of a libgpiod checkout 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> \
+#     ./bindings/python/generate_pypi_artifacts.sh -v 2.1 -o /outputs -s /work/bindings/python -c
+#
+
+usage()
+{
+    printf "\n"
+    printf "Usage: $0 -v <libgpiod_source_version> [-o <output_directory>] [-s <source_directory>] [-ch]\n"
+    printf "\t-v Version of libgpiod sources to bundle in sdist, overrides LIBGPIOD_VERSION\n"
+    printf "\t-o Directory to store outputs\n"
+    printf "\t-s Directory with python binding sources\n"
+    printf "\t-c Calculate checksums for generated outputs\n"
+    printf "\t-f Forcibly remove old files from output directory\n"
+    printf "\t-h Show this help output\n"
+    exit 1
+}
+
+src_version=${LIBGPIOD_VERSION} # Default to environment specified library version
+output_dir=$(pwd) # Default to putting outputs in the current directory
+source_dir=$(pwd) # Assume the current directory has the python binding sources
+calc_hash=0 # Do not calculate hashes by default
+force=0 # Do not forcibly remove files by default
+
+while getopts :hv:o:s:cf value; do
+    case $value in
+        c)
+            calc_hash=1
+            ;;
+        f)
+            force=1
+            ;;
+        o)
+            output_dir=${OPTARG}
+            ;;
+        s)
+            source_dir=${OPTARG}
+            ;;
+        v)
+            src_version=${OPTARG}
+            ;;
+        h | *)
+            usage
+            ;;
+    esac
+done
+
+if [ -z ${source_dir} ] || [ ! -d ${output_dir} ]; then
+    printf "Invalid source directory ${source_dir}.\n"
+    exit 1
+fi
+
+if [ -z ${output_dir} ] || [ ! -w ${output_dir} ]; then
+    printf "Output directory ${output_dir} is not writable.\n"
+    exit 1
+fi
+
+if [ -z ${src_version} ]; then
+    printf "The libgpiod source version must be specified.\n"
+    exit 1
+fi
+
+shift $((OPTIND-1))
+
+# We require Python3 for building artifacts
+if ! command -v python3 >/dev/null 2>&1; then
+    printf "Python3 is required to generate PyPI artifacts.\n"
+    exit 1
+fi
+
+# Pip is necessary for installing build dependencies
+if ! $(python3 -m pip -h >/dev/null 2>&1); then
+    printf "The pip module is required to generate wheels.\n"
+    exit 1
+fi
+
+# Check for a virtual environment tool to not pollute user installed packages
+has_venv=$(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 ] || [ $has_virtualenv -eq 1 ]); then
+    printf "A virtual environment module is required to generate wheels.\n"
+    exit 1
+fi
+
+venv_module=$([ $has_virtualenv -eq 1 ] && echo "virtualenv" || echo "venv" )
+
+# Stage the build in a temp directory. Note not all shells have pushd/popd
+cur_dir=$(pwd)
+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')
+
+# Target only CPython and X86_64 + AArch64 Linux wheels unless specified otherwise via environment variables
+CIBW_BUILD=${CIBW_BUILD:-"cp*"} CIBW_ARCHS=${CIBW_ARCHS:-"x86_64,aarch64"} \
+    $venv_python -m cibuildwheel --platform linux $sdist --output-dir dist/
+
+if [ $force -eq 1 ]; then
+    printf "\nRemoving files from ${output_dir}/dist/\n"
+    rm -rf ${output_dir}/dist/
+fi
+
+cp -fa dist/ ${output_dir}/
+
+if [ $calc_hash -eq 1 ]; then
+    printf "\nHashes for generated outputs:\n"
+    sha256sum ${output_dir}/dist/*
+fi
+
+cd $cur_dir
+rm -rf $temp_dir
-- 
2.34.1