[libgpiod] 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 [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@gmail.com>
---
 bindings/python/generate_pypi_artifacts.sh | 145 +++++++++++++++++++++
 1 file changed, 145 insertions(+)
 create mode 100755 bindings/python/generate_pypi_artifacts.sh

On Fri, May 31, 2024 at 8:07 PM Vincent Fazio <vfazio@gmail.com> wrote:
>
> 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@gmail.com>
> ---
>  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.

It's not naive, it works fine so let's not exaggerate.

> +#
> +# 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
> +#

I ran it directly and it generated the wheels, is it not recommended?

> +
> +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
>
>

We use tabs for indentation in all other scripts, can you please do it
for consistency. Also: please make sure the script passes shellcheck
as we now use it to keep the scripts at least somewhat correct and
consistent.

Bart