Re: [libgpiod][PATCH v5 1/1] bindings: python: optionally include module in sdist

[Bartosz Golaszewski <brgl@xxxxxxxx>]

On Wed, Oct 18, 2023 at 10:57 PM Phil Howard <phil@xxxxxxxxxxxxx> wrote:
>
> Optionally vendor libgpiod source into sdist so that the Python module can
> be built from source, even with a missing or mismatched system libgpiod.
>
> Add two new environment variables "LINK_SYSTEM_LIBGPIOD" and
> "GPIOD_VERSION" to control what kind of package setup.py will build.
>
> In order to build an sdist or wheel package with a vendored libgpiod a
> version must be specified via the "GPIOD_VERSION" environment variable.
>
> This will instruct setup.py to fetch the tarball matching the requested
> version from git.kernel.org, unpack it, and copy the lib and include
> directories into the package root so they can be included in sdist or used
> to build a binary wheel.
>
> eg: GPIOD_VERSION=2.0.2 python3 setup.py sdist
>
> Will build a source distribution with gpiod version 2.0.2 source included.
>
> It will also save the gpiod version into "gpiod-version.txt" so that it can
> be passed to the build when the sdist is built by pip.
>
> Requiring an explicit version ensures that the Python bindings - which
> can be changed and versions independent of libgpiod -  are built against a
> stable libgpiod release.
>
> In order to force a package with vendored gpiod source to link the system
> libgpiod, the "LINK_SYSTEM_LIBGPIOD" environment variable can be used:
>
> eg: LINK_SYSTEM_LIBGPIOD=1 pip install libgpiod
>
> Signed-off-by: Phil Howard <phil@xxxxxxxxxxxxx>
> ---
>  bindings/python/MANIFEST.in |   5 ++
>  bindings/python/setup.py    | 131 +++++++++++++++++++++++++++++++++---
>  2 files changed, 125 insertions(+), 11 deletions(-)
>
> diff --git a/bindings/python/MANIFEST.in b/bindings/python/MANIFEST.in
> index c7124d4..0aa9079 100644
> --- a/bindings/python/MANIFEST.in
> +++ b/bindings/python/MANIFEST.in
> @@ -2,6 +2,7 @@
>  # SPDX-FileCopyrightText: 2023 Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>
>
>  include setup.py
> +include gpiod-version.txt
>
>  recursive-include gpiod *.py
>  recursive-include tests *.py
> @@ -11,3 +12,7 @@ recursive-include gpiod/ext *.h
>
>  recursive-include tests/gpiosim *.c
>  recursive-include tests/procname *.c
> +
> +recursive-include lib *.c
> +recursive-include lib *.h
> +recursive-include include *.h
> diff --git a/bindings/python/setup.py b/bindings/python/setup.py
> index df10e18..f0d5c1f 100644
> --- a/bindings/python/setup.py
> +++ b/bindings/python/setup.py
> @@ -1,24 +1,136 @@
>  # SPDX-License-Identifier: GPL-2.0-or-later
>  # SPDX-FileCopyrightText: 2022 Bartosz Golaszewski <brgl@xxxxxxxx>
>
> -from os import environ, path
> -from setuptools import setup, Extension, find_packages
> +import tarfile
> +from os import getenv, path, unlink
> +from shutil import copytree, rmtree
> +from urllib.request import urlretrieve

Doesn't it make our setup.py depend on additional packages on top of
the standard library?

> +
> +from setuptools import Extension, find_packages, setup
>  from setuptools.command.build_ext import build_ext as orig_build_ext
> -from shutil import rmtree
> +from setuptools.command.sdist import sdist as orig_sdist
> +
> +LINK_SYSTEM_LIBGPIOD = getenv("LINK_SYSTEM_LIBGPIOD") == "1"
> +GPIOD_VERSION = getenv("GPIOD_VERSION")

I'd call it LIBGPIOD_VERSION to be more explicit.

> +GPIOD_WITH_TESTS = getenv("GPIOD_WITH_TESTS") == "1"
> +SRC_BASE_URL = "https://git.kernel.org/pub/scm/libs/libgpiod/libgpiod.git/snapshot/";

I would prefer to use the http mirror at
https://mirrors.edge.kernel.org/pub/software/libs/libgpiod/ rather
than git snapshots. We have better control over what's in there and we
can even verify the checksums after download if needed.

> +SRC_FILENAME = "libgpiod-{version}.tar.gz"

Maybe put it in /tmp?

Bart

> +
> +# __version__
> +with open("gpiod/version.py", "r") as fd:
> +    exec(fd.read())
> +
> +
> +def fetch_tarball(func):
> +    # If no GPIOD_VERSION is specified in env, just run the task
> +    if GPIOD_VERSION is None:
> +        return func
> +
> +    # If GPIOD_VERSION is specified, fetch the requested version tarball
> +    # and create gpiod-version.txt so the sdist package knows what version
> +    # it's building.
> +    def wrapper(self):
> +        TARBALL = SRC_FILENAME.format(version=GPIOD_VERSION)
> +
> +        print(f"fetching: {SRC_BASE_URL + TARBALL}")
> +
> +        filename, headers = urlretrieve(SRC_BASE_URL + TARBALL, TARBALL)
> +
> +        if not tarfile.is_tarfile(filename):
> +            print(f"error: refusing to build sdist (invalid tarball {TARBALL})")
> +            return
> +
> +        # Unpack the downloaded tarball
> +        print(f"unpacking: {filename}")
> +        file = tarfile.open(filename)
> +        file.extractall(".")
> +        file.close()
> +        unlink(filename)
> +
> +        # Copy the include and lib directories we need to build libgpiod
> +        copytree(f"libgpiod-{GPIOD_VERSION}/include/", "./include")
> +        copytree(f"libgpiod-{GPIOD_VERSION}/lib/", "./lib")
> +        rmtree(f"libgpiod-{GPIOD_VERSION}")
> +
> +        # Save the gpiod version for sdist
> +        open("gpiod-version.txt", "w").write(GPIOD_VERSION)
> +
> +        func(self)
> +
> +        rmtree("./lib", ignore_errors=True)
> +        rmtree("./include", ignore_errors=True)
> +        unlink("gpiod-version.txt")
> +
> +    return wrapper
>
>
>  class build_ext(orig_build_ext):
>      """
> -    setuptools install all C extentions even if they're excluded in setup().
> -    As a workaround - remove the tests directory right after all extensions
> -    were built (and possibly copied to the source directory if inplace is set).
> +    Wrap build_ext to amend the module sources and settings to build
> +    the bindings and gpiod into a combined module when a version is
> +    specified and LINK_SYSTEM_LIBGPIOD=1 is not present in env.
> +
> +    run is wrapped with @fetch_tarball in order to fetch the sources
> +    needed to build binary wheels when GPIOD_VERSION is specified, eg:
> +
> +    GPIOD_VERSION="2.0.2" python3 -m build .
>      """
>
> +    @fetch_tarball
>      def run(self):
> +        # Try to get the gpiod version from the .txt file included in sdist
> +        try:
> +            gpiod_version = open("gpiod-version.txt", "r").read()
> +        except OSError:
> +            gpiod_version = GPIOD_VERSION
> +
> +        if gpiod_version and not LINK_SYSTEM_LIBGPIOD:
> +            # When building the extension from an sdist with a vendored
> +            # amend gpiod._ext sources and settings accordingly.
> +            gpiod_ext = self.ext_map["gpiod._ext"]
> +            gpiod_ext.sources += [
> +                "lib/chip.c",
> +                "lib/chip-info.c",
> +                "lib/edge-event.c",
> +                "lib/info-event.c",
> +                "lib/internal.c",
> +                "lib/line-config.c",
> +                "lib/line-info.c",
> +                "lib/line-request.c",
> +                "lib/line-settings.c",
> +                "lib/misc.c",
> +                "lib/request-config.c",
> +            ]
> +            gpiod_ext.libraries = []
> +            gpiod_ext.include_dirs = ["include", "lib", "gpiod/ext"]
> +            gpiod_ext.extra_compile_args.append(
> +                f'-DGPIOD_VERSION_STR="{gpiod_version}"',
> +            )
> +
>          super().run()
> +
> +        # We don't ever want the module tests directory in our package
> +        # since this might include gpiosim._ext or procname._ext from a
> +        # previous dirty build tree.
>          rmtree(path.join(self.build_lib, "tests"), ignore_errors=True)
>
>
> +class sdist(orig_sdist):
> +    """
> +    Wrap sdist in order to fetch the libgpiod source files for vendoring
> +    into a source distribution.
> +
> +    run is wrapped with @fetch_tarball in order to fetch the sources
> +    needed to build binary wheels when GPIOD_VERSION is specified, eg:
> +
> +    GPIOD_VERSION="2.0.2" python3 -m build . --sdist
> +    """
> +
> +    @fetch_tarball
> +    def run(self):
> +        super().run()
> +
> +
>  gpiod_ext = Extension(
>      "gpiod._ext",
>      sources=[
> @@ -50,19 +162,16 @@ procname_ext = Extension(
>  )
>
>  extensions = [gpiod_ext]
> -if environ.get("GPIOD_WITH_TESTS") == "1":
> +if GPIOD_WITH_TESTS:
>      extensions.append(gpiosim_ext)
>      extensions.append(procname_ext)
>
> -with open("gpiod/version.py", "r") as fd:
> -    exec(fd.read())
> -
>  setup(
>      name="libgpiod",
>      packages=find_packages(exclude=["tests", "tests.*"]),
>      python_requires=">=3.9.0",
>      ext_modules=extensions,
> -    cmdclass={"build_ext": build_ext},
> +    cmdclass={"build_ext": build_ext, "sdist": sdist},
>      version=__version__,
>      author="Bartosz Golaszewski",
>      author_email="brgl@xxxxxxxx",
> --
> 2.34.1
>