Package: skbuild-conan
skbuild-conan: A conan extension for scikit-buildPyBind11andscitkit-buildenable us to easily write native C++-modules for Python.
However, you get problems if your C++-code has dependencies.
This extension tries to make defining C++-dependencies as easy
as defining the Python-dependencies. This way you can easily
add any C++-library that has a conan recipe to your Python-project.This project originates fromourneed to use complex
C++-libraries
in Python projects and missing any nice option to include C++-dependencies.
For a few projects, we wrote individual code to fetch the dependencies
or just added instructions on how to install them (which of course
can scare pure Python users).This project is currently just a nice interface to hacks we accumulated. We try to make it
as universal and robust as possible as we rely on this for multiple projects, but we are
working fast-paced and will quickly abandon this tool once there is something better.We (TU Braunschweig, Algorithms Group) are not affiliated with scikit-build or conan.InstallationYou can simply add"skbuild_conan",torequires=[...]inpyproject.toml.
E.g. Thepyproject.tomlcould look like this[build-system]requires=["conan>=2.0.0","setuptools","scikit-build>=0.17.3","skbuild-conan","cmake>=3.23","ninja",]build-backend="setuptools.build_meta"If you want to use for examplesetup.py build, you need to
installskbuild_conanto your environment. You can do so
bypip install skbuild_conan.UsageThe usage is very similar to scitkit-build (and setuptools).
We just added a few additional arguments tosetup().Seehow to use scikit-buildfirst, as this is just a small extension to it.The added options areconanfile: Path to the folder with the conanfile.[py|txt]. By default the root
is assumed. The conanfile can be used to define the dependencies.
Alternatively, you can also useconan_requirementsto define
the conan dependencies without a conanfile. This option is
exclusive. If you defineconan_requirements, this option is
ignored.conan_recipes: List of paths to further conan recipes. The conan package index
is far from perfect, so often you need to build your own recipes. You don't
always want to upload those, so this argument gives you the option to integrate
local recipes. Just the path to the folder containing theconanfile.py.conan_requirements: Instead of providing a conanfile, you can simply state
the dependencies here. E.g.["fmt/[>=10.0.0]"]to add fmt in version >=10.0.0.conan_profile_settings: Overwrite conan profile settings. Sometimes necessary
because of ABI-problems, etc.wrapped_setup: The setup-method that is going to be wrapped. This would allow
you to extend already extended setup functions. By default, it is thesetupofskbuild, which extends thesetupofsetuptools.conan_output_folder: The folder where conan will write the generated files.
No real reason to change it unless the default creates conflicts with some other
tool.cmake_args: This is actually an argument ofskbuildbut we will extend it.
It hands cmake custom arguments. We use it to tell cmake about the conan modules.conan_profile: The name of the conan profile to use. By default, it isskbuild_conan_py. This profile is created automatically and should work for
most cases. If you need to change it, you can do so by editing~/.conan2/profiles/skbuild_conan_py.conan_env: Environment variables that are used for the conan calls. By
default it will overrideCCandCXXwith empty strings. This is necessary
to work around problems with anaconda, but it should not cause any problems
with other setups. You could defineCONAN_HOMEto./conan/cacheto use
a local cache and not install anything to the user space.An example usage could be as followsfromskbuild_conanimportsetupfromsetuptoolsimportfind_packagessetup(# https://scikit-build.readthedocs.io/en/latest/usage.html#setup-optionsname="simple_skbuild_conan_example",version="0.1.1",packages=find_packages("src"),# Include all packages in `./src`.package_dir={"":"src"},# The root for our python package is in `./src`.python_requires=">=3.7",# lowest python version supported.install_requires=[],# Python Dependenciesconan_requirements=["fmt/[>=10.0.0]"],# C++ Dependenciescmake_minimum_required_version="3.23",)See./examples/simple_skbuild_conan_examplefor a full example.ExamplesIf you do not have any C++-dependencies, you can just usescikit-buildwhich also provides aset of examples.Simple Example with fmtThe example in./examples/simple_skbuild_conan_exampleprovides a minimal example of how to use fmt in Python using PyBind11 and skbuild_conan.
fmt is a nice library for formatting strings and is used by many other libraries.
Python, of course, comes with extensive inbuilt string formatting, thus, this example is not very useful.
However, it is a good starting point to understand how to use skbuild_conan with a simple external library.Complex Example with CGAL: Using CGAL in PythonSometimes, your dependencies are significantly more complex.
For example, you may want to do some geometry processing and use CGAL.
CGAL is a very complex library with many dependencies, but also the most powerful library for geometric operations and often the only choice for many problems.
CGAL has a conan recipe, but it took a while until it received updates for conan2, such that we wrote our own recipe.
In the meantime, the official recipe was updated, but for the sake of the example, we will use our own recipe.
In case you are faced with the problem of an outdated conan recipe (or none at all), you can use the same trick.See./examples/cgal_skbuild_conan_examplefor an example of how to use CGAL via a custom conan recipe in Python using PyBind11 and skbuild_conan.Note that there is also thecgalpyproject by my friends at TAU (which I visited for a few months in 2022/2023), which is a nearly complete and efficient wrapper of CGAL.
It may need some more documentation, but Efi put a lot of thought into efficiency and configurability.Common problemsFeel free to copy these comments. Attribution is appreciated but not necessary.ABI problems: Undefined symbole...__cxx1112basic_stringIcSt11char_...This problem should be automatically fixed. Please open an issue if you still encounter it.Seehttps://docs.conan.io/1/howtos/manage_gcc_abi.htmlfor more details.glibcxx problems:If you get an error such asImportError: /home/krupke/anaconda3/envs/mo310/bin/../lib/libstdc++.so.6: version `GLIBCXX_3.4.30' not found (required by /home/krupke/anaconda3/envs/mo310/lib/python3.10/site-packages/samplns/cds/_cds_bindings.cpython-310-x86_64-linux-gnu.so)you are probably using conda (good!) but need to update glibcxx. Install the latest version bycondainstall-cconda-forgelibstdcxx-ngIn some cases, this still is not enough, especially if you are using a very up to date rolling-release distribution, such as Arch Linux, or if you installedlibstdcxx-ngsome time ago.
This could lead to the system having a slightly newer version of glibcxx than conda.
First try to upgradelibstdcxx-ngwithcondaupgrade-cconda-forge--allIf this does not help, you can try to install g++ (caveat: Linux only, Mac OS needs clang) into your conda environment and use it to compile the package.condainstall-cconda-forgegxx_linux-64# This should enforce a modern g++ version.condainstall-cconda-forgecxx-compiler# This should make sure that the compiler is used.Note that just the second command first may install an outdated g++ version (at least I observed that it installed gcc11 instead of gcc13, messing up my whole environment as this is too old).
When compiling from source, you probably should delete the_skbuild-folder and do a proper uninstall of the previous installation first.conan problemsIf you encounter problems with conan, you can try to delete the conan profile and let it be recreated.rm~/.conan2/profiles/skbuild_conan_pyMaybe you can also just take a look at the file and see if conan detected your compiler correctly.
A proper profile on Linux should for example look like this (different for other systems):[settings]
arch=x86_64
build_type=Release
compiler=gcc
compiler.cppstd=gnu17
compiler.libcxx=libstdc++11
compiler.version=13
os=LinuxIf the problem persists, you can try to delete the conan cache.rm-rf~/.conan2If you still encounter problems, please open an issue.ContributionWe are happy about any contribution and also about reported issues.
Sometimes it can take some time before we are able to take care
of something, as we need to prioritize quite often.Changelog1.2.0Workaround for Windows and MSVC found by Ramin Kosfeld (TU Braunschweig).1.1.1Fixing problem if the conan default profile has been renamed via environment variable.1.1.0conan is now called directly. This is kind of hacky, but circumvents problems with conan not being in the path if only installed for build.1.0.0Custom conan profile and workaround for anaconda problem.0.2.0Improved logging.0.1.4Fixing problem with paths that contain spaces. Switching back to manual versioning.0.1.3Fixing bug if no settings are given.0.1.2Moved workaround into setup to make it more explicit.0.1.1First tested and apparently working version.