feat: integrate https://github.com/nilsnolde/osrm-bindings

[nilsnolde]

forgot to add here: @whytro did the real work during GSoC 2023. this PR is "just" integrating it into upstream.

getting to build linux was less of a hassle than I imagined. it's more of a hassle to review I guess.. my proposal: since it's mostly copy/paste from https://github.com/nilsnolde/osrm-bindings, it's not too bad to not review the code toooo much. one can somewhat trust the python packaging pipeline. I'll add more details later. IMO it's more important to understand how things work conceptually, so I'll add quite some more text to the PR description once this is a final PR. and of course feel free to ask any understanding question you have:) packaging is always awful, but honestly, python got really usable after they introduced (and widely supported) pyproject.toml.

General

• nanobind for C++ binding (i.e. no setup.py, all CMake based), very close to libosrm API, only some plumbing python code
• for PyPI distribution, we only build python 3.12 SABI (stable ABI) wheels, older version build from source

Repo Layout

everything is properly namespaced to python:

src/python/
├── CMakeLists.txt
├── README.md
├── include/
│   └── python/
│       ├── engineconfig_nb.hpp
│       ├── parameters/
│       ├── types/
│       └── utility/
├── osrm/
│   ├── __init__.py
│   ├── __main__.py
│   └── osrm_ext.pyi
└── src/
    ├── engineconfig_nb.cpp
    ├── osrm_nb.cpp
    ├── parameters/
    ├── types/
    └── utility/

test/python/
├── constants.py
├── test_index.py
├── test_match.py
├── test_nearest.py
├── test_route.py
├── test_table.py
├── test_tile.py
└── test_trip.py

Packaging Architecture

• we distribute both sdist & wheels from release-monthly.yml
• cibuildwheel to orchestrate the build, packaging, repairing (mostly vendor dynamic libs into the wheel), can be run locally too
• cibuildwheel does the build directly on the system for macos & win; however, for linux it needs an old-ish glibc version which is the ABI compatibility barrier for python extensions. this project uses a manylinux_2_28 docker image based on almalinux 8. I forked https://github.com/pypa/manylinux a while ago to https://github.com/nilsnolde/manylinux, where I added the OSRM build dependencies for both aarch64 & x86: https://github.com/nilsnolde/manylinux/pkgs/container/manylinux.
• we auth with PyPI over a "trusted publisher" so no secrets needed
• versioning & publishing is integrated with release-monthly.yml

Open Questions

1. what should we do about the package name? osrm-bindings is ok-ish, osrm would of course be much nicer:)
2. we should probably open a osrm account on PyPI?
3. is it ok to transfer fix map matching test on windows nilsnolde/osrm-bindings#40 here and have someone from the community solve the win map-matching failure? I really don't feel like going back to win and figure out how to properly debug there;)

[nilsnolde]

I tried to be really thorough, so I had claude add some python development and API docs. python doesn't work very well with vitepress with pulling out docstrings etc. it's mostly mkdocs these days in python land. not sure, but I could imagine mkdocs support JS docstrings as well. I guess you just switched to vitepress @DennisOSRM , not sure you'd be open to ditch it again potentially?

[nilsnolde]

for reference, this is the mkdocs based documentation I configured for valhalla: https://valhalla.github.io/valhalla/

[DennisOSRM]

Sure, we can discuss the feasibility of switching. Perhaps independent of this PR, but whatever we choose should be visually on par with vitepress.

[nilsnolde]

this file is the project page on pypi.org

[nilsnolde]

could probably use the standard Makefile instead of duplicating the same logic here. I know there gmake for windows, could just work..

[DennisOSRM]

Perhaps after merging this change 😉

[DennisOSRM]

The PR probably needs a rebase onto latest master to pick up a fix for macOS ci.

[nilsnolde]

jeez, thanks, was just about to diagnose!

[nilsnolde]

I also wanna say: in effect osrm is not buildable anymore with just system packages in many cases. since it removed all vendored packages and e.g. brew removed sol2 support, at least on macos vcpkg is a must. also on my manjaro linux sol2 is not in the official repos, only on the AUR (which is generally a bad habit to use). most others only have it on the very newest version like sid, rawhide & 26.06: https://pkgs.org/search/?q=sol2.

even if in theory vcpkg might be optional in cmake, in practice it's not on the majority of platforms. IMHO it was nicer before. what wasn't nice is that is was hard-vendored instead of submodule'd (in terms of maintenance). there's a way to have submodules (at least for header-only deps) to fall back to. I'm really more OSS than FOSS, but in such cases I'm all for "free". personally I really don't like being kinda locked in to smth like vcpkg (still, it's MS) without a hassle.

that's just my 2c from the packaging experience of the python bindings.

[nilsnolde]

was mostly battling x64 macos in the past commits. now everything's working and all wheels are uploaded as artifacts: https://github.com/Project-OSRM/osrm-backend/actions/runs/25164784497.

next I wanna try linux aarch64, but after merging:)

[DennisOSRM]

Great work!

[DennisOSRM]

What happens when the vcpkg pin changes? Will that incur a slow build of the many linux image once?

[nilsnolde]

mostly right. the barrier is basically whether any vcpkg update in upstream osrm-backend (only new version for whatever reason, new package etc) would break the OSRM compilation or python tests with the previous vcpkg still present in the previous manylinux image. if it does, the PR workflow will fail, I'll need to workflow_dispatch with the osrm-backend commit sha introducing that vcpkg change (i.e. build a new tagged image). if it doesn't, we don't have to care much about them being not in sync currently.

it's a bummer but kinda fair. the python builds failing won't be too obnoxious. they're the last steps to run, and only on a selection of jobs.

I do feel responsible for this now, but I invited at least you @DennisOSRM as collaborator in case I'm not available. eventually we could move the repo to the Project-OSRM org?

[DennisOSRM]

Perhaps after merging this change 😉

[nilsnolde]

thanks @DennisOSRM for the quick review. there was a master conflict, also changed a tiny thing in 4ed0a95.

[nilsnolde]

urgh, are you open to a force merge (if you have to) after I resolve this conflict and merge master @DennisOSRM ? lots of conflicts 😅

[DennisOSRM]

Thanks so much for the contribution. Glad, we could get it in this weekend.