ci: add riscv64 manylinux/musllinux wheels

[justeph]

Proposed new feature or change:

I'm opening this issue to start the discussion on what it would take to get the argon2-cffi-bindings project to build and distribute riscv64 manylinux/musllinux images.

Why now?

Until recently, it wasn't really possible for Python projects to build binary riscv64 wheels and to distribute those wheels via PyPI. Manylinux and cibuildwheel did not support riscv64 and PyPI did not allow riscv64 wheels to be uploaded. This all changed during the summer of 2025, when cibuildwheel (3.12), manylinux and warehouse all gained riscv64 support. Encouragingly, some projects (lxml, uv, maturin, and critically ninja) have already started uploading riscv64 wheels to PyPI.

Does argon2-cffi-bindings work on riscv64?

Yes. RISE has been building and distributing argon2-cffi-bindings manylinux wheels for riscv64 for several months (versions 21.2.0 and 25.1.0). Tested builds are available for riscv64 here.

What needs to be done?

If I am correct, there is no available native riscv-64 runner in GitHub. So build and test will involve emulation though QEMU.
Only a few additions to the github action file is needed to build and test a riscv64 wheel.

Note: riscv64 builds are slower due to emulation and currently take about 15 minutes.

I have a PR ready for review.

How can RISE help?

RISE is aware of the additional burden of supporting a new architecture, as mentioned scientific-python/summit-2025-nov#4. The RISE project should be able to assist by providing engineering resources, to debug riscv64 specific issues, and potentially native riscv64 runners, if required.

[hynek]

Thanks for reaching out! While I'm not enthusiastic to add a qemu build, just as I finally got rid of the ARM one, I'm open to adding RISC-V support under the condition that any problems with the build are gonna be not-my problems. I will absolutely not debug a 15 mins-long CI build if it breaks. So if it breaks and I won't be able to find anyone to help fixing it, I will remove those wheels again. How exactly do you imagine RISE's support to look like if something breaks? As in: what exactly would I be to do to get someone look at it?

[justeph]

Hi @hynek , I do understand your preoccupation. If you are ok to merge riscv-64 support you can ping me or @threexc to help. Also if you prefer, RISE should be able to freely provide native risc-v builder in a near future. Would you be interested in such builder?

[hynek]

Thanks for your understanding and as said, in general I'm open to it!

What would the exact implementation of the builder look like? I've never used anything outside GitHub Actions (and a little bit Circle CI).

[justeph]

Hi @hynek , RISE is working with an external partner, and the builders are not quite yet ready. I'll try to play around with it on my local fork of argon2-cffi-bindings, and I'll get back to you as soon as it's working properly

[hynek]

appreciated!

I have now merged your PR for now, but can you give me instructions how to independently verify the wheels are working before I do a release? Since releasing this project is a PITA (that's why I spun it out of argon2-cffi proper), I would prefer to not to have to do it more than once. :)

[justeph]

I didn't had time to dig more into the riscv64 builders yet.. This in on my todo list for sure!
Thank you for merging this :)
If you don't have any riscv64 hardware to test, you can use emulation with https://hub.docker.com/r/riscv64/ubuntu/. For example, with proper emulation set up, I use:

docker run --platform=linux/riscv64  --rm -ti riscv64/ubuntu:24.04  /bin/bash

Inside the docker you can install the riscv64 wheel and import it

[hynek]

hmmm so I've tried it and it doesn't seem to be working? I started the VM as you wrote, installed python3-venv, created one, built new wheels and tried to install them and neither Linux wheel worked:

root@e4b534b530fd:/# venv/bin/pip install argon2_cffi_bindings-25.1.1.dev35-cp39-abi3-manylinux_2_34_riscv64.manylinux_2_39_riscv64.whl
ERROR: argon2_cffi_bindings-25.1.1.dev35-cp39-abi3-manylinux_2_34_riscv64.manylinux_2_39_riscv64.whl is not a supported wheel on this platform.
root@e4b534b530fd:/# venv/bin/pip install argon2_cffi_bindings-25.1.1.dev35-cp39-abi3-musllinux_1_2_riscv64.whl
ERROR: argon2_cffi_bindings-25.1.1.dev35-cp39-abi3-musllinux_1_2_riscv64.whl is not a supported wheel on this platform.

What am I missing?

[justeph]

I think pip is too old, you need a fairly recent pip to install manylinux_riscv64 wheels, so you can:

pip install --upgrade pip

so the manylinux wheel can be processed.

But, there is another issue I forgot: when installing argon2-cffi-bindings we obviously need cffi for riscv64... which is not yet available on PyPI :(

If you look at the Action run, the wheel is built and it test correctly because when the wheel is built, cffi is also built, and cached. This is also why the build is longer for riscv64...

I already opened a PR to add riscv64 support for cffi here python-cffi/cffi#227.

If you really want to test the wheel you can use cffi from RISE registry, by adding --prefer-binary --extra-index-url https://gitlab.com/api/v4/projects/riseproject%2Fpython%2Fwheel_builder/packages/pypi/simple :

(venv) root@a2eaefe86e18:/projectt# pip install ./argon2_cffi_bindings-25.1.1.dev35-cp39-abi3-manylinux_2_34_riscv64.manylinux_2_39_riscv64.whl  --prefer-binary --extra-index-url https://gitlab.com/api/v4/projects/riseproject%2Fpython%2Fwheel_builder/packages/pypi/simple
Looking in indexes: https://pypi.org/simple, https://gitlab.com/api/v4/projects/riseproject%2Fpython%2Fwheel_builder/packages/pypi/simple
Processing ./argon2_cffi_bindings-25.1.1.dev35-cp39-abi3-manylinux_2_34_riscv64.manylinux_2_39_riscv64.whl
Collecting cffi>=1.0.1 (from argon2-cffi-bindings==25.1.1.dev35)
  Downloading https://gitlab.com/api/v4/projects/56254198/packages/pypi/files/fe8602be8166f3048be874c76d9f062154ae71c3d58cb8e995b9493b3a937484/cffi-2.0.0-cp312-cp312-manylinux_2_38_riscv64.manylinux_2_39_riscv64.whl (481 kB)
Collecting pycparser (from cffi>=1.0.1->argon2-cffi-bindings==25.1.1.dev35)
  Using cached pycparser-3.0-py3-none-any.whl.metadata (8.2 kB)
Using cached pycparser-3.0-py3-none-any.whl (48 kB)
Installing collected packages: pycparser, cffi, argon2-cffi-bindings
Successfully installed argon2-cffi-bindings-25.1.1.dev35 cffi-2.0.0 pycparser-3.0

So I guess we should wait for cffi to release riscv64 wheels first.. Maybe you can ping cffi on the issue also ;)

[hynek]

oof yeah, I've subscribed to your issue over there. maybe y'all manage to have fast builders by then 😇

[hynek]

So while waiting endlessly for my PR runs, I remembered that I've seen somewhere mentioned that RISC-V runners are a thing now?

[threexc]

So while waiting endlessly for my PR runs, I remembered that I've seen somewhere mentioned that RISC-V runners are a thing now?

Maybe you mean this? https://riseproject-dev.github.io/riscv-runner/