Re: Packaging a Python/Rust hybrid
On Mon, Nov 28, 2022 at 10:44 PM Kai A. Hiller <v02460(a)gmail.com> wrote:
Hello,
I am in the process of figuring out packaging of a Python/Rust hybrid
and have a few questions. Specifically, my work is on updating the
matrix-synapse package[0]. Synapse is originally a Python package, but
the developers started rewriting some critical parts in Rust and used
Pyo3 as glue. After a lot of experimentation, I hacked together a first
working copr build[1], but I don’t know how to get it into a clean shape
or how that even looks like exactly.
* Should I move the Rust parts into a subpackage? What are the
conventions then (e.g. for naming)?
* What is the best way to install a Rust-generated so-file as Python
module into the Python sitearch dir?
* Currently, I bypass python-setuptools-rust completely and went with
Fedora’s Rust macros. Is that the preferred path?
* Are there some useful macros/macro options I can utilize, and where
is manual work required instead?
Hi!
I suggest that you look at the python-cryptography package:
https://src.fedoraproject.org/rpms/python-cryptography/
It seems to be in the same situation, i.e. uses setuptools-rust and
PyO3. I would recommend doing something similar. setuptools-rust
actually works pretty well as far as I know, so you shouldn't need to
work around it at all.
I wonder why you think the "native" python extension should be in a
separate subpackage? It's not unusual for Python packages to ship
"native" extensions, and those aren't split off from the "main"
package - it's just no longer "noarch". setuptools_rust should already
do the correct thing here and install that extension .so into the
correct directory for architecture-dependent Python packages /
extensions.
Depending on the setup and layout of the Rust code inside
matrix-synapse, you might need to use workarounds for the
%cargo_generate_buildrequires macro, which doesn't support cargo
workspaces (yet, I mean to implement this once I have the time). Other
than that, there shouldn't be any "gotchas" if you do things like
they're done in python-cryptography.
Fabio