Add basic Rust interfaces

[gi0baro]

Basics:

• scheduling Python callbacks (mimic call_soon)
• scheduling Python callbacks with specific delay (mimic call_later)

Nice to have:

• Future wrapping (eg: create a special subclass of asyncio.Future that allows to set a result from Rust and react to cancellations

Having pyo3 and a Py<EventLoop> ref (could be stored in Rust) should be enough:

fn my_rust_fn(event_loop: &Py<EventLoop>, callback: PyObject) {
    let arg = "foo";
    let args: PyObject = Python::with_gil(|py| (arg,).into_py_any(py).unwrap());
    // call soon
    event_loop.schedule(callback, args);
    // call later (5s)
    event_loop.schedule_later(std::time::Duration::new(5, 0), callback, args);
}

[mikeleppane]

Hi! I recently watched your PyCon IT 25 talk and thought I could help. Is this issue something I could take on and try out?

[gi0baro]

@mikeleppane any form of help is very welcome ❤️

Specifically on this one though, I think the only missing part at the time being – other than discussing whether the API make sense – is docs and eventually publish the thing to crates.io, as:

• event_loop.EventLoop is already public and expose the following methods:
  • schedule0
  • schedule1
  • schedule
  • schedule_later0
  • schedule_later1
  • schedule_later
  • schedule_handle
• handles.Handle trait is already public

I guess testing is the other big missing part, as at the moment – and to my knowledge – there are no projects out there using rloop directly in Rust code.

[alanjds]

About the testing, do you think it would be helpful to have something that tests asyncio to install rloop and then check if it behaved correctly?

[gi0baro]

About the testing, do you think it would be helpful to have something that tests asyncio to install rloop and then check if it behaved correctly?

🤔 the tests already do what you're implying. Also, this issue is about the Rust interfaces, not the Python ones..

[alanjds]

Oh, ok. Sorry for that. Now I got what you meant. Thanks for the explanation 👍