Is it possible to pass generic executors in my project? #3302

inq · 2023-09-01T21:03:30Z

inq
Sep 1, 2023

Hello! I am using hyper 0.14 and implemented two custom Executors such as:

#[derive(Default, Clone)]
pub struct LocalExecutor;

impl<F> hyper::rt::Executor<F> for LocalExecutor
where
    F: std::future::Future,
{
    fn execute(&self, fut: F) {
        tokio::task::spawn_local(fut);
    }
}

#[derive(Default, Clone)]
pub struct MultiThreadExecutor;

impl<F> hyper::rt::Executor<F> for MultiThreadExecutor
where
    F: std::future::Future + Send,
    F::Output: Send,
{
    fn execute(&self, fut: F) {
        tokio::spawn(fut);
    }
}

Like the single-threaded example, It is okay to use these separately. But If I want to make a generic function to process both of them, I could not find any solution..

For example,

fn launch<S, E>(svc: S, exec: E) 
  where E: (What should I do??)
{
  // blabla...
  let server = hyper::server::Builder::new(incoming, Http::new().with_executor(exec));
  server.serve(svc)  // <- This causes error
}

Since Builder::serve requires these trait bounds, I think I should provide corresponding bounds

        E: NewSvcExec<I::Conn, S::Future, S::Service, E, NoopWatcher>,
        E: ConnStreamExec<<S::Service as HttpService<Body>>::Future, B>,

But the problem is these are crate-private traits.

And I've found these codes:

#[cfg(feature = "server")]
impl<E, F, B> ConnStreamExec<F, B> for E
where
    E: Executor<H2Stream<F, B>> + Clone,
    H2Stream<F, B>: Future<Output = ()>,
    B: HttpBody,
{
    fn execute_h2stream(&mut self, fut: H2Stream<F, B>) {
        self.execute(fut)
    }
}

#[cfg(all(feature = "server", any(feature = "http1", feature = "http2")))]
impl<I, N, S, E, W> NewSvcExec<I, N, S, E, W> for E
where
    E: Executor<NewSvcTask<I, N, S, E, W>> + Clone,
    NewSvcTask<I, N, S, E, W>: Future<Output = ()>,
    S: HttpService<Body>,
    W: Watcher<I, S, E>,
{
    fn execute_new_svc(&mut self, fut: NewSvcTask<I, N, S, E, W>) {
        self.execute(fut)
    }
}

But NewSvcTask and H2Stream are also private....

Can I ask any solution about this?

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Is it possible to pass generic executors in my project? #3302

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Is it possible to pass generic executors in my project? #3302

inq Sep 1, 2023

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inq
Sep 1, 2023