lelet
A golang like task executor
Lelet executor
Task executor that inspired by golang runtime.
The executor is running in thread pool, and when it detect blocking call inside a task, it will automatically scale the thread pool.
Because of this feature, it is always safe for you to do blocking operation in a task, you don't need to worry about blocking the entire executor thread.
Installation
With cargo add installed run:
$ cargo add leletExample
use std::thread;
use std::time::Duration;
use futures_timer::Delay;
fn main() {
lelet::spawn(async {
for _ in 0..10 {
Delay::new(Duration::from_secs(1)).await;
println!("Non-blocking Hello World");
}
});
lelet::spawn(async {
for _ in 0..10 {
thread::sleep(Duration::from_secs(1));
println!("Blocking Hello World");
}
});
thread::sleep(Duration::from_secs(11));
}How about IO
lelet-io is still on progress, in the meantime you can use async IO library from tokio
for example HTTP server using hyper
use std::convert::Infallible;
use std::thread;
use std::time::Duration;
use hyper::service::{make_service_fn, service_fn};
use hyper::{Body, Request, Response, Server, StatusCode};
async fn handler(request: Request<Body>) -> Result<Response<Body>, Infallible> {
match request.uri().path() {
"/" => Ok(Response::new(Body::from("Hello World!"))),
"/blocking" => {
thread::sleep(Duration::from_secs(5));
Ok(Response::new(Body::from("Blocking Hello World!")))
}
_ => {
let mut resp = Response::new(Body::from("404 Not Found"));
*resp.status_mut() = StatusCode::NOT_FOUND;
Ok(resp)
}
}
}
fn main() {
tokio::runtime::Builder::new()
.enable_io()
.build()
.unwrap()
.block_on(async {
let addr = "127.0.0.1:3000";
let listener = tokio::net::TcpListener::bind(addr).await.unwrap();
let make_svc =
make_service_fn(|_conn| async { Ok::<_, Infallible>(service_fn(handler)) });
let server = Server::builder(compat::TcpListener(listener))
.executor(compat::Executor)
.serve(make_svc);
println!("Listening on http://{}", addr);
server.await.unwrap();
});
}
pub mod compat {
use std::future::Future;
use std::io;
use std::pin::Pin;
use std::task::{Context, Poll};
use hyper::server::accept::Accept;
use tokio::io::{AsyncRead, AsyncWrite};
#[derive(Clone)]
pub struct Executor;
impl<F> hyper::rt::Executor<F> for Executor
where
F: Future + Send + 'static,
F::Output: Send + 'static,
{
fn execute(&self, fut: F) {
lelet::spawn(fut);
}
}
pub struct TcpListener(pub tokio::net::TcpListener);
impl Accept for TcpListener {
type Conn = TcpStream;
type Error = io::Error;
fn poll_accept(
mut self: Pin<&mut Self>,
cx: &mut Context,
) -> Poll<Option<Result<Self::Conn, Self::Error>>> {
Pin::new(&mut self.0.incoming())
.poll_accept(cx)
.map(|result| Some(result.map(TcpStream)))
}
}
pub struct TcpStream(pub tokio::net::TcpStream);
impl AsyncRead for TcpStream {
fn poll_read(
mut self: Pin<&mut Self>,
cx: &mut Context,
buf: &mut [u8],
) -> Poll<io::Result<usize>> {
Pin::new(&mut self.0).poll_read(cx, buf)
}
}
impl AsyncWrite for TcpStream {
fn poll_write(
mut self: Pin<&mut Self>,
cx: &mut Context,
buf: &[u8],
) -> Poll<io::Result<usize>> {
Pin::new(&mut self.0).poll_write(cx, buf)
}
fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<io::Result<()>> {
Pin::new(&mut self.0).poll_flush(cx)
}
fn poll_shutdown(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<io::Result<()>> {
Pin::new(&mut self.0).poll_shutdown(cx)
}
}
}then test multiple request to /blocking, all of them will complete within 5 second
bash -c '
date
for i in {0..20}; do
curl localhost:3000/blocking -s -o /dev/null &
done
wait
date
'
