Async Channels
Several crates have support for asynchronous channels. For instance tokio
:
use tokio::sync::mpsc::{self, Receiver}; async fn ping_handler(mut input: Receiver<()>) { let mut count: usize = 0; while let Some(_) = input.recv().await { count += 1; println!("Received {count} pings so far."); } println!("ping_handler complete"); } #[tokio::main] async fn main() { let (sender, receiver) = mpsc::channel(32); let ping_handler_task = tokio::spawn(ping_handler(receiver)); for i in 0..10 { sender.send(()).await.expect("Failed to send ping."); println!("Sent {} pings so far.", i + 1); } drop(sender); ping_handler_task.await.expect("Something went wrong in ping handler task."); }
This slide should take about 8 minutes.
-
Change the channel size to
3
and see how it affects the execution. -
Overall, the interface is similar to the
sync
channels as seen in the morning class. -
Try removing the
std::mem::drop
call. What happens? Why? -
The Flume crate has channels that implement both
sync
andasync
send
andrecv
. This can be convenient for complex applications with both IO and heavy CPU processing tasks. -
What makes working with
async
channels preferable is the ability to combine them with otherfuture
s to combine them and create complex control flow.