Module singleflight 

A singleflight implementation for tokio.

Inspired by async_singleflight.

Examples

use std::sync::Arc;
use std::time::Duration;

use futures::future::join_all;
use xet_runtime::utils::singleflight::Group;

const RES: usize = 7;

async fn expensive_fn() -> Result<usize, ()> {
    tokio::time::sleep(Duration::new(1, 500)).await;
    Ok(RES)
}

#[tokio::main]
async fn main() {
    let g = Arc::new(Group::<_, ()>::new());
    let mut handlers = Vec::new();
    for _ in 0..10 {
        let g = g.clone();
        handlers.push(tokio::spawn(async move {
            let res = g.work("key", expensive_fn()).await.0;
            let r = res.unwrap();
            println!("{}", r);
        }));
    }

    join_all(handlers).await;
}

Re-exports

pub use super::errors::SingleflightError;

Structs

Group

Group represents a class of work and creates a space in which units of work can be executed with duplicate suppression.

Traits

ResultError

Indicates the Error type for a singleflight Group. The response might have been generated on a separate thread, thus, we need this type to be Send + Sync.

ResultType

ResultType indicates the success type for a singleflight Group. Since the actual processing might occur on a separate thread, we need to type to be Send + Sync. It also needs to be Clone so that we can clone the response across many tasks

TaskFuture

Futures provided to a singleflight Group must produce a Result<T, E> for some T, E. This future must also be Send as it could be spawned as a tokio task.