How to simplify tokio::join! when calls too much ?

[loongs-zhang]

    tokio::join!(request("1".to_string()),
    request("2".to_string()),
    request("3".to_string()),
    request("4".to_string()),
    // If there are thousands of such calls, how to simplify it?
    request("5".to_string()));

Can calls like the following be supported?

    // here, not just Vec, better if LinkedList and other collection can be supported
    let mut array = Vec::new();
    array.push(request("1".to_string()));
    tokio::join!(array);

[Darksonn]

When you are spawning a very large number of tasks, then you should be spawning them as separate tasks rather than using things like tokio::join! as this will lead to better performance. The code below shows how you can do that:

let mut handles = Vec::new();
for i in 0..1000 {
    handles.push(tokio::spawn(request(i.to_string())));
}

let mut output = Vec::with_capacity(handles.len());
for handle in handles {
    output.push(handle.await.unwrap());
}

Be aware that the above code will run them in parallel even though they are not immediately .awaited. This is due to the tokio::spawn call, which will start any task passed to it immediately.

We are currently working on new features to make this more convenient, see e.g. #4335.

[loongs-zhang]

Got it, thanks a lot.