Crate bounded_join_set

The bounded_join_set crate provides a simple wrapper around Tokio’s JoinSet with a configurable concurrency limit. It exposes the same API as the native JoinSet, but ensures that no matter how many tasks you add to the set, only a predetermined number (based on the concurrency limit) will be polled concurrently.

Why use bounded_join_set?

In scenarios where you want to spawn multiple concurrent tasks using Tokio, but want to avoid overwhelming the system with too many simultaneous tasks, bounded_join_set comes to the rescue. It ensures that you won’t exhaust system resources, while still benefiting from concurrency.

How to use

Add bounded_join_set to your Cargo.toml dependencies:

[dependencies]
bounded_join_set = "0.3.0"

Here’s a basic usage example:

use bounded_join_set::JoinSet;

#[tokio::main]
async fn main() {
    let concurrency_limit = 5;
    let mut join_set = JoinSet::new(concurrency_limit);

    for _ in 0..10 {
        join_set.spawn(async {
            // Your concurrent task here.
        });
    }

    while join_set.join_next().await.is_some() {}
}

Features & Benefits

• Simple API: If you’re familiar with Tokio’s JoinSet, you already know how to use bounded_join_set.
• Resource Management: Prevents system overloads by controlling the number of concurrently polled tasks.
• Flexible: Set your own concurrency limit according to your system’s capabilities and requirements.

Limitations

While bounded_join_set aims to offer an enhanced concurrency control over Tokio’s native JoinSet, there are certain limitations to be aware of:

• No spawn_blocking Support: As of the current version, the crate does not support the spawn_blocking method provided by Tokio. If your application relies heavily on CPU-bound operations that would benefit from the spawn_blocking feature, you’ll need to manage that separately from this crate. We are looking into extending support for this in future releases, but there’s no definite timeline yet.

Modules

tokio_exports

Re-export tokio types that are exposed in the api

Structs

JoinSet

Same as tokio::task::JoinSet except the number of actively polled futures is limited to a set concurrency.