How can i use rate limit?

[B4TT3RY]

I want to apply a rate limit to my middleware.
I tried using RateLimitLayer on tower (v0.4.12), but I get a compile error.
How can I use it?

[davidpdrsn]

What's the error?

[davidpdrsn]

The issue is that rate limited services aren't cloneable, which kinda makes sense. If they were you'd be able to just clone them to fake being able to handle more load.

The solution is to use tower::buffer::BufferLayer to make the service cloneable by running it on a background task and sending requests to it via channel.

Something like this:

use axum::{error_handling::HandleErrorLayer, http::StatusCode, routing::get, BoxError, Router};
use std::{net::SocketAddr, time::Duration};
use tower::{buffer::BufferLayer, limit::RateLimitLayer, ServiceBuilder};

#[tokio::main]
async fn main() {
    let app = Router::new().route("/", get(|| async {})).layer(
        ServiceBuilder::new()
            .layer(HandleErrorLayer::new(|err: BoxError| async move {
                (
                    StatusCode::INTERNAL_SERVER_ERROR,
                    format!("Unhandled error: {}", err),
                )
            }))
            .layer(BufferLayer::new(1024))
            .layer(RateLimitLayer::new(5, Duration::from_secs(1))),
    );

    let addr = SocketAddr::from(([127, 0, 0, 1], 3000));
    axum::Server::bind(&addr)
        .serve(app.into_make_service())
        .await
        .unwrap();
}

[B4TT3RY]

Thank you very much!

[davidpdrsn]

np :)

[kimbauters]

Another big thanks! Most made sense, but that HandleErrorLayer was a tricky one (in hindsight obvious, of course, sigh).

[eboody]

thanks for this!