Trait RateLimitBackend

Source

pub trait RateLimitBackend:
    Send
    + Sync
    + 'static {
    // Required method
    fn check(
        &self,
        key: &str,
        quota: &Quota,
    ) -> impl Future<Output = RateLimitResult> + Send;
}

Expand description

Backend trait for rate limit state storage.

Uses native async fn in trait (MSRV 1.85) instead of #[async_trait], so a check dispatches no future boxing and no vtable call. The returned future is required to be Send so backends work on multi-threaded runtimes (the Tower layer’s boxed future, spawned tasks).

The trait is intentionally not dyn-compatible: every consumer in this crate is generic over B: RateLimitBackend, keeping the hot path statically dispatched. If you need heterogeneous backend sets, wrap them in your own enum rather than a dyn trait object.