Trait Store

Source

pub trait Store: Clone {
    type Future: Future<Output = Result<Usage, RateLimitError>>;

    // Required method
    fn increment(&self, key: &str, window: Duration) -> Self::Future;
}

Expand description

An asynchronous fixed-window rate-limit store.

Implementations receive a complete, policy-scoped key and must treat it as opaque. For each key, Store::increment must atomically create or increment one fixed window, start expiry on the first increment, and leave that expiry unchanged on later increments. The returned Usage includes the current increment, so used is at least one and reset_after is the remaining duration of the active window.

Clones of one Store value must observe the same counter state. Independently constructed Store values may use separate state. Backend failures are represented as RateLimitError::Store.

This trait intentionally requires Clone because super::RateLimitLayer clones its Store into each produced Service and super::RateLimit::call clones it into each request’s super::ResponseFuture. It does not require Send, Sync, or 'static, and its Future has no unconditional Send + 'static bound. Frameworks should add those concurrency bounds at the integration point. For example, a generic Store passed to Axum’s Router::layer normally needs S: Store + Send + Sync + 'static and S::Future: Send + 'static because Axum requires the resulting Layer, Service, and response Future to satisfy those bounds.