Struct tower::hedge::Hedge

pub struct Hedge<S, P>(/* private fields */);

Available on crate feature hedge only.

A middleware that pre-emptively retries requests which have been outstanding for longer than a given latency percentile. If either of the original future or the retry future completes, that value is used.

Implementations

impl<S, P> Hedge<S, P>

pub fn new<Request>( service: S, policy: P, min_data_points: u64, latency_percentile: f32, period: Duration, ) -> Hedge<S, P>

where S: Service<Request> + Clone, S::Error: Into<BoxError>, P: Policy<Request> + Clone,

Create a new hedge middleware.

pub fn new_with_mock_latencies<Request>( service: S, policy: P, min_data_points: u64, latency_percentile: f32, period: Duration, latencies_ms: &[u64], ) -> Hedge<S, P>

where S: Service<Request> + Clone, S::Error: Into<BoxError>, P: Policy<Request> + Clone,

A hedge middleware with a prepopulated latency histogram. This is usedful for integration tests.

Trait Implementations

impl<S: Debug, P: Debug> Debug for Hedge<S, P>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<S, P, Request> Service<Request> for Hedge<S, P>

where S: Service<Request> + Clone, S::Error: Into<BoxError>, P: Policy<Request> + Clone,

type Response = <S as Service<Request>>::Response

Responses given by the service.

type Error = Box<dyn Error + Sync + Send>

Errors produced by the service.

type Future = Future<Select<SelectPolicy<P>, Latency<Arc<Mutex<RotatingHistogram>>, S>, Delay<DelayPolicy, AsyncFilter<Latency<Arc<Mutex<RotatingHistogram>>, S>, PolicyPredicate<P>>>>, Request>

The future response value.

fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>>

Returns Poll::Ready(Ok(())) when the service is able to process requests.

fn call(&mut self, request: Request) -> Self::Future

Process the request and return the response asynchronously.