Struct RetryPolicy 

pub struct RetryPolicy { /* private fields */ }

Available on crate feature retry only.

Retries 429 Too Many Requests, 408 Request Timeout and 5xx responses, and failures to connect.

• It waits as long as the server asks, with retry-after-ms (milliseconds) or Retry-After (seconds or an HTTP date), up to RetryPolicy::max_retry_after (60 s by default). The wait is read once into a deadline, counted from when the response arrived, and the policy sleeps until it: time spent in between (reading a 429 body for RetryLayer::permanent_429) is not added. A server that asks for longer than max_retry_after gets its response returned at once: waiting less than it asked would likely fail again, and waiting an hour is rarely what a caller wants. A date in the past means retry now.
• With RetryPolicy::server_directed_429, a 429 is retried only when the server says when.
• Without those headers it backs off exponentially from RetryPolicy::base_delay (200 ms), doubling on each retry up to RetryPolicy::max_delay (8 s), with jitter: each delay is picked at random between half and all of it, so that clients that failed together do not retry together. RetryPolicy::jitter turns that off.
• It never retries a response marked Permanent (see RetryLayer::permanent_429), nor a request whose body is a stream (a streamed file upload), which cannot be sent again.

Implementations

impl RetryPolicy

pub fn new(max_retries: usize) -> Self

A policy that retries at most max_retries times (after the first attempt).

pub fn base_delay(self, delay: Duration) -> Self

The first backoff delay, doubled on each retry (default 200 ms).

pub fn max_delay(self, delay: Duration) -> Self

The longest backoff delay (default 8 s). It does not limit how long a server can ask to wait with Retry-After: that is RetryPolicy::max_retry_after.

pub fn max_retry_after(self, delay: Duration) -> Self

The longest wait a server can ask for with Retry-After or retry-after-ms (default 60 s). A response that asks for longer is not retried but returned.

pub fn jitter(self, jitter: bool) -> Self

Whether each backoff delay is picked at random between half and all of it (default true). The waits a server asks for are never jittered.

pub fn server_directed_429(self, server_directed: bool) -> Self

Whether a 429 is retried only when the server says when, with Retry-After or retry-after-ms (default false: every 429 is retried, with backoff when the server does not say when).

Some APIs answer a 429 without advice when waiting will not help (a quota, a request too large for a rate limit), and with it when it will. 408, 5xx and connect failures are retried either way.

pub fn max_retries(&self) -> usize

The number of retries allowed.

Trait Implementations

impl Clone for RetryPolicy

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for RetryPolicy

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

Formats the value using the given formatter.

impl Default for RetryPolicy

Three retries.

fn default() -> Self

Returns the “default value” for a type.

impl<B> Policy<Request<Body>, Response<B>, Box<dyn Error + Sync + Send>> for RetryPolicy

type Future = Pin<Box<dyn Future<Output = ()> + Send>>

The Future type returned by Policy::retry.

fn retry( &mut self, _request: &mut Request<Body>, result: &mut Result<Response<B>, BoxError>, ) -> Option<Self::Future>

Check the policy if a certain request should be retried.

fn clone_request(&mut self, request: &Request<Body>) -> Option<Request<Body>>

Tries to clone a request before being passed to the inner service.