tower_retry/
lib.rs

1#![doc(html_root_url = "https://docs.rs/tower-retry/0.3.0")]
2#![warn(
3    missing_debug_implementations,
4    missing_docs,
5    rust_2018_idioms,
6    unreachable_pub
7)]
8#![allow(elided_lifetimes_in_paths)]
9
10//! Tower middleware for retrying "failed" requests.
11
12pub mod budget;
13pub mod future;
14mod layer;
15mod policy;
16
17pub use crate::layer::RetryLayer;
18pub use crate::policy::Policy;
19
20use crate::future::ResponseFuture;
21use pin_project::pin_project;
22use std::task::{Context, Poll};
23use tower_service::Service;
24
25/// Configure retrying requests of "failed" responses.
26///
27/// A `Policy` classifies what is a "failed" response.
28#[pin_project]
29#[derive(Clone, Debug)]
30pub struct Retry<P, S> {
31    #[pin]
32    policy: P,
33    service: S,
34}
35
36// ===== impl Retry =====
37
38impl<P, S> Retry<P, S> {
39    /// Retry the inner service depending on this `Policy`.
40    pub fn new(policy: P, service: S) -> Self {
41        Retry { policy, service }
42    }
43}
44
45impl<P, S, Request> Service<Request> for Retry<P, S>
46where
47    P: Policy<Request, S::Response, S::Error> + Clone,
48    S: Service<Request> + Clone,
49{
50    type Response = S::Response;
51    type Error = S::Error;
52    type Future = ResponseFuture<P, S, Request>;
53
54    fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
55        // NOTE: the Future::poll impl for ResponseFuture assumes that Retry::poll_ready is
56        // equivalent to Ready.service.poll_ready. If this ever changes, that code must be updated
57        // as well.
58        self.service.poll_ready(cx)
59    }
60
61    fn call(&mut self, request: Request) -> Self::Future {
62        let cloned = self.policy.clone_request(&request);
63        let future = self.service.call(request);
64
65        ResponseFuture::new(cloned, self.clone(), future)
66    }
67}
tower_retry/lib.rs

tower_retry/
lib.rs
