Add AlbHealthCheckLayer
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| Original file line number | Diff line number | Diff line change | ||||
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| @@ -0,0 +1,176 @@ | ||||||
| /* | ||||||
| * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved. | ||||||
| * SPDX-License-Identifier: Apache-2.0 | ||||||
| */ | ||||||
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| //! Middleware for handling [ALB health | ||||||
| //! checks](https://docs.aws.amazon.com/elasticloadbalancing/latest/application/target-group-health-checks.html). | ||||||
| //! | ||||||
| //! # Example | ||||||
| //! | ||||||
| //! ```no_run | ||||||
| //! # use aws_smithy_http_server::{body, plugin::{PluginPipeline, alb_health_check::AlbHealthCheckLayer}}; | ||||||
| //! # use hyper::{Body, Response, StatusCode}; | ||||||
| //! let plugins = PluginPipeline::new() | ||||||
| //! // Handle all `/ping` health check requests by returning a `200 OK`. | ||||||
| //! .http_layer(AlbHealthCheckLayer::from_handler("/ping", |_req| async { | ||||||
| //! StatusCode::OK | ||||||
| //! })); | ||||||
| //! | ||||||
| //! ``` | ||||||
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| use std::borrow::Cow; | ||||||
| use std::convert::Infallible; | ||||||
| use std::task::{Context, Poll}; | ||||||
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| use futures_util::{Future, FutureExt}; | ||||||
| use http::StatusCode; | ||||||
| use hyper::{Body, Request, Response}; | ||||||
| use pin_project_lite::pin_project; | ||||||
| use tower::{service_fn, util::Oneshot, Layer, Service, ServiceExt}; | ||||||
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| use crate::body::BoxBody; | ||||||
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| use super::either::EitherProj; | ||||||
| use super::Either; | ||||||
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| /// A [`tower::Layer`] used to apply [`AlbHealthCheckService`]. | ||||||
| #[derive(Clone, Debug)] | ||||||
| pub struct AlbHealthCheckLayer<HealthCheckHandler> { | ||||||
| health_check_uri: Cow<'static, str>, | ||||||
| health_check_handler: HealthCheckHandler, | ||||||
| } | ||||||
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| impl AlbHealthCheckLayer<()> { | ||||||
| /// Handle health check requests at `health_check_uri` with the specified handler. | ||||||
| pub fn from_handler<HandlerFuture: Future<Output = StatusCode>, H: Fn(Request<Body>) -> HandlerFuture + Clone>( | ||||||
| health_check_uri: impl Into<Cow<'static, str>>, | ||||||
| health_check_handler: H, | ||||||
| ) -> AlbHealthCheckLayer< | ||||||
| impl Service< | ||||||
| Request<Body>, | ||||||
| Response = StatusCode, | ||||||
| Error = Infallible, | ||||||
| Future = impl Future<Output = Result<StatusCode, Infallible>>, | ||||||
| > + Clone, | ||||||
| > { | ||||||
| let service = service_fn(move |req| health_check_handler(req).map(Ok)); | ||||||
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| AlbHealthCheckLayer::new(health_check_uri, service) | ||||||
| } | ||||||
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| /// Handle health check requests at `health_check_uri` with the specified service. | ||||||
| pub fn new<H: Service<Request<Body>, Response = StatusCode>>( | ||||||
| health_check_uri: impl Into<Cow<'static, str>>, | ||||||
| health_check_handler: H, | ||||||
| ) -> AlbHealthCheckLayer<H> { | ||||||
| AlbHealthCheckLayer { | ||||||
| health_check_uri: health_check_uri.into(), | ||||||
| health_check_handler, | ||||||
| } | ||||||
| } | ||||||
| } | ||||||
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| impl<S, H: Clone> Layer<S> for AlbHealthCheckLayer<H> { | ||||||
| type Service = AlbHealthCheckService<H, S>; | ||||||
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| fn layer(&self, inner: S) -> Self::Service { | ||||||
| AlbHealthCheckService { | ||||||
| inner, | ||||||
| layer: self.clone(), | ||||||
| } | ||||||
| } | ||||||
| } | ||||||
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| /// A middleware [`Service`] responsible for handling health check requests. | ||||||
| #[derive(Clone, Debug)] | ||||||
| pub struct AlbHealthCheckService<H, S> { | ||||||
| inner: S, | ||||||
| layer: AlbHealthCheckLayer<H>, | ||||||
| } | ||||||
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| impl<H, S> Service<Request<Body>> for AlbHealthCheckService<H, S> | ||||||
| where | ||||||
| S: Service<Request<Body>, Response = Response<BoxBody>> + Clone, | ||||||
| S::Future: std::marker::Send + 'static, | ||||||
|
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| H: Service<Request<Body>, Response = StatusCode, Error = Infallible> + Clone, | ||||||
| { | ||||||
| type Response = S::Response; | ||||||
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| type Error = S::Error; | ||||||
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| type Future = AlbHealthCheckFuture<H, S>; | ||||||
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| fn poll_ready(&mut self, _cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> { | ||||||
| // The check that the service is ready is done by `Oneshot` below. | ||||||
| Poll::Ready(Ok(())) | ||||||
| } | ||||||
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| fn call(&mut self, req: Request<Body>) -> Self::Future { | ||||||
| if req.uri() == self.layer.health_check_uri.as_ref() { | ||||||
| let clone = self.layer.health_check_handler.clone(); | ||||||
| let service = std::mem::replace(&mut self.layer.health_check_handler, clone); | ||||||
| let handler_future = service.oneshot(req); | ||||||
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| AlbHealthCheckFuture::handler_future(handler_future) | ||||||
| } else { | ||||||
| let clone = self.inner.clone(); | ||||||
| let service = std::mem::replace(&mut self.inner, clone); | ||||||
| let service_future = service.oneshot(req); | ||||||
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| AlbHealthCheckFuture::service_future(service_future) | ||||||
| } | ||||||
| } | ||||||
| } | ||||||
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| type HealthCheckFutureInner<H, S> = Either<Oneshot<H, Request<Body>>, Oneshot<S, Request<Body>>>; | ||||||
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| pin_project! { | ||||||
| /// Future for [`AlbHealthCheckService`]. | ||||||
| pub struct AlbHealthCheckFuture<H: Service<Request<Body>, Response = StatusCode>, S: Service<Request<Body>>> { | ||||||
| #[pin] | ||||||
| inner: HealthCheckFutureInner<H, S> | ||||||
| } | ||||||
| } | ||||||
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| impl<H: Service<Request<Body>, Response = StatusCode>, S: Service<Request<Body>>> AlbHealthCheckFuture<H, S> { | ||||||
| fn handler_future(handler_future: Oneshot<H, Request<Body>>) -> Self { | ||||||
| Self { | ||||||
| inner: Either::Left { value: handler_future }, | ||||||
| } | ||||||
| } | ||||||
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| fn service_future(service_future: Oneshot<S, Request<Body>>) -> Self { | ||||||
| Self { | ||||||
| inner: Either::Right { value: service_future }, | ||||||
| } | ||||||
| } | ||||||
| } | ||||||
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| impl< | ||||||
| H: Service<Request<Body>, Response = StatusCode, Error = Infallible>, | ||||||
| S: Service<Request<Body>, Response = Response<BoxBody>>, | ||||||
| > Future for AlbHealthCheckFuture<H, S> | ||||||
| { | ||||||
| type Output = Result<S::Response, S::Error>; | ||||||
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| fn poll(self: std::pin::Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { | ||||||
| let either_proj = self.project().inner.project(); | ||||||
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| match either_proj { | ||||||
| EitherProj::Left { value } => { | ||||||
| let polled: Poll<Self::Output> = value.poll(cx).map(|res| { | ||||||
| res.map(|status_code| { | ||||||
| Response::builder() | ||||||
| .status(status_code) | ||||||
| .body(crate::body::empty()) | ||||||
| .unwrap() | ||||||
| }) | ||||||
| .map_err(|never| match never {}) | ||||||
| }); | ||||||
| polled | ||||||
| } | ||||||
| EitherProj::Right { value } => value.poll(cx), | ||||||
| } | ||||||
| } | ||||||
| } | ||||||
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
|
|
@@ -118,6 +118,7 @@ | |
| //! ``` | ||
| //! | ||
|
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| pub mod alb_health_check; | ||
| mod closure; | ||
| mod either; | ||
| mod filter; | ||
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|
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nit: these bounds would read nicer in a where clause.