| <!DOCTYPE html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta name="generator" content="rustdoc"><meta name="description" content="Source of the Rust file `/root/.cargo/registry/src/github.com-1ecc6299db9ec823/tower-0.4.13/src/load/pending_requests.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>pending_requests.rs - source</title><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceSerif4-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../FiraSans-Regular.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../FiraSans-Medium.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceCodePro-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceSerif4-Bold.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceCodePro-Semibold.ttf.woff2"><link rel="stylesheet" href="../../../normalize.css"><link rel="stylesheet" href="../../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" href="../../../ayu.css" disabled><link rel="stylesheet" href="../../../dark.css" disabled><link rel="stylesheet" href="../../../light.css" id="themeStyle"><script id="default-settings" ></script><script src="../../../storage.js"></script><script defer src="../../../source-script.js"></script><script defer src="../../../source-files.js"></script><script defer src="../../../main.js"></script><noscript><link rel="stylesheet" href="../../../noscript.css"></noscript><link rel="alternate icon" type="image/png" href="../../../favicon-16x16.png"><link rel="alternate icon" type="image/png" href="../../../favicon-32x32.png"><link rel="icon" type="image/svg+xml" href="../../../favicon.svg"></head><body class="rustdoc source"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><a class="sidebar-logo" href="../../../tower/index.html"><div class="logo-container"><img class="rust-logo" src="../../../rust-logo.svg" alt="logo"></div></a></nav><main><div class="width-limiter"><nav class="sub"><a class="sub-logo-container" href="../../../tower/index.html"><img class="rust-logo" src="../../../rust-logo.svg" alt="logo"></a><form class="search-form"><div class="search-container"><span></span><input class="search-input" name="search" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><div id="help-button" title="help" tabindex="-1"><a href="../../../help.html">?</a></div><div id="settings-menu" tabindex="-1"><a href="../../../settings.html" title="settings"><img width="22" height="22" alt="Change settings" src="../../../wheel.svg"></a></div></div></form></nav><section id="main-content" class="content"><div class="example-wrap"><pre class="src-line-numbers"><span id="1">1</span> |
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| </pre><pre class="rust"><code><span class="doccomment">//! A [`Load`] implementation that measures load using the number of in-flight requests. |
| |
| </span><span class="attribute">#[cfg(feature = <span class="string">"discover"</span>)] |
| </span><span class="kw">use </span><span class="kw">crate</span>::discover::{Change, Discover}; |
| <span class="attribute">#[cfg(feature = <span class="string">"discover"</span>)] |
| </span><span class="kw">use </span>futures_core::{ready, Stream}; |
| <span class="attribute">#[cfg(feature = <span class="string">"discover"</span>)] |
| </span><span class="kw">use </span>pin_project_lite::pin_project; |
| <span class="attribute">#[cfg(feature = <span class="string">"discover"</span>)] |
| </span><span class="kw">use </span>std::pin::Pin; |
| |
| <span class="kw">use </span><span class="kw">super</span>::completion::{CompleteOnResponse, TrackCompletion, TrackCompletionFuture}; |
| <span class="kw">use </span><span class="kw">super</span>::Load; |
| <span class="kw">use </span>std::sync::Arc; |
| <span class="kw">use </span>std::task::{Context, Poll}; |
| <span class="kw">use </span>tower_service::Service; |
| |
| <span class="doccomment">/// Measures the load of the underlying service using the number of currently-pending requests. |
| </span><span class="attribute">#[derive(Debug)] |
| </span><span class="kw">pub struct </span>PendingRequests<S, C = CompleteOnResponse> { |
| service: S, |
| ref_count: RefCount, |
| completion: C, |
| } |
| |
| <span class="doccomment">/// Shared between instances of [`PendingRequests`] and [`Handle`] to track active references. |
| </span><span class="attribute">#[derive(Clone, Debug, Default)] |
| </span><span class="kw">struct </span>RefCount(Arc<()>); |
| |
| <span class="attribute">#[cfg(feature = <span class="string">"discover"</span>)] |
| </span><span class="macro">pin_project! </span>{ |
| <span class="doccomment">/// Wraps a `D`-typed stream of discovered services with [`PendingRequests`]. |
| </span><span class="attribute">#[cfg_attr(docsrs, doc(cfg(feature = <span class="string">"discover"</span>)))] |
| #[derive(Debug)] |
| </span><span class="kw">pub struct </span>PendingRequestsDiscover<D, C = CompleteOnResponse> { |
| <span class="attribute">#[pin] |
| </span>discover: D, |
| completion: C, |
| } |
| } |
| |
| <span class="doccomment">/// Represents the number of currently-pending requests to a given service. |
| </span><span class="attribute">#[derive(Clone, Copy, Debug, Default, PartialOrd, PartialEq, Ord, Eq)] |
| </span><span class="kw">pub struct </span>Count(usize); |
| |
| <span class="doccomment">/// Tracks an in-flight request by reference count. |
| </span><span class="attribute">#[derive(Debug)] |
| </span><span class="kw">pub struct </span>Handle(RefCount); |
| |
| <span class="comment">// ===== impl PendingRequests ===== |
| |
| </span><span class="kw">impl</span><S, C> PendingRequests<S, C> { |
| <span class="doccomment">/// Wraps an `S`-typed service so that its load is tracked by the number of pending requests. |
| </span><span class="kw">pub fn </span>new(service: S, completion: C) -> <span class="self">Self </span>{ |
| <span class="self">Self </span>{ |
| service, |
| completion, |
| ref_count: RefCount::default(), |
| } |
| } |
| |
| <span class="kw">fn </span>handle(<span class="kw-2">&</span><span class="self">self</span>) -> Handle { |
| Handle(<span class="self">self</span>.ref_count.clone()) |
| } |
| } |
| |
| <span class="kw">impl</span><S, C> Load <span class="kw">for </span>PendingRequests<S, C> { |
| <span class="kw">type </span>Metric = Count; |
| |
| <span class="kw">fn </span>load(<span class="kw-2">&</span><span class="self">self</span>) -> Count { |
| <span class="comment">// Count the number of references that aren't `self`. |
| </span>Count(<span class="self">self</span>.ref_count.ref_count() - <span class="number">1</span>) |
| } |
| } |
| |
| <span class="kw">impl</span><S, C, Request> Service<Request> <span class="kw">for </span>PendingRequests<S, C> |
| <span class="kw">where |
| </span>S: Service<Request>, |
| C: TrackCompletion<Handle, S::Response>, |
| { |
| <span class="kw">type </span>Response = C::Output; |
| <span class="kw">type </span>Error = S::Error; |
| <span class="kw">type </span>Future = TrackCompletionFuture<S::Future, C, Handle>; |
| |
| <span class="kw">fn </span>poll_ready(<span class="kw-2">&mut </span><span class="self">self</span>, cx: <span class="kw-2">&mut </span>Context<<span class="lifetime">'_</span>>) -> Poll<<span class="prelude-ty">Result</span><(), <span class="self">Self</span>::Error>> { |
| <span class="self">self</span>.service.poll_ready(cx) |
| } |
| |
| <span class="kw">fn </span>call(<span class="kw-2">&mut </span><span class="self">self</span>, req: Request) -> <span class="self">Self</span>::Future { |
| TrackCompletionFuture::new( |
| <span class="self">self</span>.completion.clone(), |
| <span class="self">self</span>.handle(), |
| <span class="self">self</span>.service.call(req), |
| ) |
| } |
| } |
| |
| <span class="comment">// ===== impl PendingRequestsDiscover ===== |
| |
| </span><span class="attribute">#[cfg(feature = <span class="string">"discover"</span>)] |
| </span><span class="kw">impl</span><D, C> PendingRequestsDiscover<D, C> { |
| <span class="doccomment">/// Wraps a [`Discover`], wrapping all of its services with [`PendingRequests`]. |
| </span><span class="kw">pub fn </span>new<Request>(discover: D, completion: C) -> <span class="self">Self |
| </span><span class="kw">where |
| </span>D: Discover, |
| D::Service: Service<Request>, |
| C: TrackCompletion<Handle, <D::Service <span class="kw">as </span>Service<Request>>::Response>, |
| { |
| <span class="self">Self </span>{ |
| discover, |
| completion, |
| } |
| } |
| } |
| |
| <span class="attribute">#[cfg(feature = <span class="string">"discover"</span>)] |
| </span><span class="kw">impl</span><D, C> Stream <span class="kw">for </span>PendingRequestsDiscover<D, C> |
| <span class="kw">where |
| </span>D: Discover, |
| C: Clone, |
| { |
| <span class="kw">type </span>Item = <span class="prelude-ty">Result</span><Change<D::Key, PendingRequests<D::Service, C>>, D::Error>; |
| |
| <span class="doccomment">/// Yields the next discovery change set. |
| </span><span class="kw">fn </span>poll_next(<span class="self">self</span>: Pin<<span class="kw-2">&mut </span><span class="self">Self</span>>, cx: <span class="kw-2">&mut </span>Context<<span class="lifetime">'_</span>>) -> Poll<<span class="prelude-ty">Option</span><<span class="self">Self</span>::Item>> { |
| <span class="kw">use </span><span class="self">self</span>::Change::<span class="kw-2">*</span>; |
| |
| <span class="kw">let </span>this = <span class="self">self</span>.project(); |
| <span class="kw">let </span>change = <span class="kw">match </span><span class="macro">ready!</span>(this.discover.poll_discover(cx)).transpose()<span class="question-mark">? </span>{ |
| <span class="prelude-val">None </span>=> <span class="kw">return </span>Poll::Ready(<span class="prelude-val">None</span>), |
| <span class="prelude-val">Some</span>(Insert(k, svc)) => Insert(k, PendingRequests::new(svc, this.completion.clone())), |
| <span class="prelude-val">Some</span>(Remove(k)) => Remove(k), |
| }; |
| |
| Poll::Ready(<span class="prelude-val">Some</span>(<span class="prelude-val">Ok</span>(change))) |
| } |
| } |
| |
| <span class="comment">// ==== RefCount ==== |
| |
| </span><span class="kw">impl </span>RefCount { |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>ref_count(<span class="kw-2">&</span><span class="self">self</span>) -> usize { |
| Arc::strong_count(<span class="kw-2">&</span><span class="self">self</span>.<span class="number">0</span>) |
| } |
| } |
| |
| <span class="attribute">#[cfg(test)] |
| </span><span class="kw">mod </span>tests { |
| <span class="kw">use super</span>::<span class="kw-2">*</span>; |
| <span class="kw">use </span>futures_util::future; |
| <span class="kw">use </span>std::task::{Context, Poll}; |
| |
| <span class="kw">struct </span>Svc; |
| <span class="kw">impl </span>Service<()> <span class="kw">for </span>Svc { |
| <span class="kw">type </span>Response = (); |
| <span class="kw">type </span>Error = (); |
| <span class="kw">type </span>Future = future::Ready<<span class="prelude-ty">Result</span><(), ()>>; |
| |
| <span class="kw">fn </span>poll_ready(<span class="kw-2">&mut </span><span class="self">self</span>, <span class="kw">_</span>: <span class="kw-2">&mut </span>Context<<span class="lifetime">'_</span>>) -> Poll<<span class="prelude-ty">Result</span><(), ()>> { |
| Poll::Ready(<span class="prelude-val">Ok</span>(())) |
| } |
| |
| <span class="kw">fn </span>call(<span class="kw-2">&mut </span><span class="self">self</span>, (): ()) -> <span class="self">Self</span>::Future { |
| future::ok(()) |
| } |
| } |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>default() { |
| <span class="kw">let </span><span class="kw-2">mut </span>svc = PendingRequests::new(Svc, CompleteOnResponse); |
| <span class="macro">assert_eq!</span>(svc.load(), Count(<span class="number">0</span>)); |
| |
| <span class="kw">let </span>rsp0 = svc.call(()); |
| <span class="macro">assert_eq!</span>(svc.load(), Count(<span class="number">1</span>)); |
| |
| <span class="kw">let </span>rsp1 = svc.call(()); |
| <span class="macro">assert_eq!</span>(svc.load(), Count(<span class="number">2</span>)); |
| |
| <span class="kw">let </span>() = tokio_test::block_on(rsp0).unwrap(); |
| <span class="macro">assert_eq!</span>(svc.load(), Count(<span class="number">1</span>)); |
| |
| <span class="kw">let </span>() = tokio_test::block_on(rsp1).unwrap(); |
| <span class="macro">assert_eq!</span>(svc.load(), Count(<span class="number">0</span>)); |
| } |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>with_completion() { |
| <span class="attribute">#[derive(Clone)] |
| </span><span class="kw">struct </span>IntoHandle; |
| <span class="kw">impl </span>TrackCompletion<Handle, ()> <span class="kw">for </span>IntoHandle { |
| <span class="kw">type </span>Output = Handle; |
| <span class="kw">fn </span>track_completion(<span class="kw-2">&</span><span class="self">self</span>, i: Handle, (): ()) -> Handle { |
| i |
| } |
| } |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>svc = PendingRequests::new(Svc, IntoHandle); |
| <span class="macro">assert_eq!</span>(svc.load(), Count(<span class="number">0</span>)); |
| |
| <span class="kw">let </span>rsp = svc.call(()); |
| <span class="macro">assert_eq!</span>(svc.load(), Count(<span class="number">1</span>)); |
| <span class="kw">let </span>i0 = tokio_test::block_on(rsp).unwrap(); |
| <span class="macro">assert_eq!</span>(svc.load(), Count(<span class="number">1</span>)); |
| |
| <span class="kw">let </span>rsp = svc.call(()); |
| <span class="macro">assert_eq!</span>(svc.load(), Count(<span class="number">2</span>)); |
| <span class="kw">let </span>i1 = tokio_test::block_on(rsp).unwrap(); |
| <span class="macro">assert_eq!</span>(svc.load(), Count(<span class="number">2</span>)); |
| |
| drop(i1); |
| <span class="macro">assert_eq!</span>(svc.load(), Count(<span class="number">1</span>)); |
| |
| drop(i0); |
| <span class="macro">assert_eq!</span>(svc.load(), Count(<span class="number">0</span>)); |
| } |
| } |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../../" data-current-crate="tower" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |
