| <!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/limit/rate/service.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>service.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="kw">use </span><span class="kw">super</span>::Rate; |
| <span class="kw">use </span>futures_core::ready; |
| <span class="kw">use </span>std::{ |
| future::Future, |
| pin::Pin, |
| task::{Context, Poll}, |
| }; |
| <span class="kw">use </span>tokio::time::{Instant, Sleep}; |
| <span class="kw">use </span>tower_service::Service; |
| |
| <span class="doccomment">/// Enforces a rate limit on the number of requests the underlying |
| /// service can handle over a period of time. |
| </span><span class="attribute">#[derive(Debug)] |
| </span><span class="kw">pub struct </span>RateLimit<T> { |
| inner: T, |
| rate: Rate, |
| state: State, |
| sleep: Pin<Box<Sleep>>, |
| } |
| |
| <span class="attribute">#[derive(Debug)] |
| </span><span class="kw">enum </span>State { |
| <span class="comment">// The service has hit its limit |
| </span>Limited, |
| Ready { until: Instant, rem: u64 }, |
| } |
| |
| <span class="kw">impl</span><T> RateLimit<T> { |
| <span class="doccomment">/// Create a new rate limiter |
| </span><span class="kw">pub fn </span>new(inner: T, rate: Rate) -> <span class="self">Self </span>{ |
| <span class="kw">let </span>until = Instant::now(); |
| <span class="kw">let </span>state = State::Ready { |
| until, |
| rem: rate.num(), |
| }; |
| |
| RateLimit { |
| inner, |
| rate, |
| state, |
| <span class="comment">// The sleep won't actually be used with this duration, but |
| // we create it eagerly so that we can reset it in place rather than |
| // `Box::pin`ning a new `Sleep` every time we need one. |
| </span>sleep: Box::pin(tokio::time::sleep_until(until)), |
| } |
| } |
| |
| <span class="doccomment">/// Get a reference to the inner service |
| </span><span class="kw">pub fn </span>get_ref(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="kw-2">&</span>T { |
| <span class="kw-2">&</span><span class="self">self</span>.inner |
| } |
| |
| <span class="doccomment">/// Get a mutable reference to the inner service |
| </span><span class="kw">pub fn </span>get_mut(<span class="kw-2">&mut </span><span class="self">self</span>) -> <span class="kw-2">&mut </span>T { |
| <span class="kw-2">&mut </span><span class="self">self</span>.inner |
| } |
| |
| <span class="doccomment">/// Consume `self`, returning the inner service |
| </span><span class="kw">pub fn </span>into_inner(<span class="self">self</span>) -> T { |
| <span class="self">self</span>.inner |
| } |
| } |
| |
| <span class="kw">impl</span><S, Request> Service<Request> <span class="kw">for </span>RateLimit<S> |
| <span class="kw">where |
| </span>S: Service<Request>, |
| { |
| <span class="kw">type </span>Response = S::Response; |
| <span class="kw">type </span>Error = S::Error; |
| <span class="kw">type </span>Future = S::Future; |
| |
| <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="kw">match </span><span class="self">self</span>.state { |
| State::Ready { .. } => <span class="kw">return </span>Poll::Ready(<span class="macro">ready!</span>(<span class="self">self</span>.inner.poll_ready(cx))), |
| State::Limited => { |
| <span class="kw">if </span>Pin::new(<span class="kw-2">&mut </span><span class="self">self</span>.sleep).poll(cx).is_pending() { |
| <span class="macro">tracing::trace!</span>(<span class="string">"rate limit exceeded; sleeping."</span>); |
| <span class="kw">return </span>Poll::Pending; |
| } |
| } |
| } |
| |
| <span class="self">self</span>.state = State::Ready { |
| until: Instant::now() + <span class="self">self</span>.rate.per(), |
| rem: <span class="self">self</span>.rate.num(), |
| }; |
| |
| Poll::Ready(<span class="macro">ready!</span>(<span class="self">self</span>.inner.poll_ready(cx))) |
| } |
| |
| <span class="kw">fn </span>call(<span class="kw-2">&mut </span><span class="self">self</span>, request: Request) -> <span class="self">Self</span>::Future { |
| <span class="kw">match </span><span class="self">self</span>.state { |
| State::Ready { <span class="kw-2">mut </span>until, <span class="kw-2">mut </span>rem } => { |
| <span class="kw">let </span>now = Instant::now(); |
| |
| <span class="comment">// If the period has elapsed, reset it. |
| </span><span class="kw">if </span>now >= until { |
| until = now + <span class="self">self</span>.rate.per(); |
| rem = <span class="self">self</span>.rate.num(); |
| } |
| |
| <span class="kw">if </span>rem > <span class="number">1 </span>{ |
| rem -= <span class="number">1</span>; |
| <span class="self">self</span>.state = State::Ready { until, rem }; |
| } <span class="kw">else </span>{ |
| <span class="comment">// The service is disabled until further notice |
| // Reset the sleep future in place, so that we don't have to |
| // deallocate the existing box and allocate a new one. |
| </span><span class="self">self</span>.sleep.as_mut().reset(until); |
| <span class="self">self</span>.state = State::Limited; |
| } |
| |
| <span class="comment">// Call the inner future |
| </span><span class="self">self</span>.inner.call(request) |
| } |
| State::Limited => <span class="macro">panic!</span>(<span class="string">"service not ready; poll_ready must be called first"</span>), |
| } |
| } |
| } |
| |
| <span class="attribute">#[cfg(feature = <span class="string">"load"</span>)] |
| #[cfg_attr(docsrs, doc(cfg(feature = <span class="string">"load"</span>)))] |
| </span><span class="kw">impl</span><S> <span class="kw">crate</span>::load::Load <span class="kw">for </span>RateLimit<S> |
| <span class="kw">where |
| </span>S: <span class="kw">crate</span>::load::Load, |
| { |
| <span class="kw">type </span>Metric = S::Metric; |
| <span class="kw">fn </span>load(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="self">Self</span>::Metric { |
| <span class="self">self</span>.inner.load() |
| } |
| } |
| </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> |
