| <!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="Service discovery"><meta name="keywords" content="rust, rustlang, rust-lang, discover"><title>tower::discover - Rust</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="../../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 mod"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="mobile-topbar"><button class="sidebar-menu-toggle">☰</button><a class="sidebar-logo" href="../../tower/index.html"><div class="logo-container"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></div></a><h2></h2></nav><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><h2 class="location"><a href="#">Module discover</a></h2><div class="sidebar-elems"><section><ul class="block"><li><a href="#structs">Structs</a></li><li><a href="#enums">Enums</a></li><li><a href="#traits">Traits</a></li></ul></section></div></nav><main><div class="width-limiter"><nav class="sub"><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="main-heading"><h1 class="fqn">Module <a href="../index.html">tower</a>::<wbr><a class="mod" href="#">discover</a><button id="copy-path" onclick="copy_path(this)" title="Copy item path to clipboard"><img src="../../clipboard.svg" width="19" height="18" alt="Copy item path"></button></h1><span class="out-of-band"><a class="srclink" href="../../src/tower/discover/mod.rs.html#1-107">source</a> · <a id="toggle-all-docs" href="javascript:void(0)" title="collapse all docs">[<span class="inner">−</span>]</a></span></div><details class="rustdoc-toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>Service discovery</p> |
| <p>This module provides the <a href="enum.Change.html" title="Change"><code>Change</code></a> enum, which indicates the arrival or departure of a service |
| from a collection of similar services. Most implementations should use the <a href="trait.Discover.html" title="Discover"><code>Discover</code></a> trait |
| in their bounds to indicate that they can handle services coming and going. <a href="trait.Discover.html" title="Discover"><code>Discover</code></a> itself |
| is primarily a convenience wrapper around <a href="https://docs.rs/futures/latest/futures/stream/trait.TryStream.html"><code>TryStream<Ok = Change></code></a>.</p> |
| <p>Every discovered service is assigned an identifier that is distinct among the currently active |
| services. If that service later goes away, a <a href="enum.Change.html#variant.Remove" title="Change::Remove"><code>Change::Remove</code></a> is yielded with that service’s |
| identifier. From that point forward, the identifier may be re-used.</p> |
| <h2 id="examples"><a href="#examples">Examples</a></h2> |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>futures_util::{future::poll_fn, pin_mut}; |
| <span class="kw">use </span>tower::discover::{Change, Discover}; |
| <span class="kw">async fn </span>services_monitor<D: Discover>(services: D) { |
| <span class="macro">pin_mut!</span>(services); |
| <span class="kw">while let </span><span class="prelude-val">Some</span>(<span class="prelude-val">Ok</span>(change)) = poll_fn(|cx| services.as_mut().poll_discover(cx)).<span class="kw">await </span>{ |
| <span class="kw">match </span>change { |
| Change::Insert(key, svc) => { |
| <span class="comment">// a new service with identifier `key` was discovered |
| </span>} |
| Change::Remove(key) => { |
| <span class="comment">// the service with identifier `key` has gone away |
| </span>} |
| } |
| } |
| }</code></pre></div> |
| </div></details><h2 id="structs" class="small-section-header"><a href="#structs">Structs</a></h2><div class="item-table"><div class="item-row"><div class="item-left module-item"><a class="struct" href="struct.ServiceList.html" title="tower::discover::ServiceList struct">ServiceList</a></div><div class="item-right docblock-short">Static service discovery based on a predetermined list of services.</div></div></div><h2 id="enums" class="small-section-header"><a href="#enums">Enums</a></h2><div class="item-table"><div class="item-row"><div class="item-left module-item"><a class="enum" href="enum.Change.html" title="tower::discover::Change enum">Change</a></div><div class="item-right docblock-short">A change in the service set.</div></div></div><h2 id="traits" class="small-section-header"><a href="#traits">Traits</a></h2><div class="item-table"><div class="item-row"><div class="item-left module-item"><a class="trait" href="trait.Discover.html" title="tower::discover::Discover trait">Discover</a></div><div class="item-right docblock-short">A dynamically changing set of related services.</div></div></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> |
