| <!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/lib.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>lib.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="attribute">#![warn( |
| missing_debug_implementations, |
| missing_docs, |
| rust_2018_idioms, |
| unreachable_pub |
| )] |
| #![forbid(unsafe_code)] |
| #![allow(elided_lifetimes_in_paths, clippy::type_complexity)] |
| #![cfg_attr(test, allow(clippy::float_cmp))] |
| #![cfg_attr(docsrs, feature(doc_cfg))] |
| </span><span class="comment">// `rustdoc::broken_intra_doc_links` is checked on CI |
| |
| </span><span class="doccomment">//! `async fn(Request) -> Result<Response, Error>` |
| //! |
| //! # Overview |
| //! |
| //! Tower is a library of modular and reusable components for building |
| //! robust networking clients and servers. |
| //! |
| //! Tower provides a simple core abstraction, the [`Service`] trait, which |
| //! represents an asynchronous function taking a request and returning either a |
| //! response or an error. This abstraction can be used to model both clients and |
| //! servers. |
| //! |
| //! Generic components, like [timeouts], [rate limiting], and [load balancing], |
| //! can be modeled as [`Service`]s that wrap some inner service and apply |
| //! additional behavior before or after the inner service is called. This allows |
| //! implementing these components in a protocol-agnostic, composable way. Typically, |
| //! such services are referred to as _middleware_. |
| //! |
| //! An additional abstraction, the [`Layer`] trait, is used to compose |
| //! middleware with [`Service`]s. If a [`Service`] can be thought of as an |
| //! asynchronous function from a request type to a response type, a [`Layer`] is |
| //! a function taking a [`Service`] of one type and returning a [`Service`] of a |
| //! different type. The [`ServiceBuilder`] type is used to add middleware to a |
| //! service by composing it with multiple [`Layer`]s. |
| //! |
| //! ## The Tower Ecosystem |
| //! |
| //! Tower is made up of the following crates: |
| //! |
| //! * [`tower`] (this crate) |
| //! * [`tower-service`] |
| //! * [`tower-layer`] |
| //! * [`tower-test`] |
| //! |
| //! Since the [`Service`] and [`Layer`] traits are important integration points |
| //! for all libraries using Tower, they are kept as stable as possible, and |
| //! breaking changes are made rarely. Therefore, they are defined in separate |
| //! crates, [`tower-service`] and [`tower-layer`]. This crate contains |
| //! re-exports of those core traits, implementations of commonly-used |
| //! middleware, and [utilities] for working with [`Service`]s and [`Layer`]s. |
| //! Finally, the [`tower-test`] crate provides tools for testing programs using |
| //! Tower. |
| //! |
| //! # Usage |
| //! |
| //! Tower provides an abstraction layer, and generic implementations of various |
| //! middleware. This means that the `tower` crate on its own does *not* provide |
| //! a working implementation of a network client or server. Instead, Tower's |
| //! [`Service` trait][`Service`] provides an integration point between |
| //! application code, libraries providing middleware implementations, and |
| //! libraries that implement servers and/or clients for various network |
| //! protocols. |
| //! |
| //! Depending on your particular use case, you might use Tower in several ways: |
| //! |
| //! * **Implementing application logic** for a networked program. You might |
| //! use the [`Service`] trait to model your application's behavior, and use |
| //! the middleware [provided by this crate](#modules) and by other libraries |
| //! to add functionality to clients and servers provided by one or more |
| //! protocol implementations. |
| //! * **Implementing middleware** to add custom behavior to network clients and |
| //! servers in a reusable manner. This might be general-purpose middleware |
| //! (and if it is, please consider releasing your middleware as a library for |
| //! other Tower users!) or application-specific behavior that needs to be |
| //! shared between multiple clients or servers. |
| //! * **Implementing a network protocol**. Libraries that implement network |
| //! protocols (such as HTTP) can depend on `tower-service` to use the |
| //! [`Service`] trait as an integration point between the protocol and user |
| //! code. For example, a client for some protocol might implement [`Service`], |
| //! allowing users to add arbitrary Tower middleware to those clients. |
| //! Similarly, a server might be created from a user-provided [`Service`]. |
| //! |
| //! Additionally, when a network protocol requires functionality already |
| //! provided by existing Tower middleware, a protocol implementation might use |
| //! Tower middleware internally, as well as as an integration point. |
| //! |
| //! ## Library Support |
| //! |
| //! A number of third-party libraries support Tower and the [`Service`] trait. |
| //! The following is an incomplete list of such libraries: |
| //! |
| //! * [`hyper`]: A fast and correct low-level HTTP implementation. |
| //! * [`tonic`]: A [gRPC-over-HTTP/2][grpc] implementation built on top of |
| //! [`hyper`]. See [here][tonic-examples] for examples of using [`tonic`] with |
| //! Tower. |
| //! * [`warp`]: A lightweight, composable web framework. See |
| //! [here][warp-service] for details on using [`warp`] with Tower. |
| //! * [`tower-lsp`] and its fork, [`lspower`]: implementations of the [Language |
| //! Server Protocol][lsp] based on Tower. |
| //! |
| //! [`hyper`]: https://crates.io/crates/hyper |
| //! [`tonic`]: https://crates.io/crates/tonic |
| //! [tonic-examples]: https://github.com/hyperium/tonic/tree/master/examples/src/tower |
| //! [grpc]: https://grpc.io |
| //! [`warp`]: https://crates.io/crates/warp |
| //! [warp-service]: https://docs.rs/warp/0.2.5/warp/fn.service.html |
| //! [`tower-lsp`]: https://crates.io/crates/tower-lsp |
| //! [`lspower`]: https://crates.io/crates/lspower |
| //! [lsp]: https://microsoft.github.io/language-server-protocol/ |
| //! |
| //! If you're the maintainer of a crate that supports Tower, we'd love to add |
| //! your crate to this list! Please [open a PR] adding a brief description of |
| //! your library! |
| //! |
| //! ## Getting Started |
| //! |
| //! If you're brand new to Tower and want to start with the basics, we recommend you |
| //! check out some of our [guides]. |
| //! |
| //! The various middleware implementations provided by this crate are feature |
| //! flagged, so that users can only compile the parts of Tower they need. By |
| //! default, all the optional middleware are disabled. |
| //! |
| //! To get started using all of Tower's optional middleware, add this to your |
| //! `Cargo.toml`: |
| //! |
| //! ```toml |
| //! tower = { version = "0.4", features = ["full"] } |
| //! ``` |
| //! |
| //! Alternatively, you can only enable some features. For example, to enable |
| //! only the [`retry`] and [`timeout`][timeouts] middleware, write: |
| //! |
| //! ```toml |
| //! tower = { version = "0.4", features = ["retry", "timeout"] } |
| //! ``` |
| //! |
| //! See [here](#modules) for a complete list of all middleware provided by |
| //! Tower. |
| //! |
| //! |
| //! ## Supported Rust Versions |
| //! |
| //! Tower will keep a rolling MSRV (minimum supported Rust version) policy of **at |
| //! least** 6 months. When increasing the MSRV, the new Rust version must have been |
| //! released at least six months ago. The current MSRV is 1.49.0. |
| //! |
| //! [`Service`]: crate::Service |
| //! [`Layer`]: crate::Layer |
| //! [timeouts]: crate::timeout |
| //! [rate limiting]: crate::limit::rate |
| //! [load balancing]: crate::balance |
| //! [`ServiceBuilder`]: crate::ServiceBuilder |
| //! [utilities]: crate::ServiceExt |
| //! [`tower`]: https://crates.io/crates/tower |
| //! [`tower-service`]: https://crates.io/crates/tower-service |
| //! [`tower-layer`]: https://crates.io/crates/tower-layer |
| //! [`tower-test`]: https://crates.io/crates/tower-test |
| //! [`retry`]: crate::retry |
| //! [open a PR]: https://github.com/tower-rs/tower/compare |
| //! [guides]: https://github.com/tower-rs/tower/tree/master/guides |
| |
| </span><span class="attribute">#[macro_use] |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">mod </span>macros; |
| <span class="attribute">#[cfg(feature = <span class="string">"balance"</span>)] |
| #[cfg_attr(docsrs, doc(cfg(feature = <span class="string">"balance"</span>)))] |
| </span><span class="kw">pub mod </span>balance; |
| <span class="attribute">#[cfg(feature = <span class="string">"buffer"</span>)] |
| #[cfg_attr(docsrs, doc(cfg(feature = <span class="string">"buffer"</span>)))] |
| </span><span class="kw">pub mod </span>buffer; |
| <span class="attribute">#[cfg(feature = <span class="string">"discover"</span>)] |
| #[cfg_attr(docsrs, doc(cfg(feature = <span class="string">"discover"</span>)))] |
| </span><span class="kw">pub mod </span>discover; |
| <span class="attribute">#[cfg(feature = <span class="string">"filter"</span>)] |
| #[cfg_attr(docsrs, doc(cfg(feature = <span class="string">"filter"</span>)))] |
| </span><span class="kw">pub mod </span>filter; |
| <span class="attribute">#[cfg(feature = <span class="string">"hedge"</span>)] |
| #[cfg_attr(docsrs, doc(cfg(feature = <span class="string">"hedge"</span>)))] |
| </span><span class="kw">pub mod </span>hedge; |
| <span class="attribute">#[cfg(feature = <span class="string">"limit"</span>)] |
| #[cfg_attr(docsrs, doc(cfg(feature = <span class="string">"limit"</span>)))] |
| </span><span class="kw">pub mod </span>limit; |
| <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">pub mod </span>load; |
| <span class="attribute">#[cfg(feature = <span class="string">"load-shed"</span>)] |
| #[cfg_attr(docsrs, doc(cfg(feature = <span class="string">"load-shed"</span>)))] |
| </span><span class="kw">pub mod </span>load_shed; |
| |
| <span class="attribute">#[cfg(feature = <span class="string">"make"</span>)] |
| #[cfg_attr(docsrs, doc(cfg(feature = <span class="string">"make"</span>)))] |
| </span><span class="kw">pub mod </span>make; |
| <span class="attribute">#[cfg(feature = <span class="string">"ready-cache"</span>)] |
| #[cfg_attr(docsrs, doc(cfg(feature = <span class="string">"ready-cache"</span>)))] |
| </span><span class="kw">pub mod </span>ready_cache; |
| <span class="attribute">#[cfg(feature = <span class="string">"reconnect"</span>)] |
| #[cfg_attr(docsrs, doc(cfg(feature = <span class="string">"reconnect"</span>)))] |
| </span><span class="kw">pub mod </span>reconnect; |
| <span class="attribute">#[cfg(feature = <span class="string">"retry"</span>)] |
| #[cfg_attr(docsrs, doc(cfg(feature = <span class="string">"retry"</span>)))] |
| </span><span class="kw">pub mod </span>retry; |
| <span class="attribute">#[cfg(feature = <span class="string">"spawn-ready"</span>)] |
| #[cfg_attr(docsrs, doc(cfg(feature = <span class="string">"spawn-ready"</span>)))] |
| </span><span class="kw">pub mod </span>spawn_ready; |
| <span class="attribute">#[cfg(feature = <span class="string">"steer"</span>)] |
| #[cfg_attr(docsrs, doc(cfg(feature = <span class="string">"steer"</span>)))] |
| </span><span class="kw">pub mod </span>steer; |
| <span class="attribute">#[cfg(feature = <span class="string">"timeout"</span>)] |
| #[cfg_attr(docsrs, doc(cfg(feature = <span class="string">"timeout"</span>)))] |
| </span><span class="kw">pub mod </span>timeout; |
| <span class="attribute">#[cfg(feature = <span class="string">"util"</span>)] |
| #[cfg_attr(docsrs, doc(cfg(feature = <span class="string">"util"</span>)))] |
| </span><span class="kw">pub mod </span>util; |
| |
| <span class="kw">pub mod </span>builder; |
| <span class="kw">pub mod </span>layer; |
| |
| <span class="attribute">#[cfg(feature = <span class="string">"util"</span>)] |
| #[cfg_attr(docsrs, doc(cfg(feature = <span class="string">"util"</span>)))] |
| #[doc(inline)] |
| </span><span class="kw">pub use </span><span class="self">self</span>::util::{service_fn, ServiceExt}; |
| |
| <span class="attribute">#[doc(inline)] |
| </span><span class="kw">pub use </span><span class="kw">crate</span>::builder::ServiceBuilder; |
| <span class="attribute">#[cfg(feature = <span class="string">"make"</span>)] |
| #[cfg_attr(docsrs, doc(cfg(feature = <span class="string">"make"</span>)))] |
| #[doc(inline)] |
| </span><span class="kw">pub use </span><span class="kw">crate</span>::make::MakeService; |
| <span class="attribute">#[doc(inline)] |
| </span><span class="kw">pub use </span>tower_layer::Layer; |
| <span class="attribute">#[doc(inline)] |
| </span><span class="kw">pub use </span>tower_service::Service; |
| |
| <span class="attribute">#[allow(unreachable_pub)] |
| </span><span class="kw">mod </span>sealed { |
| <span class="kw">pub trait </span>Sealed<T> {} |
| } |
| |
| <span class="doccomment">/// Alias for a type-erased error type. |
| </span><span class="kw">pub type </span>BoxError = Box<<span class="kw">dyn </span>std::error::Error + Send + Sync>; |
| </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> |
