tokio 0.2.13

Tokio

A runtime for writing reliable, asynchronous, and slim applications withthe Rust programming language. It is:

• Fast: Tokio's zero-cost abstractions give you bare-metalperformance.

• Reliable: Tokio leverages Rust's ownership, type system, andconcurrency model to reduce bugs and ensure thread safety.

• Scalable: Tokio has a minimal footprint, and handles backpressureand cancellation naturally.

Website |Guides |API Docs |Chat

Overview

Tokio is an event-driven, non-blocking I/O platform for writingasynchronous applications with the Rust programming language. At a highlevel, it provides a few major components:

• A multithreaded, work-stealing based taskscheduler.
• A reactor backed by the operating system's event queue (epoll, kqueue,IOCP, etc...).
• AsynchronousTCP and UDP sockets.

These components provide the runtime components necessary for buildingan asynchronous application.

Example

To get started, add the following toCargo.toml.

tokio={version="0.2",features=["full"]}

Tokio requires components to be explicitly enabled using feature flags. As ashorthand, thefull feature enables all components.

A basic TCP echo server with Tokio:

usetokio::net::TcpListener;usetokio::prelude::*;#[tokio::main]asyncfnmain()->Result<(),Box<dynstd::error::Error>>{letmut listener=TcpListener::bind("127.0.0.1:8080").await?;loop{let(mut socket,_)= listener.accept().await?;tokio::spawn(asyncmove{letmut buf=[0;1024];// In a loop, read data from the socket and write the data back.loop{let n=match socket.read(&mut buf).await{// socket closedOk(n)if n==0=>return,Ok(n)=> n,Err(e)=>{eprintln!("failed to read from socket; err ={:?}", e);return;}};// Write the data backifletErr(e)= socket.write_all(&buf[0..n]).await{eprintln!("failed to write to socket; err ={:?}", e);return;}}});}}

More examples can be foundhere.

Getting Help

First, see if the answer to your question can be found in theGuides or theAPI documentation. If the answer is not there, there is an active community intheTokio Discord server. We would be happy to try to answer yourquestion. Last, if that doesn't work, try opening anissue with the question.

Contributing

:balloon: Thanks for your help improving the project! We are so happy to haveyou! We have acontributing guide to help you get involved in the Tokioproject.

Related Projects

In addition to the crates in this repository, the Tokio project also maintainsseveral other libraries, including:

• tracing (formerlytokio-trace): A framework for application-leveltracing and async-aware diagnostics.

• mio: A low-level, cross-platform abstraction over OS I/O APIs that powerstokio.

• bytes: Utilities for working with bytes, including efficient byte buffers.

Supported Rust Versions

Tokio is built against the latest stable, nightly, and beta Rust releases. Theminimum version supported is the stable release from three months before thecurrent stable release version. For example, if the latest stable Rust is 1.29,the minimum version supported is 1.26. The current Tokio version is notguaranteed to build on Rust versions earlier than the minimum supported version.

License

This project is licensed under theMIT license.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submittedfor inclusion in Tokio by you, shall be licensed as MIT, without any additionalterms or conditions.