<!DOCTYPE HTML> <html lang="en" class="sidebar-visible no-js"> <head> <!-- Book generated using mdBook --> <meta charset="UTF-8"> <title>External Tools - The Cargo Book</title> <meta content="text/html; charset=utf-8" http-equiv="Content-Type"> <meta name="description" content=""> <meta name="viewport" content="width=device-width, initial-scale=1"> <meta name="theme-color" content="#ffffff" /> <base href="../"> <link rel="stylesheet" href="book.css"> <link href="https://fonts.googleapis.com/css?family=Open+Sans:300italic,400italic,600italic,700italic,800italic,400,300,600,700,800" rel="stylesheet" type="text/css"> <link href="https://fonts.googleapis.com/css?family=Source+Code+Pro:500" rel="stylesheet" type="text/css"> <link rel="shortcut icon" href="favicon.png"> <!-- Font Awesome --> <link rel="stylesheet" href="_FontAwesome/css/font-awesome.css"> <link rel="stylesheet" href="highlight.css"> <link rel="stylesheet" href="tomorrow-night.css"> <link rel="stylesheet" href="ayu-highlight.css"> <!-- Custom theme stylesheets --> </head> <body class="light"> <!-- Work around some values being stored in localStorage wrapped in quotes --> <script type="text/javascript"> try { var theme = localStorage.getItem('mdbook-theme'); 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html.classList.add("sidebar-" + sidebar); </script> <nav id="sidebar" class="sidebar" aria-label="Table of contents"> <ol class="chapter"><li class="affix"><a href="index.html">Introduction</a></li><li><a href="getting-started/index.html"><strong aria-hidden="true">1.</strong> Getting Started</a></li><li><ol class="section"><li><a href="getting-started/installation.html"><strong aria-hidden="true">1.1.</strong> Installation</a></li><li><a href="getting-started/first-steps.html"><strong aria-hidden="true">1.2.</strong> First Steps with Cargo</a></li></ol></li><li><a href="guide/index.html"><strong aria-hidden="true">2.</strong> Cargo Guide</a></li><li><ol class="section"><li><a href="guide/why-cargo-exists.html"><strong aria-hidden="true">2.1.</strong> Why Cargo Exists</a></li><li><a href="guide/creating-a-new-project.html"><strong aria-hidden="true">2.2.</strong> Creating a New Project</a></li><li><a href="guide/working-on-an-existing-project.html"><strong aria-hidden="true">2.3.</strong> Working on an Existing Project</a></li><li><a href="guide/dependencies.html"><strong aria-hidden="true">2.4.</strong> Dependencies</a></li><li><a href="guide/project-layout.html"><strong aria-hidden="true">2.5.</strong> Project Layout</a></li><li><a href="guide/cargo-toml-vs-cargo-lock.html"><strong aria-hidden="true">2.6.</strong> Cargo.toml vs Cargo.lock</a></li><li><a href="guide/tests.html"><strong aria-hidden="true">2.7.</strong> Tests</a></li><li><a href="guide/continuous-integration.html"><strong aria-hidden="true">2.8.</strong> Continuous Integration</a></li><li><a href="guide/build-cache.html"><strong aria-hidden="true">2.9.</strong> Build Cache</a></li></ol></li><li><a href="reference/index.html"><strong aria-hidden="true">3.</strong> Cargo Reference</a></li><li><ol class="section"><li><a href="reference/specifying-dependencies.html"><strong aria-hidden="true">3.1.</strong> Specifying Dependencies</a></li><li><a href="reference/manifest.html"><strong aria-hidden="true">3.2.</strong> The Manifest Format</a></li><li><a href="reference/config.html"><strong aria-hidden="true">3.3.</strong> Configuration</a></li><li><a href="reference/environment-variables.html"><strong aria-hidden="true">3.4.</strong> Environment Variables</a></li><li><a href="reference/build-scripts.html"><strong aria-hidden="true">3.5.</strong> Build Scripts</a></li><li><a href="reference/publishing.html"><strong aria-hidden="true">3.6.</strong> Publishing on crates.io</a></li><li><a href="reference/pkgid-spec.html"><strong aria-hidden="true">3.7.</strong> Package ID Specifications</a></li><li><a href="reference/source-replacement.html"><strong aria-hidden="true">3.8.</strong> Source Replacement</a></li><li><a href="reference/external-tools.html" class="active"><strong aria-hidden="true">3.9.</strong> External Tools</a></li><li><a href="reference/unstable.html"><strong aria-hidden="true">3.10.</strong> Unstable Features</a></li></ol></li><li><a href="faq.html"><strong aria-hidden="true">4.</strong> FAQ</a></li></ol> </nav> <div id="page-wrapper" class="page-wrapper"> <div class="page"> <div id="menu-bar" class="menu-bar"> <div id="menu-bar-sticky-container"> <div class="left-buttons"> <button id="sidebar-toggle" class="icon-button" type="button" title="Toggle Table of Contents" aria-label="Toggle Table of Contents" aria-controls="sidebar"> <i class="fa fa-bars"></i> </button> <button id="theme-toggle" class="icon-button" type="button" title="Change theme" aria-label="Change theme" aria-haspopup="true" aria-expanded="false" aria-controls="theme-list"> <i class="fa fa-paint-brush"></i> </button> <ul id="theme-list" class="theme-popup" aria-label="Themes" role="menu"> <li role="none"><button role="menuitem" class="theme" id="light">Light <span class="default">(default)</span></button></li> <li role="none"><button role="menuitem" class="theme" id="rust">Rust</button></li> <li role="none"><button role="menuitem" class="theme" id="coal">Coal</button></li> <li role="none"><button role="menuitem" class="theme" id="navy">Navy</button></li> <li role="none"><button role="menuitem" class="theme" id="ayu">Ayu</button></li> </ul> <button id="search-toggle" class="icon-button" type="button" title="Search. (Shortkey: s)" aria-label="Toggle Searchbar" aria-expanded="false" aria-keyshortcuts="S" aria-controls="searchbar"> <i class="fa fa-search"></i> </button> </div> <h1 class="menu-title">The Cargo Book</h1> <div class="right-buttons"> <a href="print.html" title="Print this book" aria-label="Print this book"> <i id="print-button" class="fa fa-print"></i> </a> </div> </div> </div> <div id="search-wrapper" class="hidden"> <form id="searchbar-outer" class="searchbar-outer"> <input type="search" name="search" id="searchbar" name="searchbar" placeholder="Search this book ..." aria-controls="searchresults-outer" aria-describedby="searchresults-header"> </form> <div id="searchresults-outer" class="searchresults-outer hidden"> <div id="searchresults-header" class="searchresults-header"></div> <ul id="searchresults"> </ul> </div> </div> <!-- Apply ARIA attributes after the sidebar and the sidebar toggle button are added to the DOM --> <script type="text/javascript"> document.getElementById('sidebar-toggle').setAttribute('aria-expanded', sidebar === 'visible'); document.getElementById('sidebar').setAttribute('aria-hidden', sidebar !== 'visible'); Array.from(document.querySelectorAll('#sidebar a')).forEach(function(link) { link.setAttribute('tabIndex', sidebar === 'visible' ? 0 : -1); }); </script> <div id="content" class="content"> <main> <a class="header" href="reference/external-tools.html#external-tools" id="external-tools"><h2>External tools</h2></a> <p>One of the goals of Cargo is simple integration with third-party tools, like IDEs and other build systems. To make integration easier, Cargo has several facilities:</p> <ul> <li> <p>a <code>cargo metadata</code> command, which outputs project structure and dependencies information in JSON,</p> </li> <li> <p>a <code>--message-format</code> flag, which outputs information about a particular build, and</p> </li> <li> <p>support for custom subcommands.</p> </li> </ul> <a class="header" href="reference/external-tools.html#information-about-project-structure" id="information-about-project-structure"><h3>Information about project structure</h3></a> <p>You can use <code>cargo metadata</code> command to get information about project structure and dependencies. The output of the command looks like this:</p> <pre><code class="language-text">{ // Integer version number of the format. "version": integer, // List of packages for this workspace, including dependencies. "packages": [ { // Opaque package identifier. "id": PackageId, "name": string, "version": string, "source": SourceId, // A list of declared dependencies, see `resolve` field for actual dependencies. "dependencies": [ Dependency ], "targets: [ Target ], // Path to Cargo.toml "manifest_path": string, } ], "workspace_members": [ PackageId ], // Dependencies graph. "resolve": { "nodes": [ { "id": PackageId, "dependencies": [ PackageId ] } ] } } </code></pre> <p>The format is stable and versioned. When calling <code>cargo metadata</code>, you should pass <code>--format-version</code> flag explicitly to avoid forward incompatibility hazard.</p> <p>If you are using Rust, there is <a href="https://crates.io/crates/cargo_metadata">cargo_metadata</a> crate.</p> <a class="header" href="reference/external-tools.html#information-about-build" id="information-about-build"><h3>Information about build</h3></a> <p>When passing <code>--message-format=json</code>, Cargo will output the following information during the build:</p> <ul> <li> <p>compiler errors and warnings,</p> </li> <li> <p>produced artifacts,</p> </li> <li> <p>results of the build scripts (for example, native dependencies).</p> </li> </ul> <p>The output goes to stdout in the JSON object per line format. The <code>reason</code> field distinguishes different kinds of messages.</p> <p>Information about dependencies in the Makefile-compatible format is stored in the <code>.d</code> files alongside the artifacts.</p> <a class="header" href="reference/external-tools.html#custom-subcommands" id="custom-subcommands"><h3>Custom subcommands</h3></a> <p>Cargo is designed to be extensible with new subcommands without having to modify Cargo itself. This is achieved by translating a cargo invocation of the form cargo <code>(?<command>[^ ]+)</code> into an invocation of an external tool <code>cargo-${command}</code> that then needs to be present in one of the user's <code>$PATH</code> directories.</p> <p>Custom subcommand may use <code>CARGO</code> environment variable to call back to Cargo. Alternatively, it can link to <code>cargo</code> crate as a library, but this approach has drawbacks:</p> <ul> <li> <p>Cargo as a library is unstable, API changes without deprecation,</p> </li> <li> <p>versions of Cargo library and Cargo binary may be different.</p> </li> </ul> </main> <nav class="nav-wrapper" aria-label="Page navigation"> <!-- Mobile navigation buttons --> <a rel="prev" href="reference/source-replacement.html" class="mobile-nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left"> <i class="fa fa-angle-left"></i> </a> <a rel="next" href="reference/unstable.html" class="mobile-nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right"> <i class="fa fa-angle-right"></i> </a> <div style="clear: both"></div> </nav> </div> </div> <nav class="nav-wide-wrapper" aria-label="Page navigation"> <a href="reference/source-replacement.html" class="nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left"> <i class="fa fa-angle-left"></i> </a> <a href="reference/unstable.html" class="nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right"> <i class="fa fa-angle-right"></i> </a> </nav> </div> <script src="searchindex.js" type="text/javascript" charset="utf-8"></script> <script src="elasticlunr.min.js" type="text/javascript" charset="utf-8"></script> <script src="mark.min.js" type="text/javascript" charset="utf-8"></script> <script src="searcher.js" type="text/javascript" charset="utf-8"></script> <script src="clipboard.min.js" type="text/javascript" charset="utf-8"></script> <script src="highlight.js" type="text/javascript" charset="utf-8"></script> <script src="book.js" type="text/javascript" charset="utf-8"></script> <!-- Custom JS scripts --> </body> </html>