|
- <!DOCTYPE html>
-
- <html lang="en" data-content_root="../">
- <head>
- <meta charset="utf-8" />
- <meta name="viewport" content="width=device-width, initial-scale=1.0" /><meta name="viewport" content="width=device-width, initial-scale=1" />
- <meta property="og:title" content="importlib.metadata – Accessing package metadata" />
- <meta property="og:type" content="website" />
- <meta property="og:url" content="https://docs.python.org/3/library/importlib.metadata.html" />
- <meta property="og:site_name" content="Python documentation" />
- <meta property="og:description" content="Source code: Lib/importlib/metadata/__init__.py importlib.metadata is a library that provides access to the metadata of an installed Distribution Package, such as its entry points or its top-level ..." />
- <meta property="og:image" content="https://docs.python.org/3/_static/og-image.png" />
- <meta property="og:image:alt" content="Python documentation" />
- <meta name="description" content="Source code: Lib/importlib/metadata/__init__.py importlib.metadata is a library that provides access to the metadata of an installed Distribution Package, such as its entry points or its top-level ..." />
- <meta property="og:image:width" content="200" />
- <meta property="og:image:height" content="200" />
- <meta name="theme-color" content="#3776ab" />
-
- <title>importlib.metadata – Accessing package metadata — Python 3.12.3 documentation</title><meta name="viewport" content="width=device-width, initial-scale=1.0">
-
- <link rel="stylesheet" type="text/css" href="../_static/pygments.css?v=80d5e7a1" />
- <link rel="stylesheet" type="text/css" href="../_static/pydoctheme.css?v=bb723527" />
- <link id="pygments_dark_css" media="(prefers-color-scheme: dark)" rel="stylesheet" type="text/css" href="../_static/pygments_dark.css?v=b20cc3f5" />
-
- <script src="../_static/documentation_options.js?v=2c828074"></script>
- <script src="../_static/doctools.js?v=888ff710"></script>
- <script src="../_static/sphinx_highlight.js?v=dc90522c"></script>
-
- <script src="../_static/sidebar.js"></script>
-
- <link rel="search" type="application/opensearchdescription+xml"
- title="Search within Python 3.12.3 documentation"
- href="../_static/opensearch.xml"/>
- <link rel="author" title="About these documents" href="../about.html" />
- <link rel="index" title="Index" href="../genindex.html" />
- <link rel="search" title="Search" href="../search.html" />
- <link rel="copyright" title="Copyright" href="../copyright.html" />
- <link rel="next" title="The initialization of the sys.path module search path" href="sys_path_init.html" />
- <link rel="prev" title="importlib.resources.abc – Abstract base classes for resources" href="importlib.resources.abc.html" />
- <link rel="canonical" href="https://docs.python.org/3/library/importlib.metadata.html" />
-
-
-
-
-
- <style>
- @media only screen {
- table.full-width-table {
- width: 100%;
- }
- }
- </style>
- <link rel="stylesheet" href="../_static/pydoctheme_dark.css" media="(prefers-color-scheme: dark)" id="pydoctheme_dark_css">
- <link rel="shortcut icon" type="image/png" href="../_static/py.svg" />
- <script type="text/javascript" src="../_static/copybutton.js"></script>
- <script type="text/javascript" src="../_static/menu.js"></script>
- <script type="text/javascript" src="../_static/search-focus.js"></script>
- <script type="text/javascript" src="../_static/themetoggle.js"></script>
-
- </head>
- <body>
- <div class="mobile-nav">
- <input type="checkbox" id="menuToggler" class="toggler__input" aria-controls="navigation"
- aria-pressed="false" aria-expanded="false" role="button" aria-label="Menu" />
- <nav class="nav-content" role="navigation">
- <label for="menuToggler" class="toggler__label">
- <span></span>
- </label>
- <span class="nav-items-wrapper">
- <a href="https://www.python.org/" class="nav-logo">
- <img src="../_static/py.svg" alt="Python logo"/>
- </a>
- <span class="version_switcher_placeholder"></span>
- <form role="search" class="search" action="../search.html" method="get">
- <svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" viewBox="0 0 24 24" class="search-icon">
- <path fill-rule="nonzero" fill="currentColor" d="M15.5 14h-.79l-.28-.27a6.5 6.5 0 001.48-5.34c-.47-2.78-2.79-5-5.59-5.34a6.505 6.505 0 00-7.27 7.27c.34 2.8 2.56 5.12 5.34 5.59a6.5 6.5 0 005.34-1.48l.27.28v.79l4.25 4.25c.41.41 1.08.41 1.49 0 .41-.41.41-1.08 0-1.49L15.5 14zm-6 0C7.01 14 5 11.99 5 9.5S7.01 5 9.5 5 14 7.01 14 9.5 11.99 14 9.5 14z"></path>
- </svg>
- <input placeholder="Quick search" aria-label="Quick search" type="search" name="q" />
- <input type="submit" value="Go"/>
- </form>
- </span>
- </nav>
- <div class="menu-wrapper">
- <nav class="menu" role="navigation" aria-label="main navigation">
- <div class="language_switcher_placeholder"></div>
-
- <label class="theme-selector-label">
- Theme
- <select class="theme-selector" oninput="activateTheme(this.value)">
- <option value="auto" selected>Auto</option>
- <option value="light">Light</option>
- <option value="dark">Dark</option>
- </select>
- </label>
- <div>
- <h3><a href="../contents.html">Table of Contents</a></h3>
- <ul>
- <li><a class="reference internal" href="#"><code class="xref py py-mod docutils literal notranslate"><span class="pre">importlib.metadata</span></code> – Accessing package metadata</a><ul>
- <li><a class="reference internal" href="#overview">Overview</a></li>
- <li><a class="reference internal" href="#functional-api">Functional API</a><ul>
- <li><a class="reference internal" href="#entry-points">Entry points</a></li>
- <li><a class="reference internal" href="#distribution-metadata">Distribution metadata</a></li>
- <li><a class="reference internal" href="#distribution-versions">Distribution versions</a></li>
- <li><a class="reference internal" href="#distribution-files">Distribution files</a></li>
- <li><a class="reference internal" href="#distribution-requirements">Distribution requirements</a></li>
- <li><a class="reference internal" href="#mapping-import-to-distribution-packages">Mapping import to distribution packages</a></li>
- </ul>
- </li>
- <li><a class="reference internal" href="#distributions">Distributions</a></li>
- <li><a class="reference internal" href="#distribution-discovery">Distribution Discovery</a></li>
- <li><a class="reference internal" href="#extending-the-search-algorithm">Extending the search algorithm</a></li>
- </ul>
- </li>
- </ul>
-
- </div>
- <div>
- <h4>Previous topic</h4>
- <p class="topless"><a href="importlib.resources.abc.html"
- title="previous chapter"><code class="xref py py-mod docutils literal notranslate"><span class="pre">importlib.resources.abc</span></code> – Abstract base classes for resources</a></p>
- </div>
- <div>
- <h4>Next topic</h4>
- <p class="topless"><a href="sys_path_init.html"
- title="next chapter">The initialization of the <code class="xref py py-data docutils literal notranslate"><span class="pre">sys.path</span></code> module search path</a></p>
- </div>
- <div role="note" aria-label="source link">
- <h3>This Page</h3>
- <ul class="this-page-menu">
- <li><a href="../bugs.html">Report a Bug</a></li>
- <li>
- <a href="https://github.com/python/cpython/blob/main/Doc/library/importlib.metadata.rst"
- rel="nofollow">Show Source
- </a>
- </li>
- </ul>
- </div>
- </nav>
- </div>
- </div>
-
-
- <div class="related" role="navigation" aria-label="related navigation">
- <h3>Navigation</h3>
- <ul>
- <li class="right" style="margin-right: 10px">
- <a href="../genindex.html" title="General Index"
- accesskey="I">index</a></li>
- <li class="right" >
- <a href="../py-modindex.html" title="Python Module Index"
- >modules</a> |</li>
- <li class="right" >
- <a href="sys_path_init.html" title="The initialization of the sys.path module search path"
- accesskey="N">next</a> |</li>
- <li class="right" >
- <a href="importlib.resources.abc.html" title="importlib.resources.abc – Abstract base classes for resources"
- accesskey="P">previous</a> |</li>
-
- <li><img src="../_static/py.svg" alt="Python logo" style="vertical-align: middle; margin-top: -1px"/></li>
- <li><a href="https://www.python.org/">Python</a> »</li>
- <li class="switchers">
- <div class="language_switcher_placeholder"></div>
- <div class="version_switcher_placeholder"></div>
- </li>
- <li>
-
- </li>
- <li id="cpython-language-and-version">
- <a href="../index.html">3.12.3 Documentation</a> »
- </li>
-
- <li class="nav-item nav-item-1"><a href="index.html" >The Python Standard Library</a> »</li>
- <li class="nav-item nav-item-2"><a href="modules.html" accesskey="U">Importing Modules</a> »</li>
- <li class="nav-item nav-item-this"><a href=""><code class="xref py py-mod docutils literal notranslate"><span class="pre">importlib.metadata</span></code> – Accessing package metadata</a></li>
- <li class="right">
-
-
- <div class="inline-search" role="search">
- <form class="inline-search" action="../search.html" method="get">
- <input placeholder="Quick search" aria-label="Quick search" type="search" name="q" id="search-box" />
- <input type="submit" value="Go" />
- </form>
- </div>
- |
- </li>
- <li class="right">
- <label class="theme-selector-label">
- Theme
- <select class="theme-selector" oninput="activateTheme(this.value)">
- <option value="auto" selected>Auto</option>
- <option value="light">Light</option>
- <option value="dark">Dark</option>
- </select>
- </label> |</li>
-
- </ul>
- </div>
-
- <div class="document">
- <div class="documentwrapper">
- <div class="bodywrapper">
- <div class="body" role="main">
-
- <section id="module-importlib.metadata">
- <span id="importlib-metadata-accessing-package-metadata"></span><span id="using"></span><h1><code class="xref py py-mod docutils literal notranslate"><span class="pre">importlib.metadata</span></code> – Accessing package metadata<a class="headerlink" href="#module-importlib.metadata" title="Link to this heading">¶</a></h1>
- <div class="versionadded">
- <p><span class="versionmodified added">New in version 3.8.</span></p>
- </div>
- <div class="versionchanged">
- <p><span class="versionmodified changed">Changed in version 3.10: </span><code class="docutils literal notranslate"><span class="pre">importlib.metadata</span></code> is no longer provisional.</p>
- </div>
- <p><strong>Source code:</strong> <a class="reference external" href="https://github.com/python/cpython/tree/3.12/Lib/importlib/metadata/__init__.py">Lib/importlib/metadata/__init__.py</a></p>
- <p><code class="docutils literal notranslate"><span class="pre">importlib.metadata</span></code> is a library that provides access to
- the metadata of an installed <a class="reference external" href="https://packaging.python.org/en/latest/glossary/#term-Distribution-Package">Distribution Package</a>,
- such as its entry points
- or its top-level names (<a class="reference external" href="https://packaging.python.org/en/latest/glossary/#term-Import-Package">Import Package</a>s, modules, if any).
- Built in part on Python’s import system, this library
- intends to replace similar functionality in the <a class="reference external" href="https://setuptools.readthedocs.io/en/latest/pkg_resources.html#entry-points">entry point
- API</a> and <a class="reference external" href="https://setuptools.readthedocs.io/en/latest/pkg_resources.html#metadata-api">metadata API</a> of <code class="docutils literal notranslate"><span class="pre">pkg_resources</span></code>. Along with
- <a class="reference internal" href="importlib.resources.html#module-importlib.resources" title="importlib.resources: Package resource reading, opening, and access"><code class="xref py py-mod docutils literal notranslate"><span class="pre">importlib.resources</span></code></a>,
- this package can eliminate the need to use the older and less efficient
- <code class="docutils literal notranslate"><span class="pre">pkg_resources</span></code> package.</p>
- <p><code class="docutils literal notranslate"><span class="pre">importlib.metadata</span></code> operates on third-party <em>distribution packages</em>
- installed into Python’s <code class="docutils literal notranslate"><span class="pre">site-packages</span></code> directory via tools such as
- <a class="reference external" href="https://pypi.org/project/pip/">pip</a>.
- Specifically, it works with distributions with discoverable
- <code class="docutils literal notranslate"><span class="pre">dist-info</span></code> or <code class="docutils literal notranslate"><span class="pre">egg-info</span></code> directories,
- and metadata defined by the <a class="reference external" href="https://packaging.python.org/en/latest/specifications/core-metadata/#core-metadata">Core metadata specifications</a>.</p>
- <div class="admonition important">
- <p class="admonition-title">Important</p>
- <p>These are <em>not</em> necessarily equivalent to or correspond 1:1 with
- the top-level <em>import package</em> names
- that can be imported inside Python code.
- One <em>distribution package</em> can contain multiple <em>import packages</em>
- (and single modules),
- and one top-level <em>import package</em>
- may map to multiple <em>distribution packages</em>
- if it is a namespace package.
- You can use <a class="reference internal" href="#package-distributions"><span class="std std-ref">package_distributions()</span></a>
- to get a mapping between them.</p>
- </div>
- <p>By default, distribution metadata can live on the file system
- or in zip archives on
- <a class="reference internal" href="sys.html#sys.path" title="sys.path"><code class="xref py py-data docutils literal notranslate"><span class="pre">sys.path</span></code></a>. Through an extension mechanism, the metadata can live almost
- anywhere.</p>
- <div class="admonition seealso">
- <p class="admonition-title">See also</p>
- <dl class="simple">
- <dt><a class="reference external" href="https://importlib-metadata.readthedocs.io/">https://importlib-metadata.readthedocs.io/</a></dt><dd><p>The documentation for <code class="docutils literal notranslate"><span class="pre">importlib_metadata</span></code>, which supplies a
- backport of <code class="docutils literal notranslate"><span class="pre">importlib.metadata</span></code>.
- This includes an <a class="reference external" href="https://importlib-metadata.readthedocs.io/en/latest/api.html">API reference</a>
- for this module’s classes and functions,
- as well as a <a class="reference external" href="https://importlib-metadata.readthedocs.io/en/latest/migration.html">migration guide</a>
- for existing users of <code class="docutils literal notranslate"><span class="pre">pkg_resources</span></code>.</p>
- </dd>
- </dl>
- </div>
- <section id="overview">
- <h2>Overview<a class="headerlink" href="#overview" title="Link to this heading">¶</a></h2>
- <p>Let’s say you wanted to get the version string for a
- <a class="reference external" href="https://packaging.python.org/en/latest/glossary/#term-Distribution-Package">Distribution Package</a> you’ve installed
- using <code class="docutils literal notranslate"><span class="pre">pip</span></code>. We start by creating a virtual environment and installing
- something into it:</p>
- <div class="highlight-shell-session notranslate"><div class="highlight"><pre><span></span><span class="gp">$ </span>python<span class="w"> </span>-m<span class="w"> </span>venv<span class="w"> </span>example
- <span class="gp">$ </span><span class="nb">source</span><span class="w"> </span>example/bin/activate
- <span class="gp gp-VirtualEnv">(example)</span> <span class="gp">$ </span>python<span class="w"> </span>-m<span class="w"> </span>pip<span class="w"> </span>install<span class="w"> </span>wheel
- </pre></div>
- </div>
- <p>You can get the version string for <code class="docutils literal notranslate"><span class="pre">wheel</span></code> by running the following:</p>
- <div class="highlight-pycon notranslate"><div class="highlight"><pre><span></span><span class="go">(example) $ python</span>
- <span class="gp">>>> </span><span class="kn">from</span> <span class="nn">importlib.metadata</span> <span class="kn">import</span> <span class="n">version</span>
- <span class="gp">>>> </span><span class="n">version</span><span class="p">(</span><span class="s1">'wheel'</span><span class="p">)</span>
- <span class="go">'0.32.3'</span>
- </pre></div>
- </div>
- <p>You can also get a collection of entry points selectable by properties of the EntryPoint (typically ‘group’ or ‘name’), such as
- <code class="docutils literal notranslate"><span class="pre">console_scripts</span></code>, <code class="docutils literal notranslate"><span class="pre">distutils.commands</span></code> and others. Each group contains a
- collection of <a class="reference internal" href="#entry-points"><span class="std std-ref">EntryPoint</span></a> objects.</p>
- <p>You can get the <a class="reference internal" href="#metadata"><span class="std std-ref">metadata for a distribution</span></a>:</p>
- <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="nb">list</span><span class="p">(</span><span class="n">metadata</span><span class="p">(</span><span class="s1">'wheel'</span><span class="p">))</span>
- <span class="go">['Metadata-Version', 'Name', 'Version', 'Summary', 'Home-page', 'Author', 'Author-email', 'Maintainer', 'Maintainer-email', 'License', 'Project-URL', 'Project-URL', 'Project-URL', 'Keywords', 'Platform', 'Classifier', 'Classifier', 'Classifier', 'Classifier', 'Classifier', 'Classifier', 'Classifier', 'Classifier', 'Classifier', 'Classifier', 'Classifier', 'Classifier', 'Requires-Python', 'Provides-Extra', 'Requires-Dist', 'Requires-Dist']</span>
- </pre></div>
- </div>
- <p>You can also get a <a class="reference internal" href="#version"><span class="std std-ref">distribution’s version number</span></a>, list its
- <a class="reference internal" href="#files"><span class="std std-ref">constituent files</span></a>, and get a list of the distribution’s
- <a class="reference internal" href="#requirements"><span class="std std-ref">Distribution requirements</span></a>.</p>
- </section>
- <section id="functional-api">
- <h2>Functional API<a class="headerlink" href="#functional-api" title="Link to this heading">¶</a></h2>
- <p>This package provides the following functionality via its public API.</p>
- <section id="entry-points">
- <span id="id2"></span><h3>Entry points<a class="headerlink" href="#entry-points" title="Link to this heading">¶</a></h3>
- <p>The <code class="docutils literal notranslate"><span class="pre">entry_points()</span></code> function returns a collection of entry points.
- Entry points are represented by <code class="docutils literal notranslate"><span class="pre">EntryPoint</span></code> instances;
- each <code class="docutils literal notranslate"><span class="pre">EntryPoint</span></code> has a <code class="docutils literal notranslate"><span class="pre">.name</span></code>, <code class="docutils literal notranslate"><span class="pre">.group</span></code>, and <code class="docutils literal notranslate"><span class="pre">.value</span></code> attributes and
- a <code class="docutils literal notranslate"><span class="pre">.load()</span></code> method to resolve the value. There are also <code class="docutils literal notranslate"><span class="pre">.module</span></code>,
- <code class="docutils literal notranslate"><span class="pre">.attr</span></code>, and <code class="docutils literal notranslate"><span class="pre">.extras</span></code> attributes for getting the components of the
- <code class="docutils literal notranslate"><span class="pre">.value</span></code> attribute.</p>
- <p>Query all entry points:</p>
- <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">eps</span> <span class="o">=</span> <span class="n">entry_points</span><span class="p">()</span>
- </pre></div>
- </div>
- <p>The <code class="docutils literal notranslate"><span class="pre">entry_points()</span></code> function returns an <code class="docutils literal notranslate"><span class="pre">EntryPoints</span></code> object,
- a collection of all <code class="docutils literal notranslate"><span class="pre">EntryPoint</span></code> objects with <code class="docutils literal notranslate"><span class="pre">names</span></code> and <code class="docutils literal notranslate"><span class="pre">groups</span></code>
- attributes for convenience:</p>
- <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="nb">sorted</span><span class="p">(</span><span class="n">eps</span><span class="o">.</span><span class="n">groups</span><span class="p">)</span>
- <span class="go">['console_scripts', 'distutils.commands', 'distutils.setup_keywords', 'egg_info.writers', 'setuptools.installation']</span>
- </pre></div>
- </div>
- <p><code class="docutils literal notranslate"><span class="pre">EntryPoints</span></code> has a <code class="docutils literal notranslate"><span class="pre">select</span></code> method to select entry points
- matching specific properties. Select entry points in the
- <code class="docutils literal notranslate"><span class="pre">console_scripts</span></code> group:</p>
- <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">scripts</span> <span class="o">=</span> <span class="n">eps</span><span class="o">.</span><span class="n">select</span><span class="p">(</span><span class="n">group</span><span class="o">=</span><span class="s1">'console_scripts'</span><span class="p">)</span>
- </pre></div>
- </div>
- <p>Equivalently, since <code class="docutils literal notranslate"><span class="pre">entry_points</span></code> passes keyword arguments
- through to select:</p>
- <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">scripts</span> <span class="o">=</span> <span class="n">entry_points</span><span class="p">(</span><span class="n">group</span><span class="o">=</span><span class="s1">'console_scripts'</span><span class="p">)</span>
- </pre></div>
- </div>
- <p>Pick out a specific script named “wheel” (found in the wheel project):</p>
- <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="s1">'wheel'</span> <span class="ow">in</span> <span class="n">scripts</span><span class="o">.</span><span class="n">names</span>
- <span class="go">True</span>
- <span class="gp">>>> </span><span class="n">wheel</span> <span class="o">=</span> <span class="n">scripts</span><span class="p">[</span><span class="s1">'wheel'</span><span class="p">]</span>
- </pre></div>
- </div>
- <p>Equivalently, query for that entry point during selection:</p>
- <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="p">(</span><span class="n">wheel</span><span class="p">,)</span> <span class="o">=</span> <span class="n">entry_points</span><span class="p">(</span><span class="n">group</span><span class="o">=</span><span class="s1">'console_scripts'</span><span class="p">,</span> <span class="n">name</span><span class="o">=</span><span class="s1">'wheel'</span><span class="p">)</span>
- <span class="gp">>>> </span><span class="p">(</span><span class="n">wheel</span><span class="p">,)</span> <span class="o">=</span> <span class="n">entry_points</span><span class="p">()</span><span class="o">.</span><span class="n">select</span><span class="p">(</span><span class="n">group</span><span class="o">=</span><span class="s1">'console_scripts'</span><span class="p">,</span> <span class="n">name</span><span class="o">=</span><span class="s1">'wheel'</span><span class="p">)</span>
- </pre></div>
- </div>
- <p>Inspect the resolved entry point:</p>
- <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">wheel</span>
- <span class="go">EntryPoint(name='wheel', value='wheel.cli:main', group='console_scripts')</span>
- <span class="gp">>>> </span><span class="n">wheel</span><span class="o">.</span><span class="n">module</span>
- <span class="go">'wheel.cli'</span>
- <span class="gp">>>> </span><span class="n">wheel</span><span class="o">.</span><span class="n">attr</span>
- <span class="go">'main'</span>
- <span class="gp">>>> </span><span class="n">wheel</span><span class="o">.</span><span class="n">extras</span>
- <span class="go">[]</span>
- <span class="gp">>>> </span><span class="n">main</span> <span class="o">=</span> <span class="n">wheel</span><span class="o">.</span><span class="n">load</span><span class="p">()</span>
- <span class="gp">>>> </span><span class="n">main</span>
- <span class="go"><function main at 0x103528488></span>
- </pre></div>
- </div>
- <p>The <code class="docutils literal notranslate"><span class="pre">group</span></code> and <code class="docutils literal notranslate"><span class="pre">name</span></code> are arbitrary values defined by the package author
- and usually a client will wish to resolve all entry points for a particular
- group. Read <a class="reference external" href="https://setuptools.pypa.io/en/latest/userguide/entry_point.html">the setuptools docs</a>
- for more information on entry points, their definition, and usage.</p>
- <p><em>Compatibility Note</em></p>
- <p>The “selectable” entry points were introduced in <code class="docutils literal notranslate"><span class="pre">importlib_metadata</span></code>
- 3.6 and Python 3.10. Prior to those changes, <code class="docutils literal notranslate"><span class="pre">entry_points</span></code> accepted
- no parameters and always returned a dictionary of entry points, keyed
- by group. With <code class="docutils literal notranslate"><span class="pre">importlib_metadata</span></code> 5.0 and Python 3.12,
- <code class="docutils literal notranslate"><span class="pre">entry_points</span></code> always returns an <code class="docutils literal notranslate"><span class="pre">EntryPoints</span></code> object. See
- <a class="reference external" href="https://pypi.org/project/backports.entry-points-selectable">backports.entry_points_selectable</a>
- for compatibility options.</p>
- </section>
- <section id="distribution-metadata">
- <span id="metadata"></span><h3>Distribution metadata<a class="headerlink" href="#distribution-metadata" title="Link to this heading">¶</a></h3>
- <p>Every <a class="reference external" href="https://packaging.python.org/en/latest/glossary/#term-Distribution-Package">Distribution Package</a> includes some metadata,
- which you can extract using the
- <code class="docutils literal notranslate"><span class="pre">metadata()</span></code> function:</p>
- <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">wheel_metadata</span> <span class="o">=</span> <span class="n">metadata</span><span class="p">(</span><span class="s1">'wheel'</span><span class="p">)</span>
- </pre></div>
- </div>
- <p>The keys of the returned data structure, a <code class="docutils literal notranslate"><span class="pre">PackageMetadata</span></code>,
- name the metadata keywords, and
- the values are returned unparsed from the distribution metadata:</p>
- <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">wheel_metadata</span><span class="p">[</span><span class="s1">'Requires-Python'</span><span class="p">]</span>
- <span class="go">'>=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*'</span>
- </pre></div>
- </div>
- <p><code class="docutils literal notranslate"><span class="pre">PackageMetadata</span></code> also presents a <code class="docutils literal notranslate"><span class="pre">json</span></code> attribute that returns
- all the metadata in a JSON-compatible form per <span class="target" id="index-0"></span><a class="pep reference external" href="https://peps.python.org/pep-0566/"><strong>PEP 566</strong></a>:</p>
- <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">wheel_metadata</span><span class="o">.</span><span class="n">json</span><span class="p">[</span><span class="s1">'requires_python'</span><span class="p">]</span>
- <span class="go">'>=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*'</span>
- </pre></div>
- </div>
- <div class="admonition note">
- <p class="admonition-title">Note</p>
- <p>The actual type of the object returned by <code class="docutils literal notranslate"><span class="pre">metadata()</span></code> is an
- implementation detail and should be accessed only through the interface
- described by the
- <a class="reference external" href="https://importlib-metadata.readthedocs.io/en/latest/api.html#importlib_metadata.PackageMetadata">PackageMetadata protocol</a>.</p>
- </div>
- <div class="versionchanged">
- <p><span class="versionmodified changed">Changed in version 3.10: </span>The <code class="docutils literal notranslate"><span class="pre">Description</span></code> is now included in the metadata when presented
- through the payload. Line continuation characters have been removed.</p>
- <p>The <code class="docutils literal notranslate"><span class="pre">json</span></code> attribute was added.</p>
- </div>
- </section>
- <section id="distribution-versions">
- <span id="version"></span><h3>Distribution versions<a class="headerlink" href="#distribution-versions" title="Link to this heading">¶</a></h3>
- <p>The <code class="docutils literal notranslate"><span class="pre">version()</span></code> function is the quickest way to get a
- <a class="reference external" href="https://packaging.python.org/en/latest/glossary/#term-Distribution-Package">Distribution Package</a>’s version
- number, as a string:</p>
- <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">version</span><span class="p">(</span><span class="s1">'wheel'</span><span class="p">)</span>
- <span class="go">'0.32.3'</span>
- </pre></div>
- </div>
- </section>
- <section id="distribution-files">
- <span id="files"></span><h3>Distribution files<a class="headerlink" href="#distribution-files" title="Link to this heading">¶</a></h3>
- <p>You can also get the full set of files contained within a distribution. The
- <code class="docutils literal notranslate"><span class="pre">files()</span></code> function takes a <a class="reference external" href="https://packaging.python.org/en/latest/glossary/#term-Distribution-Package">Distribution Package</a> name
- and returns all of the
- files installed by this distribution. Each file object returned is a
- <code class="docutils literal notranslate"><span class="pre">PackagePath</span></code>, a <a class="reference internal" href="pathlib.html#pathlib.PurePath" title="pathlib.PurePath"><code class="xref py py-class docutils literal notranslate"><span class="pre">pathlib.PurePath</span></code></a> derived object with additional <code class="docutils literal notranslate"><span class="pre">dist</span></code>,
- <code class="docutils literal notranslate"><span class="pre">size</span></code>, and <code class="docutils literal notranslate"><span class="pre">hash</span></code> properties as indicated by the metadata. For example:</p>
- <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">util</span> <span class="o">=</span> <span class="p">[</span><span class="n">p</span> <span class="k">for</span> <span class="n">p</span> <span class="ow">in</span> <span class="n">files</span><span class="p">(</span><span class="s1">'wheel'</span><span class="p">)</span> <span class="k">if</span> <span class="s1">'util.py'</span> <span class="ow">in</span> <span class="nb">str</span><span class="p">(</span><span class="n">p</span><span class="p">)][</span><span class="mi">0</span><span class="p">]</span>
- <span class="gp">>>> </span><span class="n">util</span>
- <span class="go">PackagePath('wheel/util.py')</span>
- <span class="gp">>>> </span><span class="n">util</span><span class="o">.</span><span class="n">size</span>
- <span class="go">859</span>
- <span class="gp">>>> </span><span class="n">util</span><span class="o">.</span><span class="n">dist</span>
- <span class="go"><importlib.metadata._hooks.PathDistribution object at 0x101e0cef0></span>
- <span class="gp">>>> </span><span class="n">util</span><span class="o">.</span><span class="n">hash</span>
- <span class="go"><FileHash mode: sha256 value: bYkw5oMccfazVCoYQwKkkemoVyMAFoR34mmKBx8R1NI></span>
- </pre></div>
- </div>
- <p>Once you have the file, you can also read its contents:</p>
- <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="nb">print</span><span class="p">(</span><span class="n">util</span><span class="o">.</span><span class="n">read_text</span><span class="p">())</span>
- <span class="go">import base64</span>
- <span class="go">import sys</span>
- <span class="go">...</span>
- <span class="go">def as_bytes(s):</span>
- <span class="go"> if isinstance(s, text_type):</span>
- <span class="go"> return s.encode('utf-8')</span>
- <span class="go"> return s</span>
- </pre></div>
- </div>
- <p>You can also use the <code class="docutils literal notranslate"><span class="pre">locate</span></code> method to get a the absolute path to the
- file:</p>
- <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">util</span><span class="o">.</span><span class="n">locate</span><span class="p">()</span>
- <span class="go">PosixPath('/home/gustav/example/lib/site-packages/wheel/util.py')</span>
- </pre></div>
- </div>
- <p>In the case where the metadata file listing files
- (RECORD or SOURCES.txt) is missing, <code class="docutils literal notranslate"><span class="pre">files()</span></code> will
- return <code class="docutils literal notranslate"><span class="pre">None</span></code>. The caller may wish to wrap calls to
- <code class="docutils literal notranslate"><span class="pre">files()</span></code> in <a class="reference external" href="https://more-itertools.readthedocs.io/en/stable/api.html#more_itertools.always_iterable">always_iterable</a>
- or otherwise guard against this condition if the target
- distribution is not known to have the metadata present.</p>
- </section>
- <section id="distribution-requirements">
- <span id="requirements"></span><h3>Distribution requirements<a class="headerlink" href="#distribution-requirements" title="Link to this heading">¶</a></h3>
- <p>To get the full set of requirements for a <a class="reference external" href="https://packaging.python.org/en/latest/glossary/#term-Distribution-Package">Distribution Package</a>,
- use the <code class="docutils literal notranslate"><span class="pre">requires()</span></code>
- function:</p>
- <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">requires</span><span class="p">(</span><span class="s1">'wheel'</span><span class="p">)</span>
- <span class="go">["pytest (>=3.0.0) ; extra == 'test'", "pytest-cov ; extra == 'test'"]</span>
- </pre></div>
- </div>
- </section>
- <section id="mapping-import-to-distribution-packages">
- <span id="import-distribution-package-mapping"></span><span id="package-distributions"></span><h3>Mapping import to distribution packages<a class="headerlink" href="#mapping-import-to-distribution-packages" title="Link to this heading">¶</a></h3>
- <p>A convenience method to resolve the <a class="reference external" href="https://packaging.python.org/en/latest/glossary/#term-Distribution-Package">Distribution Package</a>
- name (or names, in the case of a namespace package)
- that provide each importable top-level
- Python module or <a class="reference external" href="https://packaging.python.org/en/latest/glossary/#term-Import-Package">Import Package</a>:</p>
- <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">packages_distributions</span><span class="p">()</span>
- <span class="go">{'importlib_metadata': ['importlib-metadata'], 'yaml': ['PyYAML'], 'jaraco': ['jaraco.classes', 'jaraco.functools'], ...}</span>
- </pre></div>
- </div>
- <p>Some editable installs, <a class="reference external" href="https://github.com/pypa/packaging-problems/issues/609">do not supply top-level names</a>, and thus this
- function is not reliable with such installs.</p>
- <div class="versionadded">
- <p><span class="versionmodified added">New in version 3.10.</span></p>
- </div>
- </section>
- </section>
- <section id="distributions">
- <span id="id9"></span><h2>Distributions<a class="headerlink" href="#distributions" title="Link to this heading">¶</a></h2>
- <p>While the above API is the most common and convenient usage, you can get all
- of that information from the <code class="docutils literal notranslate"><span class="pre">Distribution</span></code> class. A <code class="docutils literal notranslate"><span class="pre">Distribution</span></code> is an
- abstract object that represents the metadata for
- a Python <a class="reference external" href="https://packaging.python.org/en/latest/glossary/#term-Distribution-Package">Distribution Package</a>. You can
- get the <code class="docutils literal notranslate"><span class="pre">Distribution</span></code> instance:</p>
- <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="kn">from</span> <span class="nn">importlib.metadata</span> <span class="kn">import</span> <span class="n">distribution</span>
- <span class="gp">>>> </span><span class="n">dist</span> <span class="o">=</span> <span class="n">distribution</span><span class="p">(</span><span class="s1">'wheel'</span><span class="p">)</span>
- </pre></div>
- </div>
- <p>Thus, an alternative way to get the version number is through the
- <code class="docutils literal notranslate"><span class="pre">Distribution</span></code> instance:</p>
- <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">dist</span><span class="o">.</span><span class="n">version</span>
- <span class="go">'0.32.3'</span>
- </pre></div>
- </div>
- <p>There are all kinds of additional metadata available on the <code class="docutils literal notranslate"><span class="pre">Distribution</span></code>
- instance:</p>
- <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">dist</span><span class="o">.</span><span class="n">metadata</span><span class="p">[</span><span class="s1">'Requires-Python'</span><span class="p">]</span>
- <span class="go">'>=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*'</span>
- <span class="gp">>>> </span><span class="n">dist</span><span class="o">.</span><span class="n">metadata</span><span class="p">[</span><span class="s1">'License'</span><span class="p">]</span>
- <span class="go">'MIT'</span>
- </pre></div>
- </div>
- <p>The full set of available metadata is not described here.
- See the <a class="reference external" href="https://packaging.python.org/en/latest/specifications/core-metadata/#core-metadata">Core metadata specifications</a> for additional details.</p>
- </section>
- <section id="distribution-discovery">
- <h2>Distribution Discovery<a class="headerlink" href="#distribution-discovery" title="Link to this heading">¶</a></h2>
- <p>By default, this package provides built-in support for discovery of metadata
- for file system and zip file <a class="reference external" href="https://packaging.python.org/en/latest/glossary/#term-Distribution-Package">Distribution Package</a>s.
- This metadata finder search defaults to <code class="docutils literal notranslate"><span class="pre">sys.path</span></code>, but varies slightly in how it interprets those values from how other import machinery does. In particular:</p>
- <ul class="simple">
- <li><p><code class="docutils literal notranslate"><span class="pre">importlib.metadata</span></code> does not honor <a class="reference internal" href="stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a> objects on <code class="docutils literal notranslate"><span class="pre">sys.path</span></code>.</p></li>
- <li><p><code class="docutils literal notranslate"><span class="pre">importlib.metadata</span></code> will incidentally honor <a class="reference internal" href="pathlib.html#pathlib.Path" title="pathlib.Path"><code class="xref py py-class docutils literal notranslate"><span class="pre">pathlib.Path</span></code></a> objects on <code class="docutils literal notranslate"><span class="pre">sys.path</span></code> even though such values will be ignored for imports.</p></li>
- </ul>
- </section>
- <section id="extending-the-search-algorithm">
- <h2>Extending the search algorithm<a class="headerlink" href="#extending-the-search-algorithm" title="Link to this heading">¶</a></h2>
- <p>Because <a class="reference external" href="https://packaging.python.org/en/latest/glossary/#term-Distribution-Package">Distribution Package</a> metadata
- is not available through <a class="reference internal" href="sys.html#sys.path" title="sys.path"><code class="xref py py-data docutils literal notranslate"><span class="pre">sys.path</span></code></a> searches, or
- package loaders directly,
- the metadata for a distribution is found through import
- system <a class="reference internal" href="../reference/import.html#finders-and-loaders"><span class="std std-ref">finders</span></a>. To find a distribution package’s metadata,
- <code class="docutils literal notranslate"><span class="pre">importlib.metadata</span></code> queries the list of <a class="reference internal" href="../glossary.html#term-meta-path-finder"><span class="xref std std-term">meta path finders</span></a> on
- <a class="reference internal" href="sys.html#sys.meta_path" title="sys.meta_path"><code class="xref py py-data docutils literal notranslate"><span class="pre">sys.meta_path</span></code></a>.</p>
- <p>By default <code class="docutils literal notranslate"><span class="pre">importlib.metadata</span></code> installs a finder for distribution packages
- found on the file system.
- This finder doesn’t actually find any <em>distributions</em>,
- but it can find their metadata.</p>
- <p>The abstract class <a class="reference internal" href="importlib.html#importlib.abc.MetaPathFinder" title="importlib.abc.MetaPathFinder"><code class="xref py py-class docutils literal notranslate"><span class="pre">importlib.abc.MetaPathFinder</span></code></a> defines the
- interface expected of finders by Python’s import system.
- <code class="docutils literal notranslate"><span class="pre">importlib.metadata</span></code> extends this protocol by looking for an optional
- <code class="docutils literal notranslate"><span class="pre">find_distributions</span></code> callable on the finders from
- <a class="reference internal" href="sys.html#sys.meta_path" title="sys.meta_path"><code class="xref py py-data docutils literal notranslate"><span class="pre">sys.meta_path</span></code></a> and presents this extended interface as the
- <code class="docutils literal notranslate"><span class="pre">DistributionFinder</span></code> abstract base class, which defines this abstract
- method:</p>
- <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="nd">@abc</span><span class="o">.</span><span class="n">abstractmethod</span>
- <span class="k">def</span> <span class="nf">find_distributions</span><span class="p">(</span><span class="n">context</span><span class="o">=</span><span class="n">DistributionFinder</span><span class="o">.</span><span class="n">Context</span><span class="p">()):</span>
- <span class="w"> </span><span class="sd">"""Return an iterable of all Distribution instances capable of</span>
- <span class="sd"> loading the metadata for packages for the indicated ``context``.</span>
- <span class="sd"> """</span>
- </pre></div>
- </div>
- <p>The <code class="docutils literal notranslate"><span class="pre">DistributionFinder.Context</span></code> object provides <code class="docutils literal notranslate"><span class="pre">.path</span></code> and <code class="docutils literal notranslate"><span class="pre">.name</span></code>
- properties indicating the path to search and name to match and may
- supply other relevant context.</p>
- <p>What this means in practice is that to support finding distribution package
- metadata in locations other than the file system, subclass
- <code class="docutils literal notranslate"><span class="pre">Distribution</span></code> and implement the abstract methods. Then from
- a custom finder, return instances of this derived <code class="docutils literal notranslate"><span class="pre">Distribution</span></code> in the
- <code class="docutils literal notranslate"><span class="pre">find_distributions()</span></code> method.</p>
- </section>
- </section>
-
-
- <div class="clearer"></div>
- </div>
- </div>
- </div>
- <div class="sphinxsidebar" role="navigation" aria-label="main navigation">
- <div class="sphinxsidebarwrapper">
- <div>
- <h3><a href="../contents.html">Table of Contents</a></h3>
- <ul>
- <li><a class="reference internal" href="#"><code class="xref py py-mod docutils literal notranslate"><span class="pre">importlib.metadata</span></code> – Accessing package metadata</a><ul>
- <li><a class="reference internal" href="#overview">Overview</a></li>
- <li><a class="reference internal" href="#functional-api">Functional API</a><ul>
- <li><a class="reference internal" href="#entry-points">Entry points</a></li>
- <li><a class="reference internal" href="#distribution-metadata">Distribution metadata</a></li>
- <li><a class="reference internal" href="#distribution-versions">Distribution versions</a></li>
- <li><a class="reference internal" href="#distribution-files">Distribution files</a></li>
- <li><a class="reference internal" href="#distribution-requirements">Distribution requirements</a></li>
- <li><a class="reference internal" href="#mapping-import-to-distribution-packages">Mapping import to distribution packages</a></li>
- </ul>
- </li>
- <li><a class="reference internal" href="#distributions">Distributions</a></li>
- <li><a class="reference internal" href="#distribution-discovery">Distribution Discovery</a></li>
- <li><a class="reference internal" href="#extending-the-search-algorithm">Extending the search algorithm</a></li>
- </ul>
- </li>
- </ul>
-
- </div>
- <div>
- <h4>Previous topic</h4>
- <p class="topless"><a href="importlib.resources.abc.html"
- title="previous chapter"><code class="xref py py-mod docutils literal notranslate"><span class="pre">importlib.resources.abc</span></code> – Abstract base classes for resources</a></p>
- </div>
- <div>
- <h4>Next topic</h4>
- <p class="topless"><a href="sys_path_init.html"
- title="next chapter">The initialization of the <code class="xref py py-data docutils literal notranslate"><span class="pre">sys.path</span></code> module search path</a></p>
- </div>
- <div role="note" aria-label="source link">
- <h3>This Page</h3>
- <ul class="this-page-menu">
- <li><a href="../bugs.html">Report a Bug</a></li>
- <li>
- <a href="https://github.com/python/cpython/blob/main/Doc/library/importlib.metadata.rst"
- rel="nofollow">Show Source
- </a>
- </li>
- </ul>
- </div>
- </div>
- <div id="sidebarbutton" title="Collapse sidebar">
- <span>«</span>
- </div>
-
- </div>
- <div class="clearer"></div>
- </div>
- <div class="related" role="navigation" aria-label="related navigation">
- <h3>Navigation</h3>
- <ul>
- <li class="right" style="margin-right: 10px">
- <a href="../genindex.html" title="General Index"
- >index</a></li>
- <li class="right" >
- <a href="../py-modindex.html" title="Python Module Index"
- >modules</a> |</li>
- <li class="right" >
- <a href="sys_path_init.html" title="The initialization of the sys.path module search path"
- >next</a> |</li>
- <li class="right" >
- <a href="importlib.resources.abc.html" title="importlib.resources.abc – Abstract base classes for resources"
- >previous</a> |</li>
-
- <li><img src="../_static/py.svg" alt="Python logo" style="vertical-align: middle; margin-top: -1px"/></li>
- <li><a href="https://www.python.org/">Python</a> »</li>
- <li class="switchers">
- <div class="language_switcher_placeholder"></div>
- <div class="version_switcher_placeholder"></div>
- </li>
- <li>
-
- </li>
- <li id="cpython-language-and-version">
- <a href="../index.html">3.12.3 Documentation</a> »
- </li>
-
- <li class="nav-item nav-item-1"><a href="index.html" >The Python Standard Library</a> »</li>
- <li class="nav-item nav-item-2"><a href="modules.html" >Importing Modules</a> »</li>
- <li class="nav-item nav-item-this"><a href=""><code class="xref py py-mod docutils literal notranslate"><span class="pre">importlib.metadata</span></code> – Accessing package metadata</a></li>
- <li class="right">
-
-
- <div class="inline-search" role="search">
- <form class="inline-search" action="../search.html" method="get">
- <input placeholder="Quick search" aria-label="Quick search" type="search" name="q" id="search-box" />
- <input type="submit" value="Go" />
- </form>
- </div>
- |
- </li>
- <li class="right">
- <label class="theme-selector-label">
- Theme
- <select class="theme-selector" oninput="activateTheme(this.value)">
- <option value="auto" selected>Auto</option>
- <option value="light">Light</option>
- <option value="dark">Dark</option>
- </select>
- </label> |</li>
-
- </ul>
- </div>
- <div class="footer">
- ©
- <a href="../copyright.html">
-
- Copyright
-
- </a>
- 2001-2024, Python Software Foundation.
- <br />
- This page is licensed under the Python Software Foundation License Version 2.
- <br />
- Examples, recipes, and other code in the documentation are additionally licensed under the Zero Clause BSD License.
- <br />
-
- See <a href="/license.html">History and License</a> for more information.<br />
-
-
- <br />
-
- The Python Software Foundation is a non-profit corporation.
- <a href="https://www.python.org/psf/donations/">Please donate.</a>
- <br />
- <br />
- Last updated on Apr 09, 2024 (13:47 UTC).
-
- <a href="/bugs.html">Found a bug</a>?
-
- <br />
-
- Created using <a href="https://www.sphinx-doc.org/">Sphinx</a> 7.2.6.
- </div>
-
- </body>
- </html>
|