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<div class="section" id="the-internal-structure-of-python-eggs">
<h1><a class="toc-backref" href="#id1">The Internal Structure of Python Eggs</a><a class="headerlink" href="#the-internal-structure-of-python-eggs" title="Permalink to this headline">¶</a></h1>
<p>STOP! This is not the first document you should read!</p>
<div class="contents topic" id="table-of-contents">
<p class="topic-title first"><strong>Table of Contents</strong></p>
<ul class="simple">
<li><a class="reference internal" href="#the-internal-structure-of-python-eggs" id="id1">The Internal Structure of Python Eggs</a><ul>
<li><a class="reference internal" href="#eggs-and-their-formats" id="id2">Eggs and their Formats</a><ul>
<li><a class="reference internal" href="#code-and-resources" id="id3">Code and Resources</a></li>
<li><a class="reference internal" href="#project-metadata" id="id4">Project Metadata</a></li>
<li><a class="reference internal" href="#filename-embedded-metadata" id="id5">Filename-Embedded Metadata</a></li>
<li><a class="reference internal" href="#egg-links" id="id6">Egg Links</a></li>
</ul>
</li>
<li><a class="reference internal" href="#standard-metadata" id="id7">Standard Metadata</a><ul>
<li><a class="reference internal" href="#txt-file-formats" id="id8"><code class="docutils literal"><span class="pre">.txt</span></code> File Formats</a></li>
<li><a class="reference internal" href="#dependency-metadata" id="id9">Dependency Metadata</a><ul>
<li><a class="reference internal" href="#requires-txt" id="id10"><code class="docutils literal"><span class="pre">requires.txt</span></code></a></li>
<li><a class="reference internal" href="#setup-requires-txt" id="id11"><code class="docutils literal"><span class="pre">setup_requires.txt</span></code></a></li>
<li><a class="reference internal" href="#dependency-links-txt" id="id12"><code class="docutils literal"><span class="pre">dependency_links.txt</span></code></a></li>
<li><a class="reference internal" href="#depends-txt-obsolete-do-not-create" id="id13"><code class="docutils literal"><span class="pre">depends.txt</span></code> – Obsolete, do not create!</a></li>
</ul>
</li>
<li><a class="reference internal" href="#namespace-packages-txt-namespace-package-metadata" id="id14"><code class="docutils literal"><span class="pre">namespace_packages.txt</span></code> – Namespace Package Metadata</a></li>
<li><a class="reference internal" href="#entry-points-txt-entry-point-plugin-metadata" id="id15"><code class="docutils literal"><span class="pre">entry_points.txt</span></code> – “Entry Point”/Plugin Metadata</a></li>
<li><a class="reference internal" href="#the-scripts-subdirectory" id="id16">The <code class="docutils literal"><span class="pre">scripts</span></code> Subdirectory</a></li>
<li><a class="reference internal" href="#zip-support-metadata" id="id17">Zip Support Metadata</a><ul>
<li><a class="reference internal" href="#native-libs-txt" id="id18"><code class="docutils literal"><span class="pre">native_libs.txt</span></code></a></li>
<li><a class="reference internal" href="#eager-resources-txt" id="id19"><code class="docutils literal"><span class="pre">eager_resources.txt</span></code></a></li>
<li><a class="reference internal" href="#zip-safe-and-not-zip-safe" id="id20"><code class="docutils literal"><span class="pre">zip-safe</span></code> and <code class="docutils literal"><span class="pre">not-zip-safe</span></code></a></li>
</ul>
</li>
<li><a class="reference internal" href="#top-level-txt-conflict-management-metadata" id="id21"><code class="docutils literal"><span class="pre">top_level.txt</span></code> – Conflict Management Metadata</a></li>
<li><a class="reference internal" href="#sources-txt-source-files-manifest" id="id22"><code class="docutils literal"><span class="pre">SOURCES.txt</span></code> – Source Files Manifest</a></li>
</ul>
</li>
<li><a class="reference internal" href="#other-technical-considerations" id="id23">Other Technical Considerations</a><ul>
<li><a class="reference internal" href="#zip-file-issues" id="id24">Zip File Issues</a><ul>
<li><a class="reference internal" href="#the-extraction-process" id="id25">The Extraction Process</a></li>
<li><a class="reference internal" href="#extension-import-wrappers" id="id26">Extension Import Wrappers</a></li>
</ul>
</li>
<li><a class="reference internal" href="#installation-and-path-management-issues" id="id27">Installation and Path Management Issues</a><ul>
<li><a class="reference internal" href="#script-wrappers" id="id28">Script Wrappers</a></li>
</ul>
</li>
</ul>
</li>
</ul>
</li>
</ul>
</div>
<div class="section" id="eggs-and-their-formats">
<h2><a class="toc-backref" href="#id2">Eggs and their Formats</a><a class="headerlink" href="#eggs-and-their-formats" title="Permalink to this headline">¶</a></h2>
<p>A “Python egg” is a logical structure embodying the release of a
specific version of a Python project, comprising its code, resources,
and metadata. There are multiple formats that can be used to physically
encode a Python egg, and others can be developed. However, a key
principle of Python eggs is that they should be discoverable and
importable. That is, it should be possible for a Python application to
easily and efficiently find out what eggs are present on a system, and
to ensure that the desired eggs’ contents are importable.</p>
<p>There are two basic formats currently implemented for Python eggs:</p>
<ol class="arabic simple">
<li><code class="docutils literal"><span class="pre">.egg</span></code> format: a directory or zipfile <em>containing</em> the project’s
code and resources, along with an <code class="docutils literal"><span class="pre">EGG-INFO</span></code> subdirectory that
contains the project’s metadata</li>
<li><code class="docutils literal"><span class="pre">.egg-info</span></code> format: a file or directory placed <em>adjacent</em> to the
project’s code and resources, that directly contains the project’s
metadata.</li>
</ol>
<p>Both formats can include arbitrary Python code and resources, including
static data files, package and non-package directories, Python
modules, C extension modules, and so on. But each format is optimized
for different purposes.</p>
<p>The <code class="docutils literal"><span class="pre">.egg</span></code> format is well-suited to distribution and the easy
uninstallation or upgrades of code, since the project is essentially
self-contained within a single directory or file, unmingled with any
other projects’ code or resources. It also makes it possible to have
multiple versions of a project simultaneously installed, such that
individual programs can select the versions they wish to use.</p>
<p>The <code class="docutils literal"><span class="pre">.egg-info</span></code> format, on the other hand, was created to support
backward-compatibility, performance, and ease of installation for system
packaging tools that expect to install all projects’ code and resources
to a single directory (e.g. <code class="docutils literal"><span class="pre">site-packages</span></code>). Placing the metadata
in that same directory simplifies the installation process, since it
isn’t necessary to create <code class="docutils literal"><span class="pre">.pth</span></code> files or otherwise modify
<code class="docutils literal"><span class="pre">sys.path</span></code> to include each installed egg.</p>
<p>Its disadvantage, however, is that it provides no support for clean
uninstallation or upgrades, and of course only a single version of a
project can be installed to a given directory. Thus, support from a
package management tool is required. (This is why setuptools’ “install”
command refers to this type of egg installation as “single-version,
externally managed”.) Also, they lack sufficient data to allow them to
be copied from their installation source. easy_install can “ship” an
application by copying <code class="docutils literal"><span class="pre">.egg</span></code> files or directories to a target
location, but it cannot do this for <code class="docutils literal"><span class="pre">.egg-info</span></code> installs, because
there is no way to tell what code and resources belong to a particular
egg – there may be several eggs “scrambled” together in a single
installation location, and the <code class="docutils literal"><span class="pre">.egg-info</span></code> format does not currently
include a way to list the files that were installed. (This may change
in a future version.)</p>
<div class="section" id="code-and-resources">
<h3><a class="toc-backref" href="#id3">Code and Resources</a><a class="headerlink" href="#code-and-resources" title="Permalink to this headline">¶</a></h3>
<p>The layout of the code and resources is dictated by Python’s normal
import layout, relative to the egg’s “base location”.</p>
<p>For the <code class="docutils literal"><span class="pre">.egg</span></code> format, the base location is the <code class="docutils literal"><span class="pre">.egg</span></code> itself. That
is, adding the <code class="docutils literal"><span class="pre">.egg</span></code> filename or directory name to <code class="docutils literal"><span class="pre">sys.path</span></code>
makes its contents importable.</p>
<p>For the <code class="docutils literal"><span class="pre">.egg-info</span></code> format, however, the base location is the
directory that <em>contains</em> the <code class="docutils literal"><span class="pre">.egg-info</span></code>, and thus it is the
directory that must be added to <code class="docutils literal"><span class="pre">sys.path</span></code> to make the egg importable.
(Note that this means that the “normal” installation of a package to a
<code class="docutils literal"><span class="pre">sys.path</span></code> directory is sufficient to make it an “egg” if it has an
<code class="docutils literal"><span class="pre">.egg-info</span></code> file or directory installed alongside of it.)</p>
</div>
<div class="section" id="project-metadata">
<h3><a class="toc-backref" href="#id4">Project Metadata</a><a class="headerlink" href="#project-metadata" title="Permalink to this headline">¶</a></h3>
<p>If eggs contained only code and resources, there would of course be
no difference between them and any other directory or zip file on
<code class="docutils literal"><span class="pre">sys.path</span></code>. Thus, metadata must also be included, using a metadata
file or directory.</p>
<p>For the <code class="docutils literal"><span class="pre">.egg</span></code> format, the metadata is placed in an <code class="docutils literal"><span class="pre">EGG-INFO</span></code>
subdirectory, directly within the <code class="docutils literal"><span class="pre">.egg</span></code> file or directory. For the
<code class="docutils literal"><span class="pre">.egg-info</span></code> format, metadata is stored directly within the
<code class="docutils literal"><span class="pre">.egg-info</span></code> directory itself.</p>
<p>The minimum project metadata that all eggs must have is a standard
Python <code class="docutils literal"><span class="pre">PKG-INFO</span></code> file, named <code class="docutils literal"><span class="pre">PKG-INFO</span></code> and placed within the
metadata directory appropriate to the format. Because it’s possible for
this to be the only metadata file included, <code class="docutils literal"><span class="pre">.egg-info</span></code> format eggs
are not required to be a directory; they can just be a <code class="docutils literal"><span class="pre">.egg-info</span></code>
file that directly contains the <code class="docutils literal"><span class="pre">PKG-INFO</span></code> metadata. This eliminates
the need to create a directory just to store one file. This option is
<em>not</em> available for <code class="docutils literal"><span class="pre">.egg</span></code> formats, since setuptools always includes
other metadata. (In fact, setuptools itself never generates
<code class="docutils literal"><span class="pre">.egg-info</span></code> files, either; the support for using files was added so
that the requirement could easily be satisfied by other tools, such
as distutils).</p>
<p>In addition to the <code class="docutils literal"><span class="pre">PKG-INFO</span></code> file, an egg’s metadata directory may
also include files and directories representing various forms of
optional standard metadata (see the section on <a class="reference internal" href="#standard-metadata">Standard Metadata</a>,
below) or user-defined metadata required by the project. For example,
some projects may define a metadata format to describe their application
plugins, and metadata in this format would then be included by plugin
creators in their projects’ metadata directories.</p>
</div>
<div class="section" id="filename-embedded-metadata">
<h3><a class="toc-backref" href="#id5">Filename-Embedded Metadata</a><a class="headerlink" href="#filename-embedded-metadata" title="Permalink to this headline">¶</a></h3>
<p>To allow introspection of installed projects and runtime resolution of
inter-project dependencies, a certain amount of information is embedded
in egg filenames. At a minimum, this includes the project name, and
ideally will also include the project version number. Optionally, it
can also include the target Python version and required runtime
platform if platform-specific C code is included. The syntax of an
egg filename is as follows:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="n">name</span> <span class="p">[</span><span class="s2">"-"</span> <span class="n">version</span> <span class="p">[</span><span class="s2">"-py"</span> <span class="n">pyver</span> <span class="p">[</span><span class="s2">"-"</span> <span class="n">required_platform</span><span class="p">]]]</span> <span class="s2">"."</span> <span class="n">ext</span>
</pre></div>
</div>
<p>The “name” and “version” should be escaped using the <code class="docutils literal"><span class="pre">to_filename()</span></code>
function provided by <code class="docutils literal"><span class="pre">pkg_resources</span></code>, after first processing them with
<code class="docutils literal"><span class="pre">safe_name()</span></code> and <code class="docutils literal"><span class="pre">safe_version()</span></code> respectively. These latter two
functions can also be used to later “unescape” these parts of the
filename. (For a detailed description of these transformations, please
see the “Parsing Utilities” section of the <code class="docutils literal"><span class="pre">pkg_resources</span></code> manual.)</p>
<p>The “pyver” string is the Python major version, as found in the first
3 characters of <code class="docutils literal"><span class="pre">sys.version</span></code>. “required_platform” is essentially
a distutils <code class="docutils literal"><span class="pre">get_platform()</span></code> string, but with enhancements to properly
distinguish Mac OS versions. (See the <code class="docutils literal"><span class="pre">get_build_platform()</span></code>
documentation in the “Platform Utilities” section of the
<code class="docutils literal"><span class="pre">pkg_resources</span></code> manual for more details.)</p>
<p>Finally, the “ext” is either <code class="docutils literal"><span class="pre">.egg</span></code> or <code class="docutils literal"><span class="pre">.egg-info</span></code>, as appropriate
for the egg’s format.</p>
<p>Normally, an egg’s filename should include at least the project name and
version, as this allows the runtime system to find desired project
versions without having to read the egg’s PKG-INFO to determine its
version number.</p>
<p>Setuptools, however, only includes the version number in the filename
when an <code class="docutils literal"><span class="pre">.egg</span></code> file is built using the <code class="docutils literal"><span class="pre">bdist_egg</span></code> command, or when
an <code class="docutils literal"><span class="pre">.egg-info</span></code> directory is being installed by the
<code class="docutils literal"><span class="pre">install_egg_info</span></code> command. When generating metadata for use with the
original source tree, it only includes the project name, so that the
directory will not have to be renamed each time the project’s version
changes.</p>
<p>This is especially important when version numbers change frequently, and
the source metadata directory is kept under version control with the
rest of the project. (As would be the case when the project’s source
includes project-defined metadata that is not generated from by
setuptools from data in the setup script.)</p>
</div>
<div class="section" id="egg-links">
<h3><a class="toc-backref" href="#id6">Egg Links</a><a class="headerlink" href="#egg-links" title="Permalink to this headline">¶</a></h3>
<p>In addition to the <code class="docutils literal"><span class="pre">.egg</span></code> and <code class="docutils literal"><span class="pre">.egg-info</span></code> formats, there is a third
egg-related extension that you may encounter on occasion: <code class="docutils literal"><span class="pre">.egg-link</span></code>
files.</p>
<p>These files are not eggs, strictly speaking. They simply provide a way
to reference an egg that is not physically installed in the desired
location. They exist primarily as a cross-platform alternative to
symbolic links, to support “installing” code that is being developed in
a different location than the desired installation location. For
example, if a user is developing an application plugin in their home
directory, but the plugin needs to be “installed” in an application
plugin directory, running “setup.py develop -md /path/to/app/plugins”
will install an <code class="docutils literal"><span class="pre">.egg-link</span></code> file in <code class="docutils literal"><span class="pre">/path/to/app/plugins</span></code>, that
tells the egg runtime system where to find the actual egg (the user’s
project source directory and its <code class="docutils literal"><span class="pre">.egg-info</span></code> subdirectory).</p>
<p><code class="docutils literal"><span class="pre">.egg-link</span></code> files are named following the format for <code class="docutils literal"><span class="pre">.egg</span></code> and
<code class="docutils literal"><span class="pre">.egg-info</span></code> names, but only the project name is included; no version,
Python version, or platform information is included. When the runtime
searches for available eggs, <code class="docutils literal"><span class="pre">.egg-link</span></code> files are opened and the
actual egg file/directory name is read from them.</p>
<p>Each <code class="docutils literal"><span class="pre">.egg-link</span></code> file should contain a single file or directory name,
with no newlines. This filename should be the base location of one or
more eggs. That is, the name must either end in <code class="docutils literal"><span class="pre">.egg</span></code>, or else it
should be the parent directory of one or more <code class="docutils literal"><span class="pre">.egg-info</span></code> format eggs.</p>
<p>As of setuptools 0.6c6, the path may be specified as a platform-independent
(i.e. <code class="docutils literal"><span class="pre">/</span></code>-separated) relative path from the directory containing the
<code class="docutils literal"><span class="pre">.egg-link</span></code> file, and a second line may appear in the file, specifying a
platform-independent relative path from the egg’s base directory to its
setup script directory. This allows installation tools such as EasyInstall
to find the project’s setup directory and build eggs or perform other setup
commands on it.</p>
</div>
</div>
<div class="section" id="standard-metadata">
<h2><a class="toc-backref" href="#id7">Standard Metadata</a><a class="headerlink" href="#standard-metadata" title="Permalink to this headline">¶</a></h2>
<p>In addition to the minimum required <code class="docutils literal"><span class="pre">PKG-INFO</span></code> metadata, projects can
include a variety of standard metadata files or directories, as
described below. Except as otherwise noted, these files and directories
are automatically generated by setuptools, based on information supplied
in the setup script or through analysis of the project’s code and
resources.</p>
<p>Most of these files and directories are generated via “egg-info
writers” during execution of the setuptools <code class="docutils literal"><span class="pre">egg_info</span></code> command, and
are listed in the <code class="docutils literal"><span class="pre">egg_info.writers</span></code> entry point group defined by
setuptools’ own <code class="docutils literal"><span class="pre">setup.py</span></code> file.</p>
<p>Project authors can register their own metadata writers as entry points
in this group (as described in the setuptools manual under “Adding new
EGG-INFO Files”) to cause setuptools to generate project-specific
metadata files or directories during execution of the <code class="docutils literal"><span class="pre">egg_info</span></code>
command. It is up to project authors to document these new metadata
formats, if they create any.</p>
<div class="section" id="txt-file-formats">
<h3><a class="toc-backref" href="#id8"><code class="docutils literal"><span class="pre">.txt</span></code> File Formats</a><a class="headerlink" href="#txt-file-formats" title="Permalink to this headline">¶</a></h3>
<p>Files described in this section that have <code class="docutils literal"><span class="pre">.txt</span></code> extensions have a
simple lexical format consisting of a sequence of text lines, each line
terminated by a linefeed character (regardless of platform). Leading
and trailing whitespace on each line is ignored, as are blank lines and
lines whose first nonblank character is a <code class="docutils literal"><span class="pre">#</span></code> (comment symbol). (This
is the parsing format defined by the <code class="docutils literal"><span class="pre">yield_lines()</span></code> function of
the <code class="docutils literal"><span class="pre">pkg_resources</span></code> module.)</p>
<p>All <code class="docutils literal"><span class="pre">.txt</span></code> files defined by this section follow this format, but some
are also “sectioned” files, meaning that their contents are divided into
sections, using square-bracketed section headers akin to Windows
<code class="docutils literal"><span class="pre">.ini</span></code> format. Note that this does <em>not</em> imply that the lines within
the sections follow an <code class="docutils literal"><span class="pre">.ini</span></code> format, however. Please see an
individual metadata file’s documentation for a description of what the
lines and section names mean in that particular file.</p>
<p>Sectioned files can be parsed using the <code class="docutils literal"><span class="pre">split_sections()</span></code> function;
see the “Parsing Utilities” section of the <code class="docutils literal"><span class="pre">pkg_resources</span></code> manual for
for details.</p>
</div>
<div class="section" id="dependency-metadata">
<h3><a class="toc-backref" href="#id9">Dependency Metadata</a><a class="headerlink" href="#dependency-metadata" title="Permalink to this headline">¶</a></h3>
<div class="section" id="requires-txt">
<h4><a class="toc-backref" href="#id10"><code class="docutils literal"><span class="pre">requires.txt</span></code></a><a class="headerlink" href="#requires-txt" title="Permalink to this headline">¶</a></h4>
<p>This is a “sectioned” text file. Each section is a sequence of
“requirements”, as parsed by the <code class="docutils literal"><span class="pre">parse_requirements()</span></code> function;
please see the <code class="docutils literal"><span class="pre">pkg_resources</span></code> manual for the complete requirement
parsing syntax.</p>
<p>The first, unnamed section (i.e., before the first section header) in
this file is the project’s core requirements, which must be installed
for the project to function. (Specified using the <code class="docutils literal"><span class="pre">install_requires</span></code>
keyword to <code class="docutils literal"><span class="pre">setup()</span></code>).</p>
<p>The remaining (named) sections describe the project’s “extra”
requirements, as specified using the <code class="docutils literal"><span class="pre">extras_require</span></code> keyword to
<code class="docutils literal"><span class="pre">setup()</span></code>. The section name is the name of the optional feature, and
the section body lists that feature’s dependencies.</p>
<p>Note that it is not normally necessary to inspect this file directly;
<code class="docutils literal"><span class="pre">pkg_resources.Distribution</span></code> objects have a <code class="docutils literal"><span class="pre">requires()</span></code> method
that can be used to obtain <code class="docutils literal"><span class="pre">Requirement</span></code> objects describing the
project’s core and optional dependencies.</p>
</div>
<div class="section" id="setup-requires-txt">
<h4><a class="toc-backref" href="#id11"><code class="docutils literal"><span class="pre">setup_requires.txt</span></code></a><a class="headerlink" href="#setup-requires-txt" title="Permalink to this headline">¶</a></h4>
<p>Much like <code class="docutils literal"><span class="pre">requires.txt</span></code> except represents the requirements
specified by the <code class="docutils literal"><span class="pre">setup_requires</span></code> parameter to the Distribution.</p>
</div>
<div class="section" id="dependency-links-txt">
<h4><a class="toc-backref" href="#id12"><code class="docutils literal"><span class="pre">dependency_links.txt</span></code></a><a class="headerlink" href="#dependency-links-txt" title="Permalink to this headline">¶</a></h4>
<p>A list of dependency URLs, one per line, as specified using the
<code class="docutils literal"><span class="pre">dependency_links</span></code> keyword to <code class="docutils literal"><span class="pre">setup()</span></code>. These may be direct
download URLs, or the URLs of web pages containing direct download
links, and will be used by EasyInstall to find dependencies, as though
the user had manually provided them via the <code class="docutils literal"><span class="pre">--find-links</span></code> command
line option. Please see the setuptools manual and EasyInstall manual
for more information on specifying this option, and for information on
how EasyInstall processes <code class="docutils literal"><span class="pre">--find-links</span></code> URLs.</p>
</div>
<div class="section" id="depends-txt-obsolete-do-not-create">
<h4><a class="toc-backref" href="#id13"><code class="docutils literal"><span class="pre">depends.txt</span></code> – Obsolete, do not create!</a><a class="headerlink" href="#depends-txt-obsolete-do-not-create" title="Permalink to this headline">¶</a></h4>
<p>This file follows an identical format to <code class="docutils literal"><span class="pre">requires.txt</span></code>, but is
obsolete and should not be used. The earliest versions of setuptools
required users to manually create and maintain this file, so the runtime
still supports reading it, if it exists. The new filename was created
so that it could be automatically generated from <code class="docutils literal"><span class="pre">setup()</span></code> information
without overwriting an existing hand-created <code class="docutils literal"><span class="pre">depends.txt</span></code>, if one
was already present in the project’s source <code class="docutils literal"><span class="pre">.egg-info</span></code> directory.</p>
</div>
</div>
<div class="section" id="namespace-packages-txt-namespace-package-metadata">
<h3><a class="toc-backref" href="#id14"><code class="docutils literal"><span class="pre">namespace_packages.txt</span></code> – Namespace Package Metadata</a><a class="headerlink" href="#namespace-packages-txt-namespace-package-metadata" title="Permalink to this headline">¶</a></h3>
<p>A list of namespace package names, one per line, as supplied to the
<code class="docutils literal"><span class="pre">namespace_packages</span></code> keyword to <code class="docutils literal"><span class="pre">setup()</span></code>. Please see the manuals
for setuptools and <code class="docutils literal"><span class="pre">pkg_resources</span></code> for more information about
namespace packages.</p>
</div>
<div class="section" id="entry-points-txt-entry-point-plugin-metadata">
<h3><a class="toc-backref" href="#id15"><code class="docutils literal"><span class="pre">entry_points.txt</span></code> – “Entry Point”/Plugin Metadata</a><a class="headerlink" href="#entry-points-txt-entry-point-plugin-metadata" title="Permalink to this headline">¶</a></h3>
<p>This is a “sectioned” text file, whose contents encode the
<code class="docutils literal"><span class="pre">entry_points</span></code> keyword supplied to <code class="docutils literal"><span class="pre">setup()</span></code>. All sections are
named, as the section names specify the entry point groups in which the
corresponding section’s entry points are registered.</p>
<p>Each section is a sequence of “entry point” lines, each parseable using
the <code class="docutils literal"><span class="pre">EntryPoint.parse</span></code> classmethod; please see the <code class="docutils literal"><span class="pre">pkg_resources</span></code>
manual for the complete entry point parsing syntax.</p>
<p>Note that it is not necessary to parse this file directly; the
<code class="docutils literal"><span class="pre">pkg_resources</span></code> module provides a variety of APIs to locate and load
entry points automatically. Please see the setuptools and
<code class="docutils literal"><span class="pre">pkg_resources</span></code> manuals for details on the nature and uses of entry
points.</p>
</div>
<div class="section" id="the-scripts-subdirectory">
<h3><a class="toc-backref" href="#id16">The <code class="docutils literal"><span class="pre">scripts</span></code> Subdirectory</a><a class="headerlink" href="#the-scripts-subdirectory" title="Permalink to this headline">¶</a></h3>
<p>This directory is currently only created for <code class="docutils literal"><span class="pre">.egg</span></code> files built by
the setuptools <code class="docutils literal"><span class="pre">bdist_egg</span></code> command. It will contain copies of all
of the project’s “traditional” scripts (i.e., those specified using the
<code class="docutils literal"><span class="pre">scripts</span></code> keyword to <code class="docutils literal"><span class="pre">setup()</span></code>). This is so that they can be
reconstituted when an <code class="docutils literal"><span class="pre">.egg</span></code> file is installed.</p>
<p>The scripts are placed here using the distutils’ standard
<code class="docutils literal"><span class="pre">install_scripts</span></code> command, so any <code class="docutils literal"><span class="pre">#!</span></code> lines reflect the Python
installation where the egg was built. But instead of copying the
scripts to the local script installation directory, EasyInstall writes
short wrapper scripts that invoke the original scripts from inside the
egg, after ensuring that sys.path includes the egg and any eggs it
depends on. For more about <a class="reference internal" href="#script-wrappers">script wrappers</a>, see the section below on
<a class="reference internal" href="#installation-and-path-management-issues">Installation and Path Management Issues</a>.</p>
</div>
<div class="section" id="zip-support-metadata">
<h3><a class="toc-backref" href="#id17">Zip Support Metadata</a><a class="headerlink" href="#zip-support-metadata" title="Permalink to this headline">¶</a></h3>
<div class="section" id="native-libs-txt">
<h4><a class="toc-backref" href="#id18"><code class="docutils literal"><span class="pre">native_libs.txt</span></code></a><a class="headerlink" href="#native-libs-txt" title="Permalink to this headline">¶</a></h4>
<p>A list of C extensions and other dynamic link libraries contained in
the egg, one per line. Paths are <code class="docutils literal"><span class="pre">/</span></code>-separated and relative to the
egg’s base location.</p>
<p>This file is generated as part of <code class="docutils literal"><span class="pre">bdist_egg</span></code> processing, and as such
only appears in <code class="docutils literal"><span class="pre">.egg</span></code> files (and <code class="docutils literal"><span class="pre">.egg</span></code> directories created by
unpacking them). It is used to ensure that all libraries are extracted
from a zipped egg at the same time, in case there is any direct linkage
between them. Please see the <a class="reference internal" href="#zip-file-issues">Zip File Issues</a> section below for more
information on library and resource extraction from <code class="docutils literal"><span class="pre">.egg</span></code> files.</p>
</div>
<div class="section" id="eager-resources-txt">
<h4><a class="toc-backref" href="#id19"><code class="docutils literal"><span class="pre">eager_resources.txt</span></code></a><a class="headerlink" href="#eager-resources-txt" title="Permalink to this headline">¶</a></h4>
<p>A list of resource files and/or directories, one per line, as specified
via the <code class="docutils literal"><span class="pre">eager_resources</span></code> keyword to <code class="docutils literal"><span class="pre">setup()</span></code>. Paths are
<code class="docutils literal"><span class="pre">/</span></code>-separated and relative to the egg’s base location.</p>
<p>Resource files or directories listed here will be extracted
simultaneously, if any of the named resources are extracted, or if any
native libraries listed in <code class="docutils literal"><span class="pre">native_libs.txt</span></code> are extracted. Please
see the setuptools manual for details on what this feature is used for
and how it works, as well as the <a class="reference internal" href="#zip-file-issues">Zip File Issues</a> section below.</p>
</div>
<div class="section" id="zip-safe-and-not-zip-safe">
<h4><a class="toc-backref" href="#id20"><code class="docutils literal"><span class="pre">zip-safe</span></code> and <code class="docutils literal"><span class="pre">not-zip-safe</span></code></a><a class="headerlink" href="#zip-safe-and-not-zip-safe" title="Permalink to this headline">¶</a></h4>
<p>These are zero-length files, and either one or the other should exist.
If <code class="docutils literal"><span class="pre">zip-safe</span></code> exists, it means that the project will work properly
when installed as an <code class="docutils literal"><span class="pre">.egg</span></code> zipfile, and conversely the existence of
<code class="docutils literal"><span class="pre">not-zip-safe</span></code> means the project should not be installed as an
<code class="docutils literal"><span class="pre">.egg</span></code> file. The <code class="docutils literal"><span class="pre">zip_safe</span></code> option to setuptools’ <code class="docutils literal"><span class="pre">setup()</span></code>
determines which file will be written. If the option isn’t provided,
setuptools attempts to make its own assessment of whether the package
can work, based on code and content analysis.</p>
<p>If neither file is present at installation time, EasyInstall defaults
to assuming that the project should be unzipped. (Command-line options
to EasyInstall, however, take precedence even over an existing
<code class="docutils literal"><span class="pre">zip-safe</span></code> or <code class="docutils literal"><span class="pre">not-zip-safe</span></code> file.)</p>
<p>Note that these flag files appear only in <code class="docutils literal"><span class="pre">.egg</span></code> files generated by
<code class="docutils literal"><span class="pre">bdist_egg</span></code>, and in <code class="docutils literal"><span class="pre">.egg</span></code> directories created by unpacking such an
<code class="docutils literal"><span class="pre">.egg</span></code> file.</p>
</div>
</div>
<div class="section" id="top-level-txt-conflict-management-metadata">
<h3><a class="toc-backref" href="#id21"><code class="docutils literal"><span class="pre">top_level.txt</span></code> – Conflict Management Metadata</a><a class="headerlink" href="#top-level-txt-conflict-management-metadata" title="Permalink to this headline">¶</a></h3>
<p>This file is a list of the top-level module or package names provided
by the project, one Python identifier per line.</p>
<p>Subpackages are not included; a project containing both a <code class="docutils literal"><span class="pre">foo.bar</span></code>
and a <code class="docutils literal"><span class="pre">foo.baz</span></code> would include only one line, <code class="docutils literal"><span class="pre">foo</span></code>, in its
<code class="docutils literal"><span class="pre">top_level.txt</span></code>.</p>
<p>This data is used by <code class="docutils literal"><span class="pre">pkg_resources</span></code> at runtime to issue a warning if
an egg is added to <code class="docutils literal"><span class="pre">sys.path</span></code> when its contained packages may have
already been imported.</p>
<p>(It was also once used to detect conflicts with non-egg packages at
installation time, but in more recent versions, setuptools installs eggs
in such a way that they always override non-egg packages, thus
preventing a problem from arising.)</p>
</div>
<div class="section" id="sources-txt-source-files-manifest">
<h3><a class="toc-backref" href="#id22"><code class="docutils literal"><span class="pre">SOURCES.txt</span></code> – Source Files Manifest</a><a class="headerlink" href="#sources-txt-source-files-manifest" title="Permalink to this headline">¶</a></h3>
<p>This file is roughly equivalent to the distutils’ <code class="docutils literal"><span class="pre">MANIFEST</span></code> file.
The differences are as follows:</p>
<ul class="simple">
<li>The filenames always use <code class="docutils literal"><span class="pre">/</span></code> as a path separator, which must be
converted back to a platform-specific path whenever they are read.</li>
<li>The file is automatically generated by setuptools whenever the
<code class="docutils literal"><span class="pre">egg_info</span></code> or <code class="docutils literal"><span class="pre">sdist</span></code> commands are run, and it is <em>not</em>
user-editable.</li>
</ul>
<p>Although this metadata is included with distributed eggs, it is not
actually used at runtime for any purpose. Its function is to ensure
that setuptools-built <em>source</em> distributions can correctly discover
what files are part of the project’s source, even if the list had been
generated using revision control metadata on the original author’s
system.</p>
<p>In other words, <code class="docutils literal"><span class="pre">SOURCES.txt</span></code> has little or no runtime value for being
included in distributed eggs, and it is possible that future versions of
the <code class="docutils literal"><span class="pre">bdist_egg</span></code> and <code class="docutils literal"><span class="pre">install_egg_info</span></code> commands will strip it before
installation or distribution. Therefore, do not rely on its being
available outside of an original source directory or source
distribution.</p>
</div>
</div>
<div class="section" id="other-technical-considerations">
<h2><a class="toc-backref" href="#id23">Other Technical Considerations</a><a class="headerlink" href="#other-technical-considerations" title="Permalink to this headline">¶</a></h2>
<div class="section" id="zip-file-issues">
<h3><a class="toc-backref" href="#id24">Zip File Issues</a><a class="headerlink" href="#zip-file-issues" title="Permalink to this headline">¶</a></h3>
<p>Although zip files resemble directories, they are not fully
substitutable for them. Most platforms do not support loading dynamic
link libraries contained in zipfiles, so it is not possible to directly
import C extensions from <code class="docutils literal"><span class="pre">.egg</span></code> zipfiles. Similarly, there are many
existing libraries – whether in Python or C – that require actual
operating system filenames, and do not work with arbitrary “file-like”
objects or in-memory strings, and thus cannot operate directly on the
contents of zip files.</p>
<p>To address these issues, the <code class="docutils literal"><span class="pre">pkg_resources</span></code> module provides a
“resource API” to support obtaining either the contents of a resource,
or a true operating system filename for the resource. If the egg
containing the resource is a directory, the resource’s real filename
is simply returned. However, if the egg is a zipfile, then the
resource is first extracted to a cache directory, and the filename
within the cache is returned.</p>
<p>The cache directory is determined by the <code class="docutils literal"><span class="pre">pkg_resources</span></code> API; please
see the <code class="docutils literal"><span class="pre">set_cache_path()</span></code> and <code class="docutils literal"><span class="pre">get_default_cache()</span></code> documentation
for details.</p>
<div class="section" id="the-extraction-process">
<h4><a class="toc-backref" href="#id25">The Extraction Process</a><a class="headerlink" href="#the-extraction-process" title="Permalink to this headline">¶</a></h4>
<p>Resources are extracted to a cache subdirectory whose name is based
on the enclosing <code class="docutils literal"><span class="pre">.egg</span></code> filename and the path to the resource. If
there is already a file of the correct name, size, and timestamp, its
filename is returned to the requester. Otherwise, the desired file is
extracted first to a temporary name generated using
<code class="docutils literal"><span class="pre">mkstemp(".$extract",target_dir)</span></code>, and then its timestamp is set to
match the one in the zip file, before renaming it to its final name.
(Some collision detection and resolution code is used to handle the
fact that Windows doesn’t overwrite files when renaming.)</p>
<p>If a resource directory is requested, all of its contents are
recursively extracted in this fashion, to ensure that the directory
name can be used as if it were valid all along.</p>
<p>If the resource requested for extraction is listed in the
<code class="docutils literal"><span class="pre">native_libs.txt</span></code> or <code class="docutils literal"><span class="pre">eager_resources.txt</span></code> metadata files, then
<em>all</em> resources listed in <em>either</em> file will be extracted before the
requested resource’s filename is returned, thus ensuring that all
C extensions and data used by them will be simultaneously available.</p>
</div>
<div class="section" id="extension-import-wrappers">
<h4><a class="toc-backref" href="#id26">Extension Import Wrappers</a><a class="headerlink" href="#extension-import-wrappers" title="Permalink to this headline">¶</a></h4>
<p>Since Python’s built-in zip import feature does not support loading
C extension modules from zipfiles, the setuptools <code class="docutils literal"><span class="pre">bdist_egg</span></code> command
generates special import wrappers to make it work.</p>
<p>The wrappers are <code class="docutils literal"><span class="pre">.py</span></code> files (along with corresponding <code class="docutils literal"><span class="pre">.pyc</span></code>
and/or <code class="docutils literal"><span class="pre">.pyo</span></code> files) that have the same module name as the
corresponding C extension. These wrappers are located in the same
package directory (or top-level directory) within the zipfile, so that
say, <code class="docutils literal"><span class="pre">foomodule.so</span></code> will get a corresponding <code class="docutils literal"><span class="pre">foo.py</span></code>, while
<code class="docutils literal"><span class="pre">bar/baz.pyd</span></code> will get a corresponding <code class="docutils literal"><span class="pre">bar/baz.py</span></code>.</p>
<p>These wrapper files contain a short stanza of Python code that asks
<code class="docutils literal"><span class="pre">pkg_resources</span></code> for the filename of the corresponding C extension,
then reloads the module using the obtained filename. This will cause
<code class="docutils literal"><span class="pre">pkg_resources</span></code> to first ensure that all of the egg’s C extensions
(and any accompanying “eager resources”) are extracted to the cache
before attempting to link to the C library.</p>
<p>Note, by the way, that <code class="docutils literal"><span class="pre">.egg</span></code> directories will also contain these
wrapper files. However, Python’s default import priority is such that
C extensions take precedence over same-named Python modules, so the
import wrappers are ignored unless the egg is a zipfile.</p>
</div>
</div>
<div class="section" id="installation-and-path-management-issues">
<h3><a class="toc-backref" href="#id27">Installation and Path Management Issues</a><a class="headerlink" href="#installation-and-path-management-issues" title="Permalink to this headline">¶</a></h3>
<p>Python’s initial setup of <code class="docutils literal"><span class="pre">sys.path</span></code> is very dependent on the Python
version and installation platform, as well as how Python was started
(i.e., script vs. <code class="docutils literal"><span class="pre">-c</span></code> vs. <code class="docutils literal"><span class="pre">-m</span></code> vs. interactive interpreter).
In fact, Python also provides only two relatively robust ways to affect
<code class="docutils literal"><span class="pre">sys.path</span></code> outside of direct manipulation in code: the <code class="docutils literal"><span class="pre">PYTHONPATH</span></code>
environment variable, and <code class="docutils literal"><span class="pre">.pth</span></code> files.</p>
<p>However, with no cross-platform way to safely and persistently change
environment variables, this leaves <code class="docutils literal"><span class="pre">.pth</span></code> files as EasyInstall’s only
real option for persistent configuration of <code class="docutils literal"><span class="pre">sys.path</span></code>.</p>
<p>But <code class="docutils literal"><span class="pre">.pth</span></code> files are rather strictly limited in what they are allowed
to do normally. They add directories only to the <em>end</em> of <code class="docutils literal"><span class="pre">sys.path</span></code>,
after any locally-installed <code class="docutils literal"><span class="pre">site-packages</span></code> directory, and they are
only processed <em>in</em> the <code class="docutils literal"><span class="pre">site-packages</span></code> directory to start with.</p>
<p>This is a double whammy for users who lack write access to that
directory, because they can’t create a <code class="docutils literal"><span class="pre">.pth</span></code> file that Python will
read, and even if a sympathetic system administrator adds one for them
that calls <code class="docutils literal"><span class="pre">site.addsitedir()</span></code> to allow some other directory to
contain <code class="docutils literal"><span class="pre">.pth</span></code> files, they won’t be able to install newer versions of
anything that’s installed in the systemwide <code class="docutils literal"><span class="pre">site-packages</span></code>, because
their paths will still be added <em>after</em> <code class="docutils literal"><span class="pre">site-packages</span></code>.</p>
<p>So EasyInstall applies two workarounds to solve these problems.</p>
<p>The first is that EasyInstall leverages <code class="docutils literal"><span class="pre">.pth</span></code> files’ “import” feature
to manipulate <code class="docutils literal"><span class="pre">sys.path</span></code> and ensure that anything EasyInstall adds
to a <code class="docutils literal"><span class="pre">.pth</span></code> file will always appear before both the standard library
and the local <code class="docutils literal"><span class="pre">site-packages</span></code> directories. Thus, it is always
possible for a user who can write a Python-read <code class="docutils literal"><span class="pre">.pth</span></code> file to ensure
that their packages come first in their own environment.</p>
<p>Second, when installing to a <code class="docutils literal"><span class="pre">PYTHONPATH</span></code> directory (as opposed to
a “site” directory like <code class="docutils literal"><span class="pre">site-packages</span></code>) EasyInstall will also install
a special version of the <code class="docutils literal"><span class="pre">site</span></code> module. Because it’s in a
<code class="docutils literal"><span class="pre">PYTHONPATH</span></code> directory, this module will get control before the
standard library version of <code class="docutils literal"><span class="pre">site</span></code> does. It will record the state of
<code class="docutils literal"><span class="pre">sys.path</span></code> before invoking the “real” <code class="docutils literal"><span class="pre">site</span></code> module, and then
afterwards it processes any <code class="docutils literal"><span class="pre">.pth</span></code> files found in <code class="docutils literal"><span class="pre">PYTHONPATH</span></code>
directories, including all the fixups needed to ensure that eggs always
appear before the standard library in sys.path, but are in a relative
order to one another that is defined by their <code class="docutils literal"><span class="pre">PYTHONPATH</span></code> and
<code class="docutils literal"><span class="pre">.pth</span></code>-prescribed sequence.</p>
<p>The net result of these changes is that <code class="docutils literal"><span class="pre">sys.path</span></code> order will be
as follows at runtime:</p>
<ol class="arabic simple">
<li>The <code class="docutils literal"><span class="pre">sys.argv[0]</span></code> directory, or an empty string if no script
is being executed.</li>
<li>All eggs installed by EasyInstall in any <code class="docutils literal"><span class="pre">.pth</span></code> file in each
<code class="docutils literal"><span class="pre">PYTHONPATH</span></code> directory, in order first by <code class="docutils literal"><span class="pre">PYTHONPATH</span></code> order,
then normal <code class="docutils literal"><span class="pre">.pth</span></code> processing order (which is to say alphabetical
by <code class="docutils literal"><span class="pre">.pth</span></code> filename, then by the order of listing within each
<code class="docutils literal"><span class="pre">.pth</span></code> file).</li>
<li>All eggs installed by EasyInstall in any <code class="docutils literal"><span class="pre">.pth</span></code> file in each “site”
directory (such as <code class="docutils literal"><span class="pre">site-packages</span></code>), following the same ordering
rules as for the ones on <code class="docutils literal"><span class="pre">PYTHONPATH</span></code>.</li>
<li>The <code class="docutils literal"><span class="pre">PYTHONPATH</span></code> directories themselves, in their original order</li>
<li>Any paths from <code class="docutils literal"><span class="pre">.pth</span></code> files found on <code class="docutils literal"><span class="pre">PYTHONPATH</span></code> that were <em>not</em>
eggs installed by EasyInstall, again following the same relative
ordering rules.</li>
<li>The standard library and “site” directories, along with the contents
of any <code class="docutils literal"><span class="pre">.pth</span></code> files found in the “site” directories.</li>
</ol>
<p>Notice that sections 1, 4, and 6 comprise the “normal” Python setup for
<code class="docutils literal"><span class="pre">sys.path</span></code>. Sections 2 and 3 are inserted to support eggs, and
section 5 emulates what the “normal” semantics of <code class="docutils literal"><span class="pre">.pth</span></code> files on
<code class="docutils literal"><span class="pre">PYTHONPATH</span></code> would be if Python natively supported them.</p>
<p>For further discussion of the tradeoffs that went into this design, as
well as notes on the actual magic inserted into <code class="docutils literal"><span class="pre">.pth</span></code> files to make
them do these things, please see also the following messages to the
distutils-SIG mailing list:</p>
<ul class="simple">
<li><a class="reference external" href="http://mail.python.org/pipermail/distutils-sig/2006-February/006026.html">http://mail.python.org/pipermail/distutils-sig/2006-February/006026.html</a></li>
<li><a class="reference external" href="http://mail.python.org/pipermail/distutils-sig/2006-March/006123.html">http://mail.python.org/pipermail/distutils-sig/2006-March/006123.html</a></li>
</ul>
<div class="section" id="script-wrappers">
<h4><a class="toc-backref" href="#id28">Script Wrappers</a><a class="headerlink" href="#script-wrappers" title="Permalink to this headline">¶</a></h4>
<p>EasyInstall never directly installs a project’s original scripts to
a script installation directory. Instead, it writes short wrapper
scripts that first ensure that the project’s dependencies are active
on sys.path, before invoking the original script. These wrappers
have a #! line that points to the version of Python that was used to
install them, and their second line is always a comment that indicates
the type of script wrapper, the project version required for the script
to run, and information identifying the script to be invoked.</p>
<p>The format of this marker line is:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="s2">"# EASY-INSTALL-"</span> <span class="n">script_type</span> <span class="s2">": "</span> <span class="n">tuple_of_strings</span> <span class="s2">"</span><span class="se">\n</span><span class="s2">"</span>
</pre></div>
</div>
<p>The <code class="docutils literal"><span class="pre">script_type</span></code> is one of <code class="docutils literal"><span class="pre">SCRIPT</span></code>, <code class="docutils literal"><span class="pre">DEV-SCRIPT</span></code>, or
<code class="docutils literal"><span class="pre">ENTRY-SCRIPT</span></code>. The <code class="docutils literal"><span class="pre">tuple_of_strings</span></code> is a comma-separated
sequence of Python string constants. For <code class="docutils literal"><span class="pre">SCRIPT</span></code> and <code class="docutils literal"><span class="pre">DEV-SCRIPT</span></code>
wrappers, there are two strings: the project version requirement, and
the script name (as a filename within the <code class="docutils literal"><span class="pre">scripts</span></code> metadata
directory). For <code class="docutils literal"><span class="pre">ENTRY-SCRIPT</span></code> wrappers, there are three:
the project version requirement, the entry point group name, and the
entry point name. (See the “Automatic Script Creation” section in the
setuptools manual for more information about entry point scripts.)</p>
<p>In each case, the project version requirement string will be a string
parseable with the <code class="docutils literal"><span class="pre">pkg_resources</span></code> modules’ <code class="docutils literal"><span class="pre">Requirement.parse()</span></code>
classmethod. The only difference between a <code class="docutils literal"><span class="pre">SCRIPT</span></code> wrapper and a
<code class="docutils literal"><span class="pre">DEV-SCRIPT</span></code> is that a <code class="docutils literal"><span class="pre">DEV-SCRIPT</span></code> actually executes the original
source script in the project’s source tree, and is created when the
“setup.py develop” command is run. A <code class="docutils literal"><span class="pre">SCRIPT</span></code> wrapper, on the other
hand, uses the “installed” script written to the <code class="docutils literal"><span class="pre">EGG-INFO/scripts</span></code>
subdirectory of the corresponding <code class="docutils literal"><span class="pre">.egg</span></code> zipfile or directory.
(<code class="docutils literal"><span class="pre">.egg-info</span></code> eggs do not have script wrappers associated with them,
except in the “setup.py develop” case.)</p>
<p>The purpose of including the marker line in generated script wrappers is
to facilitate introspection of installed scripts, and their relationship
to installed eggs. For example, an uninstallation tool could use this
data to identify what scripts can safely be removed, and/or identify
what scripts would stop working if a particular egg is uninstalled.</p>
</div>
</div>
</div>
</div>
</div>
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<h3><a href="index.html">Table Of Contents</a></h3>
<ul>
<li><a class="reference internal" href="#">The Internal Structure of Python Eggs</a><ul>
<li><a class="reference internal" href="#eggs-and-their-formats">Eggs and their Formats</a><ul>
<li><a class="reference internal" href="#code-and-resources">Code and Resources</a></li>
<li><a class="reference internal" href="#project-metadata">Project Metadata</a></li>
<li><a class="reference internal" href="#filename-embedded-metadata">Filename-Embedded Metadata</a></li>
<li><a class="reference internal" href="#egg-links">Egg Links</a></li>
</ul>
</li>
<li><a class="reference internal" href="#standard-metadata">Standard Metadata</a><ul>
<li><a class="reference internal" href="#txt-file-formats"><code class="docutils literal"><span class="pre">.txt</span></code> File Formats</a></li>
<li><a class="reference internal" href="#dependency-metadata">Dependency Metadata</a><ul>
<li><a class="reference internal" href="#requires-txt"><code class="docutils literal"><span class="pre">requires.txt</span></code></a></li>
<li><a class="reference internal" href="#setup-requires-txt"><code class="docutils literal"><span class="pre">setup_requires.txt</span></code></a></li>
<li><a class="reference internal" href="#dependency-links-txt"><code class="docutils literal"><span class="pre">dependency_links.txt</span></code></a></li>
<li><a class="reference internal" href="#depends-txt-obsolete-do-not-create"><code class="docutils literal"><span class="pre">depends.txt</span></code> – Obsolete, do not create!</a></li>
</ul>
</li>
<li><a class="reference internal" href="#namespace-packages-txt-namespace-package-metadata"><code class="docutils literal"><span class="pre">namespace_packages.txt</span></code> – Namespace Package Metadata</a></li>
<li><a class="reference internal" href="#entry-points-txt-entry-point-plugin-metadata"><code class="docutils literal"><span class="pre">entry_points.txt</span></code> – “Entry Point”/Plugin Metadata</a></li>
<li><a class="reference internal" href="#the-scripts-subdirectory">The <code class="docutils literal"><span class="pre">scripts</span></code> Subdirectory</a></li>
<li><a class="reference internal" href="#zip-support-metadata">Zip Support Metadata</a><ul>
<li><a class="reference internal" href="#native-libs-txt"><code class="docutils literal"><span class="pre">native_libs.txt</span></code></a></li>
<li><a class="reference internal" href="#eager-resources-txt"><code class="docutils literal"><span class="pre">eager_resources.txt</span></code></a></li>
<li><a class="reference internal" href="#zip-safe-and-not-zip-safe"><code class="docutils literal"><span class="pre">zip-safe</span></code> and <code class="docutils literal"><span class="pre">not-zip-safe</span></code></a></li>
</ul>
</li>
<li><a class="reference internal" href="#top-level-txt-conflict-management-metadata"><code class="docutils literal"><span class="pre">top_level.txt</span></code> – Conflict Management Metadata</a></li>
<li><a class="reference internal" href="#sources-txt-source-files-manifest"><code class="docutils literal"><span class="pre">SOURCES.txt</span></code> – Source Files Manifest</a></li>
</ul>
</li>
<li><a class="reference internal" href="#other-technical-considerations">Other Technical Considerations</a><ul>
<li><a class="reference internal" href="#zip-file-issues">Zip File Issues</a><ul>
<li><a class="reference internal" href="#the-extraction-process">The Extraction Process</a></li>
<li><a class="reference internal" href="#extension-import-wrappers">Extension Import Wrappers</a></li>
</ul>
</li>
<li><a class="reference internal" href="#installation-and-path-management-issues">Installation and Path Management Issues</a><ul>
<li><a class="reference internal" href="#script-wrappers">Script Wrappers</a></li>
</ul>
</li>
</ul>
</li>
</ul>
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