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6ef038e78c
This started out as an easy task, just add a section describing this alternate scheme, but I found a lot of cleanup to do along the way: - fixed inverted reST targets - fixed entries for modules (hi abiflags!) or data files - avoided duplicating the same options listing five or six times - added missing entries for C headers locations - added documentation for --install-lib - fixed a few misuses of the option role (see #9312), but not all (not worth the time, but will do it in packaging docs) - fixed some markup The paths fixes were done with an eye on the source code in the install command, so they really describe what’s actually done. The situation on Mac OS X is rather messy: the fix for #8084 touched site and sysconfig, but distutils doesn’t use these files. I suspect we have a mismatched stdlib at the moment, and the fix is not even clear (see the bug report for further discussion).
202 lines
7.2 KiB
ReStructuredText
202 lines
7.2 KiB
ReStructuredText
:mod:`site` --- Site-specific configuration hook
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================================================
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.. module:: site
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:synopsis: Module responsible for site-specific configuration.
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**Source code:** :source:`Lib/site.py`
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--------------
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.. highlightlang:: none
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**This module is automatically imported during initialization.** The automatic
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import can be suppressed using the interpreter's :option:`-S` option.
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.. index:: triple: module; search; path
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Importing this module will append site-specific paths to the module search path
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and add a few builtins.
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.. index::
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pair: site-python; directory
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pair: site-packages; directory
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It starts by constructing up to four directories from a head and a tail part.
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For the head part, it uses ``sys.prefix`` and ``sys.exec_prefix``; empty heads
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are skipped. For the tail part, it uses the empty string and then
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:file:`lib/site-packages` (on Windows) or
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:file:`lib/python|version|/site-packages` and then :file:`lib/site-python` (on
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Unix and Macintosh). For each of the distinct head-tail combinations, it sees
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if it refers to an existing directory, and if so, adds it to ``sys.path`` and
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also inspects the newly added path for configuration files.
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A path configuration file is a file whose name has the form :file:`{name}.pth`
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and exists in one of the four directories mentioned above; its contents are
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additional items (one per line) to be added to ``sys.path``. Non-existing items
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are never added to ``sys.path``, and no check is made that the item refers to a
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directory rather than a file. No item is added to ``sys.path`` more than
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once. Blank lines and lines beginning with ``#`` are skipped. Lines starting
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with ``import`` (followed by space or tab) are executed.
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.. index::
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single: package
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triple: path; configuration; file
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For example, suppose ``sys.prefix`` and ``sys.exec_prefix`` are set to
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:file:`/usr/local`. The Python X.Y library is then installed in
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:file:`/usr/local/lib/python{X.Y}`. Suppose this has
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a subdirectory :file:`/usr/local/lib/python{X.Y}/site-packages` with three
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subsubdirectories, :file:`foo`, :file:`bar` and :file:`spam`, and two path
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configuration files, :file:`foo.pth` and :file:`bar.pth`. Assume
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:file:`foo.pth` contains the following::
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# foo package configuration
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foo
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bar
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bletch
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and :file:`bar.pth` contains::
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# bar package configuration
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bar
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Then the following version-specific directories are added to
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``sys.path``, in this order::
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/usr/local/lib/pythonX.Y/site-packages/bar
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/usr/local/lib/pythonX.Y/site-packages/foo
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Note that :file:`bletch` is omitted because it doesn't exist; the :file:`bar`
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directory precedes the :file:`foo` directory because :file:`bar.pth` comes
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alphabetically before :file:`foo.pth`; and :file:`spam` is omitted because it is
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not mentioned in either path configuration file.
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.. index:: module: sitecustomize
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After these path manipulations, an attempt is made to import a module named
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:mod:`sitecustomize`, which can perform arbitrary site-specific customizations.
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It is typically created by a system administrator in the site-packages
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directory. If this import fails with an :exc:`ImportError` exception, it is
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silently ignored.
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.. index:: module: usercustomize
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After this, an attempt is made to import a module named :mod:`usercustomize`,
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which can perform arbitrary user-specific customizations, if
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:data:`ENABLE_USER_SITE` is true. This file is intended to be created in the
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user site-packages directory (see below), which is part of ``sys.path`` unless
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disabled by :option:`-s`. An :exc:`ImportError` will be silently ignored.
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Note that for some non-Unix systems, ``sys.prefix`` and ``sys.exec_prefix`` are
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empty, and the path manipulations are skipped; however the import of
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:mod:`sitecustomize` and :mod:`usercustomize` is still attempted.
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.. data:: PREFIXES
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A list of prefixes for site-packages directories.
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.. data:: ENABLE_USER_SITE
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Flag showing the status of the user site-packages directory. ``True`` means
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that it is enabled and was added to ``sys.path``. ``False`` means that it
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was disabled by user request (with :option:`-s` or
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:envvar:`PYTHONNOUSERSITE`). ``None`` means it was disabled for security
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reasons (mismatch between user or group id and effective id) or by an
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administrator.
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.. data:: USER_SITE
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Path to the user site-packages for the running Python. Can be ``None`` if
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:func:`getusersitepackages` hasn't been called yet. Default value is
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:file:`~/.local/lib/python{X.Y}/site-packages` for UNIX and non-framework Mac
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OS X builds, :file:`~/Library/Python/{X.Y}/lib/python/site-packages` for Mac
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framework builds, and :file:`{%APPDATA%}\\Python\\Python{XY}\\site-packages`
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on Windows. This directory is a site directory, which means that
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:file:`.pth` files in it will be processed.
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.. data:: USER_BASE
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Path to the base directory for the user site-packages. Can be ``None`` if
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:func:`getuserbase` hasn't been called yet. Default value is
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:file:`~/.local` for UNIX and Mac OS X non-framework builds,
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:file:`~/Library/Python/{X.Y}` for Mac framework builds, and
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:file:`{%APPDATA%}\\Python` for Windows. This value is used by Distutils to
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compute the installation directories for scripts, data files, Python modules,
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etc. for the :ref:`user installation scheme <inst-alt-install-user>`. See
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also :envvar:`PYTHONUSERBASE`.
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.. function:: addsitedir(sitedir, known_paths=None)
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Add a directory to sys.path and process its :file:`.pth` files. Typically
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used in :mod:`sitecustomize` or :mod:`usercustomize` (see above).
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.. function:: getsitepackages()
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Return a list containing all global site-packages directories (and possibly
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site-python).
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.. versionadded:: 3.2
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.. function:: getuserbase()
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Return the path of the user base directory, :data:`USER_BASE`. If it is not
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initialized yet, this function will also set it, respecting
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:envvar:`PYTHONUSERBASE`.
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.. versionadded:: 3.2
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.. function:: getusersitepackages()
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Return the path of the user-specific site-packages directory,
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:data:`USER_SITE`. If it is not initialized yet, this function will also set
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it, respecting :envvar:`PYTHONNOUSERSITE` and :data:`USER_BASE`.
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.. versionadded:: 3.2
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The :mod:`site` module also provides a way to get the user directories from the
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command line:
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.. code-block:: sh
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$ python3 -m site --user-site
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/home/user/.local/lib/python3.3/site-packages
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.. program:: site
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If it is called without arguments, it will print the contents of
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:data:`sys.path` on the standard output, followed by the value of
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:data:`USER_BASE` and whether the directory exists, then the same thing for
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:data:`USER_SITE`, and finally the value of :data:`ENABLE_USER_SITE`.
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.. cmdoption:: --user-base
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Print the path to the user base directory.
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.. cmdoption:: --user-site
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Print the path to the user site-packages directory.
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If both options are given, user base and user site will be printed (always in
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this order), separated by :data:`os.pathsep`.
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If any option is given, the script will exit with one of these values: ``O`` if
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the user site-packages directory is enabled, ``1`` if it was disabled by the
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user, ``2`` if it is disabled for security reasons or by an administrator, and a
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value greater than 2 if there is an error.
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.. seealso::
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:pep:`370` -- Per user site-packages directory
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