Improve documentation for PEP 370 support in site module (#8617).

site.USER_BASE and site.USER_SITE are now fully documented.  PEP 370 is
outdated with respects to the Mac framework situation, but the code in
sysconfig and the example in the 3.2 What’s New document helped me find
the right values to document for Mac OS X.

The command-line interface of the site module, partly documented in the
3.2 What’s New, is fully described in the module docs.

The purpose of the usercustomize module is explained in the site docs,
with a gentle introduction in the tutorial (right after the section that
talks about PYTHONSTARTUP; a comment mentions it should be moved from
the tutorial to another file, but that will be another bug).

Various markup and wording improvements were made along the way in the
site module docs.  Duplicate and incomplete declarations of environment
variables have also been removed (the original bug report was actually
about these entries :).  The site module docs are still a bit messy;
I’ll see about improving them for #11553.

All these sections are copiously interlinked and findable from the doc
indexes.
This commit is contained in:
Éric Araujo 2011-08-06 01:51:07 +02:00
parent e5cad23a92
commit de4f05b741
4 changed files with 121 additions and 44 deletions

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@ -2,18 +2,21 @@
================================================
.. module:: site
:synopsis: A standard way to reference site-specific modules.
:synopsis: Module responsible for site-specific configuration.
**Source code:** :source:`Lib/site.py`
--------------
.. highlightlang:: none
**This module is automatically imported during initialization.** The automatic
import can be suppressed using the interpreter's :option:`-S` option.
.. index:: triple: module; search; path
Importing this module will append site-specific paths to the module search path.
Importing this module will append site-specific paths to the module search path
and add a few builtins.
.. index::
pair: site-python; directory
@ -28,11 +31,11 @@ Unix and Macintosh). For each of the distinct head-tail combinations, it sees
if it refers to an existing directory, and if so, adds it to ``sys.path`` and
also inspects the newly added path for configuration files.
A path configuration file is a file whose name has the form :file:`package.pth`
A path configuration file is a file whose name has the form :file:`{name}.pth`
and exists in one of the four directories mentioned above; its contents are
additional items (one per line) to be added to ``sys.path``. Non-existing items
are never added to ``sys.path``, but no check is made that the item refers to a
directory (rather than a file). No item is added to ``sys.path`` more than
are never added to ``sys.path``, and no check is made that the item refers to a
directory rather than a file. No item is added to ``sys.path`` more than
once. Blank lines and lines beginning with ``#`` are skipped. Lines starting
with ``import`` (followed by space or tab) are executed.
@ -42,8 +45,7 @@ with ``import`` (followed by space or tab) are executed.
For example, suppose ``sys.prefix`` and ``sys.exec_prefix`` are set to
:file:`/usr/local`. The Python X.Y library is then installed in
:file:`/usr/local/lib/python{X.Y}` (where only the first three characters of
``sys.version`` are used to form the installation path name). Suppose this has
:file:`/usr/local/lib/python{X.Y}`. Suppose this has
a subdirectory :file:`/usr/local/lib/python{X.Y}/site-packages` with three
subsubdirectories, :file:`foo`, :file:`bar` and :file:`spam`, and two path
configuration files, :file:`foo.pth` and :file:`bar.pth`. Assume
@ -76,74 +78,122 @@ not mentioned in either path configuration file.
After these path manipulations, an attempt is made to import a module named
:mod:`sitecustomize`, which can perform arbitrary site-specific customizations.
If this import fails with an :exc:`ImportError` exception, it is silently
ignored.
It is typically created by a system administrator in the site-packages
directory. If this import fails with an :exc:`ImportError` exception, it is
silently ignored.
.. index:: module: sitecustomize
.. index:: module: usercustomize
After this, an attempt is made to import a module named :mod:`usercustomize`,
which can perform arbitrary user-specific customizations, if
:data:`ENABLE_USER_SITE` is true. This file is intended to be created in the
user site-packages directory (see below), which is part of ``sys.path`` unless
disabled by :option:`-s`. An :exc:`ImportError` will be silently ignored.
Note that for some non-Unix systems, ``sys.prefix`` and ``sys.exec_prefix`` are
empty, and the path manipulations are skipped; however the import of
:mod:`sitecustomize` is still attempted.
:mod:`sitecustomize` and :mod:`usercustomize` is still attempted.
.. data:: PREFIXES
A list of prefixes for site package directories
A list of prefixes for site-packages directories.
.. data:: ENABLE_USER_SITE
Flag showing the status of the user site directory. True means the
user site directory is enabled and added to sys.path. When the flag
is None the user site directory is disabled for security reasons.
Flag showing the status of the user site-packages directory. ``True`` means
that it is enabled and was added to ``sys.path``. ``False`` means that it
was disabled by user request (with :option:`-s` or
:envvar:`PYTHONNOUSERSITE`). ``None`` means it was disabled for security
reasons (mismatch between user or group id and effective id) or by an
administrator.
.. data:: USER_SITE
Path to the user site directory for the current Python version or None
Path to the user site-packages for the running Python. Can be ``None`` if
:func:`getusersitepackages` hasn't been called yet. Default value is
:file:`~/.local/lib/python{X.Y}/site-packages` for UNIX and non-framework Mac
OS X builds, :file:`~/Library/Python/{X.Y}/lib/python/site-packages` for Mac
framework builds, and :file:`{%APPDATA%}\\Python\\Python{XY}\\site-packages`
on Windows. This directory is a site directory, which means that
:file:`.pth` files in it will be processed.
.. data:: USER_BASE
Path to the base directory for user site directories
.. envvar:: PYTHONNOUSERSITE
.. envvar:: PYTHONUSERBASE
Path to the base directory for the user site-packages. Can be ``None`` if
:func:`getuserbase` hasn't been called yet. Default value is
:file:`~/.local` for UNIX and Mac OS X non-framework builds,
:file:`~/Library/Python/{X.Y}` for Mac framework builds, and
:file:`{%APPDATA%}\\Python` for Windows. This value is used by Distutils to
compute the installation directories for scripts, data files, Python modules,
etc. See also :envvar:`PYTHONUSERBASE`.
.. function:: addsitedir(sitedir, known_paths=None)
Adds a directory to sys.path and processes its pth files.
Add a directory to sys.path and process its :file:`.pth` files.
.. function:: getsitepackages()
Returns a list containing all global site-packages directories
(and possibly site-python).
Return a list containing all global site-packages directories (and possibly
site-python).
.. versionadded:: 3.2
.. function:: getuserbase()
Returns the "user base" directory path.
The "user base" directory can be used to store data. If the global
variable ``USER_BASE`` is not initialized yet, this function will also set
it.
Return the path of the user base directory, :data:`USER_BASE`. If it is not
initialized yet, this function will also set it, respecting
:envvar:`PYTHONUSERBASE`.
.. versionadded:: 3.2
.. function:: getusersitepackages()
Returns the user-specific site-packages directory path.
If the global variable ``USER_SITE`` is not initialized yet, this
function will also set it.
Return the path of the user-specific site-packages directory,
:data:`USER_SITE`. If it is not initialized yet, this function will also set
it, respecting :envvar:`PYTHONNOUSERSITE` and :data:`USER_BASE`.
.. versionadded:: 3.2
.. XXX Update documentation
.. XXX document python -m site --user-base --user-site
The :mod:`site` module also provides a way to get the user directories from the
command line:
.. code-block:: sh
$ python3 -m site --user-site
/home/user/.local/lib/python3.3/site-packages
.. program:: site
If it is called without arguments, it will print the contents of
:data:`sys.path` on the standard output, followed by the value of
:data:`USER_BASE` and whether the directory exists, then the same thing for
:data:`USER_SITE`, and finally the value of :data:`ENABLE_USER_SITE`.
.. cmdoption:: --user-base
Print the path to the user base directory.
.. cmdoption:: --user-site
Print the path to the user site-packages directory.
If both options are given, user base and user site will be printed (always in
this order), separated by :data:`os.pathsep`.
If any option is given, the script will exit with one of these values: ``O`` if
the user site-packages directory is enabled, ``1`` if it was disabled by the
user, ``2`` if it is disabled for security reasons or by an administrator, and a
value greater than 2 if there is an error.
.. seealso::
:pep:`370` -- Per user site-packages directory

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@ -156,17 +156,18 @@ symbol table. A command to check (or even suggest) matching parentheses,
quotes, etc., would also be useful.
One alternative enhanced interactive interpreter that has been around for quite
some time is `IPython`_, which features tab completion, object exploration and
some time is IPython_, which features tab completion, object exploration and
advanced history management. It can also be thoroughly customized and embedded
into other applications. Another similar enhanced interactive environment is
`bpython`_.
bpython_.
.. rubric:: Footnotes
.. [#] Python will execute the contents of a file identified by the
:envvar:`PYTHONSTARTUP` environment variable when you start an interactive
interpreter.
interpreter. To customize Python even for non-interactive mode, see
:ref:`tut-customize`.
.. _GNU Readline: http://tiswww.case.edu/php/chet/readline/rltop.html

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@ -236,6 +236,29 @@ in the script::
exec(open(filename).read())
.. _tut-customize:
The Customization Modules
-------------------------
Python provides two hooks to let you customize it: :mod:`sitecustomize` and
:mod:`usercustomize`. To see how it works, you need first to find the location
of your user site-packages directory. Start Python and run this code:
>>> import site
>>> site.getusersitepackages()
'/home/user/.local/lib/python3.2/site-packages'
Now you can create a file named :file:`usercustomize.py` in that directory and
put anything you want in it. It will affect every invocation of Python, unless
it is started with the :option:`-s` option to disable the automatic import.
:mod:`sitecustomize` works in the same way, but is typically created by an
administrator of the computer in the global site-packages directory, and is
imported before :mod:`usercustomize`. See the documentation of the :mod:`site`
module for more details.
.. rubric:: Footnotes
.. [#] On Unix, the Python 3.x interpreter is by default not installed with the
@ -243,4 +266,3 @@ in the script::
simultaneously installed Python 2.x executable.
.. [#] A problem with the GNU Readline package may prevent this.

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@ -229,7 +229,8 @@ Miscellaneous options
.. cmdoption:: -s
Don't add user site directory to sys.path
Don't add the :data:`user site-packages directory <site.USER_SITE>` to
:data:`sys.path`.
.. seealso::
@ -468,7 +469,8 @@ These environment variables influence Python's behavior.
.. envvar:: PYTHONNOUSERSITE
If this is set, Python won't add the user site directory to sys.path
If this is set, Python won't add the :data:`user site-packages directory
<site.USER_SITE>` to :data:`sys.path`.
.. seealso::
@ -477,7 +479,9 @@ These environment variables influence Python's behavior.
.. envvar:: PYTHONUSERBASE
Sets the base directory for the user site directory
Defines the :data:`user base directory <site.USER_BASE>`, which is used to
compute the path of the :data:`user site-packages directory <site.USER_SITE>`
and Distutils installation paths for ``python setup.py install --user``.
.. seealso::