1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
|
:mod:`site` --- Site-specific configuration hook
================================================
.. module:: site
: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
and add a few builtins.
.. index::
pair: site-python; directory
pair: site-packages; directory
It starts by constructing up to four directories from a head and a tail part.
For the head part, it uses ``sys.prefix`` and ``sys.exec_prefix``; empty heads
are skipped. For the tail part, it uses the empty string and then
:file:`lib/site-packages` (on Windows) or
:file:`lib/python{X.Y}/site-packages` and then :file:`lib/site-python` (on
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:`{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``, 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.
.. index::
single: package
triple: path; configuration; file
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}`. 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
:file:`foo.pth` contains the following::
# foo package configuration
foo
bar
bletch
and :file:`bar.pth` contains::
# bar package configuration
bar
Then the following version-specific directories are added to
``sys.path``, in this order::
/usr/local/lib/pythonX.Y/site-packages/bar
/usr/local/lib/pythonX.Y/site-packages/foo
Note that :file:`bletch` is omitted because it doesn't exist; the :file:`bar`
directory precedes the :file:`foo` directory because :file:`bar.pth` comes
alphabetically before :file:`foo.pth`; and :file:`spam` is omitted because it is
not mentioned in either path configuration file.
.. index:: module: sitecustomize
After these path manipulations, an attempt is made to import a module named
:mod:`sitecustomize`, which can perform arbitrary site-specific customizations.
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: 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` and :mod:`usercustomize` is still attempted.
.. data:: PREFIXES
A list of prefixes for site-packages directories.
.. data:: ENABLE_USER_SITE
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-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 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. for the :ref:`user installation scheme <inst-alt-install-user>`. See
also :envvar:`PYTHONUSERBASE`.
.. function:: addsitedir(sitedir, known_paths=None)
Add a directory to sys.path and process its :file:`.pth` files. Typically
used in :mod:`sitecustomize` or :mod:`usercustomize` (see above).
.. function:: getsitepackages()
Return a list containing all global site-packages directories (and possibly
site-python).
.. versionadded:: 3.2
.. function:: getuserbase()
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()
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
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
|
