Kaydet (Commit) dbab58fd authored tarafından Georg Brandl's avatar Georg Brandl

Refactor the venv API docs into a real API doc style.

üst 1f5d2a08
...@@ -15,28 +15,26 @@ ...@@ -15,28 +15,26 @@
-------------- --------------
The :mod:`venv` module provides support for creating lightweight The :mod:`venv` module provides support for creating lightweight "virtual
"virtual environments" with their own site directories, optionally environments" with their own site directories, optionally isolated from system
isolated from system site directories. Each virtual environment has site directories. Each virtual environment has its own Python binary (allowing
its own Python binary (allowing creation of environments with various creation of environments with various Python versions) and can have its own
Python versions) and can have its own independent set of installed independent set of installed Python packages in its site directories.
Python packages in its site directories.
Creating virtual environments Creating virtual environments
----------------------------- -----------------------------
Creation of virtual environments is simplest executing the ``pyvenv`` Creation of virtual environments is simplest executing the ``pyvenv`` script::
script::
pyvenv /path/to/new/virtual/environment pyvenv /path/to/new/virtual/environment
Running this command creates the target directory (creating any parent Running this command creates the target directory (creating any parent
directories that don't exist already) and places a ``pyvenv.cfg`` file directories that don't exist already) and places a ``pyvenv.cfg`` file in it
in it with a ``home`` key pointing to the Python installation the with a ``home`` key pointing to the Python installation the command was run
command was run from. It also creates a ``bin`` (or ``Scripts`` on from. It also creates a ``bin`` (or ``Scripts`` on Windows) subdirectory
Windows) subdirectory containing a copy of the ``python`` binary (or containing a copy of the ``python`` binary (or binaries, in the case of
binaries, in the case of Windows). Windows). It also creates an (initially empty) ``lib/pythonX.Y/site-packages``
It also creates an (initially empty) ``lib/pythonX.Y/site-packages``
subdirectory (on Windows, this is ``Lib\site-packages``). subdirectory (on Windows, this is ``Lib\site-packages``).
.. highlight:: none .. highlight:: none
...@@ -71,66 +69,60 @@ The command, if run with ``-h``, will show the available options:: ...@@ -71,66 +69,60 @@ The command, if run with ``-h``, will show the available options::
--upgrade Upgrade the environment directory to use this version --upgrade Upgrade the environment directory to use this version
of Python, assuming Python has been upgraded in-place. of Python, assuming Python has been upgraded in-place.
If the target directory already exists an error will be raised, unless If the target directory already exists an error will be raised, unless the
the ``--clear`` or ``--upgrade`` option was provided. ``--clear`` or ``--upgrade`` option was provided.
The created ``pyvenv.cfg`` file also includes the The created ``pyvenv.cfg`` file also includes the
``include-system-site-packages`` key, set to ``true`` if ``venv`` is ``include-system-site-packages`` key, set to ``true`` if ``venv`` is run with
run with the ``--system-site-packages`` option, ``false`` otherwise. the ``--system-site-packages`` option, ``false`` otherwise.
Multiple paths can be given to ``pyvenv``, in which case an identical Multiple paths can be given to ``pyvenv``, in which case an identical virtualenv
virtualenv will be created, according to the given options, at each will be created, according to the given options, at each provided path.
provided path.
API API
--- ---
.. highlight:: python
The high-level method described above makes use of a simple API which provides The high-level method described above makes use of a simple API which provides
mechanisms for third-party virtual environment creators to customize mechanisms for third-party virtual environment creators to customize environment
environment creation according to their needs. creation according to their needs, the :class:`EnvBuilder` class.
The :class:`EnvBuilder` class accepts the following keyword arguments on .. class:: EnvBuilder(system_site_packages=False, clear=False, symlinks=False, upgrade=False)
instantiation:
* ``system_site_packages`` - A Boolean value indicating that the The :class:`EnvBuilder` class accepts the following keyword arguments on
system Python site-packages should be available to the instantiation:
environment (defaults to ``False``).
* ``clear`` - A Boolean value which, if True, will delete any * ``system_site_packages`` -- a Boolean value indicating that the system Python
existing target directory instead of raising an exception site-packages should be available to the environment (defaults to ``False``).
(defaults to ``False``).
* ``symlinks`` - A Boolean value indicating whether to attempt * ``clear`` -- a Boolean value which, if True, will delete any existing target
to symlink the Python binary (and any necessary DLLs or other directory instead of raising an exception (defaults to ``False``).
binaries, e.g. ``pythonw.exe``), rather than copying. Defaults to
``True`` on Linux and Unix systems, but ``False`` on Windows and
Mac OS X.
The returned env-builder is an object which has a method, ``create``, * ``symlinks`` -- a Boolean value indicating whether to attempt to symlink the
which takes as required argument the path (absolute or relative to the current Python binary (and any necessary DLLs or other binaries,
directory) of the target directory which is to contain the virtual environment. e.g. ``pythonw.exe``), rather than copying. Defaults to ``True`` on Linux and
The ``create`` method will either create the environment in the specified Unix systems, but ``False`` on Windows and Mac OS X.
directory, or raise an appropriate exception.
Creators of third-party virtual environment tools will be free to use .. XXX it also takes "upgrade"!
the provided ``EnvBuilder`` class as a base class.
.. highlight:: python
The ``venv`` module will also provide a module-level function as a Creators of third-party virtual environment tools will be free to use the
convenience:: provided ``EnvBuilder`` class as a base class.
The returned env-builder is an object which has a method, ``create``:
def create(env_dir, .. method:: create(env_dir)
system_site_packages=False, clear=False, symlinks=False):
builder = EnvBuilder(
system_site_packages=system_site_packages,
clear=clear,
symlinks=symlinks)
builder.create(env_dir)
The ``create`` method of the ``EnvBuilder`` class illustrates the This method takes as required argument the path (absolute or relative to
hooks available for subclass customization:: the current directory) of the target directory which is to contain the
virtual environment. The ``create`` method will either create the
environment in the specified directory, or raise an appropriate
exception.
The ``create`` method of the ``EnvBuilder`` class illustrates the hooks
available for subclass customization::
def create(self, env_dir): def create(self, env_dir):
""" """
...@@ -144,46 +136,64 @@ hooks available for subclass customization:: ...@@ -144,46 +136,64 @@ hooks available for subclass customization::
self.setup_scripts(context) self.setup_scripts(context)
self.post_setup(context) self.post_setup(context)
Each of the methods ``create_directories``, ``create_configuration``, Each of the methods :meth:`create_directories`,
``setup_python``, ``setup_scripts`` and ``post_setup`` can be :meth:`create_configuration`, :meth:`setup_python`,
overridden. The functions of these methods are: :meth:`setup_scripts` and :meth:`post_setup` can be overridden.
.. method:: create_directories(env_dir)
Creates the environment directory and all necessary directories, and
returns a context object. This is just a holder for attributes (such as
paths), for use by the other methods.
.. method:: create_configuration(context)
* ``create_directories`` - creates the environment directory and Creates the ``pyvenv.cfg`` configuration file in the environment.
all necessary directories, and returns a context object. This is
just a holder for attributes (such as paths), for use by the
other methods.
* ``create_configuration`` - creates the ``pyvenv.cfg`` .. method:: setup_python(context)
configuration file in the environment.
* ``setup_python`` - creates a copy of the Python executable (and, Creates a copy of the Python executable (and, under Windows, DLLs) in
under Windows, DLLs) in the environment. the environment.
* ``setup_scripts`` - Installs activation scripts appropriate to the .. method:: setup_scripts(context)
platform into the virtual environment.
* ``post_setup`` - A placeholder method which can be overridden Installs activation scripts appropriate to the platform into the virtual
in third party implementations to pre-install packages in the environment.
virtual environment or perform other post-creation steps.
In addition, ``EnvBuilder`` provides an ``install_scripts`` utility .. method:: post_setup(context)
method that can be called from ``setup_scripts`` or ``post_setup`` in
subclasses to assist in installing custom scripts into the virtual
environment. The method accepts as arguments the context object (see
above) and a path to a directory. The directory should contain
subdirectories "common", "posix", "nt", each containing scripts
destined for the bin directory in the environment. The contents of
"common" and the directory corresponding to ``os.name`` are copied
after some text replacement of placeholders:
* ``__VENV_DIR__`` is replaced with the absolute path of the A placeholder method which can be overridden in third party
environment directory. implementations to pre-install packages in the virtual environment or
perform other post-creation steps.
* ``__VENV_NAME__`` is replaced with the environment name (final path In addition, :class:`EnvBuilder` provides this utility method that can be
called from :meth:`setup_scripts` or :meth:`post_setup` in subclasses to
assist in installing custom scripts into the virtual environment.
.. method:: install_scripts(context, path)
*path* is the path to a directory that should contain subdirectories
"common", "posix", "nt", each containing scripts destined for the bin
directory in the environment. The contents of "common" and the
directory corresponding to :data:`os.name` are copied after some text
replacement of placeholders:
* ``__VENV_DIR__`` is replaced with the absolute path of the environment
directory.
* ``__VENV_NAME__`` is replaced with the environment name (final path
segment of environment directory). segment of environment directory).
* ``__VENV_BIN_NAME__`` is replaced with the name of the bin directory * ``__VENV_BIN_NAME__`` is replaced with the name of the bin directory
(either ``bin`` or ``Scripts``). (either ``bin`` or ``Scripts``).
* ``__VENV_PYTHON__`` is replaced with the absolute path of the * ``__VENV_PYTHON__`` is replaced with the absolute path of the
environment's executable. environment's executable.
There is also a module-level convenience function:
.. function:: create(env_dir, system_site_packages=False, clear=False, symlinks=False)
Create an :class:`EnvBuilder` with the given keyword arguments, and call its
:meth:`~EnvBuilder.create` method with the *env_dir* argument.
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