virtualenvwrapper 1.15

Enhancements to virtualenv

Quick Setup

1. Add two lines to your .bashrc to set the location where the virtual environments should live and the location of the script installed with this package:

   export WORKON_HOME=$HOME/.virtualenvs
   source /usr/local/bin/virtualenvwrapper_bashrc

2. Run: source ~/.bashrc

3. Run: workon

4. A list of environments, empty, is printed.

5. Run: mkvirtualenv temp

6. A new environment, temp is created and activated.

7. Run: workon

8. This time, the temp environment is included.

Path Management

Sometimes it is desirable to share installed packages that are not in the system site-pacakges directory and which you do not want to install in each virtualenv. In this case, you could symlink the source into the environment site-packages directory, but it is also easy to add extra directories to the PYTHONPATH by including them in a .pth file inside site-packages using add2virtualenv.

1. Check out the source for a big project, such as Django.

2. Run: add2virtualenv path_to_source.

3. Run: add2virtualenv.

4. A usage message and list of current “extra” paths is printed.

Hook Scripts

virtualenvwrapper adds several hook points you can use to change your settings when creating, deleting, or moving between environments. They are either sourced (allowing them to modify your shell environment) or run as an external program at the appropriate trigger time.

$VIRTUAL_ENV/bin/postactivate

The postactivate script is sourced after the new environment is enabled. $VIRTUAL_ENV refers to the new environment at the time the script runs.

This example script for the PyMOTW environment changes the current working directory and the PATH variable to refer to the source tree containing the PyMOTW source.

pymotw_root=/Users/dhellmann/Documents/PyMOTW
cd $pymotw_root
PATH=$pymotw_root/bin:$PATH

$VIRTUAL_ENV/bin/predeactivate

The predeactivate script is source before the current environment is deactivated, and can be used to disable or clear settings in your environment. $VIRTUAL_ENV refers to the old environment at the time the script runs.

$WORKON_HOME/postactivate

The global postactivate script is sourced after the new environment is enabled and the new environment’s postactivate is sourced (if it exists). $VIRTUAL_ENV refers to the new environment at the time the script runs.

This example script adds a space between the virtual environment name and your old PS1 by making use of _OLD_VIRTUAL_PS1.

PS1="(`basename \"$VIRTUAL_ENV\"`) $_OLD_VIRTUAL_PS1"

$WORKON_HOME/premkvirtualenv

The premkvirtualenv script is run as an external program after the virtual environment is created but before the current environment is switched to point to the new env. The current working directory for the script is $WORKON_HOME and the name of the new environment is passed as an argument to the script.

$WORKON_HOME/postmkvirtualenv

The postmkvirtualenv script is sourced after the new environment is created and activated.

$WORKON_HOME/prermvirtualenv

The prermvirtualenv script is run as an external program before the environment is removed. The full path to the environment directory is passed as an argument to the script.

$WORKON_HOME/postrmvirtualenv

The postrmvirtualenv script is run as an external program after the environment is removed. The full path to the environment directory is passed as an argument to the script.

Path Management

The function add2virtualenv adds the specified directories to the Python path for the active virtualenv. The directory names passed as argument are added to a path file named virtualenv_path_extensions.pth inside the virtualenv’s site-packages directory. If this file does not exist, it will be created first.

Quickly Navigating to a virtualenv

The functions cdsitepackages and cdvirtualenv provide quick shortcuts to quickly cd into the site-packages directory of the currently-active virtualenv, and to the root of the currently-active virtualenv, respectively.

References

For more details, refer to the column published in the May 2008 issue of Python Magazine: virtualenvwrapper | And Now For Something Completely Different.

Updates

1.15

• Better error handling in mkvirtualenv.

• Remove bogus VIRTUALENV_WRAPPER_BIN variable.

1.14

• Wrap the virtualenv version of deactivate() with one that lets us invoke the predeactivate hooks.

• Fix virtualenvwrapper_show_workon_options for colorized versions of ls and write myself a note so I don’t break it again later.

• Convert test.sh to use true tests with shunit2

1.13

• Fix issue #5 by correctly handling symlinks and limiting the list of envs to things that look like they can be activated.

1.12

• Check return value of virtualenvwrapper_verify_workon_home everywhere, thanks to Jeff Forcier for pointing out the errors.

• Fix instructions at top of README, pointed out by Matthew Scott.

• Add cdvirtualenv and cdsitepackages, contributed by James Bennett.

• Enhance test.sh.

1.11

• Optimize virtualenvwrapper_show_workon_options.

• Add global postactivate hook.

1.10

• Pull in fix for colorized ls from Jeff Forcier (b42a25f7b74a).

1.9

• Add more hooks for operations to run before and after creating or deleting environments based on changes from Chris Hasenpflug.

1.8.1

• Corrected a problem with change to mkvirtualenv that lead to release 1.8 by using an alternate fix proposed by James in comments on release 1.4.

1.8

• Fix for processing the argument list in mkvirtualenv from jorgevargas (BitBucket issue #1)

1.7

• Move to bitbucket.org for hosting

• clean up TODO list and svn keywords

• add license section below

1.6.1

• More zsh support (fixes to rmvirtualenv) from Byron Clark.

1.6

• Add completion support for zsh, courtesy of Ted Leung.

1.5

• Fix some issues with spaces in directory or env names. They still don’t really work with virtualenv, though.

• Added documentation for the postactivate and predeactivate scripts.

1.4

• Includes a new .pth management function based on work contributed by James Bennett and Jannis Leidel.

1.3.x

• Includes a fix for a nasty bug in rmvirtualenv identified by John Shimek.

License

Copyright Doug Hellmann, All Rights Reserved

Permission to use, copy, modify, and distribute this software and its documentation for any purpose and without fee is hereby granted, provided that the above copyright notice appear in all copies and that both that copyright notice and this permission notice appear in supporting documentation, and that the name of Doug Hellmann not be used in advertising or publicity pertaining to distribution of the software without specific, written prior permission.

DOUG HELLMANN DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL DOUG HELLMANN BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.