initializing virtualenvwrapper on Mac (10.6.8) for Django

Question

I want to use Django and create virtual environments. I don't quite understand the initializing steps documentation on the virtualenvwrapper website. I've installed virtualenvwrapper in /Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages. I've already installed XCode, Homebrew and Posgres as well.

The documentation tells me to:

$ export WORKON_HOME=~/Envs

$ mkdir -p $WORKON_HOME

$ source /usr/local/bin/virtualenvwrapper.sh

$ mkvirtualenv env1`

I'm especially confused about the first line. Is it telling me that I need to create a project folder named 'WORKON_HOME' and export it into another folder called 'Envs'? (I've searched for both folders on my mac but didn't find them). And then in the second line I make another directory 'WORKON_HOME'? If you have suggestions or links to better explanations/tutorials, I would greatly appreciate it. Thanks.

Answer 1

Place this 3 lines in your ~/.bash_profile file:-

export WORKON_HOME=$HOME/.virtualenvs
export PROJECT_HOME=$HOME/work
source `which virtualenvwrapper.sh`

The $HOME environment variable points to your user's home. Also known as the tilda "~", i.e. /Users/your_osx_username/.

WORKON_HOME is the new environment variable that you are assigning by using the export call in your ~/.bash_profile file. This is where all your newly created virtualenv directories will be kept.

PROJECT_HOME is where you normally place all your custom project directories manually. Nothing to do with your virtualenvs per say but just an easy reference point for you to cd to using the cd $PROJECT_HOME syntax.

which virtualenvwrapper.sh points to the location where the bash script virtualenvwrapper.sh is located and hence when you source it, the functions in that bash script becomes available for your mkvirtualenv calls.

Whenever you open a "new shell" (new tab, close your current tab after you first update your ~/.bash_profile file), all these environment variables and bash functions will be thus available in your shell.

When we create a new virtualenv using the mkvirtualenv -p python2.7 --distribute my_new_virtualenv_1, what actually happens is that a new directory called my_new_virtualenv_1 containing a symlink to your global python2.7 is being created and new python site-packages sub-directory are created in your ~/.virtualenvs/ directory. Reference:-

calvin$ mkvirtualenv -p python2.7 --distribute my_new_virtualenv_1
Running virtualenv with interpreter /opt/local/bin/python2.7
New python executable in my_new_virtualenv_1/bin/python
Installing distribute..........................................................................................................................................................................................................done.
Installing pip................done.
virtualenvwrapper.user_scripts creating /Users/calvin/.virtualenvs/my_new_virtualenv_1/bin/predeactivate
virtualenvwrapper.user_scripts creating /Users/calvin/.virtualenvs/my_new_virtualenv_1/bin/postdeactivate
virtualenvwrapper.user_scripts creating /Users/calvin/.virtualenvs/my_new_virtualenv_1/bin/preactivate
virtualenvwrapper.user_scripts creating /Users/calvin/.virtualenvs/my_new_virtualenv_1/bin/postactivate
virtualenvwrapper.user_scripts creating /Users/calvin/.virtualenvs/my_new_virtualenv_1/bin/get_env_details

So if you do

cd ~/.virtualenvs/my_new_virtualenv_1
calvin$ tree -d
.
├── bin
├── include
│   └── python2.7 -> /opt/local/Library/Frameworks/Python.framework/Versions/2.7/include/python2.7
└── lib
    └── python2.7
        ├── config -> /opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/config
        ├── distutils
        ├── encodings -> /opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/encodings
        ├── lib-dynload -> /opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-dynload
        └── site-packages
            ├── distribute-0.6.28-py2.7.egg
            │   ├── EGG-INFO
            │   └── setuptools
            │       ├── command
            │       └── tests
            ├── pip-1.2.1-py2.7.egg
            │   ├── EGG-INFO
            │   └── pip
            │       ├── commands
            │       └── vcs
            └── readline

You will see this directory structure in it.

Note of course that you are using Envs and I am using .virtualenvs to act as the virtual env holding directory.