My zsh Setup for Python virtualenv

One of my projects at work utilizes a Django-based API documentation tool. When I read Jeff Knupp’s Starting a Django Project the Right Way posting I decided I wanted to setup virtualenv on my machine. And not just install it but also add the virtual environment information to my zsh rprompt.

Here’s how I accomplished that goal.

##virtualenv Information Using Steve Losh’s excellent My Extravagant Zsh Prompt posting as a jumping off point, I added the following function to my zsh-theme file:

function virtualenv_info {
	[ $VIRTUAL_ENV ] && echo '('`basename $VIRTUAL_ENV`') '
}

This function tests to see if there is an active virtual environment and then echos the name of it as the function’s output.

##RPROPMT Next I added a call to the virtualenv_info function to my RPROMPT or right-prompt. I already had my RVM controlled Ruby version displayed there in red, so I set the virtualenv_info to be green.

case `uname` in
    Darwin)
	RPROMPT='%{$fg[green]%}$(virtualenv_info)%{$reset_color%}% %{$fg[red]%}$(rvm_ruby_prompt)%{$reset_color%}'
	;;
esac

The case statement test for Darwin prevents this portion of the prompt from running on my Ubuntu virtual machine, where I also have zsh setup but where I don’t have RVM.

##Usage Creating a new virtual environment is simple,

$ virtualenv <environmentname>

Activating the new (or an existing) environment requires this command:

$ source ./<environmentname>s/bin/activate

By default virtualenv wants to prepend the name of the active environment to your prompt. Since I want it only in my right-prompt I need to set VIRTUAL_ENV_DISABLE_PROMPT to any non null character before activating the environment. To make the activation command shorter, and to ensure that VIRTUAL_ENV_DISABLE_PROMPT is always set I created a new function sourced from my .zshrc:

activate() {
  export VIRTUAL_ENV_DISABLE_PROMPT='1'
  source ./$1/bin/activate
}

Now I can just type activate <environmentname> and I’m switched to that Python environment with the virtualenv name shown in the right-prompt.

mhn at palantir in ~
○ activate apidoc                               [ruby-1.9.3-head]

mhn at palantir in ~
○                                      (apidoc) [ruby-1.9.3-head]

You can view my complete zsh setup in my dotfile repository on Github.