Scripting virtualenvwrapper mkvirtualenv

Question

I'm writing a game in python 2.7, and want to script the "bootstrap" of my game's development environment, and then invoke shovel. If virtualenvwrapper is not detected, I will use a virtualenv bootstrap solution. However if virtualenvwrapper is detected, I would like to use it instead.

The problem is that the virtualenvwrapper inline shell functions are not inherited by my bootstrap script. As far as I know, that rules out running something like "mkvirtualenv NotOrion". Since the environment variable "VIRTUALENVWRAPPER_VIRTUALENV" is set (in my case, from macports: /opt/local/bin/virtualenv-2.7), I tried using it directly instead:

#!/usr/bin/env bash

# Name your first "bootstrap" environment:
ENV_NAME=NotOrion
# Options for your first environment:
ENV_OPTS='--no-site-packages --distribute'

unset PYTHONDONTWRITEBYTECODE

function create_virtualenvwrapper_venv {
  echo "installing into virtualenvwrapper directory"
  cd $WORKON_HOME
  $VIRTUALENVWRAPPER_VIRTUALENV $ENV_OPTS $ENV_NAME
  cd -
  #mkvirtualenv $ENV_NAME
  #workon $ENV_NAME
}

function create_standalone_venv {
  # not run/snipped
}

if [ -z "$VIRTUALENVWRAPPER_VIRTUALENV" ]; then
  create_standalone_venv
else
  create_virtualenvwrapper_venv
fi

pip install shovel
shovel help

My bootstrap script finishes installing shovel. However running shovel (eg the last line) produces warnings:

/Users/me/.virtualenvs/NotOrion/bin/shovel:25: UserWarning: Module argparse was already imported from /opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/argparse.pyc, but /Users/me/.virtualenvs/NotOrion/lib/python2.7/site-packages is being added to sys.path
import pkg_resources
# normal shovel output snipped

So is it possible to somehow invoke "mkvirtualenv" from a script? If not, can I run something else from my script that has the same effect but doesn't produce warnings?

Myca

Same exact problem, writing a bootstrapping script. Thank you! – Mispickel

Answer 1

Your script should be able to do:

# 'which' will print absolute path to virtualenvwrapper.sh
source `which virtualenvwrapper.sh`

I use that for some deployment scripts.

Hemminger

It seems the macports virtualenvwrapper doesn't provide "virtualenvwrapper.sh". It has other variants such as "virtualenvwrapper.sh-2.7", so it seems I can't count on this. – Myca

Ah, yes. If you use MacPorts you're sort of stuck dealing with all of the unsupported changes they make. This one is particularly annoying since there's no reason for it - a single virtualenv install can handle many different versions of Python (I have a single install used for Python 2.5, 2.6, 2.7, 3.2, 3.3, PyPy and Jython) – Hemminger

This got me on track for completing my bootstrap script; I'll paste the missing piece in above and accept this answer. – Myca

Answer 2

There doesn't appear to be a "standard" way to do this. So I manually looked in various likely places. Messy, but it appears to be the only way:

function find_virtualenvwrapper {
   # no consistent way to find 'virtualenvwrapper.sh', so try various methods
   # is it directly available in the path?
   virtualenvwrapper_path=$(which virtualenvwrapper.sh)
   if [ $? -eq 0 ]; then
      return
   fi
   # nope; how about something that looks like it in our path?
   # https://mcmap.net/q/98070/-linux-command-to-list-all-available-commands-and-aliases
   virtualenvwrapper_cmd=$(compgen -ac | grep -i 'virtualenvwrapper\.sh' | sort | uniq | head -1)
   if [ -n "$virtualenvwrapper_cmd" ]; then
      virtualenvwrapper_path=$(which $virtualenvwrapper_cmd)
      if [ $? -eq 0 ]; then
         return
      fi
   fi
   # still not; Debubuntu puts it in /etc/bash_completion.d
   virtualenvwrapper_path='/etc/bash_completion.d/virtualenvwrapper'
   if [ -e "$virtualenvwrapper_path" ]; then
      return
   fi
   # any other methods to find virtualenvwrapper can be added here
   echo "unable to find virtualenvwrapper.sh or anything that looks like it"
   exit 1
}

Myca