How to install python packages in virtual environment only with virtualenv bootstrap script?

Question

I want to create a bootstrap script for setting up a local environment and installing all requirments in it. I have been trying with virtualenv.create_bootstrap_script as described in their docs .

import virtualenv
s = virtualenv.create_bootstrap_script('''
import subprocess
def after_install(options, home_dir):
  subprocess.call(['pip', 'install', 'django'])
''')
open('bootstrap.py','w').write(s)

When running the resulting bootstrap.py, it sets up the virtual environment correctly, but it then attempts to install Django globally.

How can I write a bootstrap script that installs Django only in this local virtual environment. It has to work on both Windows and Linux.

Answer 1

You could force pip to install into your virtualenv by:

subprocess.call(['pip', 'install', '-E', home_dir, 'django'])

Furthermore, it is a nice and useful convention to store your dependencies in requirements.txt file, for django 1.3 that'd be:

django==1.3

and then in your after_install :

subprocess.call(['pip', 'install', '-E', home_dir, '-r', path_to_req_txt])

Answer 2

You need to pass it the fully qualified path to the pip script that is in your virtualenv.

subprocess.call([join(home_dir, 'bin', 'pip'),'install','django'])

Answer 3

A solution that works on both Windows and Linux. It uses the pip, just installed by the bootstrap script.

import virtualenv
s = '''
import subprocess, os
def after_install(options, home_dir):
  if os.name == 'posix':
    subprocess.call([os.path.join(home_dir, 'bin', 'pip'), 'install', '-r', 'requirements.txt'])
  else:
    subprocess.call([os.path.join(home_dir, 'Scripts', 'pip.exe'), 'install', '-r', 'requirements.txt'])
'''
script = virtualenv.create_bootstrap_script(s, python_version='2.7')
f = open('bootstrap.py','w')
f.write(script)
f.close()

Just put your requirements in requirements.txt , one line for every package:

django
django-registration==1.4.3

See: Pip - Requiremments Files

Answer 4

What worked for me is to access pip from the newly created environment .

pip = os.path.join(home_dir, 'bin', 'pip')

And after that, I try to install django as you previously did.

subprocess.call([pip, 'install', 'django'])

Remember the os import:

import os, subprocess

Hope it works for you.