python - Activate virtualenv via os.system()

Question

I'm writing a Python-based shell script to boilerplate a Django app with virtualenv, pip, and fabric. Should be straightforward enough, but it appears that I'm not able to activate and run commands in the virtualenv through the shell script.

os.system('virtualenv %s --no-site-packages' % project_name)
os.system('source %s/bin/activate' % project_name)
os.system('easy_install pip')

When running, this errors out:

$ startproject+ -s false sample
New python executable in sample/bin/python
Installing setuptools............done.
/testing
Searching for pip
Best match: pip 0.4
Processing pip-0.4-py2.6.egg
pip 0.4 is already the active version in easy-install.pth
Installing pip script to /usr/local/bin
error: /usr/local/bin/pip: Permission denied

Obviously the source line isn't being run, but why? Is it a concurrency/threading issue, or something deeper with virtualenv?

Thanks!

Answer 1

Each call to os.system runs the command in a new subshell, which has the same properties as the original python process.

Try putting the commands into one string separated by semicolons.