No activate_this.py file in venv / pyvenv

Question

I need to start venv / pyvenv from within a python script and I know the official documentation is to run:

activate_this = '/path/to/env/bin/activate_this.py'
execfile(activate_this, dict(__file__=activate_this))

But I don't have an activate_this.py file and I can't find anywhere how to create one.

I am running python 3.4.1. Any idea what I need to do?

Answer 1

As you've noted, pyvenv/the venv module doesn't ship with activate_this.py. But if you need this feature, you can borrow activate_this.py from virtualenv, put it in the expected location (virtualenv_path/bin/activate_this.py), then use it. It seems to work fine. Only issue is that the virtualenv docs are out of date for Python 3 (they claim you use execfile, which doesn't exist). The Python 3 compatible alternative would be:

activator = 'some/path/to/activate_this.py'  # Looted from virtualenv; should not require modification, since it's defined relatively
with open(activator) as f:
    exec(f.read(), {'__file__': activator})

Nothing activate_this.py does is magical, so you could manually perform the same changes without looting from virtualenv (adjusting PATH, sys.path, sys.prefix, etc.), but borrowing makes it much simpler in this case.