This is a Heroku buildpack for Python apps. It uses virtualenv and pip.
Example usage:
$ ls
Procfile requirements.txt web.py
$ heroku create --stack cedar --buildpack git@github.com:heroku/heroku-buildpack-python.git
$ git push heroku master
...
-----> Heroku receiving push
-----> Fetching custom build pack... done
-----> Python app detected
-----> Preparing virtualenv version 1.6.4
New python executable in ./bin/python
Installing setuptools............done.
Installing pip...............done.
-----> Installing dependencies using pip version 1.0.2
Downloading/unpacking Flask==0.7.2 (from -r requirements.txt (line 1))
Downloading/unpacking Werkzeug>=0.6.1 (from Flask==0.7.2->-r requirements.txt (line 1))
Downloading/unpacking Jinja2>=2.4 (from Flask==0.7.2->-r requirements.txt (line 1))
Installing collected packages: Flask, Werkzeug, Jinja2
Successfully installed Flask Werkzeug Jinja2
Cleaning up...
The buildpack will detect your app as Python if it has the file requirements.txt in the root. It will detect your app as Python/Django if there is an additional settings.py in a project subdirectory.
It will use virtualenv and pip to install your dependencies, vendoring a copy of the Python runtime into your slug. The bin/, include/ and lib/ directories will be cached between builds to allow for faster pip install time.
To use this buildpack, fork it on Github. Push up changes to your fork, then create a test app with --buildpack <your-github-url> and push to it.
To change the vendored virtualenv, unpack the desired version to the src/ folder, and update the virtualenv() function in bin/compile to prepend the virtualenv module directory to the path. The virtualenv release vendors its own versions of pip and setuptools.