python-matheval is the second example project for my book in progress on Continuous Delivery.

It is a python-based web service that evaluates a tree of mathematical expresions. For example it turns the JSON tree

["*", [" ", 2, 3], 4]

which corresponds to (2 3) * 4, into the result, 20.

It is a flask application, packaged with dh-virtualenv, run by gunicorn and controlled through systemd.