How to track usage within a desktop python application

[Ryan Holmes]

I maintain a desktop python application that is used by a decent number of folks (I would assume 10k+, though it's hard to know since it's based on number of downloads rather than number of unique users). I would like to integrate some sort of usage tracking that would enable me to determine number of users along with startups, which features are used/not used, performance metrics, exceptions, etc. Since it's an open-source project, I am looking for a free service (or a service that provides free licenses to open source projects) that has a python client library. 

Can anyone recommend something?