The documentation about how to implement new modules seems to be kind of incomplete and/or difficult to understand. The same goes for the given example.
In the particular case of authentication / authorization module, as it is right now, I can't understand where to start, what interfaces and/or files are involved, which parameters are needed...
I think this could be improved by creating a complete step by step guide explaining how to create a new custom module. A good way of being sure that it would be clear to everyone, could be to have a practical example starting with the basic/clean install of Mesos and creating a simple module (the data could also come from files, or database or somewhere else... that's just "normal/generic" programming).
This issue from Feb 2016 seems to be more or less about the same: https://issues.apache.org/jira/browse/MESOS-4631