With respect to a django / python API implementation, Cloudera HUE is one of the most elaborate and advanced codebases I have seen - it is essentially designed to serve as a pluggable "desktop service" for interacting with the Apache Hadoop and co. ecosystem (Hive, Pig, Impala,):

https://github.com/cloudera/hue/blob/master/docs/sdk/sdk.md#...

https://github.com/cloudera/hue

If your API has lots of different user roles (which can often break REST), this small library we built might be interesting to you: https://github.com/computer-lab/django-rest-framework-roles