develop an engine plugin

The Engine is the kdcloud module that executes analysis on data, thus an engine plugin is intended only to work on data, it cannot perform any request handling nor using other server code.

The boilerplate and the instructions on how to develop a plugin are located here.

Then you could just copy the plugin code into the project or upload the jar at runtime using the python client:

python kdcloud-admin-tools.py -p /engine/plugin/<YourNodeName> <path-to-your-jar>