Affects Version/s: None
Fix Version/s: None
Component/s: Documentation & Website
We really need to create a simple guide for how to build custom processor in nifi. The sort of 'hello world' example.
This was created due to finding it hard to give a nice simple short pointer for a question on the mailing list.
We do have a solid developer guide here  that goes into the key concepts and processor development a bit. The next best thing is to use the supplied maven archetype to lay down the fundamental pieces. You can read a bit more about that here . Finally something that is also quite helpful is looking at the standard processors to see if anything follows the pattern/problem you had in mind and which can serve as a good basis