This directory contains implementations of Heron bolts that can be used in user topologies.

The bolt implementations are maintained by Heron community.

Bolt Development


Directories and Files

Bolt implementation files should be organized in this directory structure:


Language: java, python, scala, etc bolt name: reduce_bolt, filter_bolt, etc

Files in each bolt should be organized into these subdirectories:

  • src/main/: source code
  • src/test/: unit tests
  • doc/ : documentations


Each bolt should have a design doc as well as related information in the doc/ directory.


All source code files should include a short Apache license header at the top.