Charms.Reactive 
This module serves as the basis for creating charms and relation implementations using the reactive pattern. You can see its goal and vision in the vision document
The full documentation is available online at: https://charmsreactive.readthedocs.io/
Usage
See Building a Charm from Layers for more information on how to use the charms.reactive framework. Also look at the layer-basic documentation for more info on how to use the basic layer.
Contributing
Want to contribute? Great! We're looking forward to your Pull Request. See HACKING.md for more information about how to contribute to charmhelpers.