recline is an opinionated derivation framework for the excellent decline command line parser.
This library is designed to be used with microservices where you'd like to configure them mostly through a configuration file, environment variables, or command line flags.
It assumes that command line flags should override environment variables, and they should both override the configuration file.
It includes two modes, one which will derive an Opt[T] where T is your configuration case class, this will require most options to be passed in on the command line or via environment variables.
The second mode allows you to derive an Opt[T => T] which is intended to be layered on top of a configuration file, or a set of defaults.