Mapstructure is a Go library for decoding generic map values to structures and
vice versa, while providing helpful error handling.

This library is most useful when decoding values from some data stream (JSON,
Gob, etc.) where you don't quite know the structure of the underlying data until
you read a part of it. You can therefore read a map[string]interface{} and use
this library to decode it into the proper underlying native Go structure.