koanf
Simple, lightweight, extensible, configuration management library
koanf (pronounced conf; a play on the Japanese Koan) is a library for reading configurations from different sources in different formats in Go applications. It is a cleaner, lighter alternative to spf13/viper with better abstractions and extensibility, and fewer dependencies. koanf comes with built-in support for reading configuration from files, command line flags, and environment variables, and can parse JSON, YAML, TOML, and Hashicorp HCL.