Package etcd is a wrapper around config package and allows reading configuration from some key in etcd server and parsing it with some encoder, where endpoints and key are defined in environment variables.

Package file is a wrapper around config package and allows reading configuration from some file on disk and parsing it with some encoder, where file name is defined in environment variable.

NewConfig function creates new configuration service using source and encoder defined in environment variables.

ErrUnknownEncoder error is returned when encoder defined in environment variable CONFIG_ENCODER is unsupported.