is possible to use tag 'env' in Unmarshal() operation to decode environment vars?

[bartsimp]

example:

type config struct {
	Host       string `env:"DB_HOST"`
}

var cfg config
err := viper.Unmarshal(&cfg)

cfg.Host should contains the value of the environment variable DB_HOST

[sagikazarmark]

No, Viper doesn't support auto-configuration via tags and that's not something we are looking at.