envconfig

type Unmarshaler ¶

type Unmarshaler interface {
	UnmarshalEnv(value string) error
}

Unmarshaler is the interface implemented by types that can parse themselves from a raw environment variable string.

UnmarshalEnv receives the raw string value (never empty) and is responsible for populating the receiver. Return a descriptive error if the value is invalid.

Example:

type LogLevel struct{ level string }

func (l *LogLevel) UnmarshalEnv(value string) error {
    switch value {
    case "DEBUG", "INFO", "WARN", "ERROR":
        l.level = value
        return nil
    default:
        return fmt.Errorf("invalid log level %q, must be one of DEBUG, INFO, WARN, ERROR", value)
    }
}