if dsecs == "" {
		return defaultExpiry, nil
	}

	d, err := strconv.Atoi(dsecs)
	if err != nil {
		return 0, auth.ErrInvalidDuration
	}

	dur := time.Duration(d) * time.Second

	if dur < minExpiry || dur > maxExpiry {
		return 0, auth.ErrInvalidDuration
	}
	return dur, nil
}

// Lookup returns a new Config by merging the given K/V config
// system with environment variables.