in log/config.go [151:168]
func (t TimeUnit) Format() string {
var timeFmt string
switch t {
case Minute:
timeFmt = TimeFormatMinute
case Hour:
timeFmt = TimeFormatHour
case Day:
timeFmt = TimeFormatDay
case Month:
timeFmt = TimeFormatMonth
case Year:
timeFmt = TimeFormatYear
default:
timeFmt = TimeFormatDay
}
return "." + timeFmt
}