in gplog/gplog.go [127:136]
func GenerateLogFileName(program, logdir string) string {
var logfile string
if logFileNameFunc != nil {
logfile = logFileNameFunc(program, logdir)
} else {
timestamp := operating.System.Now().Format("20060102")
logfile = fmt.Sprintf("%s/%s_%s.log", logdir, program, timestamp)
}
return logfile
}