func main()

in cmd/collector/collector.go [24:92]
54 lines of code
10 McCabe index (conditional complexity)

func main() {
	var err error
	defer handleExit()
	defer LOG.Close()
	defer utils.Goodbye()

	// argument options
	configuration := flag.String("conf", "", "configure file absolute path")
	verbose := flag.Int("verbose", 0, "where log goes to: 0 - file，1 - file+stdout，2 - stdout")
	version := flag.Bool("version", false, "show version")
	flag.Parse()

	if *configuration == "" || *version == true {
		fmt.Println(utils.BRANCH)
		panic(Exit{0})
	}

	var file *os.File
	if file, err = os.Open(*configuration); err != nil {
		crash(fmt.Sprintf("Configure file open failed. %v", err), -1)
	}
	defer file.Close()

	// read fcv and do comparison
	if _, err := conf.CheckFcv(*configuration, utils.FcvConfiguration.FeatureCompatibleVersion); err != nil {
		crash(err.Error(), -5)
	}

	configure := nimo.NewConfigLoader(file)
	configure.SetDateFormat(utils.GolangSecurityTime)
	if err := configure.Load(&conf.Options); err != nil {
		crash(fmt.Sprintf("Configure file %s parse failed. %v", *configuration, err), -2)
	}

	// verify collector options and revise
	if err = SanitizeOptions(); err != nil {
		crash(fmt.Sprintf("Conf.Options check failed: %s", err.Error()), -4)
	}

	if err := utils.InitialLogger(conf.Options.LogDirectory, conf.Options.LogFileName,
		conf.Options.LogLevel, conf.Options.LogFlush, *verbose); err != nil {
		crash(fmt.Sprintf("initial log.dir[%v] log.name[%v] failed[%v].", conf.Options.LogDirectory,
			conf.Options.LogFileName, err), -2)
	} else {
		LOG.Info("log init succ. log.dir[%v] log.name[%v] log.level[%v]",
			conf.Options.LogDirectory, conf.Options.LogFileName, conf.Options.LogLevel)
	}
	LOG.Info("MongoDB Version Source[%v] Target[%v]", conf.Options.SourceDBVersion, conf.Options.TargetDBVersion)

	conf.Options.Version = utils.BRANCH

	nimo.Profiling(int(conf.Options.SystemProfilePort))
	signalProfile, _ := strconv.Atoi(utils.SIGNALPROFILE)
	signalStack, _ := strconv.Atoi(utils.SIGNALSTACK)
	if signalProfile > 0 {
		nimo.RegisterSignalForProfiling(syscall.Signal(signalProfile))                     // syscall.SIGUSR2
		nimo.RegisterSignalForPrintStack(syscall.Signal(signalStack), func(bytes []byte) { // syscall.SIGUSR1
			LOG.Info(string(bytes))
		})
	}

	utils.Welcome()

	utils.Mkdirs(conf.Options.LogDirectory)
	// get exclusive process lock and write pid
	if utils.WritePidById(conf.Options.LogDirectory, conf.Options.Id) {
		startup()
	}
}