You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: dns.go
    path of file: ./repos/cloudprober/probes/dns/cmd
    
    the code of the file until where you have to start completion: // Copyright 2017 The Cloudprober Authors.
//
// Licensed
    
func main() {
	flag.Parse()

	c := &configpb.ProbeConf{}

	// If we are given a config file, read it. If not, use defaults.
	if *config != "" {
		b, err := ioutil.ReadFile(*config)
		if err != nil {
			glog.Exit(err)
		}
		if err := proto.UnmarshalText(string(b), c); err != nil {
			glog.Exitf("Error while parsing config protobuf %s: Err: %v", string(b), err)
		}
	}

	opts := &options.Options{
		Interval:  *intervalF,
		Timeout:   *timeoutF,
		Targets:   targets.StaticTargets(*targetsF),
		ProbeConf: c,
	}

	if *sourceIP != "" {
		opts.SourceIP = net.ParseIP(*sourceIP)
		if opts.SourceIP == nil {
			glog.Exitf("Error parsing source IP: %s", *sourceIP)
		}
	}
	dp := &dns.Probe{}
	if err := dp.Init("dns_test", opts); err != nil {
		glog.Exitf("Error in initializing probe %s from the config. Err: %v", "dns_test", err)
	}
	dataChan := make(chan *metrics.EventMetrics, 1000)
	go dp.Start(context.Background(), dataChan)

	for {
		em := <-dataChan
		fmt.Println(em.String())
	}
}