func main()

in cluster/addons/fluentd-elasticsearch/es-image/elasticsearch_logging_discovery.go [83:157]
61 lines of code
15 McCabe index (conditional complexity)

func main() {
	flag.Parse()

	klog.Info("Kubernetes Elasticsearch logging discovery")

	advertiseAddress, err := getAdvertiseAddress()
	if err != nil {
		klog.Fatalf("Failed to get valid advertise address: %v", err)
	}
	fmt.Printf("network.host: \"%s\"\n\n", advertiseAddress)

	cc, err := buildConfigFromEnvs(os.Getenv("APISERVER_HOST"), os.Getenv("KUBE_CONFIG_FILE"))
	if err != nil {
		klog.Fatalf("Failed to make client: %v", err)
	}
	client, err := clientset.NewForConfig(cc)

	if err != nil {
		klog.Fatalf("Failed to make client: %v", err)
	}
	namespace := metav1.NamespaceSystem
	envNamespace := os.Getenv("NAMESPACE")
	if envNamespace != "" {
		if _, err := client.CoreV1().Namespaces().Get(context.TODO(), envNamespace, metav1.GetOptions{}); err != nil {
			klog.Fatalf("%s namespace doesn't exist: %v", envNamespace, err)
		}
		namespace = envNamespace
	}

	var elasticsearch *corev1.Service
	serviceName := os.Getenv("ELASTICSEARCH_SERVICE_NAME")
	if serviceName == "" {
		serviceName = "elasticsearch-logging"
	}

	// Look for endpoints associated with the Elasticsearch logging service.
	// First wait for the service to become available.
	for t := time.Now(); time.Since(t) < 5*time.Minute; time.Sleep(10 * time.Second) {
		elasticsearch, err = client.CoreV1().Services(namespace).Get(context.TODO(), serviceName, metav1.GetOptions{})
		if err == nil {
			break
		}
	}
	// If we did not find an elasticsearch logging service then log a warning
	// and return without adding any unicast hosts.
	if elasticsearch == nil {
		klog.Warningf("Failed to find the elasticsearch-logging service: %v", err)
		return
	}

	var endpoints *corev1.Endpoints
	addrs := []string{}
	// Wait for some endpoints.
	count, _ := strconv.Atoi(os.Getenv("MINIMUM_MASTER_NODES"))
	for t := time.Now(); time.Since(t) < 5*time.Minute; time.Sleep(10 * time.Second) {
		endpoints, err = client.CoreV1().Endpoints(namespace).Get(context.TODO(), serviceName, metav1.GetOptions{})
		if err != nil {
			continue
		}
		addrs = flattenSubsets(endpoints.Subsets)
		klog.Infof("Found %s", addrs)
		if len(addrs) > 0 && len(addrs) >= count {
			break
		}
	}
	// If there was an error finding endpoints then log a warning and quit.
	if err != nil {
		klog.Warningf("Error finding endpoints: %v", err)
		return
	}

	klog.Infof("Endpoints = %s", addrs)
	fmt.Printf("discovery.seed_hosts: [%s]\n", strings.Join(addrs, ", "))
	fmt.Printf("cluster.initial_master_nodes: [%s]\n", strings.Join(addrs, ", "))
}