func()

in pkg/dns/dns.go [967:1017]

• 39 lines of code
• 14 McCabe index (conditional complexity)

func (kd *KubeDNS) getClusterZoneAndRegion() (string, string, error) {
	var node *v1.Node

	objs := kd.nodesStore.List()
	if len(objs) > 0 {
		var ok bool
		if node, ok = objs[0].(*v1.Node); !ok {
			return "", "", fmt.Errorf("expected node object, got: %T", objs[0])
		}
	} else {
		// An alternative to listing nodes each time is to set a watch, but that is totally
		// wasteful in case of non-federated independent Kubernetes clusters. So carefully
		// proceeding here.
		// TODO(madhusudancs): Move this to external/v1 API.
		nodeList, err := kd.kubeClient.CoreV1().Nodes().List(context.TODO(), metav1.ListOptions{})
		if err != nil || len(nodeList.Items) == 0 {
			return "", "", fmt.Errorf("failed to retrieve the cluster nodes: %v", err)
		}

		// Select a node (arbitrarily the first node) that has
		// `LabelZoneFailureDomain` and `LabelZoneRegion` set.
		for _, nodeItem := range nodeList.Items {
			_, zfound := nodeItem.Labels[v1.LabelZoneFailureDomain]
			_, rfound := nodeItem.Labels[v1.LabelZoneRegion]
			if !zfound || !rfound {
				continue
			}
			// Make a copy of the node, don't rely on the loop variable.
			node = &(*(&nodeItem))
			if err := kd.nodesStore.Add(node); err != nil {
				return "", "", fmt.Errorf("couldn't add the retrieved node to the cache: %v", err)
			}
			// Node is found, break out of the loop.
			break
		}
	}

	if node == nil {
		return "", "", fmt.Errorf("Could not find any nodes")
	}

	zone, ok := node.Labels[v1.LabelZoneFailureDomain]
	if !ok || zone == "" {
		return "", "", fmt.Errorf("unknown cluster zone")
	}
	region, ok := node.Labels[v1.LabelZoneRegion]
	if !ok || region == "" {
		return "", "", fmt.Errorf("unknown cluster region")
	}
	return zone, region, nil
}