func()

in pkg/controllers/clusterresourceplacement/cluster_selector.go [36:95]

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

func (r *Reconciler) selectClusters(placement *fleetv1alpha1.ClusterResourcePlacement) (clusterNames []string, err error) {
	defer func() {
		if err == nil {
			// Set the status
			placement.Status.TargetClusters = clusterNames
		}
	}()
	// no policy set
	if placement.Spec.Policy == nil {
		clusterNames, err = r.listClusters(labels.Everything())
		if err != nil {
			return nil, err
		}
		klog.V(2).InfoS("we select all the available clusters in the fleet without a policy",
			"placement", placement.Name, "clusters", clusterNames)
		return clusterNames, nil
	}
	// a fix list of clusters set
	if len(placement.Spec.Policy.ClusterNames) != 0 {
		klog.V(2).InfoS("use the cluster names provided as the list of cluster we select",
			"placement", placement.Name, "clusters", placement.Spec.Policy.ClusterNames)
		clusterNames, err = r.getClusters(placement.Spec.Policy.ClusterNames)
		if err != nil {
			return nil, err
		}
		return clusterNames, nil
	}

	// no Affinity or ClusterAffinity set
	if placement.Spec.Policy.Affinity == nil || placement.Spec.Policy.Affinity.ClusterAffinity == nil {
		clusterNames, err = r.listClusters(labels.Everything())
		if err != nil {
			return nil, err
		}
		klog.V(2).InfoS("we select all the available clusters in the fleet without a cluster affinity",
			"placement", placement.Name, "clusters", clusterNames)
		return clusterNames, nil
	}

	selectedClusters := make(map[string]bool)
	for _, clusterSelector := range placement.Spec.Policy.Affinity.ClusterAffinity.ClusterSelectorTerms {
		selector, err := metav1.LabelSelectorAsSelector(&clusterSelector.LabelSelector)
		if err != nil {
			return nil, fmt.Errorf("cannot convert the label clusterSelector to a clusterSelector: %w", err)
		}
		matchClusters, err := r.listClusters(selector)
		if err != nil {
			return nil, fmt.Errorf("selector = %v: %w", clusterSelector.LabelSelector, err)
		}
		klog.V(2).InfoS("selector matches some cluster", "clusterNum", len(matchClusters), "placement", placement.Name, "selector", clusterSelector.LabelSelector)
		for _, clusterName := range matchClusters {
			selectedClusters[clusterName] = true
		}
	}
	for cluster := range selectedClusters {
		klog.V(2).InfoS("matched a cluster", "cluster", cluster, "placement", placement.Name)
		clusterNames = append(clusterNames, cluster)
	}
	return clusterNames, nil
}