optimize the validating webhook for spreadconstraint

Signed-off-by: huone1 <huwanxing@huawei.com>

pkg/util/helper/policy.go

@@ -5,6 +5,7 @@ import (
 
 	discoveryv1 "k8s.io/api/discovery/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/util/sets"
 	"k8s.io/klog/v2"
 	"sigs.k8s.io/controller-runtime/pkg/client"
 
@@ -33,8 +34,10 @@ func SetDefaultSpreadConstraints(spreadConstraints []policyv1alpha1.SpreadConstr
 
 // ValidateSpreadConstraint tests if the constraints is valid.
 func ValidateSpreadConstraint(spreadConstraints []policyv1alpha1.SpreadConstraint) error {
-	// SpreadByField and SpreadByLabel should not co-exist
+	spreadByFields := sets.NewString()
+
 	for _, constraint := range spreadConstraints {
+		// SpreadByField and SpreadByLabel should not co-exist
 		if len(constraint.SpreadByField) > 0 && len(constraint.SpreadByLabel) > 0 {
 			return fmt.Errorf("invalid constraints: SpreadByLabel(%s) should not co-exist with spreadByField(%s)", constraint.SpreadByLabel, constraint.SpreadByField)
 		}
@@ -43,7 +46,21 @@ func ValidateSpreadConstraint(spreadConstraints []policyv1alpha1.SpreadConstrain
 		if constraint.MaxGroups > 0 && constraint.MaxGroups < constraint.MinGroups {
 			return fmt.Errorf("maxGroups(%d) lower than minGroups(%d) is not allowed", constraint.MaxGroups, constraint.MinGroups)
 		}
+
+		if len(constraint.SpreadByField) > 0 {
+			spreadByFields.Insert(string(constraint.SpreadByField))
+		}
 	}
+
+	if spreadByFields.Len() > 0 {
+		// If one of spread constraints are using 'SpreadByField', the 'SpreadByFieldCluster' must be included.
+		// For example, when using 'SpreadByFieldRegion' to specify region groups, at the meantime, you must use
+		// 'SpreadByFieldCluster' to specify how many clusters should be selected.
+		if !spreadByFields.Has(string(policyv1alpha1.SpreadByFieldCluster)) {
+			return fmt.Errorf("the cluster spread constraint must be enabled in one of the constraints in case of SpreadByField is enabled")
+		}
+	}
+
 	return nil
 }