Implement predicate

Author: fanzhangio

pkg/predicate/predicate.go

@@ -16,7 +16,12 @@ limitations under the License.
 
 package predicate
 
-import "sigs.k8s.io/controller-runtime/pkg/event"
+import (
+	"sigs.k8s.io/controller-runtime/pkg/event"
+	logf "sigs.k8s.io/controller-runtime/pkg/runtime/log"
+)
+
+var log = logf.KBLog.WithName("predicate").WithName("eventFilters")
 
 // Predicate filters events before enqueuing the keys.
 type Predicate interface {
@@ -34,6 +39,7 @@ type Predicate interface {
 }
 
 var _ Predicate = Funcs{}
+var _ Predicate = ResourceVersionChangedPredicate{}
 
 // Funcs is a function that implements Predicate.
 type Funcs struct {
@@ -81,3 +87,32 @@ func (p Funcs) Generic(e event.GenericEvent) bool {
 	}
 	return true
 }
+
+// ResourceVersionChangedPredicate implements a default update predicate function on resource version change
+type ResourceVersionChangedPredicate struct {
+	Funcs
+}
+
+// Update implements default UpdateEvent filter for validating resource version change
+func (ResourceVersionChangedPredicate) Update(e event.UpdateEvent) bool {
+	if e.MetaOld == nil {
+		log.Error(nil, "UpdateEvent has no old metadata", "UpdateEvent", e)
+		return false
+	}
+	if e.ObjectOld == nil {
+		log.Error(nil, "GenericEvent has no old runtime object to update", "GenericEvent", e)
+		return false
+	}
+	if e.ObjectNew == nil {
+		log.Error(nil, "GenericEvent has no new runtime object for update", "GenericEvent", e)
+		return false
+	}
+	if e.MetaNew == nil {
+		log.Error(nil, "UpdateEvent has no new metadata", "UpdateEvent", e)
+		return false
+	}
+	if e.MetaNew.GetResourceVersion() == e.MetaOld.GetResourceVersion() {
+		return false
+	}
+	return true
+}

pkg/predicate/predicate_suite_test.go

@@ -14,7 +14,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-package predicate
+package predicate_test
 
 import (
 	"testing"

pkg/predicate/predicate_test.go

@@ -175,4 +175,137 @@ var _ = Describe("Predicate", func() {
 			close(done)
 		})
 	})
+
+	Describe("When checking a ResourceVersionChangedPredicate", func() {
+		instance := predicate.ResourceVersionChangedPredicate{}
+
+		Context("Where the old object doesn't have a ResourceVersion or metadata", func() {
+			It("should return false", func() {
+				new := &corev1.Pod{
+					ObjectMeta: metav1.ObjectMeta{
+						Name:            "baz",
+						Namespace:       "biz",
+						ResourceVersion: "1",
+					}}
+
+				failEvnt := event.UpdateEvent{
+					MetaNew:   new.GetObjectMeta(),
+					ObjectNew: new,
+				}
+				Expect(instance.Create(event.CreateEvent{})).Should(BeTrue())
+				Expect(instance.Delete(event.DeleteEvent{})).Should(BeTrue())
+				Expect(instance.Generic(event.GenericEvent{})).Should(BeTrue())
+				Expect(instance.Update(failEvnt)).Should(BeFalse())
+			})
+		})
+
+		Context("Where the new object doesn't have a ResourceVersion or metadata", func() {
+			It("should return false", func() {
+				old := &corev1.Pod{
+					ObjectMeta: metav1.ObjectMeta{
+						Name:            "baz",
+						Namespace:       "biz",
+						ResourceVersion: "1",
+					}}
+
+				failEvnt := event.UpdateEvent{
+					MetaOld:   old.GetObjectMeta(),
+					ObjectOld: old,
+				}
+				Expect(instance.Create(event.CreateEvent{})).Should(BeTrue())
+				Expect(instance.Delete(event.DeleteEvent{})).Should(BeTrue())
+				Expect(instance.Generic(event.GenericEvent{})).Should(BeTrue())
+				Expect(instance.Update(failEvnt)).Should(BeFalse())
+				Expect(instance.Update(failEvnt)).Should(BeFalse())
+			})
+		})
+
+		Context("Where the ResourceVersion hasn't changed", func() {
+			It("should return false", func() {
+				new := &corev1.Pod{
+					ObjectMeta: metav1.ObjectMeta{
+						Name:            "baz",
+						Namespace:       "biz",
+						ResourceVersion: "v1",
+					}}
+
+				old := &corev1.Pod{
+					ObjectMeta: metav1.ObjectMeta{
+						Name:            "baz",
+						Namespace:       "biz",
+						ResourceVersion: "v1",
+					}}
+
+				failEvnt := event.UpdateEvent{
+					MetaOld:   old.GetObjectMeta(),
+					ObjectOld: old,
+					MetaNew:   new.GetObjectMeta(),
+					ObjectNew: new,
+				}
+				Expect(instance.Create(event.CreateEvent{})).Should(BeTrue())
+				Expect(instance.Delete(event.DeleteEvent{})).Should(BeTrue())
+				Expect(instance.Generic(event.GenericEvent{})).Should(BeTrue())
+				Expect(instance.Update(failEvnt)).Should(BeFalse())
+				Expect(instance.Update(failEvnt)).Should(BeFalse())
+			})
+		})
+
+		Context("Where the ResourceVersion has changed", func() {
+			It("should return true", func() {
+				new := &corev1.Pod{
+					ObjectMeta: metav1.ObjectMeta{
+						Name:            "baz",
+						Namespace:       "biz",
+						ResourceVersion: "v1",
+					}}
+
+				old := &corev1.Pod{
+					ObjectMeta: metav1.ObjectMeta{
+						Name:            "baz",
+						Namespace:       "biz",
+						ResourceVersion: "v2",
+					}}
+				passEvt := event.UpdateEvent{
+					MetaOld:   old.GetObjectMeta(),
+					ObjectOld: old,
+					MetaNew:   new.GetObjectMeta(),
+					ObjectNew: new,
+				}
+				Expect(instance.Create(event.CreateEvent{})).Should(BeTrue())
+				Expect(instance.Delete(event.DeleteEvent{})).Should(BeTrue())
+				Expect(instance.Generic(event.GenericEvent{})).Should(BeTrue())
+				Expect(instance.Update(passEvt)).Should(BeTrue())
+			})
+		})
+
+		Context("Where the objects or metadata are missing", func() {
+
+			It("should return false", func() {
+				new := &corev1.Pod{
+					ObjectMeta: metav1.ObjectMeta{
+						Name:            "baz",
+						Namespace:       "biz",
+						ResourceVersion: "v1",
+					}}
+
+				old := &corev1.Pod{
+					ObjectMeta: metav1.ObjectMeta{
+						Name:            "baz",
+						Namespace:       "biz",
+						ResourceVersion: "v1",
+					}}
+
+				failEvt1 := event.UpdateEvent{MetaOld: old.GetObjectMeta(), ObjectOld: old, MetaNew: new.GetObjectMeta()}
+				failEvt2 := event.UpdateEvent{MetaOld: old.GetObjectMeta(), MetaNew: new.GetObjectMeta(), ObjectNew: new}
+				failEvt3 := event.UpdateEvent{MetaOld: old.GetObjectMeta(), ObjectOld: old, ObjectNew: new}
+				Expect(instance.Create(event.CreateEvent{})).Should(BeTrue())
+				Expect(instance.Delete(event.DeleteEvent{})).Should(BeTrue())
+				Expect(instance.Generic(event.GenericEvent{})).Should(BeTrue())
+				Expect(instance.Update(failEvt1)).Should(BeFalse())
+				Expect(instance.Update(failEvt2)).Should(BeFalse())
+				Expect(instance.Update(failEvt3)).Should(BeFalse())
+			})
+		})
+
+	})
 })