Add FilterByName for cluster-scoped resources. (#816)

This is a precursor to reconciling named webhook configurations, and largely a copy of `FilterByNameAndNamespace`.

controller/controller.go

@@ -98,6 +98,17 @@ func Filter(gvk schema.GroupVersionKind) func(obj interface{}) bool {
 	}
 }
 
+// FilterWithName makes it simple to create FilterFunc's for use with
+// cache.FilteringResourceEventHandler that filter based on a name.
+func FilterWithName(name string) func(obj interface{}) bool {
+	return func(obj interface{}) bool {
+		if object, ok := obj.(metav1.Object); ok {
+			return name == object.GetName()
+		}
+		return false
+	}
+}
+
 // FilterWithNameAndNamespace makes it simple to create FilterFunc's for use with
 // cache.FilteringResourceEventHandler that filter based on a namespace and a name.
 func FilterWithNameAndNamespace(namespace, name string) func(obj interface{}) bool {

controller/controller_test.go

@@ -135,6 +135,69 @@ func TestFilterWithNameAndNamespace(t *testing.T) {
 	}
 }
 
+func TestFilterWithName(t *testing.T) {
+	filter := FilterWithName("test-name")
+
+	tests := []struct {
+		name  string
+		input interface{}
+		want  bool
+	}{{
+		name:  "not a metav1.Object",
+		input: "foo",
+		want:  false,
+	}, {
+		name:  "nil",
+		input: nil,
+		want:  false,
+	}, {
+		name: "name matches, namespace does not",
+		input: &Resource{
+			ObjectMeta: metav1.ObjectMeta{
+				Name:      "test-name",
+				Namespace: "wrong-namespace",
+			},
+		},
+		want: true, // Unlike FilterWithNameAndNamespace this passes
+	}, {
+		name: "namespace matches, name does not",
+		input: &Resource{
+			ObjectMeta: metav1.ObjectMeta{
+				Name:      "wrong-name",
+				Namespace: "test-namespace",
+			},
+		},
+		want: false,
+	}, {
+		name: "neither matches",
+		input: &Resource{
+			ObjectMeta: metav1.ObjectMeta{
+				Name:      "wrong-name",
+				Namespace: "wrong-namespace",
+			},
+		},
+		want: false,
+	}, {
+		name: "matches",
+		input: &Resource{
+			ObjectMeta: metav1.ObjectMeta{
+				Name:      "test-name",
+				Namespace: "test-namespace",
+			},
+		},
+		want: true,
+	}}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			got := filter(test.input)
+			if test.want != got {
+				t.Errorf("FilterWithNameAndNamespace() = %v, wanted %v", got, test.want)
+			}
+		})
+	}
+}
+
 func TestFilter(t *testing.T) {
 	filter := Filter(gvk)