Merge pull request #446 from rramkumar1/finalizer-lib

Add some utility functions to support finalizers

pkg/utils/finalizer.go

@@ -0,0 +1,62 @@
+/*
+Copyright 2018 The Kubernetes Authors.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+    http://www.apache.org/licenses/LICENSE-2.0
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package utils
+
+import (
+	"encoding/json"
+	"fmt"
+
+	meta_v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/util/strategicpatch"
+	"k8s.io/kubernetes/pkg/util/slice"
+)
+
+// FinalizerKeySuffix is a suffix for finalizers added by the controller.
+// A full key could be something like "ingress.finalizer.cloud.google.com"
+const FinalizerKeySuffix = "finalizer.cloud.google.com"
+
+// IsDeletionCandidate is true if the passed in meta contains the specified finalizer.
+func IsDeletionCandidate(m meta_v1.ObjectMeta, key string) bool {
+	return m.DeletionTimestamp != nil && hasFinalizer(m, key)
+}
+
+// NeedToAddFinalizer is true if the passed in meta does not contain the specified finalizer.
+func NeedToAddFinalizer(m meta_v1.ObjectMeta, key string) bool {
+	return m.DeletionTimestamp == nil && !hasFinalizer(m, key)
+}
+
+func hasFinalizer(m meta_v1.ObjectMeta, key string) bool {
+	return slice.ContainsString(m.Finalizers, key, nil)
+}
+
+// getPatchBytes returns a patch which is the difference between the old and new objects.
+// Note: refStruct is a empty struct of the type which the patch is being generated for.
+func getPatchBytes(old interface{}, cur interface{}, refStruct interface{}) ([]byte, error) {
+	oldBytes, err := json.Marshal(old)
+	if err != nil {
+		return nil, fmt.Errorf("failed to marshal old object: %v", err)
+	}
+
+	newBytes, err := json.Marshal(cur)
+	if err != nil {
+		return nil, fmt.Errorf("failed to marshal new object: %v", err)
+	}
+
+	patchBytes, err := strategicpatch.CreateTwoWayMergePatch(oldBytes, newBytes, refStruct)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create patch: %v", err)
+	}
+
+	return patchBytes, nil
+}

pkg/utils/finalizer_test.go

@@ -0,0 +1,51 @@
+/*
+Copyright 2018 The Kubernetes Authors.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+    http://www.apache.org/licenses/LICENSE-2.0
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package utils
+
+import (
+	"testing"
+
+	extensions "k8s.io/api/extensions/v1beta1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+)
+
+func TestGetPatchBytes(t *testing.T) {
+	// Patch an Ingress w/ a finalizer
+	ing := &extensions.Ingress{}
+	updated := &extensions.Ingress{
+		ObjectMeta: metav1.ObjectMeta{
+			Finalizers: []string{"foo"},
+		},
+	}
+	b, err := getPatchBytes(ing, updated, extensions.Ingress{})
+	if err != nil {
+		t.Fatal(err)
+	}
+	expected := `{"metadata":{"finalizers":["foo"]}}`
+	if string(b) != expected {
+		t.Errorf("getPatchBytes(%+v, %+v) = %s ; want %s", ing, updated, string(b), expected)
+	}
+
+	// Patch an Ingress with the finalizer removed
+	ing = updated
+	updated = &extensions.Ingress{}
+	b, err = getPatchBytes(ing, updated, extensions.Ingress{})
+	if err != nil {
+		t.Fatal(err)
+	}
+	expected = `{"metadata":{"finalizers":null}}`
+	if string(b) != expected {
+		t.Errorf("getPatchBytes(%+v, %+v) = %s ; want %s", ing, updated, string(b), expected)
+	}
+}