Implement Patch methods

create Patch, PatchOptions and PatchOptionFunc
add patch method to
* Client
* unstructuredClient
* typedClient
implement utility to create merge patches
add tests for both clients and for the utility

Author: adracus

Gopkg.lock

@@ -130,6 +130,15 @@ func (c *client) Delete(ctx context.Context, obj runtime.Object, opts ...DeleteO
 	return c.typedClient.Delete(ctx, obj, opts...)
 }
 
+// Patch implements client.Client
+func (c *client) Patch(ctx context.Context, obj runtime.Object, patch Patch, opts ...PatchOptionFunc) error {
+	_, ok := obj.(*unstructured.Unstructured)
+	if ok {
+		return c.unstructuredClient.Patch(ctx, obj, patch, opts...)
+	}
+	return c.typedClient.Patch(ctx, obj, patch, opts...)
+}
+
 // Get implements client.Client
 func (c *client) Get(ctx context.Context, key ObjectKey, obj runtime.Object) error {
 	_, ok := obj.(*unstructured.Unstructured)

pkg/client/client.go

@@ -18,9 +18,12 @@ package client_test
 
 import (
 	"context"
+	"encoding/json"
 	"fmt"
 	"sync/atomic"
 
+	"k8s.io/apimachinery/pkg/types"
+
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
 	appsv1 "k8s.io/api/apps/v1"
@@ -62,6 +65,7 @@ var _ = Describe("Client", func() {
 	var count uint64 = 0
 	var replicaCount int32 = 2
 	var ns = "default"
+	var mergePatch []byte
 
 	BeforeEach(func(done Done) {
 		atomic.AddUint64(&count, 1)
@@ -88,6 +92,15 @@ var _ = Describe("Client", func() {
 			Spec:       corev1.NodeSpec{},
 		}
 		scheme = kscheme.Scheme
+		var err error
+		mergePatch, err = json.Marshal(map[string]interface{}{
+			"metadata": map[string]interface{}{
+				"annotations": map[string]interface{}{
+					"foo": "bar",
+				},
+			},
+		})
+		Expect(err).NotTo(HaveOccurred())
 
 		close(done)
 	}, serverSideTimeoutSeconds)
@@ -964,6 +977,174 @@ var _ = Describe("Client", func() {
 		})
 	})
 
+	Describe("Patch", func() {
+		Context("with structured objects", func() {
+			It("should patch an existing object from a go struct", func(done Done) {
+				cl, err := client.New(cfg, client.Options{})
+				Expect(err).NotTo(HaveOccurred())
+				Expect(cl).NotTo(BeNil())
+
+				By("initially creating a Deployment")
+				dep, err := clientset.AppsV1().Deployments(ns).Create(dep)
+				Expect(err).NotTo(HaveOccurred())
+
+				By("patching the Deployment")
+				err = cl.Patch(context.TODO(), dep, client.ConstantPatch(types.MergePatchType, mergePatch))
+				Expect(err).NotTo(HaveOccurred())
+
+				By("validating patched Deployment has new annotation")
+				actual, err := clientset.AppsV1().Deployments(ns).Get(dep.Name, metav1.GetOptions{})
+				Expect(err).NotTo(HaveOccurred())
+				Expect(actual).NotTo(BeNil())
+				Expect(actual.Annotations["foo"]).To(Equal("bar"))
+
+				close(done)
+			})
+
+			It("should patch an existing object non-namespace object from a go struct", func(done Done) {
+				cl, err := client.New(cfg, client.Options{})
+				Expect(err).NotTo(HaveOccurred())
+				Expect(cl).NotTo(BeNil())
+
+				By("initially creating a Node")
+				node, err := clientset.CoreV1().Nodes().Create(node)
+				Expect(err).NotTo(HaveOccurred())
+
+				By("patching the Node")
+				nodeName := node.Name
+				err = cl.Patch(context.TODO(), node, client.ConstantPatch(types.MergePatchType, mergePatch))
+				Expect(err).NotTo(HaveOccurred())
+
+				By("validating the Node no longer exists")
+				actual, err := clientset.CoreV1().Nodes().Get(nodeName, metav1.GetOptions{})
+				Expect(err).NotTo(HaveOccurred())
+				Expect(actual).NotTo(BeNil())
+				Expect(actual.Annotations["foo"]).To(Equal("bar"))
+
+				close(done)
+			})
+
+			It("should fail if the object does not exists", func(done Done) {
+				cl, err := client.New(cfg, client.Options{})
+				Expect(err).NotTo(HaveOccurred())
+				Expect(cl).NotTo(BeNil())
+
+				By("Patching node before it is ever created")
+				err = cl.Patch(context.TODO(), node, client.ConstantPatch(types.MergePatchType, mergePatch))
+				Expect(err).To(HaveOccurred())
+
+				close(done)
+			})
+
+			PIt("should fail if the object doesn't have meta", func() {
+
+			})
+
+			It("should fail if the object cannot be mapped to a GVK", func(done Done) {
+				By("creating client with empty Scheme")
+				emptyScheme := runtime.NewScheme()
+				cl, err := client.New(cfg, client.Options{Scheme: emptyScheme})
+				Expect(err).NotTo(HaveOccurred())
+				Expect(cl).NotTo(BeNil())
+
+				By("initially creating a Deployment")
+				dep, err := clientset.AppsV1().Deployments(ns).Create(dep)
+				Expect(err).NotTo(HaveOccurred())
+
+				By("patching the Deployment fails")
+				err = cl.Patch(context.TODO(), dep, client.ConstantPatch(types.MergePatchType, mergePatch))
+				Expect(err).To(HaveOccurred())
+				Expect(err.Error()).To(ContainSubstring("no kind is registered for the type"))
+
+				close(done)
+			})
+
+			PIt("should fail if the GVK cannot be mapped to a Resource", func() {
+
+			})
+		})
+		Context("with unstructured objects", func() {
+			It("should patch an existing object from a go struct", func(done Done) {
+				cl, err := client.New(cfg, client.Options{})
+				Expect(err).NotTo(HaveOccurred())
+				Expect(cl).NotTo(BeNil())
+
+				By("initially creating a Deployment")
+				dep, err := clientset.AppsV1().Deployments(ns).Create(dep)
+				Expect(err).NotTo(HaveOccurred())
+
+				By("patching the Deployment")
+				depName := dep.Name
+				u := &unstructured.Unstructured{}
+				scheme.Convert(dep, u, nil)
+				u.SetGroupVersionKind(schema.GroupVersionKind{
+					Group:   "apps",
+					Kind:    "Deployment",
+					Version: "v1",
+				})
+				err = cl.Patch(context.TODO(), u, client.ConstantPatch(types.MergePatchType, mergePatch))
+				Expect(err).NotTo(HaveOccurred())
+
+				By("validating patched Deployment has new annotation")
+				actual, err := clientset.AppsV1().Deployments(ns).Get(depName, metav1.GetOptions{})
+				Expect(err).NotTo(HaveOccurred())
+				Expect(actual).NotTo(BeNil())
+				Expect(actual.Annotations["foo"]).To(Equal("bar"))
+
+				close(done)
+			})
+
+			It("should patch an existing object non-namespace object from a go struct", func(done Done) {
+				cl, err := client.New(cfg, client.Options{})
+				Expect(err).NotTo(HaveOccurred())
+				Expect(cl).NotTo(BeNil())
+
+				By("initially creating a Node")
+				node, err := clientset.CoreV1().Nodes().Create(node)
+				Expect(err).NotTo(HaveOccurred())
+
+				By("patching the Node")
+				nodeName := node.Name
+				u := &unstructured.Unstructured{}
+				scheme.Convert(node, u, nil)
+				u.SetGroupVersionKind(schema.GroupVersionKind{
+					Group:   "",
+					Kind:    "Node",
+					Version: "v1",
+				})
+				err = cl.Patch(context.TODO(), u, client.ConstantPatch(types.MergePatchType, mergePatch))
+				Expect(err).NotTo(HaveOccurred())
+
+				By("validating pathed Node has new annotation")
+				actual, err := clientset.CoreV1().Nodes().Get(nodeName, metav1.GetOptions{})
+				Expect(err).NotTo(HaveOccurred())
+				Expect(actual).NotTo(BeNil())
+				Expect(actual.Annotations["foo"]).To(Equal("bar"))
+
+				close(done)
+			})
+
+			It("should fail if the object does not exist", func(done Done) {
+				cl, err := client.New(cfg, client.Options{})
+				Expect(err).NotTo(HaveOccurred())
+				Expect(cl).NotTo(BeNil())
+
+				By("Patching node before it is ever created")
+				u := &unstructured.Unstructured{}
+				scheme.Convert(node, u, nil)
+				u.SetGroupVersionKind(schema.GroupVersionKind{
+					Group:   "",
+					Kind:    "Node",
+					Version: "v1",
+				})
+				err = cl.Patch(context.TODO(), node, client.ConstantPatch(types.MergePatchType, mergePatch))
+				Expect(err).To(HaveOccurred())
+
+				close(done)
+			})
+		})
+	})
+
 	Describe("Get", func() {
 		Context("with structured objects", func() {
 			It("should fetch an existing object for a go struct", func(done Done) {
@@ -1984,6 +2165,46 @@ var _ = Describe("DelegatingReader", func() {
 	})
 })
 
+var _ = Describe("Patch", func() {
+	Describe("CreateMergePatch", func() {
+		var cm *corev1.ConfigMap
+
+		BeforeEach(func() {
+			cm = &corev1.ConfigMap{
+				ObjectMeta: metav1.ObjectMeta{
+					Namespace: metav1.NamespaceDefault,
+					Name:      "cm",
+				},
+			}
+		})
+
+		It("creates a merge patch with the modifications applied during the mutation", func() {
+			const (
+				annotationKey   = "test"
+				annotationValue = "foo"
+			)
+
+			By("creating a merge patch")
+			patch := client.MergeFrom(cm.DeepCopy())
+
+			By("returning a patch with type MergePatch")
+			Expect(patch.Type()).To(Equal(types.MergePatchType))
+
+			By("retrieving modifying the config map")
+			metav1.SetMetaDataAnnotation(&cm.ObjectMeta, annotationKey, annotationValue)
+
+			By("computing the patch data")
+			data, err := patch.Data(cm)
+
+			By("returning no error")
+			Expect(err).NotTo(HaveOccurred())
+
+			By("returning a patch with data only containing the annotation change")
+			Expect(data).To(Equal([]byte(fmt.Sprintf(`{"metadata":{"annotations":{"%s":"%s"}}}`, annotationKey, annotationValue))))
+		})
+	})
+})
+
 type fakeReader struct {
 	Called int
 }

pkg/client/client_test.go

@@ -194,6 +194,38 @@ func (c *fakeClient) Update(ctx context.Context, obj runtime.Object, opts ...cli
 	return c.tracker.Update(gvr, obj, accessor.GetNamespace())
 }
 
+func (c *fakeClient) Patch(ctx context.Context, obj runtime.Object, patch client.Patch, opts ...client.PatchOptionFunc) error {
+	gvr, err := getGVRFromObject(obj, c.scheme)
+	if err != nil {
+		return err
+	}
+	accessor, err := meta.Accessor(obj)
+	if err != nil {
+		return err
+	}
+	data, err := patch.Data(obj)
+	if err != nil {
+		return err
+	}
+
+	reaction := testing.ObjectReaction(c.tracker)
+	handled, o, err := reaction(testing.NewPatchAction(gvr, accessor.GetNamespace(), accessor.GetName(), patch.Type(), data))
+	if err != nil {
+		return err
+	}
+	if !handled {
+		panic("tracker could not handle patch method")
+	}
+
+	j, err := json.Marshal(o)
+	if err != nil {
+		return err
+	}
+	decoder := scheme.Codecs.UniversalDecoder()
+	_, _, err = decoder.Decode(j, nil, obj)
+	return err
+}
+
 func (c *fakeClient) Status() client.StatusWriter {
 	return &fakeStatusWriter{client: c}
 }

pkg/client/fake/client.go

@@ -17,6 +17,8 @@ limitations under the License.
 package fake
 
 import (
+	"encoding/json"
+
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
 
@@ -205,6 +207,30 @@ var _ = Describe("Fake client", func() {
 				Expect(obj).To(Equal(cm))
 			})
 		})
+
+		It("should be able to Patch", func() {
+			By("Patching a deployment")
+			mergePatch, err := json.Marshal(map[string]interface{}{
+				"metadata": map[string]interface{}{
+					"annotations": map[string]interface{}{
+						"foo": "bar",
+					},
+				},
+			})
+			Expect(err).NotTo(HaveOccurred())
+			err = cl.Patch(nil, dep, client.ConstantPatch(types.JSONPatchType, mergePatch))
+			Expect(err).NotTo(HaveOccurred())
+
+			By("Getting the patched deployment")
+			namespacedName := types.NamespacedName{
+				Name:      "test-deployment",
+				Namespace: "ns1",
+			}
+			obj := &appsv1.Deployment{}
+			err = cl.Get(nil, namespacedName, obj)
+			Expect(err).NotTo(HaveOccurred())
+			Expect(obj.Annotations["foo"]).To(Equal("bar"))
+		})
 	}
 
 	Context("with default scheme.Scheme", func() {