Support Patch request in client

pkg/client/client.go

@@ -24,6 +24,7 @@ import (
 	"k8s.io/apimachinery/pkg/api/meta"
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/runtime/serializer"
+	"k8s.io/apimachinery/pkg/types"
 	"k8s.io/client-go/kubernetes/scheme"
 	"k8s.io/client-go/rest"
 	"sigs.k8s.io/controller-runtime/pkg/client/apiutil"
@@ -124,6 +125,22 @@ func (c *client) Delete(ctx context.Context, obj runtime.Object) error {
 		Error()
 }
 
+// Patch implements client.Client
+func (c *client) Patch(ctx context.Context, pt types.PatchType, data []byte, obj runtime.Object, subresources ...string) error {
+	o, err := c.cache.getObjMeta(obj)
+	if err != nil {
+		return err
+	}
+	return o.Patch(pt).
+		NamespaceIfScoped(o.GetNamespace(), o.isNamespaced()).
+		Resource(o.resource()).
+		SubResource(subresources...).
+		Name(o.GetName()).
+		Body(data).
+		Do().
+		Into(obj)
+}
+
 // Get implements client.Client
 func (c *client) Get(ctx context.Context, key ObjectKey, obj runtime.Object) error {
 	r, err := c.cache.getResource(obj)

pkg/client/client_test.go

@@ -18,6 +18,7 @@ package client_test
 
 import (
 	"context"
+	"encoding/json"
 	"fmt"
 	"sync/atomic"
 
@@ -28,6 +29,7 @@ import (
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/types"
 	"sigs.k8s.io/controller-runtime/pkg/client"
 
 	kscheme "k8s.io/client-go/kubernetes/scheme"
@@ -499,6 +501,164 @@ var _ = Describe("Client", func() {
 		})
 	})
 
+	Describe("Patch", 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")
+			mergePatch, err := json.Marshal(map[string]interface{}{
+				"metadata": map[string]interface{}{
+					"annotations": map[string]interface{}{
+						"foo": "bar",
+					},
+				},
+			})
+			Expect(err).NotTo(HaveOccurred())
+
+			err = cl.Patch(context.TODO(), types.MergePatchType, mergePatch, dep)
+			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 new object from an unstructured object", 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("updating and encoding the Deployment as unstructured")
+			var u runtime.Unstructured = &unstructured.Unstructured{}
+			dep.Annotations = map[string]string{"foo": "bar"}
+			scheme.Convert(dep, u, nil)
+
+			By("patching the 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(context.TODO(), types.MergePatchType, mergePatch, u)
+			Expect(err).NotTo(HaveOccurred())
+
+			By("fetching newly created unstructured 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())
+
+			node, err := clientset.CoreV1().Nodes().Create(node)
+			Expect(err).NotTo(HaveOccurred())
+
+			By("patching the object")
+			mergePatch, err := json.Marshal(map[string]interface{}{
+				"metadata": map[string]interface{}{
+					"annotations": map[string]interface{}{
+						"foo": "bar",
+					},
+				},
+			})
+			Expect(err).NotTo(HaveOccurred())
+
+			err = cl.Patch(context.TODO(), types.MergePatchType, mergePatch, node)
+			Expect(err).NotTo(HaveOccurred())
+
+			By("validate patched Node had new annotation")
+			actual, err := clientset.CoreV1().Nodes().Get(node.Name, 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 non-existent object")
+			mergePatch, err := json.Marshal(map[string]interface{}{
+				"metadata": map[string]interface{}{
+					"annotations": map[string]interface{}{
+						"foo": "bar",
+					},
+				},
+			})
+			Expect(err).NotTo(HaveOccurred())
+			err = cl.Patch(context.TODO(), types.MergePatchType, mergePatch, dep)
+			Expect(err).To(HaveOccurred())
+
+			close(done)
+		})
+
+		It("should fail if the object does not pass server-side validation", func() {
+
+		})
+
+		It("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")
+			mergePatch, err := json.Marshal(map[string]interface{}{
+				"metadata": map[string]interface{}{
+					"annotations": map[string]interface{}{
+						"foo": "bar",
+					},
+				},
+			})
+			Expect(err).NotTo(HaveOccurred())
+			err = cl.Patch(context.TODO(), types.MergePatchType, mergePatch, dep)
+			Expect(err).To(HaveOccurred())
+			Expect(err.Error()).To(ContainSubstring("no kind is registered for the type"))
+
+			close(done)
+		})
+
+		It("should fail if the GVK cannot be mapped to a Resource", func() {
+
+		})
+	})
+
 	Describe("Get", func() {
 		It("should fetch an existing object for a go struct", func(done Done) {
 			By("first creating the Deployment")

pkg/client/interfaces.go

@@ -55,6 +55,10 @@ type Writer interface {
 	// Update updates the given obj in the Kubernetes cluster. obj must be a
 	// struct pointer so that obj can be updated with the content returned by the Server.
 	Update(ctx context.Context, obj runtime.Object) error
+
+	// Patch patches the given obj in the Kubernetes cluster. obj must be a
+	// struct pointer so that obj can be updated with the content returned by the Server.
+	Patch(ctx context.Context, pt types.PatchType, data []byte, obj runtime.Object, subresources ...string) error
 }
 
 // Client knows how to perform CRUD operations on Kubernetes objects.