🐛 Fakeclient: Support WithWatch

pkg/client/fake/client.go

@@ -31,6 +31,7 @@ import (
 	"k8s.io/apimachinery/pkg/runtime/schema"
 	utilrand "k8s.io/apimachinery/pkg/util/rand"
 	"k8s.io/apimachinery/pkg/util/validation/field"
+	"k8s.io/apimachinery/pkg/watch"
 	"k8s.io/client-go/kubernetes/scheme"
 	"k8s.io/client-go/testing"
 
@@ -49,7 +50,7 @@ type fakeClient struct {
 	scheme  *runtime.Scheme
 }
 
-var _ client.Client = &fakeClient{}
+var _ client.WithWatch = &fakeClient{}
 
 const (
 	maxNameLength          = 63
@@ -61,7 +62,7 @@ const (
 // You can choose to initialize it with a slice of runtime.Object.
 //
 // Deprecated: Please use NewClientBuilder instead.
-func NewFakeClient(initObjs ...runtime.Object) client.Client {
+func NewFakeClient(initObjs ...runtime.Object) client.WithWatch {
 	return NewClientBuilder().WithRuntimeObjects(initObjs...).Build()
 }
 
@@ -70,7 +71,7 @@ func NewFakeClient(initObjs ...runtime.Object) client.Client {
 // You can choose to initialize it with a slice of runtime.Object.
 //
 // Deprecated: Please use NewClientBuilder instead.
-func NewFakeClientWithScheme(clientScheme *runtime.Scheme, initObjs ...runtime.Object) client.Client {
+func NewFakeClientWithScheme(clientScheme *runtime.Scheme, initObjs ...runtime.Object) client.WithWatch {
 	return NewClientBuilder().WithScheme(clientScheme).WithRuntimeObjects(initObjs...).Build()
 }
 
@@ -113,7 +114,7 @@ func (f *ClientBuilder) WithRuntimeObjects(initRuntimeObjs ...runtime.Object) *C
 }
 
 // Build builds and returns a new fake client.
-func (f *ClientBuilder) Build() client.Client {
+func (f *ClientBuilder) Build() client.WithWatch {
 	if f.scheme == nil {
 		f.scheme = scheme.Scheme
 	}
@@ -284,6 +285,23 @@ func (c *fakeClient) Get(ctx context.Context, key client.ObjectKey, obj client.O
 	return err
 }
 
+func (c *fakeClient) Watch(ctx context.Context, list client.ObjectList, opts ...client.ListOption) (watch.Interface, error) {
+	gvk, err := apiutil.GVKForObject(list, c.scheme)
+	if err != nil {
+		return nil, err
+	}
+
+	if strings.HasSuffix(gvk.Kind, "List") {
+		gvk.Kind = gvk.Kind[:len(gvk.Kind)-4]
+	}
+
+	listOpts := client.ListOptions{}
+	listOpts.ApplyOptions(opts)
+
+	gvr, _ := meta.UnsafeGuessKindToResource(gvk)
+	return c.tracker.Watch(gvr, listOpts.Namespace)
+}
+
 func (c *fakeClient) List(ctx context.Context, obj client.ObjectList, opts ...client.ListOption) error {
 	gvk, err := apiutil.GVKForObject(obj, c.scheme)
 	if err != nil {

pkg/client/fake/client_test.go

@@ -20,6 +20,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"time"
 
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
@@ -33,14 +34,15 @@ import (
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/types"
+	"k8s.io/apimachinery/pkg/watch"
 	"sigs.k8s.io/controller-runtime/pkg/client"
 )
 
 var _ = Describe("Fake client", func() {
 	var dep *appsv1.Deployment
 	var dep2 *appsv1.Deployment
 	var cm *corev1.ConfigMap
-	var cl client.Client
+	var cl client.WithWatch
 
 	BeforeEach(func() {
 		dep = &appsv1.Deployment{
@@ -541,6 +543,32 @@ var _ = Describe("Fake client", func() {
 			}
 		})
 
+		It("should be able to watch", func() {
+			By("Creating a watch")
+			objWatch, err := cl.Watch(context.Background(), &corev1.ServiceList{})
+			Expect(err).NotTo(HaveOccurred())
+
+			defer objWatch.Stop()
+
+			go func() {
+				defer GinkgoRecover()
+				// It is likely starting a new goroutine is slower than progressing
+				// in the outer routine, sleep to make sure this is always true
+				time.Sleep(100 * time.Millisecond)
+
+				err := cl.Create(context.Background(), &corev1.Service{ObjectMeta: metav1.ObjectMeta{Namespace: "default", Name: "for-watch"}})
+				Expect(err).ToNot(HaveOccurred())
+			}()
+
+			event, ok := <-objWatch.ResultChan()
+			Expect(ok).To(BeTrue())
+			Expect(event.Type).To(Equal(watch.Added))
+
+			service, ok := event.Object.(*corev1.Service)
+			Expect(ok).To(BeTrue())
+			Expect(service.Name).To(Equal("for-watch"))
+		})
+
 		Context("with the DryRun option", func() {
 			It("should not create a new object", func() {
 				By("Creating a new configmap with DryRun")