Implement ReaderClient

Author: adracus

clientutils/clientutils.go

@@ -25,13 +25,37 @@ import (
 	"github.com/onmetal/controller-utils/unstructuredutils"
 	"k8s.io/apimachinery/pkg/api/equality"
 	apierrors "k8s.io/apimachinery/pkg/api/errors"
+	"k8s.io/apimachinery/pkg/api/meta"
 	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	"k8s.io/apimachinery/pkg/conversion"
+	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/runtime/schema"
 	"sigs.k8s.io/controller-runtime/pkg/client"
 	"sigs.k8s.io/controller-runtime/pkg/controller/controllerutil"
 )
 
+type clientMeta interface {
+	Scheme() *runtime.Scheme
+	RESTMapper() meta.RESTMapper
+}
+
+type nonReaderClient interface {
+	client.Writer
+	client.StatusClient
+	clientMeta
+}
+
+type readerClient struct {
+	client.Reader
+	nonReaderClient
+}
+
+// ReaderClient returns a client.Client that uses the given client.Reader for all read operations and the
+// client.Client for the remaining operations.
+func ReaderClient(r client.Reader, c client.Client) client.Client {
+	return readerClient{r, c}
+}
+
 // IgnoreAlreadyExists returns nil if the given error matches apierrors.IsAlreadyExists.
 func IgnoreAlreadyExists(err error) error {
 	if apierrors.IsAlreadyExists(err) {

clientutils/clientutils_test.go

@@ -59,6 +59,8 @@ var _ = Describe("Clientutils", func() {
 		cm    *corev1.ConfigMap
 		cmKey client.ObjectKey
 
+		cmList *corev1.ConfigMapList
+
 		uPod *unstructured.Unstructured
 
 		secret    *corev1.Secret
@@ -84,6 +86,10 @@ var _ = Describe("Clientutils", func() {
 		}
 		cmKey = client.ObjectKeyFromObject(cm)
 
+		cmList = &corev1.ConfigMapList{
+			Items: []corev1.ConfigMap{*cm},
+		}
+
 		uPod = &unstructured.Unstructured{
 			Object: map[string]interface{}{
 				"apiVersion": "v1",
@@ -106,6 +112,23 @@ var _ = Describe("Clientutils", func() {
 		patchProvider = mockclientutils.NewMockPatchProvider(ctrl)
 	})
 
+	Describe("ReaderClient", func() {
+		It("should return a client that dispatches methods correctly", func() {
+			r := mockclient.NewMockClient(ctrl)
+			gomock.InOrder(
+				r.EXPECT().Get(ctx, cmKey, cm),
+				r.EXPECT().List(ctx, cmList),
+				c.EXPECT().Delete(ctx, cm),
+			)
+
+			rc := ReaderClient(r, c)
+
+			Expect(rc.Get(ctx, cmKey, cm)).To(Succeed())
+			Expect(rc.List(ctx, cmList)).To(Succeed())
+			Expect(rc.Delete(ctx, cm)).To(Succeed())
+		})
+	})
+
 	Describe("IgnoreAlreadyExists", func() {
 		It("should ignore already exists errors", func() {
 			alreadyExistsErr := IgnoreAlreadyExists(apierrors.NewAlreadyExists(cmGR, ""))