#47568 - Added delegateError + Improve delegate Test Coverage (#318)

* added delegate error / improve delegate coverage / add new mocks

* fixing ci lint

* addressing comments from @ericpromislow

* addressing comments from @tomleb

* fixing apistatus type casting assert

pkg/ext/apiserver.go

@@ -239,23 +239,25 @@ func InstallStore[T runtime.Object, TList runtime.Object](
 		apiGroup.VersionedResourcesStorageMap[gvk.Version] = make(map[string]rest.Storage)
 	}
 
-	delegate := &delegate[T, TList]{
-		scheme: s.scheme,
-
-		t:            t,
-		tList:        tList,
-		singularName: singularName,
-		gvk:          gvk,
-		gvr: schema.GroupVersionResource{
-			Group:    gvk.Group,
-			Version:  gvk.Version,
-			Resource: resourceName,
+	del := &delegateError[T, TList]{
+		inner: &delegate[T, TList]{
+			scheme: s.scheme,
+
+			t:            t,
+			tList:        tList,
+			singularName: singularName,
+			gvk:          gvk,
+			gvr: schema.GroupVersionResource{
+				Group:    gvk.Group,
+				Version:  gvk.Version,
+				Resource: resourceName,
+			},
+			authorizer: s.authorizer,
+			store:      store,
 		},
-		authorizer: s.authorizer,
-		store:      store,
 	}
 
-	apiGroup.VersionedResourcesStorageMap[gvk.Version][resourceName] = delegate
+	apiGroup.VersionedResourcesStorageMap[gvk.Version][resourceName] = del
 	s.apiGroups[gvk.Group] = apiGroup
 	return nil
 }

pkg/ext/delegate.go

@@ -2,6 +2,7 @@ package ext
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"sync"
 
@@ -16,6 +17,10 @@ import (
 	"k8s.io/apiserver/pkg/registry/rest"
 )
 
+var (
+	errMissingUserInfo = errors.New("missing user info")
+)
+
 // delegate is the bridge between k8s.io/apiserver's [rest.Storage] interface and
 // our own Store interface we want developers to use
 //
@@ -328,7 +333,7 @@ func (s *delegate[T, TList]) GetSingularName() string {
 func (s *delegate[T, TList]) makeContext(parentCtx context.Context) (Context, error) {
 	userInfo, ok := request.UserFrom(parentCtx)
 	if !ok {
-		return Context{}, fmt.Errorf("missing user info")
+		return Context{}, errMissingUserInfo
 	}
 
 	ctx := Context{

pkg/ext/delegate_error.go

@@ -0,0 +1,110 @@
+package ext
+
+import (
+	"context"
+
+	"k8s.io/apimachinery/pkg/api/errors"
+	metainternalversion "k8s.io/apimachinery/pkg/apis/meta/internalversion"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+	"k8s.io/apimachinery/pkg/watch"
+	"k8s.io/apiserver/pkg/registry/rest"
+)
+
+// delegateError wraps an inner delegate and converts unknown errors.
+type delegateError[T runtime.Object, TList runtime.Object] struct {
+	inner *delegate[T, TList]
+}
+
+func (d *delegateError[T, TList]) New() runtime.Object {
+	return d.inner.New()
+}
+
+func (d *delegateError[T, TList]) Destroy() {
+	d.inner.Destroy()
+}
+
+func (d *delegateError[T, TList]) NewList() runtime.Object {
+	return d.inner.NewList()
+}
+
+func (d *delegateError[T, TList]) List(parentCtx context.Context, internaloptions *metainternalversion.ListOptions) (runtime.Object, error) {
+	result, err := d.inner.List(parentCtx, internaloptions)
+	if err != nil {
+		return nil, convertError(err)
+	}
+	return result, nil
+}
+
+func (d *delegateError[T, TList]) ConvertToTable(ctx context.Context, object runtime.Object, tableOptions runtime.Object) (*metav1.Table, error) {
+	result, err := d.inner.ConvertToTable(ctx, object, tableOptions)
+	if err != nil {
+		return nil, convertError(err)
+	}
+	return result, nil
+}
+
+func (d *delegateError[T, TList]) Get(parentCtx context.Context, name string, options *metav1.GetOptions) (runtime.Object, error) {
+	result, err := d.inner.Get(parentCtx, name, options)
+	if err != nil {
+		return nil, convertError(err)
+	}
+	return result, nil
+}
+
+func (d *delegateError[T, TList]) Delete(parentCtx context.Context, name string, deleteValidation rest.ValidateObjectFunc, options *metav1.DeleteOptions) (runtime.Object, bool, error) {
+	result, completed, err := d.inner.Delete(parentCtx, name, deleteValidation, options)
+	if err != nil {
+		return nil, false, convertError(err)
+	}
+	return result, completed, nil
+}
+
+func (d *delegateError[T, TList]) Create(parentCtx context.Context, obj runtime.Object, createValidation rest.ValidateObjectFunc, options *metav1.CreateOptions) (runtime.Object, error) {
+	result, err := d.inner.Create(parentCtx, obj, createValidation, options)
+	if err != nil {
+		return nil, convertError(err)
+	}
+	return result, nil
+}
+
+func (d *delegateError[T, TList]) Update(parentCtx context.Context, name string, objInfo rest.UpdatedObjectInfo, createValidation rest.ValidateObjectFunc, updateValidation rest.ValidateObjectUpdateFunc, forceAllowCreate bool, options *metav1.UpdateOptions) (runtime.Object, bool, error) {
+	result, created, err := d.inner.Update(parentCtx, name, objInfo, createValidation, updateValidation, forceAllowCreate, options)
+	if err != nil {
+		return nil, false, convertError(err)
+	}
+	return result, created, nil
+}
+
+func (d *delegateError[T, TList]) Watch(parentCtx context.Context, internaloptions *metainternalversion.ListOptions) (watch.Interface, error) {
+	result, err := d.inner.Watch(parentCtx, internaloptions)
+	if err != nil {
+		return nil, convertError(err)
+	}
+	return result, nil
+}
+
+func (d *delegateError[T, TList]) GroupVersionKind(groupVersion schema.GroupVersion) schema.GroupVersionKind {
+	return d.inner.GroupVersionKind(groupVersion)
+}
+
+func (d *delegateError[T, TList]) NamespaceScoped() bool {
+	return d.inner.NamespaceScoped()
+}
+
+func (d *delegateError[T, TList]) Kind() string {
+	return d.inner.Kind()
+}
+
+func (d *delegateError[T, TList]) GetSingularName() string {
+	return d.inner.GetSingularName()
+}
+
+func convertError(err error) error {
+	if _, ok := err.(errors.APIStatus); ok {
+		return err
+	}
+
+	return errors.NewInternalError(err)
+}