remove unwanted values returned from dry-run

Remove the uid and the resourceVersion from dry-run results per kep 576

https://github.com/kubernetes/enhancements/blob/master/keps/sig-api-machinery/576-dry-run/README.md#generated-values

staging/src/k8s.io/apiserver/pkg/registry/generic/registry/store.go

@@ -433,6 +433,11 @@ func (e *Store) Create(ctx context.Context, obj runtime.Object, createValidation
 	if e.Decorator != nil {
 		e.Decorator(out)
 	}
+	if dryrun.IsDryRun(options.DryRun) {
+		if err := dryrun.ResetMetadata(obj, out); err != nil {
+			return nil, err
+		}
+	}
 	return out, nil
 }
 

staging/src/k8s.io/apiserver/pkg/util/dryrun/dryrun.go

@@ -16,7 +16,41 @@ limitations under the License.
 
 package dryrun
 
+import (
+	"k8s.io/apimachinery/pkg/api/errors"
+	"k8s.io/apimachinery/pkg/api/meta"
+	"k8s.io/apimachinery/pkg/runtime"
+)
+
 // IsDryRun returns true if the DryRun flag is an actual dry-run.
 func IsDryRun(flag []string) bool {
 	return len(flag) > 0
 }
+
+// ResetMetadata resets metadata fields that are not allowed to be set by dry-run.
+func ResetMetadata(originalObj, newObj runtime.Object) error {
+	originalObjMeta, err := meta.Accessor(originalObj)
+	if err != nil {
+		return errors.NewInternalError(err)
+	}
+	newObjMeta, err := meta.Accessor(newObj)
+	if err != nil {
+		return errors.NewInternalError(err)
+	}
+	// If a resource is created with dry-run enabled where generateName is set, the
+	// store will set the name to the generated name. We need to reset the name and restore
+	// the generateName metadata fields in order for the returned object to match the intent
+	// of the original template.
+	if originalObjMeta.GetGenerateName() != "" {
+		newObjMeta.SetName("")
+	}
+	newObjMeta.SetGenerateName(originalObjMeta.GetGenerateName())
+	// If UID is set in the dry-run output then that output cannot be used to create a resource. Reset
+	// the UID to allow the output to be used to create resources.
+	newObjMeta.SetUID("")
+	// If the resourceVersion is set in the dry-run output then that output cannot be used to create
+	// a resource. Reset the resourceVersion to allow the output to be used to create resources.
+	newObjMeta.SetResourceVersion("")
+
+	return nil
+}

test/integration/dryrun/dryrun_test.go

@@ -18,6 +18,7 @@ package dryrun
 
 import (
 	"context"
+	"strings"
 	"testing"
 
 	v1 "k8s.io/api/core/v1"
@@ -47,7 +48,11 @@ var kindAllowList = sets.NewString()
 const testNamespace = "dryrunnamespace"
 
 func DryRunCreateWithGenerateNameTest(t *testing.T, rsc dynamic.ResourceInterface, obj *unstructured.Unstructured, gvResource schema.GroupVersionResource) {
-	// Create a new object with generateName
+	// special resources with dots in the name cannot use generateName
+	if strings.Contains(obj.GetName(), ".") {
+		return
+	}
+	// Create a new object with generateName to ensure we don't taint the original object
 	gnObj := obj.DeepCopy()
 	gnObj.SetGenerateName(obj.GetName() + "-")
 	gnObj.SetName("")
@@ -74,8 +79,11 @@ func DryRunCreateTest(t *testing.T, rsc dynamic.ResourceInterface, obj *unstruct
 		t.Fatalf("created object's name should be an empty string if using GenerateName: %v", createdObj)
 	}
 
+	// we won't have a generated name here, so we won't check for this case
+	if obj.GetGenerateName() == "" {
 		if _, err := rsc.Get(context.TODO(), obj.GetName(), metav1.GetOptions{}); !apierrors.IsNotFound(err) {
-		t.Fatalf("object shouldn't exist: %v", err)
+			t.Fatalf("object shouldn't exist: %v, %v", obj, err)
+		}
 	}
 }