storage: Move precondition check as a method of preconditions

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

@@ -18,9 +18,7 @@ package registry
 
 import (
 	"context"
-	"fmt"
 
-	"k8s.io/apimachinery/pkg/api/meta"
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/watch"
 	"k8s.io/apiserver/pkg/storage"
@@ -51,7 +49,7 @@ func (s *DryRunnableStorage) Delete(ctx context.Context, key string, out runtime
 		if err := s.Storage.Get(ctx, key, "", out, false); err != nil {
 			return err
 		}
-		return checkPreconditions(key, preconditions, out)
+		return preconditions.Check(key, out)
 	}
 	return s.Storage.Delete(ctx, key, out, preconditions)
 }
@@ -84,7 +82,7 @@ func (s *DryRunnableStorage) GuaranteedUpdate(
 		if err != nil {
 			return err
 		}
-		err = checkPreconditions(key, preconditions, ptrToType)
+		err = preconditions.Check(key, ptrToType)
 		if err != nil {
 			return err
 		}
@@ -103,21 +101,6 @@ func (s *DryRunnableStorage) Count(key string) (int64, error) {
 	return s.Storage.Count(key)
 }
 
-func checkPreconditions(key string, preconditions *storage.Preconditions, obj runtime.Object) error {
-	if preconditions == nil {
-		return nil
-	}
-	objMeta, err := meta.Accessor(obj)
-	if err != nil {
-		return storage.NewInternalErrorf("can't enforce preconditions %v on un-introspectable object %v, got error: %v", *preconditions, obj, err)
-	}
-	if preconditions.UID != nil && *preconditions.UID != objMeta.GetUID() {
-		errMsg := fmt.Sprintf("Precondition failed: UID in precondition: %v, UID in object meta: %v", *preconditions.UID, objMeta.GetUID())
-		return storage.NewInvalidObjError(key, errMsg)
-	}
-	return nil
-}
-
 func (s *DryRunnableStorage) copyInto(in, out runtime.Object) error {
 	var data []byte
 

staging/src/k8s.io/apiserver/pkg/storage/etcd/etcd_helper.go

@@ -153,21 +153,6 @@ func (h *etcdHelper) Create(ctx context.Context, key string, obj, out runtime.Ob
 	return err
 }
 
-func checkPreconditions(key string, preconditions *storage.Preconditions, out runtime.Object) error {
-	if preconditions == nil {
-		return nil
-	}
-	objMeta, err := meta.Accessor(out)
-	if err != nil {
-		return storage.NewInternalErrorf("can't enforce preconditions %v on un-introspectable object %v, got error: %v", *preconditions, out, err)
-	}
-	if preconditions.UID != nil && *preconditions.UID != objMeta.GetUID() {
-		errMsg := fmt.Sprintf("Precondition failed: UID in precondition: %v, UID in object meta: %v", preconditions.UID, objMeta.GetUID())
-		return storage.NewInvalidObjError(key, errMsg)
-	}
-	return nil
-}
-
 // Implements storage.Interface.
 func (h *etcdHelper) Delete(ctx context.Context, key string, out runtime.Object, preconditions *storage.Preconditions) error {
 	if ctx == nil {
@@ -199,7 +184,7 @@ func (h *etcdHelper) Delete(ctx context.Context, key string, out runtime.Object,
 		if err != nil {
 			return toStorageErr(err, key, 0)
 		}
-		if err := checkPreconditions(key, preconditions, obj); err != nil {
+		if err := preconditions.Check(key, obj); err != nil {
 			return toStorageErr(err, key, 0)
 		}
 		index := uint64(0)
@@ -493,7 +478,7 @@ func (h *etcdHelper) GuaranteedUpdate(
 		if err != nil {
 			return toStorageErr(err, key, 0)
 		}
-		if err := checkPreconditions(key, preconditions, obj); err != nil {
+		if err := preconditions.Check(key, obj); err != nil {
 			return toStorageErr(err, key, 0)
 		}
 		meta := storage.ResponseMeta{}

staging/src/k8s.io/apiserver/pkg/storage/etcd3/store.go

@@ -233,7 +233,7 @@ func (s *store) conditionalDelete(ctx context.Context, key string, out runtime.O
 		if err != nil {
 			return err
 		}
-		if err := checkPreconditions(key, preconditions, origState.obj); err != nil {
+		if err := preconditions.Check(key, origState.obj); err != nil {
 			return err
 		}
 		txnResp, err := s.client.KV.Txn(ctx).If(
@@ -294,7 +294,7 @@ func (s *store) GuaranteedUpdate(
 
 	transformContext := authenticatedDataString(key)
 	for {
-		if err := checkPreconditions(key, preconditions, origState.obj); err != nil {
+		if err := preconditions.Check(key, origState.obj); err != nil {
 			return err
 		}
 
@@ -791,21 +791,6 @@ func appendListItem(v reflect.Value, data []byte, rev uint64, pred storage.Selec
 	return nil
 }
 
-func checkPreconditions(key string, preconditions *storage.Preconditions, out runtime.Object) error {
-	if preconditions == nil {
-		return nil
-	}
-	objMeta, err := meta.Accessor(out)
-	if err != nil {
-		return storage.NewInternalErrorf("can't enforce preconditions %v on un-introspectable object %v, got error: %v", *preconditions, out, err)
-	}
-	if preconditions.UID != nil && *preconditions.UID != objMeta.GetUID() {
-		errMsg := fmt.Sprintf("Precondition failed: UID in precondition: %v, UID in object meta: %v", *preconditions.UID, objMeta.GetUID())
-		return storage.NewInvalidObjError(key, errMsg)
-	}
-	return nil
-}
-
 func notFound(key string) clientv3.Cmp {
 	return clientv3.Compare(clientv3.ModRevision(key), "=", 0)
 }

staging/src/k8s.io/apiserver/pkg/storage/interfaces.go

@@ -18,7 +18,9 @@ package storage
 
 import (
 	"context"
+	"fmt"
 
+	"k8s.io/apimachinery/pkg/api/meta"
 	"k8s.io/apimachinery/pkg/fields"
 	"k8s.io/apimachinery/pkg/labels"
 	"k8s.io/apimachinery/pkg/runtime"
@@ -106,6 +108,29 @@ func NewUIDPreconditions(uid string) *Preconditions {
 	return &Preconditions{UID: &u}
 }
 
+func (p *Preconditions) Check(key string, obj runtime.Object) error {
+	if p == nil {
+		return nil
+	}
+	objMeta, err := meta.Accessor(obj)
+	if err != nil {
+		return NewInternalErrorf(
+			"can't enforce preconditions %v on un-introspectable object %v, got error: %v",
+			*p,
+			obj,
+			err)
+	}
+	if p.UID != nil && *p.UID != objMeta.GetUID() {
+		err := fmt.Sprintf(
+			"Precondition failed: UID in precondition: %v, UID in object meta: %v",
+			*p.UID,
+			objMeta.GetUID())
+		return NewInvalidObjError(key, err)
+	}
+	return nil
+
+}
+
 // Interface offers a common interface for object marshaling/unmarshaling operations and
 // hides all the storage-related operations behind it.
 type Interface interface {