Add REST PrepareForUpdate() hook

As per discussion with @snmarterclayton.  I implemented this for most
types in the "obvious" way.  I am not sure how to implement
this for a couple types, though.

pkg/api/rest/types.go

@@ -66,6 +66,14 @@ func (svcStrategy) PrepareForCreate(obj runtime.Object) {
 	service.Status = api.ServiceStatus{}
 }
 
+// PrepareForUpdate clears fields that are not allowed to be set by end users on update.
+func (svcStrategy) PrepareForUpdate(obj, old runtime.Object) {
+	// TODO: once service has a status sub-resource we can enable this.
+	//newService := obj.(*api.Service)
+	//oldService := old.(*api.Service)
+	//newService.Status = oldService.Status
+}
+
 // Validate validates a new service.
 func (svcStrategy) Validate(obj runtime.Object) fielderrors.ValidationErrorList {
 	service := obj.(*api.Service)

pkg/api/rest/update.go

@@ -33,6 +33,10 @@ type RESTUpdateStrategy interface {
 	NamespaceScoped() bool
 	// AllowCreateOnUpdate returns true if the object can be created by a PUT.
 	AllowCreateOnUpdate() bool
+	// PrepareForUpdate is invoked on update before validation to normalize
+	// the object.  For example: remove fields that are not to be persisted,
+	// sort order-insensitive list fields, etc.
+	PrepareForUpdate(obj, old runtime.Object)
 	// ValidateUpdate is invoked after default fields in the object have been filled in before
 	// the object is persisted.
 	ValidateUpdate(obj, old runtime.Object) fielderrors.ValidationErrorList
@@ -53,6 +57,7 @@ func BeforeUpdate(strategy RESTUpdateStrategy, ctx api.Context, obj, old runtime
 	} else {
 		objectMeta.Namespace = api.NamespaceNone
 	}
+	strategy.PrepareForUpdate(obj, old)
 	if errs := strategy.ValidateUpdate(obj, old); len(errs) > 0 {
 		return errors.NewInvalid(kind, objectMeta.Name, errs)
 	}

pkg/registry/controller/rest.go

@@ -48,6 +48,14 @@ func (rcStrategy) PrepareForCreate(obj runtime.Object) {
 	controller.Status = api.ReplicationControllerStatus{}
 }
 
+// PrepareForUpdate clears fields that are not allowed to be set by end users on update.
+func (rcStrategy) PrepareForUpdate(obj, old runtime.Object) {
+	// TODO: once RC has a status sub-resource we can enable this.
+	//newController := obj.(*api.ReplicationController)
+	//oldController := old.(*api.ReplicationController)
+	//newController.Status = oldController.Status
+}
+
 // Validate validates a new replication controller.
 func (rcStrategy) Validate(obj runtime.Object) fielderrors.ValidationErrorList {
 	controller := obj.(*api.ReplicationController)

pkg/registry/endpoint/rest.go

@@ -48,6 +48,12 @@ func (endpointsStrategy) PrepareForCreate(obj runtime.Object) {
 	_ = obj.(*api.Endpoints)
 }
 
+// PrepareForUpdate clears fields that are not allowed to be set by end users on update.
+func (endpointsStrategy) PrepareForUpdate(obj, old runtime.Object) {
+	_ = obj.(*api.Endpoints)
+	_ = old.(*api.Endpoints)
+}
+
 // Validate validates a new endpoints.
 func (endpointsStrategy) Validate(obj runtime.Object) fielderrors.ValidationErrorList {
 	return validation.ValidateEndpoints(obj.(*api.Endpoints))

pkg/registry/generic/etcd/etcd_test.go

@@ -43,7 +43,8 @@ type testRESTStrategy struct {
 func (t *testRESTStrategy) NamespaceScoped() bool     { return t.namespaceScoped }
 func (t *testRESTStrategy) AllowCreateOnUpdate() bool { return t.allowCreateOnUpdate }
 
-func (t *testRESTStrategy) PrepareForCreate(obj runtime.Object) {}
+func (t *testRESTStrategy) PrepareForCreate(obj runtime.Object)      {}
+func (t *testRESTStrategy) PrepareForUpdate(obj, old runtime.Object) {}
 func (t *testRESTStrategy) Validate(obj runtime.Object) fielderrors.ValidationErrorList {
 	return nil
 }

pkg/registry/minion/rest.go

@@ -59,6 +59,13 @@ func (nodeStrategy) PrepareForCreate(obj runtime.Object) {
 	// Nodes allow *all* fields, including status, to be set.
 }
 
+// PrepareForUpdate clears fields that are not allowed to be set by end users on update.
+func (nodeStrategy) PrepareForUpdate(obj, old runtime.Object) {
+	_ = obj.(*api.Node)
+	_ = old.(*api.Node)
+	// Nodes allow *all* fields, including status, to be set.
+}
+
 // Validate validates a new node.
 func (nodeStrategy) Validate(obj runtime.Object) fielderrors.ValidationErrorList {
 	node := obj.(*api.Node)

pkg/registry/namespace/rest.go

@@ -68,6 +68,14 @@ func (namespaceStrategy) PrepareForCreate(obj runtime.Object) {
 	}
 }
 
+// PrepareForUpdate clears fields that are not allowed to be set by end users on update.
+func (namespaceStrategy) PrepareForUpdate(obj, old runtime.Object) {
+	newNamespace := obj.(*api.Namespace)
+	oldNamespace := old.(*api.Namespace)
+	newNamespace.Spec.Finalizers = oldNamespace.Spec.Finalizers
+	newNamespace.Status = oldNamespace.Status
+}
+
 // Validate validates a new namespace.
 func (namespaceStrategy) Validate(obj runtime.Object) fielderrors.ValidationErrorList {
 	namespace := obj.(*api.Namespace)
@@ -90,6 +98,12 @@ type namespaceStatusStrategy struct {
 
 var StatusStrategy = namespaceStatusStrategy{Strategy}
 
+func (namespaceStatusStrategy) PrepareForUpdate(obj, old runtime.Object) {
+	newNamespace := obj.(*api.Namespace)
+	oldNamespace := old.(*api.Namespace)
+	newNamespace.Spec = oldNamespace.Spec
+}
+
 func (namespaceStatusStrategy) ValidateUpdate(obj, old runtime.Object) fielderrors.ValidationErrorList {
 	return validation.ValidateNamespaceStatusUpdate(obj.(*api.Namespace), old.(*api.Namespace))
 }

pkg/registry/pod/rest.go

@@ -59,6 +59,13 @@ func (podStrategy) PrepareForCreate(obj runtime.Object) {
 	}
 }
 
+// PrepareForUpdate clears fields that are not allowed to be set by end users on update.
+func (podStrategy) PrepareForUpdate(obj, old runtime.Object) {
+	newPod := obj.(*api.Pod)
+	oldPod := old.(*api.Pod)
+	newPod.Status = oldPod.Status
+}
+
 // Validate validates a new pod.
 func (podStrategy) Validate(obj runtime.Object) fielderrors.ValidationErrorList {
 	pod := obj.(*api.Pod)
@@ -86,6 +93,12 @@ type podStatusStrategy struct {
 
 var StatusStrategy = podStatusStrategy{Strategy}
 
+func (podStatusStrategy) PrepareForUpdate(obj, old runtime.Object) {
+	newPod := obj.(*api.Pod)
+	oldPod := old.(*api.Pod)
+	newPod.Spec = oldPod.Spec
+}
+
 func (podStatusStrategy) ValidateUpdate(obj, old runtime.Object) fielderrors.ValidationErrorList {
 	// TODO: merge valid fields after update
 	return validation.ValidatePodStatusUpdate(obj.(*api.Pod), old.(*api.Pod))

pkg/registry/resourcequota/rest.go

@@ -49,6 +49,13 @@ func (resourcequotaStrategy) PrepareForCreate(obj runtime.Object) {
 	resourcequota.Status = api.ResourceQuotaStatus{}
 }
 
+// PrepareForUpdate clears fields that are not allowed to be set by end users on update.
+func (resourcequotaStrategy) PrepareForUpdate(obj, old runtime.Object) {
+	newResourcequota := obj.(*api.ResourceQuota)
+	oldResourcequota := old.(*api.ResourceQuota)
+	newResourcequota.Status = oldResourcequota.Status
+}
+
 // Validate validates a new resourcequota.
 func (resourcequotaStrategy) Validate(obj runtime.Object) fielderrors.ValidationErrorList {
 	resourcequota := obj.(*api.ResourceQuota)
@@ -71,6 +78,12 @@ type resourcequotaStatusStrategy struct {
 
 var StatusStrategy = resourcequotaStatusStrategy{Strategy}
 
+func (resourcequotaStatusStrategy) PrepareForUpdate(obj, old runtime.Object) {
+	newResourcequota := obj.(*api.ResourceQuota)
+	oldResourcequota := old.(*api.ResourceQuota)
+	newResourcequota.Spec = oldResourcequota.Spec
+}
+
 func (resourcequotaStatusStrategy) ValidateUpdate(obj, old runtime.Object) fielderrors.ValidationErrorList {
 	return validation.ValidateResourceQuotaStatusUpdate(obj.(*api.ResourceQuota), old.(*api.ResourceQuota))
 }