Add Validators for Scale Objects

This commit introduces a validator for use with Scale updates.
The validator checks that we have > 0 replica count, as well
as the normal ObjectMeta checks (some of which have to be
faked since they don't exist on the Scale object).

pkg/apis/extensions/validation/validation.go

@@ -564,3 +564,14 @@ func ValidatePodSelectorRequirement(sr extensions.PodSelectorRequirement) errs.V
 	allErrs = append(allErrs, apivalidation.ValidateLabelName(sr.Key, "key")...)
 	return allErrs
 }
+
+func ValidateScale(scale *extensions.Scale) errs.ValidationErrorList {
+	allErrs := errs.ValidationErrorList{}
+	allErrs = append(allErrs, apivalidation.ValidateObjectMeta(&scale.ObjectMeta, true, apivalidation.NameIsDNSSubdomain).Prefix("metadata")...)
+
+	if scale.Spec.Replicas < 0 {
+		allErrs = append(allErrs, errs.NewFieldInvalid("spec.replicas", scale.Spec.Replicas, "must be non-negative"))
+	}
+
+	return allErrs
+}

pkg/apis/extensions/validation/validation_test.go

@@ -1145,6 +1145,70 @@ func TestValidateClusterAutoscaler(t *testing.T) {
 	}
 }
 
+func TestValidateScale(t *testing.T) {
+	successCases := []extensions.Scale{
+		{
+			ObjectMeta: api.ObjectMeta{
+				Name:      "frontend",
+				Namespace: api.NamespaceDefault,
+			},
+			Spec: extensions.ScaleSpec{
+				Replicas: 1,
+			},
+		},
+		{
+			ObjectMeta: api.ObjectMeta{
+				Name:      "frontend",
+				Namespace: api.NamespaceDefault,
+			},
+			Spec: extensions.ScaleSpec{
+				Replicas: 10,
+			},
+		},
+		{
+			ObjectMeta: api.ObjectMeta{
+				Name:      "frontend",
+				Namespace: api.NamespaceDefault,
+			},
+			Spec: extensions.ScaleSpec{
+				Replicas: 0,
+			},
+		},
+	}
+
+	for _, successCase := range successCases {
+		if errs := ValidateScale(&successCase); len(errs) != 0 {
+			t.Errorf("expected success: %v", errs)
+		}
+	}
+
+	errorCases := []struct {
+		scale extensions.Scale
+		msg   string
+	}{
+		{
+			scale: extensions.Scale{
+				ObjectMeta: api.ObjectMeta{
+					Name:      "frontend",
+					Namespace: api.NamespaceDefault,
+				},
+				Spec: extensions.ScaleSpec{
+					Replicas: -1,
+				},
+			},
+			msg: "must be non-negative",
+		},
+	}
+
+	for _, c := range errorCases {
+		if errs := ValidateScale(&c.scale); len(errs) == 0 {
+			t.Errorf("expected failure for %s", c.msg)
+		} else if !strings.Contains(errs[0].Error(), c.msg) {
+			t.Errorf("unexpected error: %v, expected: %s", errs[0], c.msg)
+		}
+	}
+}
+
 func newInt(val int) *int {
 	p := new(int)
 	*p = val

pkg/registry/deployment/etcd/etcd.go

@@ -30,6 +30,8 @@ import (
 	etcdgeneric "k8s.io/kubernetes/pkg/registry/generic/etcd"
 	"k8s.io/kubernetes/pkg/runtime"
 	"k8s.io/kubernetes/pkg/storage"
+
+	extvalidation "k8s.io/kubernetes/pkg/apis/extensions/validation"
 )
 
 // DeploymentStorage includes dummy storage for Deployments and for Scale subresource.
@@ -149,6 +151,11 @@ func (r *ScaleREST) Update(ctx api.Context, obj runtime.Object) (runtime.Object,
 	if !ok {
 		return nil, false, errors.NewBadRequest(fmt.Sprintf("wrong object passed to Scale update: %v", obj))
 	}
+
+	if errs := extvalidation.ValidateScale(scale); len(errs) > 0 {
+		return nil, false, errors.NewInvalid("scale", scale.Name, errs)
+	}
+
 	deployment, err := (*r.registry).GetDeployment(ctx, scale.Name)
 	if err != nil {
 		return nil, false, errors.NewNotFound("scale", scale.Name)

pkg/registry/experimental/controller/etcd/etcd.go

@@ -29,6 +29,8 @@ import (
 	"k8s.io/kubernetes/pkg/registry/controller/etcd"
 
 	"k8s.io/kubernetes/pkg/apis/extensions"
+
+	extvalidation "k8s.io/kubernetes/pkg/apis/extensions/validation"
 )
 
 // Container includes dummy storage for RC pods and experimental storage for Scale.
@@ -89,6 +91,11 @@ func (r *ScaleREST) Update(ctx api.Context, obj runtime.Object) (runtime.Object,
 	if !ok {
 		return nil, false, errors.NewBadRequest(fmt.Sprintf("wrong object passed to Scale update: %v", obj))
 	}
+
+	if errs := extvalidation.ValidateScale(scale); len(errs) > 0 {
+		return nil, false, errors.NewInvalid("scale", scale.Name, errs)
+	}
+
 	rc, err := (*r.registry).GetController(ctx, scale.Name)
 	if err != nil {
 		return nil, false, errors.NewNotFound("scale", scale.Name)