Define the new Scale type in the autoscaling API group.

This new Scale type supports the more powerful set-based label selector
semantics. The selector, however, is stored in a serialized format, as
a string.

pkg/apis/autoscaling/register.go

@@ -47,8 +47,11 @@ func AddToScheme(scheme *runtime.Scheme) {
 // Adds the list of known types to api.Scheme.
 func addKnownTypes(scheme *runtime.Scheme) {
 	scheme.AddKnownTypes(SchemeGroupVersion,
+		&Scale{},
 		&extensions.HorizontalPodAutoscaler{},
 		&extensions.HorizontalPodAutoscalerList{},
 		&api.ListOptions{},
 	)
 }
+
+func (obj *Scale) GetObjectKind() unversioned.ObjectKind { return &obj.TypeMeta }

pkg/apis/autoscaling/types.go

@@ -0,0 +1,53 @@
+/*
+Copyright 2016 The Kubernetes Authors All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package autoscaling
+
+import (
+	"k8s.io/kubernetes/pkg/api"
+	"k8s.io/kubernetes/pkg/api/unversioned"
+)
+
+// Scale represents a scaling request for a resource.
+type Scale struct {
+	unversioned.TypeMeta `json:",inline"`
+	// Standard object metadata; More info: http://releases.k8s.io/HEAD/docs/devel/api-conventions.md#metadata.
+	api.ObjectMeta `json:"metadata,omitempty"`
+
+	// defines the behavior of the scale. More info: http://releases.k8s.io/HEAD/docs/devel/api-conventions.md#spec-and-status.
+	Spec ScaleSpec `json:"spec,omitempty"`
+
+	// current status of the scale. More info: http://releases.k8s.io/HEAD/docs/devel/api-conventions.md#spec-and-status. Read-only.
+	Status ScaleStatus `json:"status,omitempty"`
+}
+
+// ScaleSpec describes the attributes of a scale subresource.
+type ScaleSpec struct {
+	// desired number of instances for the scaled object.
+	Replicas int `json:"replicas,omitempty"`
+}
+
+// ScaleStatus represents the current status of a scale subresource.
+type ScaleStatus struct {
+	// actual number of observed instances of the scaled object.
+	Replicas int `json:"replicas"`
+
+	// label query over pods that should match the replicas count. This is same
+	// as the label selector but in the string format to avoid introspection
+	// by clients. The string will be in the same format as the query-param syntax.
+	// More info: http://releases.k8s.io/HEAD/docs/user-guide/labels.md#label-selectors
+	Selector string `json:"selector,omitempty"`
+}

pkg/apis/autoscaling/v1/register.go

@@ -39,9 +39,11 @@ func addKnownTypes(scheme *runtime.Scheme) {
 	scheme.AddKnownTypes(SchemeGroupVersion,
 		&HorizontalPodAutoscaler{},
 		&HorizontalPodAutoscalerList{},
+		&Scale{},
 		&v1.ListOptions{},
 	)
 }
 
 func (obj *HorizontalPodAutoscaler) GetObjectKind() unversioned.ObjectKind     { return &obj.TypeMeta }
 func (obj *HorizontalPodAutoscalerList) GetObjectKind() unversioned.ObjectKind { return &obj.TypeMeta }
+func (obj *Scale) GetObjectKind() unversioned.ObjectKind                       { return &obj.TypeMeta }

pkg/apis/autoscaling/v1/types.go

@@ -86,3 +86,34 @@ type HorizontalPodAutoscalerList struct {
 	// list of horizontal pod autoscaler objects.
 	Items []HorizontalPodAutoscaler `json:"items"`
 }
+
+// Scale represents a scaling request for a resource.
+type Scale struct {
+	unversioned.TypeMeta `json:",inline"`
+	// Standard object metadata; More info: http://releases.k8s.io/HEAD/docs/devel/api-conventions.md#metadata.
+	v1.ObjectMeta `json:"metadata,omitempty"`
+
+	// defines the behavior of the scale. More info: http://releases.k8s.io/HEAD/docs/devel/api-conventions.md#spec-and-status.
+	Spec ScaleSpec `json:"spec,omitempty"`
+
+	// current status of the scale. More info: http://releases.k8s.io/HEAD/docs/devel/api-conventions.md#spec-and-status. Read-only.
+	Status ScaleStatus `json:"status,omitempty"`
+}
+
+// ScaleSpec describes the attributes of a scale subresource.
+type ScaleSpec struct {
+	// desired number of instances for the scaled object.
+	Replicas int32 `json:"replicas,omitempty"`
+}
+
+// ScaleStatus represents the current status of a scale subresource.
+type ScaleStatus struct {
+	// actual number of observed instances of the scaled object.
+	Replicas int32 `json:"replicas"`
+
+	// label query over pods that should match the replicas count. This is same
+	// as the label selector but in the string format to avoid introspection
+	// by clients. The string will be in the same format as the query-param syntax.
+	// More info about label selectors: http://releases.k8s.io/HEAD/docs/user-guide/labels.md#label-selectors
+	Selector string `json:"selector,omitempty"`
+}

pkg/apis/autoscaling/validation/validation.go

@@ -0,0 +1,34 @@
+/*
+Copyright 2016 The Kubernetes Authors All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package validation
+
+import (
+	apivalidation "k8s.io/kubernetes/pkg/api/validation"
+	"k8s.io/kubernetes/pkg/apis/autoscaling"
+	"k8s.io/kubernetes/pkg/util/validation/field"
+)
+
+func ValidateScale(scale *autoscaling.Scale) field.ErrorList {
+	allErrs := field.ErrorList{}
+	allErrs = append(allErrs, apivalidation.ValidateObjectMeta(&scale.ObjectMeta, true, apivalidation.NameIsDNSSubdomain, field.NewPath("metadata"))...)
+
+	if scale.Spec.Replicas < 0 {
+		allErrs = append(allErrs, field.Invalid(field.NewPath("spec", "replicas"), scale.Spec.Replicas, "must be greater than or equal to 0"))
+	}
+
+	return allErrs
+}

pkg/apis/autoscaling/validation/validation_test.go

@@ -0,0 +1,89 @@
+/*
+Copyright 2016 The Kubernetes Authors All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package validation
+
+import (
+	"strings"
+	"testing"
+
+	"k8s.io/kubernetes/pkg/api"
+	"k8s.io/kubernetes/pkg/apis/autoscaling"
+)
+
+func TestValidateScale(t *testing.T) {
+	successCases := []autoscaling.Scale{
+		{
+			ObjectMeta: api.ObjectMeta{
+				Name:      "frontend",
+				Namespace: api.NamespaceDefault,
+			},
+			Spec: autoscaling.ScaleSpec{
+				Replicas: 1,
+			},
+		},
+		{
+			ObjectMeta: api.ObjectMeta{
+				Name:      "frontend",
+				Namespace: api.NamespaceDefault,
+			},
+			Spec: autoscaling.ScaleSpec{
+				Replicas: 10,
+			},
+		},
+		{
+			ObjectMeta: api.ObjectMeta{
+				Name:      "frontend",
+				Namespace: api.NamespaceDefault,
+			},
+			Spec: autoscaling.ScaleSpec{
+				Replicas: 0,
+			},
+		},
+	}
+
+	for _, successCase := range successCases {
+		if errs := ValidateScale(&successCase); len(errs) != 0 {
+			t.Errorf("expected success: %v", errs)
+		}
+	}
+
+	errorCases := []struct {
+		scale autoscaling.Scale
+		msg   string
+	}{
+		{
+			scale: autoscaling.Scale{
+				ObjectMeta: api.ObjectMeta{
+					Name:      "frontend",
+					Namespace: api.NamespaceDefault,
+				},
+				Spec: autoscaling.ScaleSpec{
+					Replicas: -1,
+				},
+			},
+			msg: "must be greater than or equal to 0",
+		},
+	}
+
+	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)
+		}
+	}
+}