Validation of HPA custom metrics annotation

pkg/apis/extensions/validation/validation.go

@@ -17,6 +17,7 @@ limitations under the License.
 package validation
 
 import (
+	"encoding/json"
 	"net"
 	"regexp"
 	"strconv"
@@ -25,6 +26,7 @@ import (
 	"k8s.io/kubernetes/pkg/api"
 	apivalidation "k8s.io/kubernetes/pkg/api/validation"
 	"k8s.io/kubernetes/pkg/apis/extensions"
+	"k8s.io/kubernetes/pkg/controller/podautoscaler"
 	"k8s.io/kubernetes/pkg/labels"
 	"k8s.io/kubernetes/pkg/util/intstr"
 	"k8s.io/kubernetes/pkg/util/sets"
@@ -83,9 +85,34 @@ func ValidateSubresourceReference(ref extensions.SubresourceReference, fldPath *
 	return allErrs
 }
 
+func validateHorizontalPodAutoscalerAnnotations(annotations map[string]string, fldPath *field.Path) field.ErrorList {
+	allErrs := field.ErrorList{}
+	if annotationValue, found := annotations[podautoscaler.HpaCustomMetricsTargetAnnotationName]; found {
+		// Try to parse the annotation
+		var targetList extensions.CustomMetricTargetList
+		if err := json.Unmarshal([]byte(annotationValue), &targetList); err != nil {
+			allErrs = append(allErrs, field.Invalid(fldPath.Child("annotations"), annotations, "failed to parse custom metrics target annotation"))
+		} else {
+			if len(targetList.Items) == 0 {
+				allErrs = append(allErrs, field.Required(fldPath.Child("annotations", "items"), "custom metrics target must not be empty"))
+			}
+			for _, target := range targetList.Items {
+				if target.Name == "" {
+					allErrs = append(allErrs, field.Required(fldPath.Child("annotations", "items", "name"), "missing custom metric target name"))
+				}
+				if target.TargetValue.MilliValue() <= 0 {
+					allErrs = append(allErrs, field.Invalid(fldPath.Child("annotations", "items", "value"), target.TargetValue, "custom metric target value must be greater than 0"))
+				}
+			}
+		}
+	}
+	return allErrs
+}
+
 func ValidateHorizontalPodAutoscaler(autoscaler *extensions.HorizontalPodAutoscaler) field.ErrorList {
 	allErrs := apivalidation.ValidateObjectMeta(&autoscaler.ObjectMeta, true, ValidateHorizontalPodAutoscalerName, field.NewPath("metadata"))
 	allErrs = append(allErrs, validateHorizontalPodAutoscalerSpec(autoscaler.Spec, field.NewPath("spec"))...)
+	allErrs = append(allErrs, validateHorizontalPodAutoscalerAnnotations(autoscaler.Annotations, field.NewPath("metadata"))...)
 	return allErrs
 }
 

pkg/apis/extensions/validation/validation_test.go

@@ -23,6 +23,7 @@ import (
 
 	"k8s.io/kubernetes/pkg/api"
 	"k8s.io/kubernetes/pkg/apis/extensions"
+	"k8s.io/kubernetes/pkg/controller/podautoscaler"
 	"k8s.io/kubernetes/pkg/util/intstr"
 )
 
@@ -59,6 +60,24 @@ func TestValidateHorizontalPodAutoscaler(t *testing.T) {
 				MaxReplicas: 5,
 			},
 		},
+		{
+			ObjectMeta: api.ObjectMeta{
+				Name:      "myautoscaler",
+				Namespace: api.NamespaceDefault,
+				Annotations: map[string]string{
+					podautoscaler.HpaCustomMetricsTargetAnnotationName: "{\"items\":[{\"name\":\"qps\",\"value\":\"20\"}]}",
+				},
+			},
+			Spec: extensions.HorizontalPodAutoscalerSpec{
+				ScaleRef: extensions.SubresourceReference{
+					Kind:        "ReplicationController",
+					Name:        "myrc",
+					Subresource: "scale",
+				},
+				MinReplicas: newInt(1),
+				MaxReplicas: 5,
+			},
+		},
 	}
 	for _, successCase := range successCases {
 		if errs := ValidateHorizontalPodAutoscaler(&successCase); len(errs) != 0 {
@@ -203,6 +222,90 @@ func TestValidateHorizontalPodAutoscaler(t *testing.T) {
 			},
 			msg: "must be greater than 0",
 		},
+		{
+			horizontalPodAutoscaler: extensions.HorizontalPodAutoscaler{
+				ObjectMeta: api.ObjectMeta{
+					Name:      "myautoscaler",
+					Namespace: api.NamespaceDefault,
+					Annotations: map[string]string{
+						podautoscaler.HpaCustomMetricsTargetAnnotationName: "broken",
+					},
+				},
+				Spec: extensions.HorizontalPodAutoscalerSpec{
+					ScaleRef: extensions.SubresourceReference{
+						Kind:        "ReplicationController",
+						Name:        "myrc",
+						Subresource: "scale",
+					},
+					MinReplicas: newInt(1),
+					MaxReplicas: 5,
+				},
+			},
+			msg: "failed to parse custom metrics target annotation",
+		},
+		{
+			horizontalPodAutoscaler: extensions.HorizontalPodAutoscaler{
+				ObjectMeta: api.ObjectMeta{
+					Name:      "myautoscaler",
+					Namespace: api.NamespaceDefault,
+					Annotations: map[string]string{
+						podautoscaler.HpaCustomMetricsTargetAnnotationName: "{}",
+					},
+				},
+				Spec: extensions.HorizontalPodAutoscalerSpec{
+					ScaleRef: extensions.SubresourceReference{
+						Kind:        "ReplicationController",
+						Name:        "myrc",
+						Subresource: "scale",
+					},
+					MinReplicas: newInt(1),
+					MaxReplicas: 5,
+				},
+			},
+			msg: "custom metrics target must not be empty",
+		},
+		{
+			horizontalPodAutoscaler: extensions.HorizontalPodAutoscaler{
+				ObjectMeta: api.ObjectMeta{
+					Name:      "myautoscaler",
+					Namespace: api.NamespaceDefault,
+					Annotations: map[string]string{
+						podautoscaler.HpaCustomMetricsTargetAnnotationName: "{\"items\":[{\"value\":\"20\"}]}",
+					},
+				},
+				Spec: extensions.HorizontalPodAutoscalerSpec{
+					ScaleRef: extensions.SubresourceReference{
+						Kind:        "ReplicationController",
+						Name:        "myrc",
+						Subresource: "scale",
+					},
+					MinReplicas: newInt(1),
+					MaxReplicas: 5,
+				},
+			},
+			msg: "missing custom metric target name",
+		},
+		{
+			horizontalPodAutoscaler: extensions.HorizontalPodAutoscaler{
+				ObjectMeta: api.ObjectMeta{
+					Name:      "myautoscaler",
+					Namespace: api.NamespaceDefault,
+					Annotations: map[string]string{
+						podautoscaler.HpaCustomMetricsTargetAnnotationName: "{\"items\":[{\"name\":\"qps\",\"value\":\"0\"}]}",
+					},
+				},
+				Spec: extensions.HorizontalPodAutoscalerSpec{
+					ScaleRef: extensions.SubresourceReference{
+						Kind:        "ReplicationController",
+						Name:        "myrc",
+						Subresource: "scale",
+					},
+					MinReplicas: newInt(1),
+					MaxReplicas: 5,
+				},
+			},
+			msg: "custom metric target value must be greater than 0",
+		},
 	}
 
 	for _, c := range errorCases {

pkg/controller/podautoscaler/horizontal.go

@@ -39,7 +39,7 @@ const (
 	// TODO: make it a flag or HPA spec element.
 	tolerance = 0.1
 
-	HpaCustomMetricsDefinitionAnnotationName = "alpha/definiton.custom-metrics.podautoscaler.kubernetes.io"
+	HpaCustomMetricsTargetAnnotationName = "alpha/target.custom-metrics.podautoscaler.kubernetes.io"
 	HpaCustomMetricsStatusAnnotationName = "alpha/status.custom-metrics.podautoscaler.kubernetes.io"
 )
 
@@ -190,7 +190,7 @@ func (a *HorizontalController) reconcileAutoscaler(hpa extensions.HorizontalPodA
 		}
 	}
 
-	if cmAnnotation, cmAnnotationFound := hpa.Annotations[HpaCustomMetricsDefinitionAnnotationName]; cmAnnotationFound {
+	if cmAnnotation, cmAnnotationFound := hpa.Annotations[HpaCustomMetricsTargetAnnotationName]; cmAnnotationFound {
 		cmDesiredReplicas, cmStatus, cmTimestamp, err = a.computeReplicasForCustomMetrics(hpa, scale, cmAnnotation)
 		if err != nil {
 			a.eventRecorder.Event(&hpa, api.EventTypeWarning, "FailedComputeCMReplicas", err.Error())

pkg/controller/podautoscaler/horizontal_test.go

@@ -110,7 +110,7 @@ func (tc *testCase) prepareTestClient(t *testing.T) *fake.Clientset {
 				t.Fatalf("Failed to marshal cm: %v", err)
 			}
 			obj.Items[0].Annotations = make(map[string]string)
-			obj.Items[0].Annotations[HpaCustomMetricsDefinitionAnnotationName] = string(b)
+			obj.Items[0].Annotations[HpaCustomMetricsTargetAnnotationName] = string(b)
 		}
 		return true, obj, nil
 	})