Make HPA controller use polymorphic scale client

cmd/kube-controller-manager/app/BUILD

@@ -124,6 +124,7 @@ go_library(
         "//vendor/k8s.io/client-go/kubernetes:go_default_library",
         "//vendor/k8s.io/client-go/kubernetes/typed/core/v1:go_default_library",
         "//vendor/k8s.io/client-go/rest:go_default_library",
+        "//vendor/k8s.io/client-go/scale:go_default_library",
         "//vendor/k8s.io/client-go/tools/clientcmd:go_default_library",
         "//vendor/k8s.io/client-go/tools/leaderelection:go_default_library",
         "//vendor/k8s.io/client-go/tools/leaderelection/resourcelock:go_default_library",

cmd/kube-controller-manager/app/autoscaling.go

@@ -21,7 +21,12 @@ limitations under the License.
 package app
 
 import (
+	apimeta "k8s.io/apimachinery/pkg/api/meta"
 	"k8s.io/apimachinery/pkg/runtime/schema"
+	"k8s.io/client-go/discovery"
+	discocache "k8s.io/client-go/discovery/cached" // Saturday Night Fever
+	"k8s.io/client-go/dynamic"
+	"k8s.io/client-go/scale"
 	"k8s.io/kubernetes/pkg/controller/podautoscaler"
 	"k8s.io/kubernetes/pkg/controller/podautoscaler/metrics"
 	resourceclient "k8s.io/metrics/pkg/client/clientset_generated/clientset/typed/metrics/v1beta1"
@@ -63,16 +68,33 @@ func startHPAControllerWithLegacyClient(ctx ControllerContext) (bool, error) {
 }
 
 func startHPAControllerWithMetricsClient(ctx ControllerContext, metricsClient metrics.MetricsClient) (bool, error) {
+	hpaClientGoClient := ctx.ClientBuilder.ClientGoClientOrDie("horizontal-pod-autoscaler")
 	hpaClient := ctx.ClientBuilder.ClientOrDie("horizontal-pod-autoscaler")
+	hpaClientConfig := ctx.ClientBuilder.ConfigOrDie("horizontal-pod-autoscaler")
+
+	// TODO: we need something like deferred discovery REST mapper that calls invalidate
+	// on cache misses.
+	cachedDiscovery := discocache.NewMemCacheClient(hpaClientGoClient.Discovery())
+	restMapper := discovery.NewDeferredDiscoveryRESTMapper(cachedDiscovery, apimeta.InterfacesForUnstructured)
+	restMapper.Reset()
+	// we don't use cached discovery because DiscoveryScaleKindResolver does its own caching,
+	// so we want to re-fetch every time when we actually ask for it
+	scaleKindResolver := scale.NewDiscoveryScaleKindResolver(hpaClientGoClient.Discovery())
+	scaleClient, err := scale.NewForConfig(hpaClientConfig, restMapper, dynamic.LegacyAPIPathResolverFunc, scaleKindResolver)
+	if err != nil {
+		return false, err
+	}
+
 	replicaCalc := podautoscaler.NewReplicaCalculator(
 		metricsClient,
 		hpaClient.Core(),
 		ctx.Options.HorizontalPodAutoscalerTolerance,
 	)
 	go podautoscaler.NewHorizontalController(
-		ctx.ClientBuilder.ClientGoClientOrDie("horizontal-pod-autoscaler").Core(),
-		hpaClient.Extensions(),
+		hpaClientGoClient.Core(),
+		scaleClient,
 		hpaClient.Autoscaling(),
+		restMapper,
 		replicaCalc,
 		ctx.InformerFactory.Autoscaling().V1().HorizontalPodAutoscalers(),
 		ctx.Options.HorizontalPodAutoscalerSyncPeriod.Duration,

pkg/apis/extensions/fuzzer/BUILD

@@ -12,7 +12,6 @@ go_library(
     deps = [
         "//pkg/apis/extensions:go_default_library",
         "//vendor/github.com/google/gofuzz:go_default_library",
-        "//vendor/k8s.io/apimachinery/pkg/apis/meta/v1:go_default_library",
         "//vendor/k8s.io/apimachinery/pkg/runtime/serializer:go_default_library",
         "//vendor/k8s.io/apimachinery/pkg/util/intstr:go_default_library",
     ],

pkg/controller/podautoscaler/BUILD

@@ -24,9 +24,9 @@ go_library(
         "//vendor/k8s.io/api/autoscaling/v1:go_default_library",
         "//vendor/k8s.io/api/autoscaling/v2beta1:go_default_library",
         "//vendor/k8s.io/api/core/v1:go_default_library",
-        "//vendor/k8s.io/api/extensions/v1beta1:go_default_library",
         "//vendor/k8s.io/apimachinery/pkg/api/equality:go_default_library",
         "//vendor/k8s.io/apimachinery/pkg/api/errors:go_default_library",
+        "//vendor/k8s.io/apimachinery/pkg/api/meta:go_default_library",
         "//vendor/k8s.io/apimachinery/pkg/api/resource:go_default_library",
         "//vendor/k8s.io/apimachinery/pkg/apis/meta/v1:go_default_library",
         "//vendor/k8s.io/apimachinery/pkg/labels:go_default_library",
@@ -39,8 +39,8 @@ go_library(
         "//vendor/k8s.io/client-go/kubernetes/scheme:go_default_library",
         "//vendor/k8s.io/client-go/kubernetes/typed/autoscaling/v1:go_default_library",
         "//vendor/k8s.io/client-go/kubernetes/typed/core/v1:go_default_library",
-        "//vendor/k8s.io/client-go/kubernetes/typed/extensions/v1beta1:go_default_library",
         "//vendor/k8s.io/client-go/listers/autoscaling/v1:go_default_library",
+        "//vendor/k8s.io/client-go/scale:go_default_library",
         "//vendor/k8s.io/client-go/tools/cache:go_default_library",
         "//vendor/k8s.io/client-go/tools/record:go_default_library",
         "//vendor/k8s.io/client-go/util/workqueue:go_default_library",
@@ -58,6 +58,7 @@ go_test(
     importpath = "k8s.io/kubernetes/pkg/controller/podautoscaler",
     library = ":go_default_library",
     deps = [
+        "//pkg/api/install:go_default_library",
         "//pkg/api/legacyscheme:go_default_library",
         "//pkg/apis/autoscaling:go_default_library",
         "//pkg/apis/autoscaling/install:go_default_library",
@@ -69,15 +70,16 @@ go_test(
         "//vendor/k8s.io/api/autoscaling/v1:go_default_library",
         "//vendor/k8s.io/api/autoscaling/v2beta1:go_default_library",
         "//vendor/k8s.io/api/core/v1:go_default_library",
-        "//vendor/k8s.io/api/extensions/v1beta1:go_default_library",
         "//vendor/k8s.io/apimachinery/pkg/api/resource:go_default_library",
         "//vendor/k8s.io/apimachinery/pkg/apis/meta/v1:go_default_library",
+        "//vendor/k8s.io/apimachinery/pkg/labels:go_default_library",
         "//vendor/k8s.io/apimachinery/pkg/runtime:go_default_library",
         "//vendor/k8s.io/apimachinery/pkg/runtime/schema:go_default_library",
         "//vendor/k8s.io/apimachinery/pkg/watch:go_default_library",
         "//vendor/k8s.io/client-go/informers:go_default_library",
         "//vendor/k8s.io/client-go/kubernetes/fake:go_default_library",
         "//vendor/k8s.io/client-go/rest:go_default_library",
+        "//vendor/k8s.io/client-go/scale/fake:go_default_library",
         "//vendor/k8s.io/client-go/testing:go_default_library",
         "//vendor/k8s.io/heapster/metrics/api/v1/types:go_default_library",
         "//vendor/k8s.io/metrics/pkg/apis/custom_metrics/v1beta1:go_default_library",

pkg/controller/podautoscaler/horizontal.go

@@ -25,9 +25,9 @@ import (
 	autoscalingv1 "k8s.io/api/autoscaling/v1"
 	autoscalingv2 "k8s.io/api/autoscaling/v2beta1"
 	"k8s.io/api/core/v1"
-	extensions "k8s.io/api/extensions/v1beta1"
 	apiequality "k8s.io/apimachinery/pkg/api/equality"
 	"k8s.io/apimachinery/pkg/api/errors"
+	apimeta "k8s.io/apimachinery/pkg/api/meta"
 	"k8s.io/apimachinery/pkg/api/resource"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/labels"
@@ -39,8 +39,8 @@ import (
 	"k8s.io/client-go/kubernetes/scheme"
 	autoscalingclient "k8s.io/client-go/kubernetes/typed/autoscaling/v1"
 	v1core "k8s.io/client-go/kubernetes/typed/core/v1"
-	extensionsclient "k8s.io/client-go/kubernetes/typed/extensions/v1beta1"
 	autoscalinglisters "k8s.io/client-go/listers/autoscaling/v1"
+	scaleclient "k8s.io/client-go/scale"
 	"k8s.io/client-go/tools/cache"
 	"k8s.io/client-go/tools/record"
 	"k8s.io/client-go/util/workqueue"
@@ -57,8 +57,9 @@ var (
 // in the system with the actual deployments/replication controllers they
 // control.
 type HorizontalController struct {
-	scaleNamespacer extensionsclient.ScalesGetter
+	scaleNamespacer scaleclient.ScalesGetter
 	hpaNamespacer   autoscalingclient.HorizontalPodAutoscalersGetter
+	mapper          apimeta.RESTMapper
 
 	replicaCalc   *ReplicaCalculator
 	eventRecorder record.EventRecorder
@@ -78,8 +79,9 @@ type HorizontalController struct {
 // NewHorizontalController creates a new HorizontalController.
 func NewHorizontalController(
 	evtNamespacer v1core.EventsGetter,
-	scaleNamespacer extensionsclient.ScalesGetter,
+	scaleNamespacer scaleclient.ScalesGetter,
 	hpaNamespacer autoscalingclient.HorizontalPodAutoscalersGetter,
+	mapper apimeta.RESTMapper,
 	replicaCalc *ReplicaCalculator,
 	hpaInformer autoscalinginformers.HorizontalPodAutoscalerInformer,
 	resyncPeriod time.Duration,
@@ -99,7 +101,8 @@ func NewHorizontalController(
 		hpaNamespacer:            hpaNamespacer,
 		upscaleForbiddenWindow:   upscaleForbiddenWindow,
 		downscaleForbiddenWindow: downscaleForbiddenWindow,
-		queue: workqueue.NewNamedRateLimitingQueue(NewDefaultHPARateLimiter(resyncPeriod), "horizontalpodautoscaler"),
+		queue:  workqueue.NewNamedRateLimitingQueue(NewDefaultHPARateLimiter(resyncPeriod), "horizontalpodautoscaler"),
+		mapper: mapper,
 	}
 
 	hpaInformer.Informer().AddEventHandlerWithResyncPeriod(
@@ -189,7 +192,7 @@ func (a *HorizontalController) processNextWorkItem() bool {
 // Computes the desired number of replicas for the metric specifications listed in the HPA, returning the maximum
 // of the computed replica counts, a description of the associated metric, and the statuses of all metrics
 // computed.
-func (a *HorizontalController) computeReplicasForMetrics(hpa *autoscalingv2.HorizontalPodAutoscaler, scale *extensions.Scale,
+func (a *HorizontalController) computeReplicasForMetrics(hpa *autoscalingv2.HorizontalPodAutoscaler, scale *autoscalingv1.Scale,
 	metricSpecs []autoscalingv2.MetricSpec) (replicas int32, metric string, statuses []autoscalingv2.MetricStatus, timestamp time.Time, err error) {
 
 	currentReplicas := scale.Status.Replicas
@@ -197,21 +200,14 @@ func (a *HorizontalController) computeReplicasForMetrics(hpa *autoscalingv2.Hori
 	statuses = make([]autoscalingv2.MetricStatus, len(metricSpecs))
 
 	for i, metricSpec := range metricSpecs {
-		if len(scale.Status.Selector) == 0 && len(scale.Status.TargetSelector) == 0 {
+		if scale.Status.Selector == "" {
 			errMsg := "selector is required"
 			a.eventRecorder.Event(hpa, v1.EventTypeWarning, "SelectorRequired", errMsg)
 			setCondition(hpa, autoscalingv2.ScalingActive, v1.ConditionFalse, "InvalidSelector", "the HPA target's scale is missing a selector")
 			return 0, "", nil, time.Time{}, fmt.Errorf(errMsg)
 		}
 
-		var selector labels.Selector
-		var err error
-		if len(scale.Status.Selector) > 0 {
-			selector = labels.SelectorFromSet(labels.Set(scale.Status.Selector))
-			err = nil
-		} else {
-			selector, err = labels.Parse(scale.Status.TargetSelector)
-		}
+		selector, err := labels.Parse(scale.Status.Selector)
 		if err != nil {
 			errMsg := fmt.Sprintf("couldn't convert selector into a corresponding internal selector object: %v", err)
 			a.eventRecorder.Event(hpa, v1.EventTypeWarning, "InvalidSelector", errMsg)
@@ -349,7 +345,28 @@ func (a *HorizontalController) reconcileAutoscaler(hpav1Shared *autoscalingv1.Ho
 
 	reference := fmt.Sprintf("%s/%s/%s", hpa.Spec.ScaleTargetRef.Kind, hpa.Namespace, hpa.Spec.ScaleTargetRef.Name)
 
-	scale, err := a.scaleNamespacer.Scales(hpa.Namespace).Get(hpa.Spec.ScaleTargetRef.Kind, hpa.Spec.ScaleTargetRef.Name)
+	targetGV, err := schema.ParseGroupVersion(hpa.Spec.ScaleTargetRef.APIVersion)
+	if err != nil {
+		a.eventRecorder.Event(hpa, v1.EventTypeWarning, "FailedGetScale", err.Error())
+		setCondition(hpa, autoscalingv2.AbleToScale, v1.ConditionFalse, "FailedGetScale", "the HPA controller was unable to get the target's current scale: %v", err)
+		a.updateStatusIfNeeded(hpaStatusOriginal, hpa)
+		return fmt.Errorf("invalid API version in scale target reference: %v", err)
+	}
+
+	targetGK := schema.GroupKind{
+		Group: targetGV.Group,
+		Kind:  hpa.Spec.ScaleTargetRef.Kind,
+	}
+
+	mappings, err := a.mapper.RESTMappings(targetGK)
+	if err != nil {
+		a.eventRecorder.Event(hpa, v1.EventTypeWarning, "FailedGetScale", err.Error())
+		setCondition(hpa, autoscalingv2.AbleToScale, v1.ConditionFalse, "FailedGetScale", "the HPA controller was unable to get the target's current scale: %v", err)
+		a.updateStatusIfNeeded(hpaStatusOriginal, hpa)
+		return fmt.Errorf("unable to determine resource for scale target reference: %v", err)
+	}
+
+	scale, targetGR, err := a.scaleForResourceMappings(hpa.Namespace, hpa.Spec.ScaleTargetRef.Name, mappings)
 	if err != nil {
 		a.eventRecorder.Event(hpa, v1.EventTypeWarning, "FailedGetScale", err.Error())
 		setCondition(hpa, autoscalingv2.AbleToScale, v1.ConditionFalse, "FailedGetScale", "the HPA controller was unable to get the target's current scale: %v", err)
@@ -479,7 +496,7 @@ func (a *HorizontalController) reconcileAutoscaler(hpav1Shared *autoscalingv1.Ho
 
 	if rescale {
 		scale.Spec.Replicas = desiredReplicas
-		_, err = a.scaleNamespacer.Scales(hpa.Namespace).Update(hpa.Spec.ScaleTargetRef.Kind, scale)
+		_, err = a.scaleNamespacer.Scales(hpa.Namespace).Update(targetGR, scale)
 		if err != nil {
 			a.eventRecorder.Eventf(hpa, v1.EventTypeWarning, "FailedRescale", "New size: %d; reason: %s; error: %v", desiredReplicas, rescaleReason, err.Error())
 			setCondition(hpa, autoscalingv2.AbleToScale, v1.ConditionFalse, "FailedUpdateScale", "the HPA controller was unable to update the target scale: %v", err)
@@ -526,6 +543,35 @@ func (a *HorizontalController) shouldScale(hpa *autoscalingv2.HorizontalPodAutos
 	return false
 }
 
+// scaleForResourceMappings attempts to fetch the scale for the
+// resource with the given name and namespace, trying each RESTMapping
+// in turn until a working one is found.  If none work, the first error
+// is returned.  It returns both the scale, as well as the group-resource from
+// the working mapping.
+func (a *HorizontalController) scaleForResourceMappings(namespace, name string, mappings []*apimeta.RESTMapping) (*autoscalingv1.Scale, schema.GroupResource, error) {
+	var firstErr error
+	for i, mapping := range mappings {
+		targetGR := mapping.GroupVersionKind.GroupVersion().WithResource(mapping.Resource).GroupResource()
+		scale, err := a.scaleNamespacer.Scales(namespace).Get(targetGR, name)
+		if err == nil {
+			return scale, targetGR, nil
+		}
+
+		// if this is the first error, remember it,
+		// then go on and try other mappings until we find a good one
+		if i == 0 {
+			firstErr = err
+		}
+	}
+
+	// make sure we handle an empty set of mappings
+	if firstErr == nil {
+		firstErr = fmt.Errorf("unrecognized resource")
+	}
+
+	return nil, schema.GroupResource{}, firstErr
+}
+
 // setCurrentReplicasInStatus sets the current replica count in the status of the HPA.
 func (a *HorizontalController) setCurrentReplicasInStatus(hpa *autoscalingv2.HorizontalPodAutoscaler, currentReplicas int32) {
 	a.setStatus(hpa, currentReplicas, hpa.Status.DesiredReplicas, hpa.Status.CurrentMetrics, false)