Add Custom Resource support to "kubectl autoscale"

Generalize the autoscsale command to simply let the dynamic client check
if a scale subresource is registered for the supplied type. This allows
using the autoscale command for built in types as well as custom
resources.

pkg/kubectl/cmd/autoscale/BUILD

@@ -10,7 +10,6 @@ go_library(
         "//pkg/kubectl/cmd/util:go_default_library",
         "//pkg/kubectl/generate:go_default_library",
         "//pkg/kubectl/generate/versioned:go_default_library",
-        "//pkg/kubectl/polymorphichelpers:go_default_library",
         "//pkg/kubectl/scheme:go_default_library",
         "//pkg/kubectl/util/i18n:go_default_library",
         "//pkg/kubectl/util/templates:go_default_library",
@@ -20,6 +19,7 @@ go_library(
         "//staging/src/k8s.io/cli-runtime/pkg/genericclioptions/printers:go_default_library",
         "//staging/src/k8s.io/cli-runtime/pkg/genericclioptions/resource:go_default_library",
         "//staging/src/k8s.io/client-go/kubernetes/typed/autoscaling/v1:go_default_library",
+        "//staging/src/k8s.io/client-go/scale:go_default_library",
         "//vendor/github.com/spf13/cobra:go_default_library",
         "//vendor/k8s.io/klog:go_default_library",
     ],

pkg/kubectl/cmd/autoscale/autoscale.go

@@ -28,11 +28,11 @@ import (
 	"k8s.io/cli-runtime/pkg/genericclioptions/printers"
 	"k8s.io/cli-runtime/pkg/genericclioptions/resource"
 	autoscalingv1client "k8s.io/client-go/kubernetes/typed/autoscaling/v1"
+	"k8s.io/client-go/scale"
 	"k8s.io/kubernetes/pkg/kubectl"
 	cmdutil "k8s.io/kubernetes/pkg/kubectl/cmd/util"
 	"k8s.io/kubernetes/pkg/kubectl/generate"
 	generateversioned "k8s.io/kubernetes/pkg/kubectl/generate/versioned"
-	"k8s.io/kubernetes/pkg/kubectl/polymorphichelpers"
 	"k8s.io/kubernetes/pkg/kubectl/scheme"
 	"k8s.io/kubernetes/pkg/kubectl/util/i18n"
 	"k8s.io/kubernetes/pkg/kubectl/util/templates"
@@ -74,10 +74,10 @@ type AutoscaleOptions struct {
 	namespace        string
 	dryRun           bool
 	builder          *resource.Builder
-	canBeAutoscaled  polymorphichelpers.CanBeAutoscaledFunc
 	generatorFunc    func(string, *meta.RESTMapping) (generate.StructuredGenerator, error)
 
 	HPAClient         autoscalingv1client.HorizontalPodAutoscalersGetter
+	scaleKindResolver scale.ScaleKindResolver
 
 	genericclioptions.IOStreams
 }
@@ -133,7 +133,11 @@ func (o *AutoscaleOptions) Complete(f cmdutil.Factory, cmd *cobra.Command, args
 	o.dryRun = cmdutil.GetFlagBool(cmd, "dry-run")
 	o.createAnnotation = cmdutil.GetFlagBool(cmd, cmdutil.ApplyAnnotationsFlag)
 	o.builder = f.NewBuilder()
-	o.canBeAutoscaled = polymorphichelpers.CanBeAutoscaledFn
+	discoveryClient, err := f.ToDiscoveryClient()
+	if err != nil {
+		return err
+	}
+	o.scaleKindResolver = scale.NewDiscoveryScaleKindResolver(discoveryClient)
 	o.args = args
 	o.RecordFlags.Complete(cmd)
 
@@ -196,7 +200,7 @@ func (o *AutoscaleOptions) Validate() error {
 
 func (o *AutoscaleOptions) Run() error {
 	r := o.builder.
-		WithScheme(scheme.Scheme, scheme.Scheme.PrioritizedVersionsAllGroups()...).
+		Unstructured().
 		ContinueOnError().
 		NamespaceParam(o.namespace).DefaultNamespace().
 		FilenameParam(o.enforceNamespace, o.FilenameOptions).
@@ -214,8 +218,9 @@ func (o *AutoscaleOptions) Run() error {
 		}
 
 		mapping := info.ResourceMapping()
-		if err := o.canBeAutoscaled(mapping.GroupVersionKind.GroupKind()); err != nil {
+		gvr := mapping.GroupVersionKind.GroupVersion().WithResource(mapping.Resource.Resource)
-			return err
+		if _, err := o.scaleKindResolver.ScaleForResource(gvr); err != nil {
+			return fmt.Errorf("cannot autoscale a %v: %v", mapping.GroupVersionKind.Kind, err)
 		}
 
 		generator, err := o.generatorFunc(info.Name, mapping)

pkg/kubectl/polymorphichelpers/BUILD

@@ -4,7 +4,6 @@ go_library(
     name = "go_default_library",
     srcs = [
         "attachablepodforobject.go",
-        "canbeautoscaled.go",
         "canbeexposed.go",
         "helpers.go",
         "historyviewer.go",
@@ -51,7 +50,6 @@ go_library(
 go_test(
     name = "go_default_test",
     srcs = [
-        "canbeautoscaled_test.go",
         "canbeexposed_test.go",
         "helpers_test.go",
         "logsforobject_test.go",

pkg/kubectl/polymorphichelpers/canbeautoscaled.go

@@ -1,42 +0,0 @@
-/*
-Copyright 2018 The Kubernetes Authors.
-
-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 polymorphichelpers
-
-import (
-	"fmt"
-
-	appsv1 "k8s.io/api/apps/v1"
-	corev1 "k8s.io/api/core/v1"
-	extensionsv1beta1 "k8s.io/api/extensions/v1beta1"
-	"k8s.io/apimachinery/pkg/runtime/schema"
-)
-
-func canBeAutoscaled(kind schema.GroupKind) error {
-	switch kind {
-	case
-		corev1.SchemeGroupVersion.WithKind("ReplicationController").GroupKind(),
-		appsv1.SchemeGroupVersion.WithKind("Deployment").GroupKind(),
-		appsv1.SchemeGroupVersion.WithKind("ReplicaSet").GroupKind(),
-		appsv1.SchemeGroupVersion.WithKind("StatefulSet").GroupKind(),
-		extensionsv1beta1.SchemeGroupVersion.WithKind("Deployment").GroupKind(),
-		extensionsv1beta1.SchemeGroupVersion.WithKind("ReplicaSet").GroupKind():
-		// nothing to do here
-	default:
-		return fmt.Errorf("cannot autoscale a %v", kind)
-	}
-	return nil
-}

pkg/kubectl/polymorphichelpers/canbeautoscaled_test.go

@@ -1,72 +0,0 @@
-/*
-Copyright 2018 The Kubernetes Authors.
-
-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 polymorphichelpers
-
-import (
-	"testing"
-
-	appsv1 "k8s.io/api/apps/v1"
-	corev1 "k8s.io/api/core/v1"
-	extensionsv1beta1 "k8s.io/api/extensions/v1beta1"
-	"k8s.io/apimachinery/pkg/runtime/schema"
-)
-
-func TestCanBeAutoscaled(t *testing.T) {
-	tests := []struct {
-		kind      schema.GroupKind
-		expectErr bool
-	}{
-		{
-			kind:      corev1.SchemeGroupVersion.WithKind("ReplicationController").GroupKind(),
-			expectErr: false,
-		},
-		{
-			kind:      appsv1.SchemeGroupVersion.WithKind("Deployment").GroupKind(),
-			expectErr: false,
-		},
-		{
-			kind:      appsv1.SchemeGroupVersion.WithKind("StatefulSet").GroupKind(),
-			expectErr: false,
-		},
-		{
-			kind:      extensionsv1beta1.SchemeGroupVersion.WithKind("ReplicaSet").GroupKind(),
-			expectErr: false,
-		},
-		{
-			kind:      corev1.SchemeGroupVersion.WithKind("Node").GroupKind(),
-			expectErr: true,
-		},
-		{
-			kind:      corev1.SchemeGroupVersion.WithKind("Service").GroupKind(),
-			expectErr: true,
-		},
-		{
-			kind:      corev1.SchemeGroupVersion.WithKind("Pod").GroupKind(),
-			expectErr: true,
-		},
-	}
-
-	for _, test := range tests {
-		err := canBeAutoscaled(test.kind)
-		if test.expectErr && err == nil {
-			t.Error("unexpected non-error")
-		}
-		if !test.expectErr && err != nil {
-			t.Errorf("unexpected error: %v", err)
-		}
-	}
-}

pkg/kubectl/polymorphichelpers/interface.go

@@ -79,12 +79,6 @@ type PortsForObjectFunc func(object runtime.Object) ([]string, error)
 // PortsForObjectFn gives a way to easily override the function for unit testing if needed
 var PortsForObjectFn PortsForObjectFunc = portsForObject
 
-// CanBeAutoscaledFunc checks whether the kind of resources could be autoscaled
-type CanBeAutoscaledFunc func(kind schema.GroupKind) error
-
-// CanBeAutoscaledFn gives a way to easily override the function for unit testing if needed
-var CanBeAutoscaledFn CanBeAutoscaledFunc = canBeAutoscaled
-
 // CanBeExposedFunc is a function type that can tell you whether a given GroupKind is capable of being exposed
 type CanBeExposedFunc func(kind schema.GroupKind) error