Add support to enable or disable scale-to-zero

- Init autoscaling subcommand
- Support scale-to-zero config
- Update examples in README
knative#18

plugins/admin/README.adoc

@@ -16,21 +16,24 @@ A plugin of kn client to manage Knative for administrators.
 For example:
 kn admin domain set - to set Knative route domain
 kn admin private-registry enable - to enable deployment from the private registry
+kn admin autoscaling update - to manage autoscaling config
 
 Usage:
   kn admin [command]
 
 Available Commands:
-  domain           Manage route domain
-  help             Help about any command
-  private-registry Manage private-registry
+  autoscaling Manage autoscaling config
+  domain      Manage route domain
+  help        Help about any command
+  registry    Manage registry
+  version     Prints the plugin version
 
 Flags:
-      --config string   config file (default is $HOME/.config/kn/plugins/kn-admin.yaml)
-  -h, --help            help for admin
+      --config string   config file (default is $HOME/.config/kn/plugins/admin.yaml)
+  -h, --help            help for kn admin
   -t, --toggle          Help message for toggle
 
-Use "admin [command] --help" for more information about a command.
+Use "kn admin [command] --help" for more information about a command.
 ----
 
 #### `kn admin domain`
@@ -87,6 +90,28 @@ Use "admin registry [command] --help" for more information about a command.
 
 ----
 
+#### `kn admin autoscaling`
+
+----
+Manage autoscaling provided by Knative Pod Autoscaler (KPA). For example:
+
+kn admin autoscaling update - to manage autoscaling config
+
+Usage:
+  kn admin autoscaling [command]
+
+Available Commands:
+  update      update autoscaling config
+
+Flags:
+  -h, --help   help for autoscaling
+
+Global Flags:
+      --config string   config file (default is $HOME/.config/kn/plugins/admin.yaml)
+
+Use "kn admin autoscaling [command] --help" for more information about a command.
+
+----
 ### Examples
 
 #### As a Knative administrator, I want to update Knative route domain with my custom domain.
@@ -121,3 +146,13 @@ $ kn admin registry add \
   --docker-password=[PRIVATE_REGISTRY_PASSWORD]
 -----
 =====
+
+#### As a Knative administrator, I want to enable scale-to-zero for autoscaling.
+
+.Enable scale-to-zero for autoscaling.
+=====
+-----
+$ kn admin autoscaling update --scale-to-zero
+Updated Knative autoscaling config enable-scale-to-zero: true
+-----
+=====

plugins/admin/core/root.go

@@ -23,6 +23,7 @@ import (
 	"github.com/spf13/viper"
 	"knative.dev/client-contrib/plugins/admin/pkg"
 	"knative.dev/client-contrib/plugins/admin/pkg/command"
+	"knative.dev/client-contrib/plugins/admin/pkg/command/autoscaling"
 	"knative.dev/client-contrib/plugins/admin/pkg/command/domain"
 	private_registry "knative.dev/client-contrib/plugins/admin/pkg/command/registry"
 )
@@ -43,6 +44,7 @@ func NewAdminCommand(params ...pkg.AdminParams) *cobra.Command {
 For example:
 kn admin domain set - to set Knative route domain
 kn admin registry add - to add registry with credentials
+kn admin autoscaling update - to manage autoscaling config
 `,
 	}
 	cobra.OnInitialize(initConfig)
@@ -51,6 +53,7 @@ kn admin registry add - to add registry with credentials
 	//
 	rootCmd.AddCommand(domain.NewDomainCmd(p))
 	rootCmd.AddCommand(private_registry.NewPrivateRegistryCmd(p))
+	rootCmd.AddCommand(autoscaling.NewAutoscalingCmd(p))
 	rootCmd.AddCommand(command.NewVersionCommand())
 
 	// Add default help page if there's unknown command

plugins/admin/go.mod

@@ -7,7 +7,8 @@ require (
 	github.com/spf13/cobra v0.0.5
 	github.com/spf13/viper v1.6.2
 	gotest.tools v2.2.0+incompatible
-	k8s.io/api v0.17.3
-	k8s.io/apimachinery v0.17.3
-	k8s.io/client-go v0.17.0
+	k8s.io/api v0.17.4
+	k8s.io/apimachinery v0.17.4
+	k8s.io/client-go v0.17.4
+	knative.dev/client v0.14.0
 )

plugins/admin/pkg/command/autoscaling/autoscaling.go

@@ -0,0 +1,34 @@
+// Copyright © 2020 The Knative 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 autoscaling
+
+import (
+	"github.com/spf13/cobra"
+	"knative.dev/client-contrib/plugins/admin/pkg"
+)
+
+// domainCmd represents the domain command
+func NewAutoscalingCmd(p *pkg.AdminParams) *cobra.Command {
+	var AutoscalingCmd = &cobra.Command{
+		Use:   "autoscaling",
+		Short: "Manage autoscaling config",
+		Long: `Manage autoscaling provided by Knative Pod Autoscaler (KPA). For example:
+
+kn admin autoscaling update - to manage autoscaling config`,
+	}
+	AutoscalingCmd.AddCommand(NewAutoscalingUpdateCommand(p))
+	AutoscalingCmd.InitDefaultHelpFlag()
+	return AutoscalingCmd
+}

plugins/admin/pkg/command/autoscaling/update.go

@@ -0,0 +1,90 @@
+// Copyright © 2020 The Knative 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 autoscaling
+
+import (
+	"errors"
+	"fmt"
+	"os"
+
+	"knative.dev/client-contrib/plugins/admin/pkg"
+
+	"github.com/spf13/cobra"
+	corev1 "k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/api/equality"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	_ "k8s.io/client-go/plugin/pkg/client/auth/oidc"
+
+	"knative.dev/client/pkg/kn/flags"
+)
+
+var (
+	ScaleToZero       bool
+	enableScaleToZero = "enable-scale-to-zero"
+	knativeServing    = "knative-serving"
+	configAutoscaler  = "config-autoscaler"
+)
+
+func NewAutoscalingUpdateCommand(p *pkg.AdminParams) *cobra.Command {
+	AutoscalingUpdateCommand := &cobra.Command{
+		Use:   "update",
+		Short: "update autoscaling config",
+		Long: `update autoscaling config provided by Knative Pod Autoscaler (KPA)
+
+For example:
+# To enable scale-to-zero
+kn admin autoscaling update --scale-to-zero
+# To disable scale-to-zero
+kn admin autoscaling update --no-scale-to-zero
+`,
+		PreRunE: func(cmd *cobra.Command, args []string) error {
+			if cmd.Flags().NFlag() == 0 {
+				return errors.New("'autoscaling update' requires flag(s)")
+			}
+			return nil
+		},
+		Run: func(cmd *cobra.Command, args []string) {
+			var scaleToZero string
+			if cmd.Flags().Changed("scale-to-zero") {
+				scaleToZero = "true"
+			} else if cmd.Flags().Changed("no-scale-to-zero") {
+				scaleToZero = "false"
+			}
+			currentCm := &corev1.ConfigMap{}
+			currentCm, err := p.ClientSet.CoreV1().ConfigMaps(knativeServing).Get(configAutoscaler, metav1.GetOptions{})
+			if err != nil {
+				fmt.Println("Failed to get ConfigMaps:", err)
+				os.Exit(1)
+			}
+			desiredCm := currentCm.DeepCopy()
+			desiredCm.Data[enableScaleToZero] = scaleToZero
+			if !equality.Semantic.DeepEqual(desiredCm.Data[enableScaleToZero], currentCm.Data[enableScaleToZero]) {
+				_, err = p.ClientSet.CoreV1().ConfigMaps(knativeServing).Update(desiredCm)
+				if err != nil {
+					fmt.Println("Failed to update ConfigMaps:", err)
+					os.Exit(1)
+				}
+				fmt.Printf("Updated Knative autoscaling config %s: %s\n", enableScaleToZero, scaleToZero)
+			} else {
+				fmt.Printf("Knative autoscaling config %s: %s not changed\n", enableScaleToZero, currentCm.Data[enableScaleToZero])
+			}
+		},
+	}
+
+	flags.AddBothBoolFlagsUnhidden(AutoscalingUpdateCommand.Flags(), &ScaleToZero, "scale-to-zero", "", true,
+		"Enable scale-to-zero if set.")
+
+	return AutoscalingUpdateCommand
+}