Add `set instancegroup` command

This change adds a new command and functionality for updating
instance group configuration via command line arguments. This
behavior mimics the `set cluster` command.

cmd/kops/BUILD.bazel

@@ -43,6 +43,7 @@ go_library(
         "root.go",
         "set.go",
         "set_cluster.go",
+        "set_instancegroups.go",
         "toolbox.go",
         "toolbox_convert_imported.go",
         "toolbox_dump.go",

cmd/kops/set.go

@@ -33,7 +33,8 @@ var (
 
 	setExample = templates.Examples(i18n.T(`
     # Set cluster to run kubernetes version 1.17.0
-    kops set cluster k8s-cluster.example.com spec.kubernetesVersion=1.17.0
+	kops set cluster k8s-cluster.example.com spec.kubernetesVersion=1.17.0
+	kops set instancegroup k8s-cluster.example.com spec.maxSize=4
 	`))
 )
 
@@ -47,6 +48,7 @@ func NewCmdSet(f *util.Factory, out io.Writer) *cobra.Command {
 
 	// create subcommands
 	cmd.AddCommand(NewCmdSetCluster(f, out))
+	cmd.AddCommand(NewCmdSetInstancegroup(f, out))
 
 	return cmd
 }

cmd/kops/set_instancegroups.go

@@ -0,0 +1,85 @@
+/*
+Copyright 2021 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 main
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"strings"
+
+	"github.com/spf13/cobra"
+	"k8s.io/kubectl/pkg/util/i18n"
+	"k8s.io/kubectl/pkg/util/templates"
+
+	"k8s.io/kops/cmd/kops/util"
+	"k8s.io/kops/pkg/commands"
+)
+
+var (
+	setInstancegroupLong = templates.LongDesc(i18n.T(`Set an instance group field value.
+
+		This command changes the desired instance group configuration in the registry.
+
+        kops set does not update the cloud resources; to apply the changes use "kops update cluster".`))
+
+	setInstancegroupExample = templates.Examples(i18n.T(`
+		# Set instance group to run image custom-ami-image
+		kops set instancegroup --name k8s-cluster.example.com nodes spec.image=custom-ami-image
+	`))
+)
+
+// NewCmdSetInstancegroup builds a cobra command for the kops set instancegroup command.
+func NewCmdSetInstancegroup(f *util.Factory, out io.Writer) *cobra.Command {
+	options := &commands.SetInstanceGroupOptions{}
+
+	cmd := &cobra.Command{
+		Use:     "instancegroup",
+		Aliases: []string{"instancegroups", "ig"},
+		Short:   i18n.T("Set instancegroup fields."),
+		Long:    setInstancegroupLong,
+		Example: setInstancegroupExample,
+		Run: func(cmd *cobra.Command, args []string) {
+			ctx := context.TODO()
+
+			for i, arg := range args {
+				index := strings.Index(arg, "=")
+
+				if i == 0 {
+					if index != -1 {
+						exitWithError(fmt.Errorf("Specify name of instance group to edit"))
+					}
+					options.InstanceGroupName = arg
+				} else {
+					if index == -1 {
+						exitWithError(fmt.Errorf("unrecognized parameter %q (missing '=')", arg))
+						return
+					}
+					options.Fields = append(options.Fields, arg)
+				}
+			}
+
+			options.ClusterName = rootCommand.ClusterName()
+
+			if err := commands.RunSetInstancegroup(ctx, f, cmd, out, options); err != nil {
+				exitWithError(err)
+			}
+		},
+	}
+
+	return cmd
+}

docs/cli/kops_set.md

@@ -16,6 +16,7 @@ Set a configuration field.
 ```
   # Set cluster to run kubernetes version 1.17.0
   kops set cluster k8s-cluster.example.com spec.kubernetesVersion=1.17.0
+  kops set instancegroup k8s-cluster.example.com spec.maxSize=4
 ```
 
 ### Options
@@ -49,4 +50,5 @@ Set a configuration field.
 
 * [kops](kops.md)	 - kOps is Kubernetes Operations.
 * [kops set cluster](kops_set_cluster.md)	 - Set cluster fields.
+* [kops set instancegroup](kops_set_instancegroup.md)	 - Set instancegroup fields.
 

docs/cli/kops_set_instancegroup.md

@@ -0,0 +1,57 @@
+
+<!--- This file is automatically generated by make gen-cli-docs; changes should be made in the go CLI command code (under cmd/kops) -->
+
+## kops set instancegroup
+
+Set instancegroup fields.
+
+### Synopsis
+
+Set an instance group field value.
+
+ This command changes the desired instance group configuration in the registry.
+
+    kops set does not update the cloud resources; to apply the changes use "kops update cluster".
+
+```
+kops set instancegroup [flags]
+```
+
+### Examples
+
+```
+  # Set instance group to run image custom-ami-image
+  kops set instancegroup --name k8s-cluster.example.com nodes spec.image=custom-ami-image
+```
+
+### Options
+
+```
+  -h, --help   help for instancegroup
+```
+
+### Options inherited from parent commands
+
+```
+      --add_dir_header                   If true, adds the file directory to the header of the log messages
+      --alsologtostderr                  log to standard error as well as files
+      --config string                    yaml config file (default is $HOME/.kops.yaml)
+      --log_backtrace_at traceLocation   when logging hits line file:N, emit a stack trace (default :0)
+      --log_dir string                   If non-empty, write log files in this directory
+      --log_file string                  If non-empty, use this log file
+      --log_file_max_size uint           Defines the maximum size a log file can grow to. Unit is megabytes. If the value is 0, the maximum file size is unlimited. (default 1800)
+      --logtostderr                      log to standard error instead of files (default true)
+      --name string                      Name of cluster. Overrides KOPS_CLUSTER_NAME environment variable
+      --one_output                       If true, only write logs to their native severity level (vs also writing to each lower severity level
+      --skip_headers                     If true, avoid header prefixes in the log messages
+      --skip_log_headers                 If true, avoid headers when opening log files
+      --state string                     Location of state storage (kops 'config' file). Overrides KOPS_STATE_STORE environment variable
+      --stderrthreshold severity         logs at or above this threshold go to stderr (default 2)
+  -v, --v Level                          number for the log level verbosity
+      --vmodule moduleSpec               comma-separated list of pattern=N settings for file-filtered logging
+```
+
+### SEE ALSO
+
+* [kops set](kops_set.md)	 - Set fields on clusters and other resources.
+

pkg/commands/BUILD.bazel

@@ -6,6 +6,7 @@ go_library(
         "helpers.go",
         "helpers_readwrite.go",
         "set_cluster.go",
+        "set_instancegroups.go",
         "status_discovery.go",
         "version.go",
     ],
@@ -39,7 +40,10 @@ go_library(
 
 go_test(
     name = "go_default_test",
-    srcs = ["set_cluster_test.go"],
+    srcs = [
+        "set_cluster_test.go",
+        "set_instancegroups_test.go",
+    ],
     embed = [":go_default_library"],
     deps = [
         "//pkg/apis/kops:go_default_library",

pkg/commands/helpers_readwrite.go

@@ -67,6 +67,38 @@ func UpdateCluster(ctx context.Context, clientset simple.Clientset, cluster *kop
 	return nil
 }
 
+// UpdateInstanceGroup writes the updated instance group to the state store after performing validation
+func UpdateInstanceGroup(ctx context.Context, clientset simple.Clientset, cluster *kops.Cluster, allInstanceGroups []*kops.InstanceGroup, instanceGroupToUpdate *kops.InstanceGroup) error {
+	cloud, err := cloudup.BuildCloud(cluster)
+	if err != nil {
+		return err
+	}
+
+	err = cloudup.PerformAssignments(cluster, cloud)
+	if err != nil {
+		return fmt.Errorf("error populating configuration: %v", err)
+	}
+
+	assetBuilder := assets.NewAssetBuilder(cluster, "")
+	fullCluster, err := cloudup.PopulateClusterSpec(clientset, cluster, cloud, assetBuilder)
+	if err != nil {
+		return err
+	}
+
+	err = validation.DeepValidate(fullCluster, allInstanceGroups, true, nil)
+	if err != nil {
+		return err
+	}
+
+	// Validation was successful so commit the changed instance group.
+	_, err = clientset.InstanceGroupsFor(cluster).Update(ctx, instanceGroupToUpdate, metav1.UpdateOptions{})
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
 // ReadAllInstanceGroups reads all the instance groups for the cluster
 func ReadAllInstanceGroups(ctx context.Context, clientset simple.Clientset, cluster *kops.Cluster) ([]*kops.InstanceGroup, error) {
 	list, err := clientset.InstanceGroupsFor(cluster).List(ctx, metav1.ListOptions{})

pkg/commands/set_cluster_test.go

@@ -24,6 +24,17 @@ import (
 	"k8s.io/kops/upup/pkg/fi"
 )
 
+func TestSetClusterBadInput(t *testing.T) {
+	fields := []string{
+		"bad-set-input",
+	}
+
+	err := SetClusterFields(fields, &kops.Cluster{}, []*kops.InstanceGroup{})
+	if err == nil {
+		t.Errorf("expected a field parsing error, but received none")
+	}
+}
+
 func TestSetClusterFields(t *testing.T) {
 	grid := []struct {
 		Fields []string

pkg/commands/set_instancegroups.go

@@ -0,0 +1,109 @@
+/*
+Copyright 2019 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 commands
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"strings"
+
+	"github.com/spf13/cobra"
+	"k8s.io/apimachinery/pkg/util/validation/field"
+
+	"k8s.io/kops/cmd/kops/util"
+	api "k8s.io/kops/pkg/apis/kops"
+	"k8s.io/kops/pkg/featureflag"
+	"k8s.io/kops/util/pkg/reflectutils"
+)
+
+// SetInstanceGroupOptions contains the options for setting configuration on an
+// instance group.
+type SetInstanceGroupOptions struct {
+	Fields            []string
+	ClusterName       string
+	InstanceGroupName string
+}
+
+// RunSetInstancegroup implements the set instancegroup command logic.
+func RunSetInstancegroup(ctx context.Context, f *util.Factory, cmd *cobra.Command, out io.Writer, options *SetInstanceGroupOptions) error {
+	if !featureflag.SpecOverrideFlag.Enabled() {
+		return fmt.Errorf("set instancegroup is currently feature gated; set `export KOPS_FEATURE_FLAGS=SpecOverrideFlag`")
+	}
+
+	if options.ClusterName == "" {
+		return field.Required(field.NewPath("clusterName"), "Cluster name is required")
+	}
+	if options.InstanceGroupName == "" {
+		return field.Required(field.NewPath("instancegroupName"), "Instance Group name is required")
+	}
+
+	clientset, err := f.Clientset()
+	if err != nil {
+		return err
+	}
+
+	cluster, err := clientset.GetCluster(ctx, options.ClusterName)
+	if err != nil {
+		return err
+	}
+
+	instanceGroups, err := ReadAllInstanceGroups(ctx, clientset, cluster)
+	if err != nil {
+		return err
+	}
+	var instanceGroupToUpdate *api.InstanceGroup
+	for _, instanceGroup := range instanceGroups {
+		if instanceGroup.GetName() == options.InstanceGroupName {
+			instanceGroupToUpdate = instanceGroup
+		}
+	}
+	if instanceGroupToUpdate == nil {
+		return fmt.Errorf("unable to find instance group with name %q", options.InstanceGroupName)
+	}
+
+	err = SetInstancegroupFields(options.Fields, instanceGroupToUpdate)
+	if err != nil {
+		return err
+	}
+
+	err = UpdateInstanceGroup(ctx, clientset, cluster, instanceGroups, instanceGroupToUpdate)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// SetInstancegroupFields sets field values in the instance group.
+func SetInstancegroupFields(fields []string, instanceGroup *api.InstanceGroup) error {
+	for _, field := range fields {
+		kv := strings.SplitN(field, "=", 2)
+		if len(kv) != 2 {
+			return fmt.Errorf("unhandled field: %q", field)
+		}
+
+		key := kv[0]
+		key = strings.TrimPrefix(key, "instancegroup.")
+
+		if err := reflectutils.SetString(instanceGroup, key, kv[1]); err != nil {
+			return fmt.Errorf("failed to set %s=%s: %v", kv[0], kv[1], err)
+		}
+	}
+
+	return nil
+}

pkg/commands/set_instancegroups_test.go

@@ -0,0 +1,122 @@
+/*
+Copyright 2021 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 commands
+
+import (
+	"reflect"
+	"testing"
+
+	"k8s.io/kops/pkg/apis/kops"
+	"k8s.io/kops/upup/pkg/fi"
+)
+
+func TestSetInstanceGroupsBadInput(t *testing.T) {
+	fields := []string{
+		"bad-set-input",
+	}
+
+	err := SetInstancegroupFields(fields, &kops.InstanceGroup{})
+	if err == nil {
+		t.Errorf("expected a field parsing error, but received none")
+	}
+}
+
+func TestSetInstanceGroupsFields(t *testing.T) {
+	grid := []struct {
+		Fields []string
+		Input  kops.InstanceGroup
+		Output kops.InstanceGroup
+	}{
+		{
+			Fields: []string{
+				"spec.image=ami-test-2",
+			},
+			Input: kops.InstanceGroup{
+				Spec: kops.InstanceGroupSpec{
+					Image: "ami-test-1",
+				},
+			},
+			Output: kops.InstanceGroup{
+				Spec: kops.InstanceGroupSpec{
+					Image: "ami-test-2",
+				},
+			},
+		},
+		{
+			Fields: []string{
+				"spec.machineType=m5.large",
+			},
+			Output: kops.InstanceGroup{
+				Spec: kops.InstanceGroupSpec{
+					MachineType: "m5.large",
+				},
+			},
+		},
+		{
+			Fields: []string{
+				"spec.minSize=1",
+				"spec.maxSize=3",
+			},
+			Output: kops.InstanceGroup{
+				Spec: kops.InstanceGroupSpec{
+					MinSize: fi.Int32(1),
+					MaxSize: fi.Int32(3),
+				},
+			},
+		},
+		{
+			Fields: []string{
+				"spec.role=Master",
+			},
+			Output: kops.InstanceGroup{
+				Spec: kops.InstanceGroupSpec{
+					Role: "Master",
+				},
+			},
+		},
+		{
+			Fields: []string{
+				"spec.additionalSecurityGroups=group1,group2,group3",
+			},
+			Output: kops.InstanceGroup{
+				Spec: kops.InstanceGroupSpec{
+					AdditionalSecurityGroups: []string{
+						"group1",
+						"group2",
+						"group3",
+					},
+				},
+			},
+		},
+	}
+
+	for _, g := range grid {
+		ig := g.Input
+
+		err := SetInstancegroupFields(g.Fields, &ig)
+		if err != nil {
+			t.Errorf("unexpected error from setClusterFields %v: %v", g.Fields, err)
+			continue
+		}
+
+		if !reflect.DeepEqual(ig, g.Output) {
+			t.Errorf("unexpected output from setClusterFields %v.  expected=%v, actual=%v", g.Fields, g.Output, ig)
+			continue
+		}
+
+	}
+}