Add a label command.

pkg/kubectl/cmd/label.go

@@ -0,0 +1,170 @@
+/*
+Copyright 2014 Google Inc. All rights reserved.
+
+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 cmd
+
+import (
+	"fmt"
+	"io"
+	"strings"
+
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/api/meta"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/kubectl/cmd/util"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/kubectl/resource"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/runtime"
+	"github.com/spf13/cobra"
+)
+
+func (f *Factory) NewCmdLabel(out io.Writer) *cobra.Command {
+	cmd := &cobra.Command{
+		Use:   "label [--overwrite] <resource> <name> <key-1>=<val-1> ... <key-n>=<val-n> [--resource-version=<version>]",
+		Short: "Update the labels on a resource",
+		Long: `Update the labels on a resource.
+
+If --overwrite is true, then existing labels can be overwritten, otherwise attempting to overwrite a label will result in an error.
+If --resource-version is specified, then updates will use this resource version, otherwise the existing resource-version will be used.
+
+Examples:
+  $ kubectl label pods foo unhealthy=true
+  <update a pod with the label 'unhealthy' and the value 'true'>
+
+  $ kubectl label --overwrite pods foo status=unhealthy
+  <update a pod with the label 'status' and the value 'unhealthy' overwritting an existing value>
+  
+  $ kubectl label pods foo status=unhealthy --resource-version=1
+  <update a pod with the label 'status' and the value 'unhealthy' if the resource is unchanged from version 1>
+  
+  $ kubectl label pods foo bar-
+  <update a pod by removing a label named 'bar' if it exists. Does not require the --overwrite flag.>`,
+		Run: func(cmd *cobra.Command, args []string) {
+			if len(args) < 2 {
+				usageError(cmd, "<resource> <name> is required")
+			}
+			if len(args) < 3 {
+				usageError(cmd, "at least one label update is required.")
+			}
+			res := args[:2]
+			cmdNamespace, err := f.DefaultNamespace(cmd)
+			checkErr(err)
+
+			mapper, _ := f.Object(cmd)
+			mapping, namespace, name := util.ResourceFromArgs(cmd, res, mapper, cmdNamespace)
+			client, err := f.RESTClient(cmd, mapping)
+			checkErr(err)
+
+			labels, remove, err := parseLabels(args[2:])
+			checkErr(err)
+			overwrite := util.GetFlagBool(cmd, "overwrite")
+			resourceVersion := util.GetFlagString(cmd, "resource-version")
+
+			obj, err := updateObject(client, mapping, namespace, name, func(obj runtime.Object) runtime.Object {
+				outObj, err := labelFunc(obj, overwrite, resourceVersion, labels, remove)
+				checkErr(err)
+				return outObj
+			})
+			checkErr(err)
+
+			printer, err := f.PrinterForMapping(cmd, mapping)
+			checkErr(err)
+
+			printer.PrintObj(obj, out)
+		},
+	}
+	util.AddPrinterFlags(cmd)
+	cmd.Flags().Bool("overwrite", false, "If true, allow labels to be overwritten, otherwise reject label updates that overwrite existing labels.")
+	cmd.Flags().String("resource-version", "", "If non-empty, the labels update will only succeed if this is the current resource-version for the object.")
+	return cmd
+}
+
+func updateObject(client resource.RESTClient, mapping *meta.RESTMapping, namespace, name string, updateFn func(runtime.Object) runtime.Object) (runtime.Object, error) {
+	helper := resource.NewHelper(client, mapping)
+
+	obj, err := helper.Get(namespace, name)
+	if err != nil {
+		return nil, err
+	}
+
+	obj = updateFn(obj)
+
+	data, err := helper.Codec.Encode(obj)
+	if err != nil {
+		return nil, err
+	}
+
+	_, err = helper.Update(namespace, name, true, data)
+	if err != nil {
+		return nil, err
+	}
+	return obj, nil
+}
+
+func validateNoOverwrites(meta *api.ObjectMeta, labels map[string]string) error {
+	for key := range labels {
+		if value, found := meta.Labels[key]; found {
+			return fmt.Errorf("'%s' already has a value (%s), and --overwrite is false", key, value)
+		}
+	}
+	return nil
+}
+
+func parseLabels(spec []string) (map[string]string, []string, error) {
+	labels := map[string]string{}
+	var remove []string
+	for _, labelSpec := range spec {
+		if strings.Index(labelSpec, "=") != -1 {
+			parts := strings.Split(labelSpec, "=")
+			if len(parts) != 2 {
+				return nil, nil, fmt.Errorf("invalid label spec: %v", labelSpec)
+			}
+			labels[parts[0]] = parts[1]
+		} else if strings.HasSuffix(labelSpec, "-") {
+			remove = append(remove, labelSpec[:len(labelSpec)-1])
+		} else {
+			return nil, nil, fmt.Errorf("unknown label spec: %v")
+		}
+	}
+	for _, removeLabel := range remove {
+		if _, found := labels[removeLabel]; found {
+			return nil, nil, fmt.Errorf("can not both modify and remove a label in the same command")
+		}
+	}
+	return labels, remove, nil
+}
+
+func labelFunc(obj runtime.Object, overwrite bool, resourceVersion string, labels map[string]string, remove []string) (runtime.Object, error) {
+	meta, err := api.ObjectMetaFor(obj)
+	if err != nil {
+		return nil, err
+	}
+	if !overwrite {
+		if err := validateNoOverwrites(meta, labels); err != nil {
+			return nil, err
+		}
+	}
+
+	for key, value := range labels {
+		meta.Labels[key] = value
+	}
+	for _, label := range remove {
+		delete(meta.Labels, label)
+	}
+
+	if len(resourceVersion) != 0 {
+		meta.ResourceVersion = resourceVersion
+	}
+	return obj, nil
+}