Allow modifying current context with kubectl set-context

pkg/kubectl/cmd/config/create_context.go

@@ -34,6 +34,7 @@ import (
 type createContextOptions struct {
 	configAccess clientcmd.ConfigAccess
 	name         string
+	currContext  bool
 	cluster      flag.StringFlag
 	authInfo     flag.StringFlag
 	namespace    flag.StringFlag
@@ -54,23 +55,24 @@ func NewCmdConfigSetContext(out io.Writer, configAccess clientcmd.ConfigAccess)
 	options := &createContextOptions{configAccess: configAccess}
 
 	cmd := &cobra.Command{
-		Use: fmt.Sprintf("set-context NAME [--%v=cluster_nickname] [--%v=user_nickname] [--%v=namespace]", clientcmd.FlagClusterName, clientcmd.FlagAuthInfoName, clientcmd.FlagNamespace),
+		Use: fmt.Sprintf("set-context [NAME | --current] [--%v=cluster_nickname] [--%v=user_nickname] [--%v=namespace]", clientcmd.FlagClusterName, clientcmd.FlagAuthInfoName, clientcmd.FlagNamespace),
 		DisableFlagsInUseLine: true,
 		Short:   i18n.T("Sets a context entry in kubeconfig"),
 		Long:    create_context_long,
 		Example: create_context_example,
 		Run: func(cmd *cobra.Command, args []string) {
 			cmdutil.CheckErr(options.complete(cmd))
-			exists, err := options.run()
+			name, exists, err := options.run()
 			cmdutil.CheckErr(err)
 			if exists {
-				fmt.Fprintf(out, "Context %q modified.\n", options.name)
+				fmt.Fprintf(out, "Context %q modified.\n", name)
 			} else {
-				fmt.Fprintf(out, "Context %q created.\n", options.name)
+				fmt.Fprintf(out, "Context %q created.\n", name)
 			}
 		},
 	}
 
+	cmd.Flags().BoolVar(&options.currContext, "current", options.currContext, "Modify the current context")
 	cmd.Flags().Var(&options.cluster, clientcmd.FlagClusterName, clientcmd.FlagClusterName+" for the context entry in kubeconfig")
 	cmd.Flags().Var(&options.authInfo, clientcmd.FlagAuthInfoName, clientcmd.FlagAuthInfoName+" for the context entry in kubeconfig")
 	cmd.Flags().Var(&options.namespace, clientcmd.FlagNamespace, clientcmd.FlagNamespace+" for the context entry in kubeconfig")
@@ -78,29 +80,37 @@ func NewCmdConfigSetContext(out io.Writer, configAccess clientcmd.ConfigAccess)
 	return cmd
 }
 
-func (o createContextOptions) run() (bool, error) {
+func (o createContextOptions) run() (string, bool, error) {
 	err := o.validate()
 	if err != nil {
-		return false, err
+		return "", false, err
 	}
 
 	config, err := o.configAccess.GetStartingConfig()
 	if err != nil {
-		return false, err
+		return "", false, err
 	}
 
-	startingStanza, exists := config.Contexts[o.name]
+	name := o.name
+	if o.currContext {
+		if len(config.CurrentContext) == 0 {
+			return "", false, errors.New("no current context is set")
+		}
+		name = config.CurrentContext
+	}
+
+	startingStanza, exists := config.Contexts[name]
 	if !exists {
 		startingStanza = clientcmdapi.NewContext()
 	}
 	context := o.modifyContext(*startingStanza)
-	config.Contexts[o.name] = &context
+	config.Contexts[name] = &context
 
 	if err := clientcmd.ModifyConfig(o.configAccess, *config, true); err != nil {
-		return exists, err
+		return name, exists, err
 	}
 
-	return exists, nil
+	return name, exists, nil
 }
 
 func (o *createContextOptions) modifyContext(existingContext clientcmdapi.Context) clientcmdapi.Context {
@@ -121,17 +131,21 @@ func (o *createContextOptions) modifyContext(existingContext clientcmdapi.Contex
 
 func (o *createContextOptions) complete(cmd *cobra.Command) error {
 	args := cmd.Flags().Args()
-	if len(args) != 1 {
+	if len(args) > 1 {
 		return helpErrorf(cmd, "Unexpected args: %v", args)
 	}
-
+	if len(args) == 1 {
-	o.name = args[0]
+		o.name = args[0]
+	}
 	return nil
 }
 
 func (o createContextOptions) validate() error {
-	if len(o.name) == 0 {
+	if len(o.name) == 0 && !o.currContext {
-		return errors.New("you must specify a non-empty context name")
+		return errors.New("you must specify a non-empty context name or --current-context")
+	}
+	if len(o.name) > 0 && o.currContext {
+		return errors.New("you cannot specify a context name and --current-context")
 	}
 
 	return nil

pkg/kubectl/cmd/config/create_context_test.go

@@ -28,6 +28,7 @@ import (
 
 type createContextTest struct {
 	description    string
+	testContext    string              // name of the context being modified
 	config         clientcmdapi.Config //initiate kubectl config
 	args           []string            //kubectl set-context args
 	flags          []string            //kubectl set-context flags
@@ -38,6 +39,7 @@ type createContextTest struct {
 func TestCreateContext(t *testing.T) {
 	conf := clientcmdapi.Config{}
 	test := createContextTest{
+		testContext: "shaker-context",
 		description: "Testing for create a new context",
 		config:      conf,
 		args:        []string{"shaker-context"},
@@ -60,6 +62,7 @@ func TestModifyContext(t *testing.T) {
 			"shaker-context": {AuthInfo: "blue-user", Cluster: "big-cluster", Namespace: "saw-ns"},
 			"not-this":       {AuthInfo: "blue-user", Cluster: "big-cluster", Namespace: "saw-ns"}}}
 	test := createContextTest{
+		testContext: "shaker-context",
 		description: "Testing for modify a already exist context",
 		config:      conf,
 		args:        []string{"shaker-context"},
@@ -77,6 +80,32 @@ func TestModifyContext(t *testing.T) {
 	test.run(t)
 }
 
+func TestModifyCurrentContext(t *testing.T) {
+	conf := clientcmdapi.Config{
+		CurrentContext: "shaker-context",
+		Contexts: map[string]*clientcmdapi.Context{
+			"shaker-context": {AuthInfo: "blue-user", Cluster: "big-cluster", Namespace: "saw-ns"},
+			"not-this":       {AuthInfo: "blue-user", Cluster: "big-cluster", Namespace: "saw-ns"}}}
+	test := createContextTest{
+		testContext: "shaker-context",
+		description: "Testing for modify a current context",
+		config:      conf,
+		args:        []string{},
+		flags: []string{
+			"--current",
+			"--cluster=cluster_nickname",
+			"--user=user_nickname",
+			"--namespace=namespace",
+		},
+		expected: `Context "shaker-context" modified.` + "\n",
+		expectedConfig: clientcmdapi.Config{
+			Contexts: map[string]*clientcmdapi.Context{
+				"shaker-context": {AuthInfo: "user_nickname", Cluster: "cluster_nickname", Namespace: "namespace"},
+				"not-this":       {AuthInfo: "blue-user", Cluster: "big-cluster", Namespace: "saw-ns"}}},
+	}
+	test.run(t)
+}
+
 func (test createContextTest) run(t *testing.T) {
 	fakeKubeFile, err := ioutil.TempFile(os.TempDir(), "")
 	if err != nil {
@@ -108,8 +137,8 @@ func (test createContextTest) run(t *testing.T) {
 		}
 	}
 	if test.expectedConfig.Contexts != nil {
-		expectContext := test.expectedConfig.Contexts[test.args[0]]
+		expectContext := test.expectedConfig.Contexts[test.testContext]
-		actualContext := config.Contexts[test.args[0]]
+		actualContext := config.Contexts[test.testContext]
 		if expectContext.AuthInfo != actualContext.AuthInfo || expectContext.Cluster != actualContext.Cluster ||
 			expectContext.Namespace != actualContext.Namespace {
 			t.Errorf("Fail in %q:\n expected Context %v\n but found %v in kubeconfig\n", test.description, expectContext, actualContext)