Merge pull request #46114 from arthur0/rename_context

Automatic merge from submit-queue (batch tested with PRs 46489, 46281, 46463, 46114, 43946)

Add `kubectl config rename-context`

Add `kubectl config rename-context`

This command allows renaming a context, instead of editing manually in .kubeconfig

Fix https://github.com/kubernetes/kubernetes/issues/45131

```release-note
Add `kubectl config rename-context`
```

docs/.generated_docs

@@ -34,6 +34,7 @@ docs/man/man1/kubectl-config-delete-cluster.1
 docs/man/man1/kubectl-config-delete-context.1
 docs/man/man1/kubectl-config-get-clusters.1
 docs/man/man1/kubectl-config-get-contexts.1
+docs/man/man1/kubectl-config-rename-context.1
 docs/man/man1/kubectl-config-set-cluster.1
 docs/man/man1/kubectl-config-set-context.1
 docs/man/man1/kubectl-config-set-credentials.1
@@ -131,6 +132,7 @@ docs/user-guide/kubectl/kubectl_config_delete-cluster.md
 docs/user-guide/kubectl/kubectl_config_delete-context.md
 docs/user-guide/kubectl/kubectl_config_get-clusters.md
 docs/user-guide/kubectl/kubectl_config_get-contexts.md
+docs/user-guide/kubectl/kubectl_config_rename-context.md
 docs/user-guide/kubectl/kubectl_config_set-cluster.md
 docs/user-guide/kubectl/kubectl_config_set-context.md
 docs/user-guide/kubectl/kubectl_config_set-credentials.md

docs/man/man1/kubectl-config-rename-context.1

@@ -0,0 +1,3 @@
+This file is autogenerated, but we've stopped checking such files into the
+repository to reduce the need for rebases. Please run hack/generate-docs.sh to
+populate this file.

docs/user-guide/kubectl/kubectl_config_rename-context.md

@@ -0,0 +1,3 @@
+This file is autogenerated, but we've stopped checking such files into the
+repository to reduce the need for rebases. Please run hack/generate-docs.sh to
+populate this file.

pkg/kubectl/cmd/config/BUILD

@@ -19,6 +19,7 @@ go_library(
         "get_clusters.go",
         "get_contexts.go",
         "navigation_step_parser.go",
+        "rename_context.go",
         "set.go",
         "unset.go",
         "use_context.go",
@@ -57,6 +58,7 @@ go_test(
         "get_clusters_test.go",
         "get_contexts_test.go",
         "navigation_step_parser_test.go",
+        "rename_context_test.go",
         "set_test.go",
         "unset_test.go",
         "use_context_test.go",

pkg/kubectl/cmd/config/config.go

@@ -64,6 +64,7 @@ func NewCmdConfig(pathOptions *clientcmd.PathOptions, out, errOut io.Writer) *co
 	cmd.AddCommand(NewCmdConfigGetClusters(out, pathOptions))
 	cmd.AddCommand(NewCmdConfigDeleteCluster(out, pathOptions))
 	cmd.AddCommand(NewCmdConfigDeleteContext(out, errOut, pathOptions))
+	cmd.AddCommand(NewCmdConfigRenameContext(out, pathOptions))
 
 	return cmd
 }

pkg/kubectl/cmd/config/rename_context.go

@@ -0,0 +1,136 @@
+/*
+Copyright 2017 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 config
+
+import (
+	"errors"
+	"fmt"
+	"io"
+
+	"github.com/spf13/cobra"
+
+	"k8s.io/client-go/tools/clientcmd"
+	"k8s.io/kubernetes/pkg/kubectl/cmd/templates"
+	cmdutil "k8s.io/kubernetes/pkg/kubectl/cmd/util"
+)
+
+// RenameContextOptions contains the options for running the rename-context cli command.
+type RenameContextOptions struct {
+	configAccess clientcmd.ConfigAccess
+	contextName  string
+	newName      string
+}
+
+const (
+	renameContextUse = "rename-context CONTEXT_NAME NEW_NAME"
+
+	renameContextShort = "Renames a context from the kubeconfig file."
+)
+
+var (
+	renameContextLong = templates.LongDesc(`
+		Renames a context from the kubeconfig file .
+
+		CONTEXT_NAME is the context name that you wish change.
+
+		NEW_NAME is the new name you wish to set.
+		
+		Note: In case the context being renamed is the 'current-context', this field will also be updated.`)
+
+	renameContextExample = templates.Examples(`
+		# Rename the context 'old-name' to 'new-name' in your kubeconfig file
+		kubectl config rename-context old-name new-name`)
+)
+
+// NewCmdConfigRenameContext creates a command object for the "rename-context" action
+func NewCmdConfigRenameContext(out io.Writer, configAccess clientcmd.ConfigAccess) *cobra.Command {
+	options := &RenameContextOptions{configAccess: configAccess}
+
+	cmd := &cobra.Command{
+		Use:     renameContextUse,
+		Short:   renameContextShort,
+		Long:    renameContextLong,
+		Example: renameContextExample,
+		Run: func(cmd *cobra.Command, args []string) {
+			if err := options.Complete(cmd, args, out); err != nil {
+				cmdutil.CheckErr(err)
+			}
+			if err := options.Validate(); err != nil {
+				cmdutil.UsageError(cmd, err.Error())
+			}
+			if err := options.RunRenameContext(out); err != nil {
+				cmdutil.CheckErr(err)
+			}
+		},
+	}
+	return cmd
+}
+
+// Complete assigns RenameContextOptions from the args.
+func (o *RenameContextOptions) Complete(cmd *cobra.Command, args []string, out io.Writer) error {
+	if len(args) != 2 {
+		cmd.Help()
+		return fmt.Errorf("Unexpected args: %v", args)
+	}
+
+	o.contextName = args[0]
+	o.newName = args[1]
+	return nil
+}
+
+func (o RenameContextOptions) Validate() error {
+	if len(o.newName) == 0 {
+		return errors.New("You must specify a new non-empty context name")
+	}
+	return nil
+}
+
+func (o RenameContextOptions) RunRenameContext(out io.Writer) error {
+	config, err := o.configAccess.GetStartingConfig()
+	if err != nil {
+		return err
+	}
+
+	configFile := o.configAccess.GetDefaultFilename()
+	if o.configAccess.IsExplicitFile() {
+		configFile = o.configAccess.GetExplicitFile()
+	}
+
+	context, exists := config.Contexts[o.contextName]
+	if !exists {
+		return fmt.Errorf("cannot rename the context %q, it's not in %s", o.contextName, configFile)
+	}
+
+	_, newExists := config.Contexts[o.newName]
+	if newExists {
+		return fmt.Errorf("cannot rename the context %q, the context %q already exists in %s", o.contextName, o.newName, configFile)
+	}
+
+	config.Contexts[o.newName] = context
+	delete(config.Contexts, o.contextName)
+
+	if config.CurrentContext == o.contextName {
+		config.CurrentContext = o.newName
+	}
+
+	if err := clientcmd.ModifyConfig(o.configAccess, *config, true); err != nil {
+		return err
+	}
+
+	fmt.Fprintf(out, "Context %q was renamed to %q.\n", o.contextName, o.newName)
+	return nil
+}

pkg/kubectl/cmd/config/rename_context_test.go

@@ -0,0 +1,156 @@
+/*
+Copyright 2017 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 config
+
+import (
+	"bytes"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"strings"
+	"testing"
+
+	"k8s.io/client-go/tools/clientcmd"
+	clientcmdapi "k8s.io/client-go/tools/clientcmd/api"
+)
+
+const (
+	currentContext            = "current-context"
+	newContext                = "new-context"
+	nonexistentCurrentContext = "nonexistent-current-context"
+	existentNewContext        = "existent-new-context"
+)
+
+var (
+	contextData *clientcmdapi.Context = clientcmdapi.NewContext()
+)
+
+type renameContextTest struct {
+	description    string
+	initialConfig  clientcmdapi.Config // initial config
+	expectedConfig clientcmdapi.Config // expected config
+	args           []string            // kubectl rename-context args
+	expectedOut    string              // expected out message
+	expectedErr    string              // expected error message
+}
+
+func TestRenameContext(t *testing.T) {
+	initialConfig := clientcmdapi.Config{
+		CurrentContext: currentContext,
+		Contexts:       map[string]*clientcmdapi.Context{currentContext: contextData}}
+
+	expectedConfig := clientcmdapi.Config{
+		CurrentContext: newContext,
+		Contexts:       map[string]*clientcmdapi.Context{newContext: contextData}}
+
+	test := renameContextTest{
+		description:    "Testing for kubectl config rename-context whose context to be renamed is the CurrentContext",
+		initialConfig:  initialConfig,
+		expectedConfig: expectedConfig,
+		args:           []string{currentContext, newContext},
+		expectedOut:    fmt.Sprintf("Context %q was renamed to %q.\n", currentContext, newContext),
+		expectedErr:    "",
+	}
+	test.run(t)
+}
+
+func TestRenameNonexistentContext(t *testing.T) {
+	initialConfig := clientcmdapi.Config{
+		CurrentContext: currentContext,
+		Contexts:       map[string]*clientcmdapi.Context{currentContext: contextData}}
+
+	test := renameContextTest{
+		description:    "Testing for kubectl config rename-context whose context to be renamed no exists",
+		initialConfig:  initialConfig,
+		expectedConfig: initialConfig,
+		args:           []string{nonexistentCurrentContext, newContext},
+		expectedOut:    "",
+		expectedErr:    fmt.Sprintf("cannot rename the context %q, it's not in", nonexistentCurrentContext),
+	}
+	test.run(t)
+}
+
+func TestRenameToAlreadyExistingContext(t *testing.T) {
+	initialConfig := clientcmdapi.Config{
+		CurrentContext: currentContext,
+		Contexts: map[string]*clientcmdapi.Context{
+			currentContext:     contextData,
+			existentNewContext: contextData}}
+
+	test := renameContextTest{
+		description:    "Testing for kubectl config rename-context whose the new name is already in another context.",
+		initialConfig:  initialConfig,
+		expectedConfig: initialConfig,
+		args:           []string{currentContext, existentNewContext},
+		expectedOut:    "",
+		expectedErr:    fmt.Sprintf("cannot rename the context %q, the context %q already exists", currentContext, existentNewContext),
+	}
+	test.run(t)
+}
+
+func (test renameContextTest) run(t *testing.T) {
+	fakeKubeFile, _ := ioutil.TempFile("", "")
+	defer os.Remove(fakeKubeFile.Name())
+	err := clientcmd.WriteToFile(test.initialConfig, fakeKubeFile.Name())
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	pathOptions := clientcmd.NewDefaultPathOptions()
+	pathOptions.GlobalFile = fakeKubeFile.Name()
+	pathOptions.EnvVar = ""
+	options := RenameContextOptions{
+		configAccess: pathOptions,
+		contextName:  test.args[0],
+		newName:      test.args[1],
+	}
+	buf := bytes.NewBuffer([]byte{})
+	cmd := NewCmdConfigRenameContext(buf, options.configAccess)
+
+	options.Complete(cmd, test.args, buf)
+	options.Validate()
+	err = options.RunRenameContext(buf)
+
+	if len(test.expectedErr) != 0 {
+		if err == nil {
+			t.Errorf("Did not get %v", test.expectedErr)
+		} else {
+			if !strings.Contains(err.Error(), test.expectedErr) {
+				t.Errorf("Expected error %v, but got %v", test.expectedErr, err)
+			}
+		}
+		return
+	}
+
+	config, err := clientcmd.LoadFromFile(fakeKubeFile.Name())
+	if err != nil {
+		t.Fatalf("unexpected error loading kubeconfig file: %v", err)
+	}
+
+	_, oldExists := config.Contexts[currentContext]
+	_, newExists := config.Contexts[newContext]
+
+	if (!newExists) || (oldExists) || (config.CurrentContext != newContext) {
+		t.Errorf("Failed in: %q\n expected %v\n but got %v", test.description, test.expectedConfig, *config)
+	}
+
+	if len(test.expectedOut) != 0 {
+		if buf.String() != test.expectedOut {
+			t.Errorf("Failed in:%q\n expected out %v\n but got %v", test.description, test.expectedOut, buf.String())
+		}
+	}
+}