feat: new talosctl config remove to remove context

Adds a new sub-command to talosctl config. It takes in the context to be
deleted as argument and supports glob matching.

A local flag --noconfirm|-y can be passed to bypass the confirmation
prompt.

It also supports dry run by passing the --dry-run flag similar to
apply-config and edit commands.

Example:

    $ talosctl config remove 'ctx-*'
    Remove context ctx-a? (y/N): y
    Remove context ctx-b? (y/N): y

Signed-off-by: Murtaza Udaipurwala <murtaza@murtazau.xyz>
Signed-off-by: Dmitriy Matrenichev <dmitry.matrenichev@siderolabs.com>

cmd/talosctl/cmd/talos/config.go

@@ -10,6 +10,7 @@ import (
 	"crypto/x509"
 	"encoding/base64"
 	"encoding/pem"
+	"errors"
 	"fmt"
 	"os"
 	"sort"
@@ -19,6 +20,7 @@ import (
 	"time"
 
 	"github.com/dustin/go-humanize"
+	"github.com/ryanuber/go-glob"
 	"github.com/siderolabs/gen/maps"
 	"github.com/spf13/cobra"
 	"google.golang.org/protobuf/types/known/durationpb"
@@ -186,6 +188,89 @@ var configAddCmd = &cobra.Command{
 	},
 }
 
+// configRemoveCmdFlags represents the `config remove` command flags.
+var configRemoveCmdFlags struct {
+	noconfirm bool
+	dry       bool
+}
+
+// configRemoveCmd represents the `config remove` command.
+var configRemoveCmd = &cobra.Command{
+	Use:   "remove <context>",
+	Short: "Remove contexts",
+	Args:  cobra.ExactArgs(1),
+	RunE: func(cmd *cobra.Command, args []string) error {
+		pattern := args[0]
+		if pattern == "" {
+			return fmt.Errorf("no context specified")
+		}
+
+		c, err := clientconfig.Open(GlobalArgs.Talosconfig)
+		if err != nil {
+			return fmt.Errorf("error reading config: %w", err)
+		}
+
+		if len(c.Contexts) == 0 {
+			return errors.New("no contexts defined")
+		}
+
+		matches := sortInPlace(maps.Keys(
+			maps.Filter(c.Contexts, func(context string, _ *clientconfig.Context) bool {
+				return glob.Glob(pattern, context)
+			}),
+		))
+		if len(matches) == 0 {
+			return fmt.Errorf("no contexts matched %q", pattern)
+		}
+
+		// we want to prevent file updates in case there were no changes
+		noChanges := true
+
+		for _, match := range matches {
+			if match == c.Context {
+				fmt.Fprintf(
+					os.Stderr,
+					"skipping removal of current context %q, please change it to another before removing\n",
+					match,
+				)
+
+				continue
+			}
+
+			if !configRemoveCmdFlags.noconfirm {
+				prompt := fmt.Sprintf("remove context %q", match)
+
+				if !helpers.Confirm(prompt + "?") {
+					continue
+				}
+			} else {
+				fmt.Fprintf(os.Stderr, "removing context %q\n", match)
+			}
+
+			noChanges = false
+			delete(c.Contexts, match)
+		}
+
+		if configRemoveCmdFlags.dry || noChanges {
+			return nil
+		}
+
+		err = c.Save(GlobalArgs.Talosconfig)
+		if err != nil {
+			return fmt.Errorf("error writing config: %w", err)
+		}
+
+		return nil
+	},
+	ValidArgsFunction: CompleteConfigContext,
+}
+
+func sortInPlace(slc []string) []string {
+	sort.Slice(slc, func(i, j int) bool { return slc[i] < slc[j] })
+
+	return slc
+}
+
 func checkAndSetCrtAndKey(configContext *clientconfig.Context) error {
 	crt := configAddCmdFlags.crt
 	key := configAddCmdFlags.key
@@ -430,7 +515,8 @@ var configInfoCmd = &cobra.Command{
 	},
 }
 
-// CompleteConfigContext represents tab completion for `--context` argument and `config context` command.
+// CompleteConfigContext represents tab completion for `--context`
+// argument and `config [context|remove]` command.
 func CompleteConfigContext(cmd *cobra.Command, args []string, toComplete string) ([]string, cobra.ShellCompDirective) {
 	c, err := clientconfig.Open(GlobalArgs.Talosconfig)
 	if err != nil {
@@ -449,6 +535,7 @@ func init() {
 		configNodeCmd,
 		configContextCmd,
 		configAddCmd,
+		configRemoveCmd,
 		configGetContextsCmd,
 		configMergeCmd,
 		configNewCmd,
@@ -459,6 +546,14 @@ func init() {
 	configAddCmd.Flags().StringVar(&configAddCmdFlags.crt, "crt", "", "the path to the certificate")
 	configAddCmd.Flags().StringVar(&configAddCmdFlags.key, "key", "", "the path to the key")
 
+	configRemoveCmd.Flags().BoolVarP(
+		&configRemoveCmdFlags.noconfirm, "noconfirm", "y", false,
+		"do not ask for confirmation",
+	)
+	configRemoveCmd.Flags().BoolVar(
+		&configRemoveCmdFlags.dry, "dry-run", false, "dry run",
+	)
+
 	configNewCmd.Flags().StringSliceVar(&configNewCmdFlags.roles, "roles", role.MakeSet(role.Admin).Strings(), "roles")
 	configNewCmd.Flags().DurationVar(&configNewCmdFlags.crtTTL, "crt-ttl", 87600*time.Hour, "certificate TTL")
 

cmd/talosctl/pkg/talos/helpers/confirm.go

@@ -0,0 +1,30 @@
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package helpers
+
+import (
+	"fmt"
+	"strings"
+)
+
+var okays = []string{"y", "yes"}
+
+// Confirm asks the user to confirm their action. Anything other than
+// `y` and `yes` returns false.
+func Confirm(prompt string) bool {
+	var inp string
+
+	fmt.Printf("%s (y/N): ", prompt)
+	fmt.Scanf("%s", &inp)
+	inp = strings.TrimSpace(inp)
+
+	for _, ok := range okays {
+		if strings.EqualFold(inp, ok) {
+			return true
+		}
+	}
+
+	return false
+}

website/content/v1.4/reference/cli.md

@@ -571,6 +571,36 @@ talosctl config node <endpoint>... [flags]
 
 * [talosctl config](#talosctl-config)	 - Manage the client configuration file (talosconfig)
 
+## talosctl config remove
+
+Remove contexts
+
+```
+talosctl config remove <context> [flags]
+```
+
+### Options
+
+```
+      --dry-run     dry run
+  -h, --help        help for remove
+  -y, --noconfirm   do not ask for confirmation
+```
+
+### Options inherited from parent commands
+
+```
+      --cluster string       Cluster to connect to if a proxy endpoint is used.
+      --context string       Context to be used in command
+  -e, --endpoints strings    override default endpoints in Talos configuration
+  -n, --nodes strings        target the specified nodes
+      --talosconfig string   The path to the Talos configuration file. Defaults to 'TALOSCONFIG' env variable if set, otherwise '$HOME/.talos/config' and '/var/run/secrets/talos.dev/config' in order.
+```
+
+### SEE ALSO
+
+* [talosctl config](#talosctl-config)	 - Manage the client configuration file (talosconfig)
+
 ## talosctl config
 
 Manage the client configuration file (talosconfig)
@@ -602,6 +632,7 @@ Manage the client configuration file (talosconfig)
 * [talosctl config merge](#talosctl-config-merge)	 - Merge additional contexts from another client configuration file
 * [talosctl config new](#talosctl-config-new)	 - Generate a new client configuration file
 * [talosctl config node](#talosctl-config-node)	 - Set the node(s) for the current context
+* [talosctl config remove](#talosctl-config-remove)	 - Remove contexts
 
 ## talosctl conformance kubernetes