Create util for etcdctl, move helper of cobra from main package to

etcdctl util, create normalizer of examples in util, add some more
examples, change indent of etcdctl from "\t" to "  "

Signed-off-by: ah8ad3 <ah8ad3@gmail.com>

etcdctl/ctlv3/command/snapshot_command.go

@@ -23,14 +23,37 @@ import (
 
 	"go.etcd.io/etcd/client/pkg/v3/logutil"
 	snapshot "go.etcd.io/etcd/client/v3/snapshot"
+	"go.etcd.io/etcd/etcdctl/v3/util"
 	"go.etcd.io/etcd/pkg/v3/cobrautl"
 )
 
+var (
+	snapshotExample = util.Normalize(`
+	# Save snapshot to a given file
+	etcdctl snapshot save /backup/etcd-snapshot.db
+
+	# Get snapshot from given address and save it to file
+	etcdctl snapshot save --endpoints=127.0.0.1:3000 /backup/etcd-snapshot.db 
+	
+	# Get snapshot from given address with certificates
+	etcdctl --endpoints=https://127.0.0.1:2379 --cacert=/etc/etcd/ca.crt --cert=/etc/etcd/etcd.crt --key=/etc/etcd/etcd.key snapshot save /backup/etcd-snapshot.db
+
+	# Get snapshot wih certain user and password
+	etcdctl --user=root --password=password123 snapshot save /backup/etcd-snapshot.db
+
+	# Get snapshot from given address with timeout
+	etcdctl --endpoints=https://127.0.0.1:2379 --dial-timeout=20s snapshot save /backup/etcd-snapshot.db
+
+	# Save snapshot with desirable time format
+	etcdctl snapshot save /mnt/backup/etcd/backup_$(date +%Y%m%d_%H%M%S).db`)
+)
+
 // NewSnapshotCommand returns the cobra command for "snapshot".
 func NewSnapshotCommand() *cobra.Command {
 	cmd := &cobra.Command{
-		Use:   "snapshot <subcommand>",
-		Short: "Manages etcd node snapshots",
+		Use:     "snapshot <subcommand>",
+		Short:   "Manages etcd node snapshots",
+		Example: snapshotExample,
 	}
 	cmd.AddCommand(NewSnapshotSaveCommand())
 	return cmd
@@ -38,15 +61,16 @@ func NewSnapshotCommand() *cobra.Command {
 
 func NewSnapshotSaveCommand() *cobra.Command {
 	return &cobra.Command{
-		Use:   "save <filename>",
-		Short: "Stores an etcd node backend snapshot to a given file",
-		Run:   snapshotSaveCommandFunc,
+		Use:     "save <filename>",
+		Short:   "Stores an etcd node backend snapshot to a given file",
+		Run:     snapshotSaveCommandFunc,
+		Example: snapshotExample,
 	}
 }
 
 func snapshotSaveCommandFunc(cmd *cobra.Command, args []string) {
 	if len(args) != 1 {
-		err := fmt.Errorf("snapshot save expects one argument")
+		err := fmt.Errorf("snapshot save expects one argument <filename>")
 		cobrautl.ExitWithError(cobrautl.ExitBadArgs, err)
 	}
 

etcdctl/util/normalizer.go

@@ -0,0 +1,49 @@
+// Copyright 2024 The etcd 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 util
+
+import "strings"
+
+const indentation = "  "
+
+// Normalize normalizes a string:
+//  1. trim the leading and trailing space
+//  2. add an indentation before each line
+func Normalize(s string) string {
+	if len(s) == 0 {
+		return s
+	}
+	return normalizer{s}.trim().indent().string
+}
+
+type normalizer struct {
+	string
+}
+
+func (n normalizer) trim() normalizer {
+	n.string = strings.TrimSpace(n.string)
+	return n
+}
+
+func (n normalizer) indent() normalizer {
+	indentedLines := []string{}
+	for _, line := range strings.Split(n.string, "\n") {
+		trimmed := strings.TrimSpace(line)
+		indented := indentation + trimmed
+		indentedLines = append(indentedLines, indented)
+	}
+	n.string = strings.Join(indentedLines, "\n")
+	return n
+}

pkg/cobrautl/help.go

@@ -43,6 +43,10 @@ var (
 			}
 			return strings.Join(parts, " ")
 		},
+		"indent": func(s string) string {
+			pad := strings.Repeat(" ", 2)
+			return pad + strings.Replace(s, "\n", "\n"+pad, -1)
+		},
 	}
 )
 
@@ -51,39 +55,43 @@ func init() {
 {{ $cmd := .Cmd }}\
 {{ $cmdname := cmdName .Cmd .Cmd.Root }}\
 NAME:
-{{ if not .Cmd.HasParent }}\
-{{printf "\t%s - %s" .Cmd.Name .Cmd.Short}}
+{{if not .Cmd.HasParent}}\
+{{printf "%s - %s" .Cmd.Name .Cmd.Short | indent}}
 {{else}}\
-{{printf "\t%s - %s" $cmdname .Cmd.Short}}
+{{printf "%s - %s" $cmdname .Cmd.Short | indent}}
 {{end}}\
 
 USAGE:
-{{printf "\t%s" .Cmd.UseLine}}
+{{printf "%s" .Cmd.UseLine | indent}}
 {{ if not .Cmd.HasParent }}\
 
 VERSION:
-{{printf "\t%s" .Version}}
+{{printf "%s" .Version | indent}}
 {{end}}\
 {{if .Cmd.HasSubCommands}}\
 
 API VERSION:
-{{printf "\t%s" .APIVersion}}
+{{.APIVersion | indent}}
+{{end}}\
+{{if .Cmd.HasExample}}\
+
+Examples:
+{{.Cmd.Example}}
 {{end}}\
 {{if .Cmd.HasSubCommands}}\
 
-
 COMMANDS:
 {{range .SubCommands}}\
 {{ $cmdname := cmdName . $cmd }}\
 {{ if .Runnable }}\
-{{printf "\t%s\t%s" $cmdname .Short}}
+{{printf "%s\t%s" $cmdname .Short | indent}}
 {{end}}\
 {{end}}\
 {{end}}\
 {{ if .Cmd.Long }}\
 
 DESCRIPTION:
-{{range $line := descToLines .Cmd.Long}}{{printf "\t%s" $line}}
+{{range $line := descToLines .Cmd.Long}}{{printf "%s" $line | indent}}
 {{end}}\
 {{end}}\
 {{if .Cmd.HasLocalFlags}}\