Merge pull request #18183 from ah8ad3/etcdctl-doc

Add examples to `etcdctl snapshot` command's help

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",
+		Example: snapshotExample,
 	}
 	cmd.AddCommand(NewSnapshotSaveCommand())
 	return cmd
@@ -41,12 +64,13 @@ func NewSnapshotSaveCommand() *cobra.Command {
 		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)
+		},
 	}
 )
 
@@ -52,38 +56,42 @@ func init() {
 {{ $cmdname := cmdName .Cmd .Cmd.Root }}\
 NAME:
 {{if not .Cmd.HasParent}}\
-{{printf "\t%s - %s" .Cmd.Name .Cmd.Short}}
+{{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}}\