cmd: extend decode cmd to print any field (#519)

Signed-off-by: Neil Shen <overvenus@gmail.com>

cmd/cmd.go

@@ -4,6 +4,7 @@ package cmd
 
 import (
 	"context"
+	"fmt"
 	"os"
 	"path/filepath"
 	"sync"
@@ -70,7 +71,7 @@ func AddFlags(cmd *cobra.Command) {
 	_ = cmd.PersistentFlags().MarkHidden(FlagSlowLogFile)
 }
 
-// Init ...
+// Init initializes BR cli.
 func Init(cmd *cobra.Command) (err error) {
 	initOnce.Do(func() {
 		// Initialize the logger.
@@ -95,7 +96,8 @@ func Init(cmd *cobra.Command) (err error) {
 		if len(conf.File.Filename) != 0 {
 			atomic.StoreUint64(&hasLogFile, 1)
 			summary.InitCollector(true)
-			cmd.Printf("Detail BR log in %s\n", conf.File.Filename)
+			// cmd.PrintErr prints to stderr, but PrintErrf prints to stdout.
+			cmd.PrintErr(fmt.Sprintf("Detail BR log in %s \n", conf.File.Filename))
 		}
 		lg, p, e := log.InitLogger(conf)
 		if e != nil {

cmd/validate.go → cmd/debug.go

@@ -8,7 +8,8 @@ import (
 	"crypto/sha256"
 	"encoding/hex"
 	"encoding/json"
-	"fmt"
+	"path"
+	"reflect"
 	"strings"
 
 	"github.com/gogo/protobuf/proto"
@@ -29,10 +30,10 @@ import (
 	"github.com/pingcap/br/pkg/utils"
 )
 
-// NewValidateCommand return a debug subcommand.
-func NewValidateCommand() *cobra.Command {
+// NewDebugCommand return a debug subcommand.
+func NewDebugCommand() *cobra.Command {
 	meta := &cobra.Command{
-		Use:          "validate <subcommand>",
+		Use:          "debug <subcommand>",
 		Short:        "commands to check/debug backup data",
 		SilenceUsage: false,
 		PersistentPreRunE: func(c *cobra.Command, args []string) error {
@@ -43,6 +44,8 @@ func NewValidateCommand() *cobra.Command {
 			task.LogArguments(c)
 			return nil
 		},
+		// To be compatible with older BR.
+		Aliases: []string{"validate"},
 	}
 	meta.AddCommand(newCheckSumCommand())
 	meta.AddCommand(newBackupMetaCommand())
@@ -244,33 +247,46 @@ func decodeBackupMetaCommand() *cobra.Command {
 
 			var cfg task.Config
 			if err := cfg.ParseFromFlags(cmd.Flags()); err != nil {
-				return err
+				return errors.Trace(err)
 			}
 			_, s, backupMeta, err := task.ReadBackupMeta(ctx, utils.MetaFile, &cfg)
-			if err != nil {
-				return err
-			}
-
-			backupMetaJSON, err := json.Marshal(backupMeta)
 			if err != nil {
 				return errors.Trace(err)
 			}
 
-			err = s.Write(ctx, utils.MetaJSONFile, backupMetaJSON)
-			if err != nil {
-				return errors.Trace(err)
+			fieldName, _ := cmd.Flags().GetString("field")
+			if fieldName == "" {
+				// No field flag, write backupmeta to external storage in JSON format.
+				backupMetaJSON, err := json.Marshal(backupMeta)
+				if err != nil {
+					return errors.Trace(err)
+				}
+				err = s.Write(ctx, utils.MetaJSONFile, backupMetaJSON)
+				if err != nil {
+					return errors.Trace(err)
+				}
+				cmd.Printf("backupmeta decoded at %s\n", path.Join(cfg.Storage, utils.MetaJSONFile))
+				return nil
 			}
 
-			field, err := cmd.Flags().GetString("field")
-			if err != nil {
-				log.Error("get field flag failed", zap.Error(err))
-				return err
-			}
-			switch field {
+			switch fieldName {
+			// To be compatible with older BR.
 			case "start-version":
-				fmt.Println(backupMeta.StartVersion)
+				fieldName = "StartVersion"
 			case "end-version":
-				fmt.Println(backupMeta.EndVersion)
+				fieldName = "EndVersion"
+			}
+
+			_, found := reflect.TypeOf(*backupMeta).FieldByName(fieldName)
+			if !found {
+				cmd.Printf("field '%s' not found\n", fieldName)
+				return nil
+			}
+			field := reflect.ValueOf(*backupMeta).FieldByName(fieldName)
+			if !field.CanInterface() {
+				cmd.Printf("field '%s' can not print\n", fieldName)
+			} else {
+				cmd.Printf("%v\n", field.Interface())
 			}
 			return nil
 		},

main.go

@@ -49,10 +49,13 @@ func main() {
 	cmd.AddFlags(rootCmd)
 	cmd.SetDefaultContext(ctx)
 	rootCmd.AddCommand(
-		cmd.NewValidateCommand(),
+		cmd.NewDebugCommand(),
 		cmd.NewBackupCommand(),
 		cmd.NewRestoreCommand(),
 	)
+	// Ouputs cmd.Print to stdout.
+	rootCmd.SetOut(os.Stdout)
+
 	rootCmd.SetArgs(os.Args[1:])
 	if err := rootCmd.Execute(); err != nil {
 		log.Error("br failed", zap.Error(err))

tests/br_other/run.sh

@@ -33,6 +33,12 @@ done
 echo "backup start..."
 run_br --pd $PD_ADDR backup full -s "local://$TEST_DIR/$DB" --ratelimit 5 --concurrency 4
 
+# Test debug decode
+run_br -s "local://$TEST_DIR/$DB" debug decode --field "Schemas"
+run_br -s "local://$TEST_DIR/$DB" debug decode --field "EndVersion"
+# Ensure compatibility
+run_br -s "local://$TEST_DIR/$DB" validate decode --field "end-version"
+
 # Test validate backupmeta
 run_br validate backupmeta -s "local://$TEST_DIR/$DB"
 run_br validate backupmeta -s "local://$TEST_DIR/$DB" --offset 100
@@ -62,7 +68,6 @@ run_br --pd $PD_ADDR backup full -s "local://$TEST_DIR/$DB/lock" --remove-schedu
 # record last backup pid
 _pid=$!
 
-
 # give the former backup some time to write down lock file (and initialize signal listener).
 sleep 1
 pkill -10 -P $_pid
@@ -93,7 +98,7 @@ else
    exit 1
 fi
 
-# make sure we won't stuck in non-scheduler state, even we send a SIGTERM to it. 
+# make sure we won't stuck in non-scheduler state, even we send a SIGTERM to it.
 # give enough time to BR so it can gracefully stop.
 sleep 5
 if curl http://$PD_ADDR/pd/api/v1/config/schedule | jq '[."schedulers-v2"][0][0]' | grep -q '"disable": false'