config(ticdc): Fix old value configuration check for maxwell protocol (…

…pingcap#3747) (pingcap#3783)

cdc/sink/codec/interface.go

@@ -177,6 +177,26 @@ func (p *Protocol) FromString(protocol string) {
 	}
 }
 
+// String converts the Protocol enum type string to string.
+func (p Protocol) String() string {
+	switch p {
+	case ProtocolDefault:
+		return "default"
+	case ProtocolCanal:
+		return "canal"
+	case ProtocolAvro:
+		return "avro"
+	case ProtocolMaxwell:
+		return "maxwell"
+	case ProtocolCanalJSON:
+		return "canal-json"
+	case ProtocolCraft:
+		return "craft"
+	default:
+		panic("unreachable")
+	}
+}
+
 type EncoderBuilder interface {
 	Build(ctx context.Context) (EventBatchEncoder, error)
 }

cdc/sink/mq.go

@@ -15,6 +15,7 @@ package sink
 
 import (
 	"context"
+	"fmt"
 	"net/url"
 	"strings"
 	"sync/atomic"
@@ -68,9 +69,10 @@ func newMqSink(
 ) (*mqSink, error) {
 	var protocol codec.Protocol
 	protocol.FromString(config.Sink.Protocol)
-	if (protocol == codec.ProtocolCanal || protocol == codec.ProtocolCanalJSON) && !config.EnableOldValue {
-		log.Error("Old value is not enabled when using Canal protocol. Please update changefeed config")
-		return nil, cerror.WrapError(cerror.ErrKafkaInvalidConfig, errors.New("Canal requires old value to be enabled"))
+	if (protocol == codec.ProtocolCanal || protocol == codec.ProtocolCanalJSON || protocol == codec.ProtocolMaxwell) && !config.EnableOldValue {
+		log.Error(fmt.Sprintf("Old value is not enabled when using `%s` protocol. "+
+			"Please update changefeed config", protocol.String()))
+		return nil, cerror.WrapError(cerror.ErrKafkaInvalidConfig, errors.New(fmt.Sprintf("%s protocol requires old value to be enabled", protocol.String())))
 	}
 
 	encoderBuilder, err := codec.NewEventBatchEncoderBuilder(protocol, credential, opts)

pkg/cmd/cli/cli_changefeed_create.go

@@ -46,6 +46,7 @@ import (
 // forceEnableOldValueProtocols specifies which protocols need to be forced to enable old value.
 var forceEnableOldValueProtocols = []string{
 	"canal",
+	"canal-json",
 	"maxwell",
 }
 
@@ -205,9 +206,12 @@ func (o *createChangefeedOptions) completeCfg(ctx context.Context, cmd *cobra.Co
 		}
 
 		protocol := sinkURIParsed.Query().Get("protocol")
+		if protocol != "" {
+			cfg.Sink.Protocol = protocol
+		}
 		for _, fp := range forceEnableOldValueProtocols {
-			if protocol == fp {
-				log.Warn("Attempting to replicate without old value enabled. CDC will enable old value and continue.", zap.String("protocol", protocol))
+			if cfg.Sink.Protocol == fp {
+				log.Warn("Attempting to replicate without old value enabled. CDC will enable old value and continue.", zap.String("protocol", cfg.Sink.Protocol))
 				cfg.EnableOldValue = true
 				break
 			}