feat: support kafka writer batch conf (#3495)

Signed-off-by: Song Gao <disxiaofei@163.com>

extensions/sinks/kafka/ext/kafka.go

@@ -19,6 +19,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"strings"
+	"time"
 
 	kafkago "github.com/segmentio/kafka-go"
 
@@ -46,10 +47,17 @@ type sinkConf struct {
 }
 
 type kafkaConf struct {
-	MaxAttempts  int         `json:"maxAttempts"`
-	RequiredACKs int         `json:"requiredACKs"`
-	Key          string      `json:"key"`
-	Headers      interface{} `json:"headers"`
+	MaxAttempts  int             `json:"maxAttempts"`
+	RequiredACKs int             `json:"requiredACKs"`
+	Key          string          `json:"key"`
+	Headers      interface{}     `json:"headers"`
+	WriterConf   kafkaWriterConf `json:"writerConf"`
+}
+
+type kafkaWriterConf struct {
+	BatchSize    int           `json:"batchSize"`
+	BatchTimeout time.Duration `json:"batchTimeout"`
+	BatchBytes   int64         `json:"batchBytes"`
 }
 
 func (m *kafkaSink) Ping(_ string, props map[string]interface{}) error {
@@ -92,10 +100,7 @@ func (m *kafkaSink) Configure(props map[string]interface{}) error {
 		return err
 	}
 	m.tlsConfig = tlsConfig
-	kc := &kafkaConf{
-		RequiredACKs: -1,
-		MaxAttempts:  1,
-	}
+	kc := getDefaultKafkaConf()
 	if err := cast.MapToStruct(props, kc); err != nil {
 		return err
 	}
@@ -122,7 +127,9 @@ func (m *kafkaSink) buildKafkaWriter() error {
 		AllowAutoTopicCreation: true,
 		MaxAttempts:            m.kc.MaxAttempts,
 		RequiredAcks:           kafkago.RequiredAcks(m.kc.RequiredACKs),
-		BatchSize:              1,
+		BatchSize:              m.kc.WriterConf.BatchSize,
+		BatchBytes:             m.kc.WriterConf.BatchBytes,
+		BatchTimeout:           m.kc.WriterConf.BatchTimeout,
 		Transport: &kafkago.Transport{
 			SASL: mechanism,
 			TLS:  m.tlsConfig,
@@ -310,3 +317,16 @@ func (m *kafkaSink) ping(address string) error {
 	defer c.Close()
 	return nil
 }
+
+func getDefaultKafkaConf() *kafkaConf {
+	c := &kafkaConf{
+		RequiredACKs: -1,
+		MaxAttempts:  1,
+		WriterConf: kafkaWriterConf{
+			BatchSize:    100,
+			BatchTimeout: 5 * time.Millisecond,
+			BatchBytes:   1048576,
+		},
+	}
+	return c
+}