feat: add producer interceptor interface

batch_producer_interceptor.go

@@ -0,0 +1,14 @@
+package kafka
+
+import (
+	"context"
+)
+
+type BatchProducerInterceptorContext struct {
+	Context context.Context
+	Message *Message
+}
+
+type BatchProducerInterceptor interface {
+	OnProduce(ctx context.Context, msg Message)
+}

examples/with-deadletter/main.go

@@ -21,7 +21,7 @@ func main() {
 		Writer: kafka.WriterConfig{
 			Brokers: []string{"localhost:29092"},
 		},
-	})
+	}, nil)
 
 	_ = producer.Produce(context.Background(), kafka.Message{
 		Topic: topicName,

examples/with-kafka-producer/main.go

@@ -10,7 +10,7 @@ func main() {
 		Writer: kafka.WriterConfig{
 			Brokers: []string{"localhost:29092"},
 		},
-	})
+	}, nil)
 
 	const topicName = "standart-topic"
 

examples/with-kafka-transactional-retry-disabled/main.go

@@ -13,7 +13,7 @@ import (
 func main() {
 	producer, _ := kafka.NewProducer(&kafka.ProducerConfig{
 		Writer: kafka.WriterConfig{Brokers: []string{"localhost:29092"}, Topic: "standart-topic"},
-	})
+	}, nil)
 
 	producer.ProduceBatch(context.Background(), []kafka.Message{
 		{Key: []byte("key1"), Value: []byte("message1")},

producer.go

@@ -18,10 +18,11 @@ type Writer interface {
 }
 
 type producer struct {
-	w Writer
+	w           Writer
+	interceptor *ProducerInterceptor
 }
 
-func NewProducer(cfg *ProducerConfig) (Producer, error) {
+func NewProducer(cfg *ProducerConfig, interceptor *ProducerInterceptor) (Producer, error) {
 	kafkaWriter := &kafka.Writer{
 		Addr:                   kafka.TCP(cfg.Writer.Brokers...),
 		Topic:                  cfg.Writer.Topic,
@@ -51,7 +52,7 @@ func NewProducer(cfg *ProducerConfig) (Producer, error) {
 		kafkaWriter.Transport = transport
 	}
 
-	p := &producer{w: kafkaWriter}
+	p := &producer{w: kafkaWriter, interceptor: interceptor}
 
 	if cfg.DistributedTracingEnabled {
 		otelWriter, err := NewOtelProducer(cfg, kafkaWriter)
@@ -64,18 +65,27 @@ func NewProducer(cfg *ProducerConfig) (Producer, error) {
 	return p, nil
 }
 
-func (c *producer) Produce(ctx context.Context, message Message) error {
-	return c.w.WriteMessages(ctx, message.toKafkaMessage())
+func (p *producer) Produce(ctx context.Context, message Message) error {
+	if p.interceptor != nil {
+		(*p.interceptor).OnProduce(ProducerInterceptorContext{Context: ctx, Message: &message})
+	}
+
+	return p.w.WriteMessages(ctx, message.toKafkaMessage())
 }
 
-func (c *producer) ProduceBatch(ctx context.Context, messages []Message) error {
+func (p *producer) ProduceBatch(ctx context.Context, messages []Message) error {
 	kafkaMessages := make([]kafka.Message, 0, len(messages))
 	for i := range messages {
+		if p.interceptor != nil {
+			(*p.interceptor).OnProduce(ProducerInterceptorContext{Context: ctx, Message: &messages[i]})
+		}
+
 		kafkaMessages = append(kafkaMessages, messages[i].toKafkaMessage())
 	}
-	return c.w.WriteMessages(ctx, kafkaMessages...)
+
+	return p.w.WriteMessages(ctx, kafkaMessages...)
 }
 
-func (c *producer) Close() error {
-	return c.w.Close()
+func (p *producer) Close() error {
+	return p.w.Close()
 }

producer_interceptor.go

@@ -0,0 +1,14 @@
+package kafka
+
+import (
+	"context"
+)
+
+type ProducerInterceptorContext struct {
+	Context context.Context
+	Message *Message
+}
+
+type ProducerInterceptor interface {
+	OnProduce(ctx ProducerInterceptorContext)
+}

producer_test.go

@@ -2,6 +2,8 @@ package kafka
 
 import (
 	"context"
+	stubData "github.com/Trendyol/kafka-konsumer/v2/test/stub-data"
+	"github.com/gofiber/fiber/v2/utils"
 	"testing"
 
 	"github.com/segmentio/kafka-go"
@@ -20,6 +22,27 @@ func Test_producer_Produce_Successfully(t *testing.T) {
 	}
 }
 
+func Test_producer_Produce_interceptor_Successfully(t *testing.T) {
+	// Given
+	mw := &mockWriter{}
+	msg := Message{Headers: make([]Header, 0)}
+	msg.Headers = append(msg.Headers, kafka.Header{
+		Key:   "x-correlation-id",
+		Value: []byte(utils.UUIDv4()),
+	})
+	interceptor := stubData.NewMockProducerInterceptor()
+
+	p := producer{w: mw, interceptor: &interceptor}
+
+	// When
+	err := p.Produce(context.Background(), msg)
+
+	// Then
+	if err != nil {
+		t.Fatalf("Producing err %s", err.Error())
+	}
+}
+
 func Test_producer_ProduceBatch_Successfully(t *testing.T) {
 	// Given
 	mw := &mockWriter{}
@@ -33,6 +56,20 @@ func Test_producer_ProduceBatch_Successfully(t *testing.T) {
 	}
 }
 
+func Test_producer_ProduceBatch_interceptor_Successfully(t *testing.T) {
+	// Given
+	mw := &mockWriter{}
+	interceptor := stubData.NewMockProducerInterceptor()
+	p := producer{w: mw, interceptor: &interceptor}
+
+	// When
+	err := p.ProduceBatch(context.Background(), []Message{{}, {}, {}})
+	// Then
+	if err != nil {
+		t.Fatalf("Batch Producing err %s", err.Error())
+	}
+}
+
 func Test_producer_Close_Successfully(t *testing.T) {
 	// Given
 	mw := &mockWriter{}
@@ -48,7 +85,7 @@ func Test_producer_Close_Successfully(t *testing.T) {
 
 type mockWriter struct{}
 
-func (m *mockWriter) WriteMessages(_ context.Context, _ ...kafka.Message) error {
+func (m *mockWriter) WriteMessages(_ context.Context, msg ...kafka.Message) error {
 	return nil
 }
 

test/integration/docker-compose.yml

@@ -1,7 +1,7 @@
 version: "3.8"
 services:
   redpanda:
-    image: docker.redpanda.com/redpandadata/redpanda:v23.3.9-amd64 #for m1 => v23.3.9-arm64
+    image: docker.redpanda.com/redpandadata/redpanda:v23.3.9-arm64 #for m1 => v23.3.9-arm64
     container_name: redpanda-1
     command:
       - redpanda

test/integration/integration_test.go

@@ -6,6 +6,7 @@ import (
 	"errors"
 	"fmt"
 	"github.com/Trendyol/kafka-konsumer/v2"
+	stub_data "github.com/Trendyol/kafka-konsumer/v2/test/stub-data"
 	segmentio "github.com/segmentio/kafka-go"
 	"testing"
 	"time"
@@ -14,40 +15,99 @@ import (
 func Test_Should_Produce_Successfully(t *testing.T) {
 	// Given
 	t.Parallel()
-	topic := "produce-topic"
 	brokerAddress := "localhost:9092"
 
-	producer, _ := kafka.NewProducer(&kafka.ProducerConfig{
-		Writer: kafka.WriterConfig{AllowAutoTopicCreation: true, Topic: topic, Brokers: []string{brokerAddress}},
-		Transport: &kafka.TransportConfig{
-			MetadataTopics: []string{
-				topic,
+	t.Run("without interceptor", func(t *testing.T) {
+		//Given
+
+		topic := "produce-topic"
+		producer, _ := kafka.NewProducer(&kafka.ProducerConfig{
+			Writer: kafka.WriterConfig{AllowAutoTopicCreation: true, Topic: topic, Brokers: []string{brokerAddress}},
+			Transport: &kafka.TransportConfig{
+				MetadataTopics: []string{
+					topic,
+				},
 			},
-		},
-	})
+		}, nil)
 
-	// When
-	err := producer.Produce(context.Background(), kafka.Message{
-		Key:   []byte("1"),
-		Value: []byte(`foo`),
+		// When
+		err := producer.Produce(context.Background(), kafka.Message{
+			Key:   []byte("1"),
+			Value: []byte(`foo`),
+		})
+
+		// Then
+		if err != nil {
+			t.Fatalf("Error while producing err %s", err.Error())
+		}
 	})
 
-	// Then
-	if err != nil {
-		t.Fatalf("Error while producing err %s", err.Error())
-	}
+	t.Run("with interceptor", func(t *testing.T) {
+		// Given
+		topic := "produce-interceptor-topic"
+		consumerGroup := "produce-topic-cg"
+		interceptor := stub_data.NewMockProducerInterceptor()
+
+		producer, _ := kafka.NewProducer(&kafka.ProducerConfig{
+			Writer: kafka.WriterConfig{AllowAutoTopicCreation: true, Topic: topic, Brokers: []string{brokerAddress}},
+			Transport: &kafka.TransportConfig{
+				MetadataTopics: []string{
+					topic,
+				},
+			},
+		}, &interceptor)
+
+		// When
+		err := producer.Produce(context.Background(), kafka.Message{
+			Key:   []byte("1"),
+			Value: []byte(`foo`),
+		})
+
+		messageCh := make(chan *kafka.Message)
+
+		consumerCfg := &kafka.ConsumerConfig{
+			Reader: kafka.ReaderConfig{Brokers: []string{brokerAddress}, Topic: topic, GroupID: consumerGroup},
+			ConsumeFn: func(message *kafka.Message) error {
+				messageCh <- message
+				return nil
+			},
+		}
+
+		consumer, _ := kafka.NewConsumer(consumerCfg)
+		defer consumer.Stop()
+
+		consumer.Consume()
+
+		// Then
+
+		if err != nil {
+			t.Fatalf("Error while producing err %s", err.Error())
+		}
+
+		actual := <-messageCh
+		if string(actual.Value) != "foo" {
+			t.Fatalf("Value does not equal %s", actual.Value)
+		}
+		if string(actual.Key) != "1" {
+			t.Fatalf("Key does not equal %s", actual.Key)
+		}
+		if len(actual.Headers) != 1 {
+			t.Fatalf("Header size does not equal %d", len(actual.Headers))
+		}
+		if string(actual.Headers[0].Key) != stub_data.XSourceAppKey {
+			t.Fatalf("Header key does not equal %s", actual.Headers[0].Key)
+		}
+		if string(actual.Headers[0].Value) != stub_data.XSourceAppValue {
+			t.Fatalf("Header value does not equal %s", actual.Headers[0].Value)
+		}
+	})
 }
 
 func Test_Should_Batch_Produce_Successfully(t *testing.T) {
 	// Given
 	t.Parallel()
 	topic := "batch-produce-topic"
 	brokerAddress := "localhost:9092"
-
-	producer, _ := kafka.NewProducer(&kafka.ProducerConfig{
-		Writer: kafka.WriterConfig{AllowAutoTopicCreation: true, Topic: topic, Brokers: []string{brokerAddress}}})
-
-	// When
 	msgs := []kafka.Message{
 		{
 			Key:   []byte("1"),
@@ -59,13 +119,33 @@ func Test_Should_Batch_Produce_Successfully(t *testing.T) {
 		},
 	}
 
-	// When
-	err := producer.ProduceBatch(context.Background(), msgs)
+	t.Run("without interceptor", func(t *testing.T) {
+		producer, _ := kafka.NewProducer(&kafka.ProducerConfig{
+			Writer: kafka.WriterConfig{AllowAutoTopicCreation: true, Topic: topic, Brokers: []string{brokerAddress}}}, nil)
 
-	// Then
-	if err != nil {
-		t.Fatalf("Error while producing err %s", err.Error())
-	}
+		// When
+		err := producer.ProduceBatch(context.Background(), msgs)
+
+		// Then
+		if err != nil {
+			t.Fatalf("Error while producing err %s", err.Error())
+		}
+	})
+
+	t.Run("with interceptor", func(t *testing.T) {
+		interceptor := stub_data.NewMockProducerInterceptor()
+
+		producer, _ := kafka.NewProducer(&kafka.ProducerConfig{
+			Writer: kafka.WriterConfig{AllowAutoTopicCreation: true, Topic: topic, Brokers: []string{brokerAddress}}}, &interceptor)
+
+		// When
+		err := producer.ProduceBatch(context.Background(), msgs)
+
+		// Then
+		if err != nil {
+			t.Fatalf("Error while producing err %s", err.Error())
+		}
+	})
 }
 
 func Test_Should_Consume_Message_Successfully(t *testing.T) {

test/stub-data/producer_interceptor_stub.go

@@ -0,0 +1,21 @@
+package test
+
+import "github.com/Trendyol/kafka-konsumer/v2"
+
+type MockProducerInterceptor struct{}
+
+const (
+	XSourceAppKey   = "x-source-app"
+	XSourceAppValue = "kafka-konsumer"
+)
+
+func (i *MockProducerInterceptor) OnProduce(ctx kafka.ProducerInterceptorContext) {
+	ctx.Message.Headers = append(ctx.Message.Headers, kafka.Header{
+		Key:   XSourceAppKey,
+		Value: []byte(XSourceAppValue),
+	})
+}
+
+func NewMockProducerInterceptor() kafka.ProducerInterceptor {
+	return &MockProducerInterceptor{}
+}