align package decoding

test/kafka/sarama_e2e_test.go

@@ -146,6 +146,9 @@ func TestSaramaConsumerGroup(t *testing.T) {
 	config.Consumer.Group.Rebalance.Strategy = sarama.BalanceStrategyRoundRobin
 	config.Consumer.Offsets.Initial = sarama.OffsetOldest
 	config.Consumer.Return.Errors = true
+	// Producer configuration for SyncProducer
+	config.Producer.Return.Successes = true
+	config.Producer.Return.Errors = true
 
 	t.Logf("=== Testing Sarama Consumer Group ===")
 

weed/mq/kafka/protocol/handler.go

@@ -527,7 +527,13 @@ func (h *Handler) HandleConn(ctx context.Context, conn net.Conn) error {
 		case 8: // OffsetCommit
 			response, err = h.handleOffsetCommit(correlationID, requestBody)
 		case 9: // OffsetFetch
-			response, err = h.handleOffsetFetch(correlationID, requestBody)
+			fmt.Printf("DEBUG: *** OFFSETFETCH REQUEST RECEIVED *** Correlation: %d, Version: %d\n", correlationID, apiVersion)
+			response, err = h.handleOffsetFetch(correlationID, apiVersion, requestBody)
+			if err != nil {
+				fmt.Printf("DEBUG: OffsetFetch error: %v\n", err)
+			} else {
+				fmt.Printf("DEBUG: OffsetFetch response hex dump (%d bytes): %x\n", len(response), response)
+			}
 		case 10: // FindCoordinator
 			fmt.Printf("DEBUG: *** FINDCOORDINATOR REQUEST RECEIVED *** Correlation: %d, Version: %d\n", correlationID, apiVersion)
 			response, err = h.handleFindCoordinator(correlationID, requestBody)

weed/mq/kafka/protocol/joingroup.go

@@ -897,13 +897,8 @@ func (h *Handler) getTopicPartitions(group *consumer.ConsumerGroup) map[string][
 }
 
 func (h *Handler) serializeMemberAssignment(assignments []consumer.PartitionAssignment) []byte {
-	// Build a simple serialized format for partition assignments
-	// Format: version(2) + num_topics(4) + topics...
-	// For each topic: topic_name_len(2) + topic_name + num_partitions(4) + partitions...
-
-	if len(assignments) == 0 {
-		return []byte{0, 1, 0, 0, 0, 0} // Version 1, 0 topics
-	}
+	// Build ConsumerGroupMemberAssignment format exactly as Sarama expects:
+	// Version(2) + Topics array + UserData bytes
 
 	// Group assignments by topic
 	topicAssignments := make(map[string][]int32)
@@ -916,22 +911,20 @@ func (h *Handler) serializeMemberAssignment(assignments []consumer.PartitionAssi
 	// Version (2 bytes) - use version 1
 	result = append(result, 0, 1)
 
-	// Number of topics (4 bytes)
+	// Number of topics (4 bytes) - array length
 	numTopicsBytes := make([]byte, 4)
 	binary.BigEndian.PutUint32(numTopicsBytes, uint32(len(topicAssignments)))
 	result = append(result, numTopicsBytes...)
 
-	// Topics
+	// Topics - each topic follows Kafka string + int32 array format
 	for topic, partitions := range topicAssignments {
-		// Topic name length (2 bytes)
+		// Topic name as Kafka string: length(2) + content
 		topicLenBytes := make([]byte, 2)
 		binary.BigEndian.PutUint16(topicLenBytes, uint16(len(topic)))
 		result = append(result, topicLenBytes...)
-
-		// Topic name
 		result = append(result, []byte(topic)...)
 
-		// Number of partitions (4 bytes)
+		// Partitions as int32 array: length(4) + elements
 		numPartitionsBytes := make([]byte, 4)
 		binary.BigEndian.PutUint32(numPartitionsBytes, uint32(len(partitions)))
 		result = append(result, numPartitionsBytes...)
@@ -944,9 +937,11 @@ func (h *Handler) serializeMemberAssignment(assignments []consumer.PartitionAssi
 		}
 	}
 
-	// User data length (4 bytes) - no user data
+	// UserData as Kafka bytes: length(4) + data (empty in our case)
+	// For empty user data, just put length = 0
 	result = append(result, 0, 0, 0, 0)
 
+	fmt.Printf("DEBUG: Generated assignment bytes (%d): %x\n", len(result), result)
 	return result
 }
 

weed/mq/kafka/protocol/offset_management.go

@@ -180,7 +180,7 @@ func (h *Handler) handleOffsetCommit(correlationID uint32, requestBody []byte) (
 	return h.buildOffsetCommitResponse(response), nil
 }
 
-func (h *Handler) handleOffsetFetch(correlationID uint32, requestBody []byte) ([]byte, error) {
+func (h *Handler) handleOffsetFetch(correlationID uint32, apiVersion uint16, requestBody []byte) ([]byte, error) {
 	// Parse OffsetFetch request
 	request, err := h.parseOffsetFetchRequest(requestBody)
 	if err != nil {
@@ -266,7 +266,7 @@ func (h *Handler) handleOffsetFetch(correlationID uint32, requestBody []byte) ([
 		response.Topics = append(response.Topics, topicResponse)
 	}
 
-	return h.buildOffsetFetchResponse(response), nil
+	return h.buildOffsetFetchResponse(response, apiVersion), nil
 }
 
 func (h *Handler) parseOffsetCommitRequest(data []byte) (*OffsetCommitRequest, error) {
@@ -579,7 +579,7 @@ func (h *Handler) buildOffsetCommitResponse(response OffsetCommitResponse) []byt
 	return result
 }
 
-func (h *Handler) buildOffsetFetchResponse(response OffsetFetchResponse) []byte {
+func (h *Handler) buildOffsetFetchResponse(response OffsetFetchResponse, apiVersion uint16) []byte {
 	estimatedSize := 32
 	for _, topic := range response.Topics {
 		estimatedSize += len(topic.Name) + 16 + len(topic.Partitions)*32
@@ -627,10 +627,12 @@ func (h *Handler) buildOffsetFetchResponse(response OffsetFetchResponse) []byte
 			binary.BigEndian.PutUint64(offsetBytes, uint64(partition.Offset))
 			result = append(result, offsetBytes...)
 
-			// Leader epoch (4 bytes)
+			// Leader epoch (4 bytes) - only included in version 5+
+			if apiVersion >= 5 {
 				epochBytes := make([]byte, 4)
 				binary.BigEndian.PutUint32(epochBytes, uint32(partition.LeaderEpoch))
 				result = append(result, epochBytes...)
+			}
 
 			// Metadata length (2 bytes)
 			metadataLength := make([]byte, 2)
@@ -652,8 +654,10 @@ func (h *Handler) buildOffsetFetchResponse(response OffsetFetchResponse) []byte
 	binary.BigEndian.PutUint16(groupErrorBytes, uint16(response.ErrorCode))
 	result = append(result, groupErrorBytes...)
 
-	// Throttle time (4 bytes, 0 = no throttling)
+	// Throttle time (4 bytes) - only included in version 3+
+	if apiVersion >= 3 {
 		result = append(result, 0, 0, 0, 0)
+	}
 
 	return result
 }
@@ -681,5 +685,5 @@ func (h *Handler) buildOffsetFetchErrorResponse(correlationID uint32, errorCode
 		ErrorCode:     errorCode,
 	}
 
-	return h.buildOffsetFetchResponse(response)
+	return h.buildOffsetFetchResponse(response, 0)
 }

weed/mq/kafka/protocol/offset_management_test.go

@@ -156,7 +156,7 @@ func TestHandler_handleOffsetFetch(t *testing.T) {
 	requestBody := createOffsetFetchRequestBody("test-group")
 
 	correlationID := uint32(126)
-	response, err := h.handleOffsetFetch(correlationID, requestBody)
+	response, err := h.handleOffsetFetch(correlationID, 2, requestBody)
 
 	if err != nil {
 		t.Fatalf("handleOffsetFetch failed: %v", err)
@@ -188,7 +188,7 @@ func TestHandler_handleOffsetFetch_NoCommittedOffset(t *testing.T) {
 	requestBody := createOffsetFetchRequestBody("test-group")
 
 	correlationID := uint32(127)
-	response, err := h.handleOffsetFetch(correlationID, requestBody)
+	response, err := h.handleOffsetFetch(correlationID, 2, requestBody)
 
 	if err != nil {
 		t.Fatalf("handleOffsetFetch failed: %v", err)
@@ -369,7 +369,7 @@ func TestHandler_OffsetCommitFetch_EndToEnd(t *testing.T) {
 
 	// Test offset fetch
 	fetchRequestBody := createOffsetFetchRequestBody("test-group")
-	fetchResponse, err := server.handleOffsetFetch(457, fetchRequestBody)
+	fetchResponse, err := server.handleOffsetFetch(457, 2, fetchRequestBody)
 	if err != nil {
 		t.Fatalf("offset fetch failed: %v", err)
 	}