init

internal/adapter/streamers/kafka/consumer/message.go

@@ -0,0 +1,94 @@
+package consumer
+
+import (
+	"context"
+	"encoding/json"
+	"io"
+	"time"
+
+	"github.com/aykhans/oh-my-chat/internal/adapter/config"
+	"github.com/aykhans/oh-my-chat/internal/adapter/logger"
+	"github.com/aykhans/oh-my-chat/internal/core/domain"
+	"github.com/google/uuid"
+
+	"github.com/segmentio/kafka-go"
+)
+
+var log = logger.NewStdLogger()
+
+type MessageConsumer struct {
+	kafkaConsumerConfig *config.KafkaConsumerConfig
+}
+
+type ConsumerMessage struct {
+	UserID    uuid.UUID `json:"user_id"`
+	ChatID    string    `json:"chat_id"`
+	Content   string    `json:"content"`
+	Timestamp time.Time `json:"timestamp"`
+}
+
+func NewMessageConsumer(consumerConfig *config.KafkaConsumerConfig) *MessageConsumer {
+	return &MessageConsumer{consumerConfig}
+}
+
+func (messageConsumer *MessageConsumer) ConsumeMessage(
+	ctx context.Context,
+	uid string,
+	getChats func() []string,
+	message chan<- *domain.StreamMessage,
+) error {
+	consumer := kafka.NewReader(kafka.ReaderConfig{
+		Brokers:         messageConsumer.kafkaConsumerConfig.BootstrapServers,
+		GroupID:         uid,
+		GroupTopics:     getChats(),
+		MaxBytes:        10e6, // 10MB
+		ReadLagInterval: -1,
+		MaxWait:         300 * time.Millisecond,
+		GroupBalancers:  []kafka.GroupBalancer{kafka.RoundRobinGroupBalancer{}},
+		StartOffset:     kafka.FirstOffset,
+	})
+
+	defer func() {
+		if err := consumer.Close(); err != nil {
+			log.Error("Error closing consumer", "error", err.Error())
+		}
+	}()
+
+	for {
+		msg, err := consumer.FetchMessage(ctx)
+		if err != nil {
+			switch err {
+			case io.EOF:
+				return nil
+			case context.Canceled:
+				return nil
+			}
+			log.Error("Error fetching message from kafka", "error", err.Error())
+			continue
+		}
+
+		consumerMeesage := &ConsumerMessage{}
+		err = json.Unmarshal(msg.Value, consumerMeesage)
+		if err != nil {
+			log.Error("Error unmarshalling message", "error", err.Error())
+			return domain.ErrInternal
+		}
+
+		message <- &domain.StreamMessage{
+			Message: &domain.Message{
+				UserID:    consumerMeesage.UserID,
+				ChatID:    consumerMeesage.ChatID,
+				Content:   consumerMeesage.Content,
+				Timestamp: consumerMeesage.Timestamp,
+			},
+			Commit: func() error {
+				err := consumer.CommitMessages(ctx, msg)
+				if err != nil {
+					log.Error("Error committing kafka message", "error", err.Error())
+					return domain.ErrInternal
+				}
+				return nil
+			},
+		}
+	}
+}