authDB/cmd/main.go

package main

import (
	"context"
	"fmt"
	"log"

	kafka "github.com/segmentio/kafka-go"
)

func main() {
	ctx := context.Background()
	consumer := kafka.NewReader(kafka.ReaderConfig{
		Brokers:   []string{"localhost:9092"},
		Topic:     "topic-A",
		Partition: 0,
		MinBytes:  10e3, // 10KB
		MaxBytes:  10e6, // 10MB
	})
	defer consumer.Close()

	//
	// consumer.SetOffset(42)

	//
	for {
		m, err := consumer.ReadMessage(ctx)
		if err != nil {
			log.Fatal(err)
		}

		fmt.Printf("message at offset %d: %s = %s\n", m.Offset, string(m.Key), string(m.Value))
	}
}