isabella232 / kafka-client

Go client library for Apache Kafka

Go Kafka Client Library

A high level Go client library for Apache Kafka that provides the following primitives on top of sarama-cluster:

• Competing consumer semantics with dead letter queue (DLQ)
  • Ability to process messages across multiple goroutines
  • Ability to Ack or Nack messages out of order (with optional DLQ)
• Ability to consume from topics spread across different kafka clusters

Stability

This library is in alpha. APIs are subject to change, use at your own risk

Contributing

If you are interested in contributing, please sign the License Agreement and see our development guide

Installation

go get -u github.com/uber-go/kafka-client

Quick Start

package main

import (
	"os"
	"os/signal"

	"github.com/uber-go/kafka-client"
	"github.com/uber-go/kafka-client/kafka"
	"github.com/uber-go/tally"
	"go.uber.org/zap"
)

func main() {
	// mapping from cluster name to list of broker ip addresses
	brokers := map[string][]string{
		"sample_cluster":     []string{"127.0.0.1:9092"},
		"sample_dlq_cluster": []string{"127.0.0.1:9092"},
	}
	// mapping from topic name to cluster that has that topic
	topicClusterAssignment := map[string][]string{
		"sample_topic": []string{"sample_cluster"},
	}

	// First create the kafkaclient, its the entry point for creating consumers or producers
	// It takes as input a name resolver that knows how to map topic names to broker ip addrs
	client := kafkaclient.New(kafka.NewStaticNameResolver(topicClusterAssignment, brokers), zap.NewNop(), tally.NoopScope)

	// Next, setup the consumer config for consuming from a set of topics
	config := &kafka.ConsumerConfig{
		TopicList: kafka.ConsumerTopicList{
			kafka.ConsumerTopic{ // Consumer Topic is a combination of topic + dead-letter-queue
				Topic: kafka.Topic{ // Each topic is a tuple of (name, clusterName)
					Name:    "sample_topic",
					Cluster: "sample_cluster",
				},
				DLQ: kafka.Topic{
					Name:    "sample_consumer_dlq",
					Cluster: "sample_dlq_cluster",
				},
			},
		},
		GroupName:   "sample_consumer",
		Concurrency: 100, // number of go routines processing messages in parallel
	}

	// Create the consumer through the previously created client
	consumer, err := client.NewConsumer(config)
	if err != nil {
		panic(err)
	}

	// Finally, start consuming
	if err := consumer.Start(); err != nil {
		panic(err)
	}

	sigCh := make(chan os.Signal, 1)
	signal.Notify(sigCh, os.Interrupt)

	for {
		select {
		case msg, ok := <-consumer.Messages():
			if !ok {
				return // channel closed
			}
			if err := process(msg); err != nil {
				msg.Nack()
			} else {
				msg.Ack()
			}
		case <-sigCh:
			consumer.Stop()
			<-consumer.Closed()
		}
	}
}