Go接入kafka

需要借助的库

github.com/Shopify/sarama // kafka主要的库*
github.com/bsm/sarama-cluster // kafka消费组

生产者

package producer

import (
	"fmt"
	"github.com/HappyTeemo7569/teemoKit/tlog"
	"github.com/Shopify/sarama"
	"kafkaDemo/define"
)

var (
	ProducerId = 1
)

type Producer struct {
	Producer   sarama.SyncProducer
	Topic      string //主题
	ProducerID int    //生产者Id
	MessageId  int
}

func (p *Producer) InitProducer() {
	config := sarama.NewConfig()
	config.Producer.RequiredAcks = sarama.WaitForAll          // 发送完数据需要leader和follow都确认
	config.Producer.Partitioner = sarama.NewRandomPartitioner // 新选出一个partition
	config.Producer.Return.Successes = true                   // 成功交付的消息将在success channel返回

	// 连接kafka
	client, err := sarama.NewSyncProducer([]string{define.SERVER_LIST}, config)
	if err != nil {
		tlog.Error("producer closed, err:", err)
		return
	}

	p.Producer = client
	p.Topic = define.TOPIC
	p.ProducerID = ProducerId
	p.MessageId = 1

	ProducerId++
}

func (p *Producer) SendMessage() {
	// 构造一个消息
	msg := &sarama.ProducerMessage{}
	msg.Topic = p.Topic
	txt := fmt.Sprintf("ProducerID:%d  this is a test log %d",
		p.ProducerID, p.MessageId)
	msg.Value = sarama.StringEncoder(txt)

	// 发送消息
	pid, offset, err := p.Producer.SendMessage(msg)
	//_, _, err := client.SendMessage(msg)
	if err != nil {
		fmt.Println("send msg failed, err:", err)
		return
	}
	tlog.Info(fmt.Sprintf("ProducerID:%d pid:%v offset:%v msg:%s",
		p.ProducerID, pid, offset, txt))

	p.MessageId++
}

func (p *Producer) Close() {
	p.Producer.Close()
}

消费者

package consumer

import (
	"github.com/HappyTeemo7569/teemoKit/tlog"
	"github.com/Shopify/sarama"
	"kafkaDemo/define"
)

type Consumer struct {
	Consumer   sarama.Consumer
	Topic      string
	ConsumerId int //消费者Id
}

func (c *Consumer) InitConsumer() error {
	consumer, err := sarama.NewConsumer([]string{define.SERVER_LIST}, nil)
	if err != nil {
		return err
	}
	c.Consumer = consumer
	c.Topic = define.TOPIC
	c.ConsumerId = ConsumerId
	ConsumerId++
	return nil
}

//指定partition
//offset 可以指定，传-1为获取最新offest
func (c *Consumer) GetMessage(partitionId int32, offset int64) {
	if offset == -1 {
		offset = sarama.OffsetNewest
	}
	pc, err := c.Consumer.ConsumePartition(c.Topic, partitionId, offset)
	if err != nil {
		tlog.Error("failed to start consumer for partition %d,err:%v", partitionId, err)
		//That topic/partition is already being consumed
		return
	}

	// 异步从每个分区消费信息
	go func(sarama.PartitionConsumer) {
		for msg := range pc.Messages() {
			tlog.Info("ConsumerId:%d Partition:%d Offset:%d Key:%v Value:%v", c.ConsumerId, msg.Partition, msg.Offset, msg.Key, string(msg.Value))
		}
	}(pc)
}

//遍历所有分区
func (c *Consumer) GetMessageToAll(offset int64) {
	partitionList, err := c.Consumer.Partitions(c.Topic) // 根据topic取到所有的分区
	if err != nil {
		tlog.Error("fail to get list of partition:err%v", err)
		return
	}
	tlog.Info("所有partition:", partitionList)

	for partition := range partitionList { // 遍历所有的分区
		c.GetMessage(int32(partition), offset)
	}
}

主函数

func main() {
	tlog.Info("开始")

	go producer.Put()
	go consumer.Get()

	for {
		time.Sleep(time.Hour * 60)
	}
}


func Put() {
	producer := new(Producer)
	producer.InitProducer()
	go func() {
		for {
			producer.SendMessage()
			time.Sleep(1 * time.Second)
		}
	}()
}

func Get() {

	offest := int64(0)

	consumer := new(Consumer)
	err := consumer.InitConsumer()
	if err != nil {
		tlog.Error("fail to init consumer, err:%v", err)
		return
	}
	consumer.GetMessageToAll(offest)
}

具体源码可以查看：
kafka_demo

生产环境中的优化

可以存储消费的节点到redis
需要顺序的消费的放到一个partition，或者利用哈希算法投递
传入一个通道，将业务逻辑和底层逻辑解耦。

package kafka

import (
	"crypto/tls"
	"crypto/x509"
	"fmt"
	"github.com/Shopify/sarama"
	"io/ioutil"
	"log"
	"sync"
	"vliao.com/stellar/internal/core"
)

type KafkaConsumer struct {
	Node         []string
	Consumer     sarama.Consumer
	Topic        string
	MessageQueue chan []byte
}

func NewKafkaConsumer(topic string) KafkaConsumer {
	return KafkaConsumer{
		Node:  core.GetKafkaConn().Conn,
		Topic: core.GetServerMode() + "_" + topic,
	}
}

// Consume 获取所有分区
func (c *KafkaConsumer) Consume() {
	config := sarama.NewConfig()

	config.Net.SASL.Enable = true
	config.Net.SASL.User = core.GetKafkaConn().SASLUser
	config.Net.SASL.Password = core.GetKafkaConn().SASLPassword
	config.Net.SASL.Handshake = true

	certBytes, err := ioutil.ReadFile(GetFullPath("only-4096-ca-cert"))
	if err != nil {
		fmt.Println("kafka client read cert file failed ", err.Error())
		return
	}
	clientCertPool := x509.NewCertPool()
	ok := clientCertPool.AppendCertsFromPEM(certBytes)
	if !ok {
		fmt.Println("kafka client failed to parse root certificate")
		return
	}
	config.Net.TLS.Config = &tls.Config{
		RootCAs:            clientCertPool,
		InsecureSkipVerify: true,
	}
	config.Net.TLS.Enable = true

	consumer, err := sarama.NewConsumer(c.Node, config)
	if err != nil {
		log.Fatal("NewConsumer err: ", err)
	}
	defer consumer.Close()

	// 先查询该 topic 有多少分区
	partitions, err := consumer.Partitions(c.Topic)
	if err != nil {
		log.Fatal("Partitions err: ", err)
	}
	var wg sync.WaitGroup
	wg.Add(len(partitions))
	// 然后每个分区开一个 goroutine 来消费
	for _, partitionId := range partitions {
		//不开异步会导致一个消费完才会消费另外一个
		go c.consumeByPartition(consumer, c.Topic, partitionId, &wg)
	}
	wg.Wait()
}

// 暂时只是业务一对一，也就是一个生产者产生的消息不会触发多个业务的变动
// 但是可以开多个消费者增加处理能力
func getOffsetCacheKey(topic string, partitionId int32) string {
	return fmt.Sprintf("kafka_offset_%s_%d", topic, partitionId)
}

func setConsumeOffset(topic string, partitionId int32, offset int64) {
	core.RedisBy(core.RedisTypeServer).SetInt64(getOffsetCacheKey(topic, partitionId), offset)
}
func getConsumeOffset(topic string, partitionId int32) (offset int64) {
	key := getOffsetCacheKey(topic, partitionId)
	if core.RedisBy(core.RedisTypeServer).Exists(key) {
		return core.RedisBy(core.RedisTypeServer).GetInt64(key) + 1
	}

	//默认从最新开始
	setConsumeOffset(topic, partitionId, sarama.OffsetNewest)
	return sarama.OffsetNewest
}

func (c *KafkaConsumer) consumeByPartition(consumer sarama.Consumer, topic string, partitionId int32, wg *sync.WaitGroup) {
	defer wg.Done()
	offset := getConsumeOffset(topic, partitionId)
	partitionConsumer, err := consumer.ConsumePartition(topic, partitionId, offset)
	if err != nil {
		log.Fatal("ConsumePartition err: ", err)
	}
	defer partitionConsumer.Close()
	for message := range partitionConsumer.Messages() {
		log.Printf("[Consumer] topic: %s ; partitionid: %d; offset:%d, value: %s\n", topic, message.Partition, message.Offset, string(message.Value))
		setConsumeOffset(topic, partitionId, message.Offset)
		c.MessageQueue <- message.Value
	}
}

package kafka

import (
	"log"
	"testing"
	"vliao.com/stellar/internal/core"
)

func Test_Get(t *testing.T) {
	core.TestMain()
	topic := "test_log"
	var kafkaConsumer = NewKafkaConsumer(topic)

	kafkaConsumer.MessageQueue = make(chan []byte, 1000)
	go kafkaConsumer.Consume()

	for {
		msg := <-kafkaConsumer.MessageQueue
		deal(msg)
	}

}

func deal(msg []byte) {
	log.Printf(string(msg))
}