操作Kafka
Kafka 是一种高吞吐量的分布式发布订阅消息系统，它可以处理消费者规模的网站中的所有动作流数据，具有高性能、持久化、多副本备份、横向扩展等特点。本文介绍了如何使用 Go 语言发送和接收 kafka 消息。
sarama
Go 语言中连接 kafka 使用第三方库:github.com/Shopify/sar…。
下载及安装
go get github.com/Shopify/sarama
注意事项
sarama v1.20 之后的版本加入了zstd压缩算法，需要用到 cgo，在 Windows 平台编译时会提示类似如下错误：
# github.com/DataDog/zstd
exec: "gcc":executable file not found in %PATH%
所以在 Windows 平台请使用 v1.19 版本的 sarama。
连接 kafka 发送消息
package main
import (
"fmt"
"github.com/Shopify/sarama"
)
// 基于sarama第三方库开发的kafka client
func main() {
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
// 构造一个消息
msg := &sarama.ProducerMessage{}
msg.Topic = "web_log"
msg.Value = sarama.StringEncoder("this is a test log")
// 连接kafka
client, err := sarama.NewSyncProducer([]string{"192.168.1.7:9092"}, config)
if err != nil {
fmt.Println("producer closed, err:", err)
return
}
defer client.Close()
// 发送消息
pid, offset, err := client.SendMessage(msg)
if err != nil {
fmt.Println("send msg failed, err:", err)
return
}
fmt.Printf("pid:%v offset:%v\n", pid, offset)
}
连接 kafka 消费消息
package main
import (
"fmt"
"github.com/Shopify/sarama"
)
// kafka consumer
func main() {
consumer, err := sarama.NewConsumer([]string{"127.0.0.1:9092"}, nil)
if err != nil {
fmt.Printf("fail to start consumer, err:%v\n", err)
return
}
partitionList, err := consumer.Partitions("web_log") // 根据topic取到所有的分区
if err != nil {
fmt.Printf("fail to get list of partition:err%v\n", err)
return
}
fmt.Println(partitionList)
for partition := range partitionList { // 遍历所有的分区
// 针对每个分区创建一个对应的分区消费者
pc, err := consumer.ConsumePartition("web_log", int32(partition), sarama.OffsetNewest)
if err != nil {
fmt.Printf("failed to start consumer for partition %d,err:%v\n", partition, err)
return
}
defer pc.AsyncClose()
// 异步从每个分区消费信息
go func(sarama.PartitionConsumer) {
for msg := range pc.Messages() {
fmt.Printf("Partition:%d Offset:%d Key:%v Value:%v", msg.Partition, msg.Offset, msg.Key, msg.Value)
}
}(pc)
}
}
操作Etcd
这里使用官方的etcd/clientv3包来连接etcd并进行相关操作。
安装
go get go.etcd.io/etcd/clientv3
put和get操作
put命令用来设置键值对数据，get命令用来根据key获取值。
package main
import (
"context"
"fmt"
"time"
"go.etcd.io/etcd/clientv3"
)
func main(){
cli, err := clientv3.New(clientv3.Config{
Endpoints: []string{"122.51.79.172:2379"},
DialTimeout: 5 * time.Second,
})
if err != nil {
// handle error!
fmt.Printf("connect to etcd failed, err:%v\n", err)
return
}
fmt.Println("connect to etcd success")
defer cli.Close()
// put
ctx, cancel := context.WithTimeout(context.Background(), time.Second)
_, err = cli.Put(ctx, "coolops", "test")
cancel()
if err != nil {
fmt.Printf("put to etcd failed, err:%v\n", err)
return
}
// get
ctx, cancel = context.WithTimeout(context.Background(), time.Second)
resp, err := cli.Get(ctx, "coolops")
cancel()
if err != nil {
fmt.Printf("get from etcd failed, err:%v\n", err)
return
}
for _, ev := range resp.Kvs {
fmt.Printf("%s:%s\n", ev.Key, ev.Value)
}
}
watch操作
watch用来获取未来更改的通知。
package main
import (
"context"
"fmt"
"time"
"go.etcd.io/etcd/clientv3"
)
func main(){
cli, err := clientv3.New(clientv3.Config{
Endpoints: []string{"122.51.79.172:2379"},
DialTimeout: 5 * time.Second,
})
if err != nil {
// handle error!
fmt.Printf("connect to etcd failed, err:%v\n", err)
return
}
fmt.Println("connect to etcd success")
defer cli.Close()
// watch 操作，返回的是一个通道
rch := cli.Watch(context.Background(), "coolops") // <-chan WatchResponse
for wresp := range rch {
for _, ev := range wresp.Events {
fmt.Printf("Type: %s Key:%s Value:%s\n", ev.Type, ev.Kv.Key, ev.Kv.Value)
}
}
}
安装报错：
go: finding github.com/coreos/pkg latest
# github.com/coreos/etcd/clientv3/balancer/resolver/endpoint
E:\DEV\Go\pkg\mod\github.com\coreos\etcd@v3.3.19+incompatible\clientv3\balancer\resolver\endpoint\endpoint.go:114:78: undefined: resolver.BuildOption
E:\DEV\Go\pkg\mod\github.com\coreos\etcd@v3.3.19+incompatible\clientv3\balancer\resolver\endpoint\endpoint.go:182:31: undefined: resolver.ResolveNowOption
# github.com/coreos/etcd/clientv3/balancer/picker
E:\DEV\Go\pkg\mod\github.com\coreos\etcd@v3.3.19+incompatible\clientv3\balancer\picker\err.go:37:44: undefined: balancer.PickOptions
E:\DEV\Go\pkg\mod\github.com\coreos\etcd@v3.3.19+incompatible\clientv3\balancer\picker\roundrobin_balanced.go:55:54: undefined: balancer.PickOptions
解决： 将go.mod里的prpc改为1.26.0版本
google.golang.org/grpc v1.26.0以上就是Go操作Kafka和Etcd方法详解的详细内容，更多关于Go操作Kafka Etcd的资料请关注编程网其它相关文章！
