下面一个客户端代码例子访问kafka服务器，来发送和接受消息。
使用方式
1、命令行参数
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$ ./kafkaclient -h
Usage of ./client:
-ca string
CA Certificate (default "ca.pem")
-cert string
Client Certificate (default "cert.pem")
-command string
consumer|producer (default "consumer")
-host string
Common separated kafka hosts (default "localhost:9093")
-key string
Client Key (default "key.pem")
-partition int
Kafka topic partition
-tls
TLS enable
-topic string
Kafka topic (default "test--topic")
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2、作为producer启动
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$ ./kafkaclient -command producer \
-host kafka1:9092,kafka2:9092
## TLS-enabled
$ ./kafkaclient -command producer \
-tls -cert client.pem -key client.key -ca ca.pem \
-host kafka1:9093,kafka2:9093
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producer发送消息给kafka：
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> aaa
2018/12/15 07:11:21 Produced message: [aaa]
> bbb
2018/12/15 07:11:30 Produced message: [bbb]
> quit
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3、作为consumer启动
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$ ./kafkaclient -command consumer \
-host kafka1:9092,kafka2:9092
## TLS-enabled
$ ./kafkaclient -command consumer \
-tls -cert client.pem -key client.key -ca ca.pem \
-host kafka1:9093,kafka2:9093
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consumer从kafka接受消息：
2018/12/15 07:11:21 Consumed message: [aaa], offset: [4]
2018/12/15 07:11:30 Consumed message: [bbb], offset: [5]
完整源代码如下
这个代码使用到了Shopify/sarama库，请自行下载使用。
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$ cat kafkaclient.go
package main
import (
"flag"
"fmt"
"log"
"os"
"io/ioutil"
"bufio"
"strings"
"crypto/tls"
"crypto/x509"
"github.com/Shopify/sarama"
)
var (
command string
tlsEnable bool
hosts string
topic string
partition int
clientcert string
clientkey string
cacert string
)
func main() {
flag.StringVar(&command, "command", "consumer", "consumer|producer")
flag.BoolVar(&tlsEnable, "tls", false, "TLS enable")
flag.StringVar(&hosts, "host", "localhost:9093", "Common separated kafka hosts")
flag.StringVar(&topic, "topic", "test--topic", "Kafka topic")
flag.IntVar(&partition, "partition", 0, "Kafka topic partition")
flag.StringVar(&clientcert, "cert", "cert.pem", "Client Certificate")
flag.StringVar(&clientkey, "key", "key.pem", "Client Key")
flag.StringVar(&cacert, "ca", "ca.pem", "CA Certificate")
flag.Parse()
config := sarama.NewConfig()
if tlsEnable {
//sarama.Logger = log.New(os.Stdout, "[sarama] ", log.LstdFlags)
tlsConfig, err := genTLSConfig(clientcert, clientkey, cacert)
if err != nil {
log.Fatal(err)
}
config.Net.TLS.Enable = true
config.Net.TLS.Config = tlsConfig
}
client, err := sarama.NewClient(strings.Split(hosts, ","), config)
if err != nil {
log.Fatalf("unable to create kafka client: %q", err)
}
if command == "consumer" {
consumer, err := sarama.NewConsumerFromClient(client)
if err != nil {
log.Fatal(err)
}
defer consumer.Close()
loopConsumer(consumer, topic, partition)
} else {
producer, err := sarama.NewAsyncProducerFromClient(client)
if err != nil {
log.Fatal(err)
}
defer producer.Close()
loopProducer(producer, topic, partition)
}
}
func genTLSConfig(clientcertfile, clientkeyfile, cacertfile string) (*tls.Config, error) {
// load client cert
clientcert, err := tls.LoadX509KeyPair(clientcertfile, clientkeyfile)
if err != nil {
return nil, err
}
// load ca cert pool
cacert, err := ioutil.ReadFile(cacertfile)
if err != nil {
return nil, err
}
cacertpool := x509.NewCertPool()
cacertpool.AppendCertsFromPEM(cacert)
// generate tlcconfig
tlsConfig := tls.Config{}
tlsConfig.RootCAs = cacertpool
tlsConfig.Certificates = []tls.Certificate{clientcert}
tlsConfig.BuildNameToCertificate()
// tlsConfig.InsecureSkipVerify = true // This can be used on test server if domain does not match cert:
return &tlsConfig, err
}
func loopProducer(producer sarama.AsyncProducer, topic string, partition int) {
scanner := bufio.NewScanner(os.Stdin)
fmt.Print("> ")
for scanner.Scan() {
text := scanner.Text()
if text == "" {
} else if text == "exit" || text == "quit" {
break
} else {
producer.Input() <- &sarama.ProducerMessage{Topic: topic, Key: nil, Value: sarama.StringEncoder(text)}
log.Printf("Produced message: [%s]\n",text)
}
fmt.Print("> ")
}
}
func loopConsumer(consumer sarama.Consumer, topic string, partition int) {
partitionConsumer, err := consumer.ConsumePartition(topic, int32(partition), sarama.OffsetNewest)
if err != nil {
log.Println(err)
return
}
defer partitionConsumer.Close()
for {
msg := <-partitionConsumer.Messages()
log.Printf("Consumed message: [%s], offset: [%d]\n", msg.Value, msg.Offset)
}
}
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编译：
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$ go build kafkaclient.go
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以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持服务器之家。
原文链接：https://www.jianshu.com/p/3102418e5a7d