上篇文章《RocketMQ消息队列(一)------ 基本概念和消息类型》记录了RocketMQ的一些基本的概念,本文主要写几个go语言操作RocketMQ的示例代码
一、发送普通消息
go
import (
"context"
"fmt"
"github.com/apache/rocketmq-client-go/v2"
"github.com/apache/rocketmq-client-go/v2/primitive"
"github.com/apache/rocketmq-client-go/v2/producer"
)
func main() {
p, err := rocketmq.NewProducer(
producer.WithNsResolver(primitive.NewPassthroughResolver([]string{"127.0.0.1:9876"})),
producer.WithRetry(2), //指定重试次数
)
if err != nil {
panic(err)
}
if err = p.Start(); err != nil {
panic("启动producer失败")
}
topic := "test"
// 构建一个消息
message := primitive.NewMessage(topic, []byte("hello world!"))
res, err := p.SendSync(context.Background(), message)
if err != nil {
fmt.Printf("send message error: %s\n", err)
} else {
fmt.Printf("send message success: result=%s\n", res.String())
}
if err = p.Shutdown(); err != nil {
panic("关闭producer失败")
}
}
二、消费消息
go
import (
"context"
"fmt"
"github.com/apache/rocketmq-client-go/v2"
"github.com/apache/rocketmq-client-go/v2/consumer"
"github.com/apache/rocketmq-client-go/v2/primitive"
"time"
)
func main() {
c, err := rocketmq.NewPushConsumer(
consumer.WithGroupName("test"),
consumer.WithNsResolver(primitive.NewPassthroughResolver([]string{"127.0.0.1:9876"})),
)
if err != nil {
panic(err)
}
if err := c.Subscribe("test",
consumer.MessageSelector{},
// 收到消息后的回调函数
func(ctx context.Context, msgs ...*primitive.MessageExt) (consumer.ConsumeResult, error) {
for i := range msgs {
fmt.Printf("获取到值: %v \n", msgs[i])
}
return consumer.ConsumeSuccess, nil
}); err != nil {
}
err = c.Start()
if err != nil {
panic("启动consumer失败")
}
//不能让主goroutine退出
time.Sleep(time.Hour)
_ = c.Shutdown()
}
三、发送延迟消息
延迟消息和普通的发送区别就是在需要发送的消息上,用下面的代码设置发送的级别即可
go
message.WithDelayTimeLevel(3)
全部代码如下:
go
import (
"context"
"fmt"
"github.com/apache/rocketmq-client-go/v2"
"github.com/apache/rocketmq-client-go/v2/primitive"
"github.com/apache/rocketmq-client-go/v2/producer"
)
func main() {
p, err := rocketmq.NewProducer(
producer.WithNsResolver(primitive.NewPassthroughResolver([]string{"127.0.0.1:9876"})),
producer.WithRetry(2), //指定重试次数
)
if err != nil {
panic(err)
}
if err = p.Start(); err != nil {
panic("启动producer失败")
}
topic := "test"
// 构建一个消息
message := primitive.NewMessage(topic, []byte("this is a delay message!"))
// 给message设置延迟级别
message.WithDelayTimeLevel(3)
res, err := p.SendSync(context.Background(), message)
if err != nil {
fmt.Printf("send message error: %s\n", err)
} else {
fmt.Printf("send message success: result=%s\n", res.String())
}
if err = p.Shutdown(); err != nil {
panic("关闭producer失败")
}
}
四、发送事务消息
发送事务消息需要我们写一个TransactionListener接口的方法,指明事务执行成功和回调的具体操作,接口如下
go
type TransactionListener interface {
// When send transactional prepare(half) message succeed, this method will be invoked to execute local transaction.
ExecuteLocalTransaction(*Message) LocalTransactionState
// When no response to prepare(half) message. broker will send check message to check the transaction status, and this
// method will be invoked to get local transaction status.
CheckLocalTransaction(*MessageExt) LocalTransactionState
}
完整的代码如下:
go
import (
"context"
"fmt"
"os"
"time"
"github.com/apache/rocketmq-client-go/v2"
"github.com/apache/rocketmq-client-go/v2/primitive"
"github.com/apache/rocketmq-client-go/v2/producer"
)
type DemoListener struct {
}
func (dl *DemoListener) ExecuteLocalTransaction(msg *primitive.Message) primitive.LocalTransactionState {
fmt.Println("开始执行本地逻辑")
time.Sleep(time.Second * 3)
fmt.Println("执行本地逻辑失败")
//本地执行逻辑无缘无故失败 代码异常 宕机
return primitive.UnknowState
}
func (dl *DemoListener) CheckLocalTransaction(msg *primitive.MessageExt) primitive.LocalTransactionState {
fmt.Println("rocketmq的消息回查")
return primitive.CommitMessageState
}
func main() {
p, _ := rocketmq.NewTransactionProducer(
&DemoListener{},
producer.WithNsResolver(primitive.NewPassthroughResolver([]string{"127.0.0.1:9876"})),
producer.WithRetry(1),
)
err := p.Start()
if err != nil {
fmt.Printf("start producer error: %s\n", err.Error())
os.Exit(1)
}
res, err := p.SendMessageInTransaction(context.Background(),
primitive.NewMessage("TopicTest5", []byte("Hello RocketMQ again ")))
if err != nil {
fmt.Printf("send message error: %s\n", err)
} else {
fmt.Printf("send message success: result=%s\n", res.String())
}
time.Sleep(5 * time.Minute)
err = p.Shutdown()
if err != nil {
fmt.Printf("shutdown producer error: %s", err.Error())
}
}
后记
个人总结,欢迎转载、评论、批评指正