RabbitMQ消息确认(发送确认,接收确认)

前面几篇记录了收发消息的demo,今天记录下关于消息确认方面的问题.

下面是几个问题:

1.为什么要进行消息确认?

2.rabbitmq消息确认机制是什么样的?

3.发送方如何确认消息发送成功?什么样才算发送成功?

4.消费方如何告知rabbitmq消息消费成功或失败?

5.使用spring的代码示例

1.为什么要进行消息确认?

经常会听到丢消息的字眼, 对于前面的demo来说,就存在丢消息的隐患.

发送者没法确认是否发送成功,消费者处理失败也无法反馈.

没有消息确认机制,就会出现消息莫名其妙的没了,也不知道什么情况.

2.rabbitmq消息确认机制是什么样的?

首先看官网对消息确认的介绍http://www.rabbitmq.com/confirms.html

网上会有很多总结的博客(包括现在看的),很多就是对官网的翻译.所以看资料首先要去官网看看,这很关键.

看上图官网的介绍.唯一保证消息不丢失的是使用事务,但是性能太差,作为补偿,有了消息确认机制.

并说明了开启方法,以及和事务模式不共存.

还写了一个例子,但是点进去那个链接已经失效了,新版的源码上也没有这个例子,我找了最近一版是3.6.7上面还有.

点这里看官方的例子

3.发送的消息什么样才算成功或失败? 如何确认?

判断消息成功或失败,其实就是看进行消息确认的时机,因为成功或失败后就会把结果告诉发送方.还是看官方解释:

意思如下:

确认消息不能路由时(exchange确认不能路由到任何queue),进行确认操作(确认失败).如果发送方设置了mandatory模式,则会先调用basic.return方法.

消息可以路由时,当需要发送的队列都发送成功后,进行消息确认.对于持久化的队列,意味着已经写入磁盘,对于镜像队列,意味着所有镜像都接受成功.

至于如何确认的问题,上面已经写了 basic.ack方法

4.消费方如何告知rabbitmq消息消费成功或失败?

如图可知,根据消费方不同的确认模式,确认时机也不同.

自动确认会在消息发送给消费者后立即确认,如果手动则当消费者调用ack,nack,reject几种方法时进行确认.

一般会设置手动模式,业务失败后可以进行一些操作.

5.使用spring的代码示例

下面是一个使用spring整合的代码示例:

首先是rabbitmq的配置文件:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:rabbit="http://www.springframework.org/schema/rabbit"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/rabbit
http://www.springframework.org/schema/rabbit/spring-rabbit-1.4.xsd">
<bean id="jsonMessageConverter" class="org.springframework.amqp.support.converter.Jackson2JsonMessageConverter" />
<rabbit:connection-factory
id="connectionFactory"
host="${rabbit.host}"
port="${rabbit.port}"
username="${rabbit.username}"
password="${rabbit.password}"
publisher-confirms="true"
/>
<rabbit:admin connection-factory="connectionFactory" />
<rabbit:template id="amqpTemplate" connection-factory="connectionFactory"
confirm-callback="confirmCallBackListener"
return-callback="returnCallBackListener"
mandatory="true"
/>
<rabbit:queue name="CONFIRM_TEST" />
<rabbit:direct-exchange name="DIRECT_EX" id="DIRECT_EX" >
<rabbit:bindings>
<rabbit:binding queue="CONFIRM_TEST" />
</rabbit:bindings>
</rabbit:direct-exchange>
<rabbit:listener-container
connection-factory="connectionFactory" acknowledge="manual" >
<rabbit:listener queues="CONFIRM_TEST" ref="receiveConfirmTestListener" />
</rabbit:listener-container>
</beans>

然后发送方:

import org.springframework.amqp.core.AmqpTemplate;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
@Service("publishService")
public class PublishService {
@Autowired
private AmqpTemplate amqpTemplate;
public void send(String exchange, String routingKey, Object message) {
amqpTemplate.convertAndSend(exchange, routingKey, message);
}
}

消费方:

import org.springframework.amqp.core.Message;
import org.springframework.amqp.rabbit.core.ChannelAwareMessageListener;
import org.springframework.stereotype.Service;
import com.rabbitmq.client.Channel;
@Service("receiveConfirmTestListener")
public class ReceiveConfirmTestListener implements ChannelAwareMessageListener {
@Override
public void onMessage(Message message, Channel channel) throws Exception {
try{
System.out.println("consumer--:"+message.getMessageProperties()+":"+new String(message.getBody()));
channel.basicAck(message.getMessageProperties().getDeliveryTag(), false);
}catch(Exception e){
e.printStackTrace();//TODO 业务处理
channel.basicNack(message.getMessageProperties().getDeliveryTag(), false,false);
}
}
}

确认后回调:

import org.springframework.amqp.rabbit.core.RabbitTemplate.ConfirmCallback;
import org.springframework.amqp.rabbit.support.CorrelationData;
import org.springframework.stereotype.Service;
@Service("confirmCallBackListener")
public class ConfirmCallBackListener implements ConfirmCallback{
@Override
public void confirm(CorrelationData correlationData, boolean ack, String cause) {
System.out.println("confirm--:correlationData:"+correlationData+",ack:"+ack+",cause:"+cause);
}
}

失败后return回调:

import org.springframework.amqp.core.Message;
import org.springframework.amqp.rabbit.core.RabbitTemplate.ReturnCallback;
import org.springframework.stereotype.Service;
@Service("returnCallBackListener")
public class ReturnCallBackListener implements ReturnCallback{
@Override
public void returnedMessage(Message message, int replyCode, String replyText, String exchange, String routingKey) {
System.out.println("return--message:"+new String(message.getBody())+",replyCode:"+replyCode+",replyText:"+replyText+",exchange:"+exchange+",routingKey:"+routingKey);
}
}

测试类:

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import com.dingcheng.confirms.publish.PublishService;
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = {"classpath:application-context.xml"})
public class TestConfirm {
@Autowired
private PublishService publishService;
private static String exChange = "DIRECT_EX";
@Test
public void test1() throws InterruptedException{
String message = "currentTime:"+System.currentTimeMillis();
System.out.println("test1---message:"+message);
//exchange,queue 都正确,confirm被回调, ack=true
publishService.send(exChange,"CONFIRM_TEST",message);
Thread.sleep(1000);
}
@Test
public void test2() throws InterruptedException{
String message = "currentTime:"+System.currentTimeMillis();
System.out.println("test2---message:"+message);
//exchange 错误,queue 正确,confirm被回调, ack=false
publishService.send(exChange+"NO","CONFIRM_TEST",message);
Thread.sleep(1000);
}
@Test
public void test3() throws InterruptedException{
String message = "currentTime:"+System.currentTimeMillis();
System.out.println("test3---message:"+message);
//exchange 正确,queue 错误 ,confirm被回调, ack=true; return被回调 replyText:NO_ROUTE
publishService.send(exChange,"",message);
// Thread.sleep(1000);
}
@Test
public void test4() throws InterruptedException{
String message = "currentTime:"+System.currentTimeMillis();
System.out.println("test4---message:"+message);
//exchange 错误,queue 错误,confirm被回调, ack=false
publishService.send(exChange+"NO","CONFIRM_TEST",message);
Thread.sleep(1000);
}
}

测试结果:

test1---message:currentTime:1483786948506
test2---message:currentTime:1483786948532
consumer--:MessageProperties [headers={spring_return_correlation=445bc7ca-a5bd-47e2-8ba3-f0448420e441}, timestamp=null, messageId=null, userId=null, appId=null, clusterId=null, type=null, correlationId=null, replyTo=null, contentType=text/plain, contentEncoding=UTF-8, contentLength=0, deliveryMode=PERSISTENT, expiration=null, priority=0, redelivered=false, receivedExchange=DIRECT_EX, receivedRoutingKey=CONFIRM_TEST, deliveryTag=1, messageCount=0]:currentTime:1483786948506
test3---message:currentTime:1483786948536
confirm--:correlationData:null,ack:false,cause:channel error; protocol method: #method<channel.close>(reply-code=404, reply-text=NOT_FOUND - no exchange 'DIRECT_EXNO' in vhost '/', class-id=60, method-id=40)
confirm--:correlationData:null,ack:false,cause:Channel closed by application
[ERROR] 2017-01-07 19:02:28 org.springframework.amqp.rabbit.connection.CachingConnectionFactory.shutdownCompleted(CachingConnectionFactory.java:281):--> Channel shutdown: channel error; protocol method: #method<channel.close>(reply-code=404, reply-text=NOT_FOUND - no exchange 'DIRECT_EXNO' in vhost '/', class-id=60, method-id=40)
return--message:currentTime:1483786948536,replyCode:312,replyText:NO_ROUTE,exchange:DIRECT_EX,routingKey:
confirm--:correlationData:null,ack:true,cause:null
test4---message:currentTime:1483786948546
confirm--:correlationData:null,ack:false,cause:channel error; protocol method: #method<channel.close>(reply-code=404, reply-text=NOT_FOUND - no exchange 'DIRECT_EXNO' in vhost '/', class-id=60, method-id=40)
[ERROR] 2017-01-07 19:02:28 org.springframework.amqp.rabbit.connection.CachingConnectionFactory.shutdownCompleted(CachingConnectionFactory.java:281):--> Channel shutdown: channel error; protocol method: #method<channel.close>(reply-code=404, reply-text=NOT_FOUND - no exchange 'DIRECT_EXNO' in vhost '/', class-id=60, method-id=40)

代码和配置里面,已经都有注释,就不在多说明了.(callback是异步的,所以测试中sleep1秒钟等待下)

总结下就是:

如果消息没有到exchange,则confirm回调,ack=false

如果消息到达exchange,则confirm回调,ack=true

exchange到queue成功,则不回调return

exchange到queue失败,则回调return(需设置mandatory=true,否则不回回调,消息就丢了)

备注:需要说明,spring-rabbit和原生的rabbit-client ,表现是不一样的.

测试的时候,原生的client,exchange错误的话,直接就报错了,是不会到confirmListener和returnListener的

巴特西

RabbitMQ消息确认(发送确认,接收确认)

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