RabbitMQ(二) RabbitMQ高级特性

消息如何保障100%的投递成功

什么是生产端的可靠性投递

  • 保障消息的成功发出
  • 保障MQ节点的成功接收
  • 发送端收到MQ节点(Borker)确认应答
  • 完善的消息进行补偿机制

生产端-可靠性投递(一)

  • 消息落库,对消息状态进行打标
  • 消息的延迟投递,做二次确认,回调检查

生产端-可靠性投递(二)

消息落库,对消息状态进行打标
RabbitMQ(二) RabbitMQ高级特性

消息落库,对消息进行打标(对消息设置状态,发送中,broker收到,)

定时器轮训,检测未发送的消息,进行二次投递,最大努力尝试(设置最大次数)

  • step1 消息落库(唯一的消息id) ,一定是数据库入库成功以后在进行发送消息
  • step2 发送消息 到MQ Broker
  • step3 Broker Confirm (发送消息确认)
  • step4 生产者ConfirmListener (异步监听,Broker回送的响应)
  • step5 成功,通过messageId更新消息状态

补偿

分布式定时任务,抓取数据(超过第一时长),尝试重发,重试次数限制

生产端-可靠性投递(三)

消息的延迟投递,做二次确认,回调检查 (最大限度的减少消息落库)
RabbitMQ(二) RabbitMQ高级特性
方案一在高并发场景下,每次消息落库,影响性能(IO操作)

step1: 业务消息落库 ,一定是数据库入库成功以后在进行发送消息

step2:第一次消息的发送

step3:延迟消息的检测

step4:监听,处理完,生成一条新消息

step5:通过队列发送,确认 不是之前的ack

幂等性概念

幂等性是什么

借鉴数据库的乐观锁机制

执行一条更新SQL

update t_reps set count=count-1,version=version+1  where verison=1

消费端幂等性保障

在业务高峰期,如何避免消息的重复消费问题

消费端实现幂等性,就意味着,我们的消息永远不会被消费多次,即时收到多条一样的消息。

幂等性,通俗点说,就一个数据,或者一个请求,给你重复来多次,你得确保对应的数据是不会改变的,不能出错
https://github.com/doocs/advanced-java/blob/master/docs/high-concurrency/how-to-ensure-that-messages-are-not-repeatedly-consumed.md

业界主流的幂等性操作

  • 唯一ID+指纹码机制,利用数据库主键去重
  • 利用Redis的原子性实现

方案一

唯一ID+指纹码机制

  • 唯一ID+指纹码机制,利用数据库主键去重
  • select count(1) from t_order where id=唯一id+指纹码
  • 好处:实现简单
  • 坏处:高并发下有数据库写入的性能瓶颈
  • 解决方案:跟进ID进行分库分表进行路由算法

方案二:利用Redis的原子性实现

Confirm确认消息

理解Confirm消息确认机制:

  • 消息的去人,是指生产者投递消息后,如果Broker收到消息,则会给生产者一个应答
  • 生产者进行接收应该,用来确定这条消息是否正常的发送到broker,这种方式也是消息的可靠性投递的核心保障

confirm确认消息流程解析
RabbitMQ(二) RabbitMQ高级特性
confirm确认消息实现

  • 第一步:在channel上开启确认模式: channel.sconfirmSelect()
  • 第二步:在channel上添加监听:addConfirmListener,监听成功和失败的返回结果,根据具体的结果对消息进行重新发送、或记录日志等后续处理。

示例

生产者

/**
 * @author niugang
 */
public class Producer {
	public static void main(String[] args) throws Exception {		
		//1 创建ConnectionFactory
		ConnectionFactory connectionFactory = new ConnectionFactory();
		connectionFactory.setHost("localhost");
		connectionFactory.setPort(5672);
		connectionFactory.setVirtualHost("/");
		
		//2 获取C	onnection
		Connection connection = connectionFactory.newConnection();
		
		//3 通过Connection创建一个新的Channel
		Channel channel = connection.createChannel();		
		//4 指定我们的消息投递模式: 消息的确认模式 
		channel.confirmSelect();
		
		String exchangeName = "test_confirm_exchange";
		String routingKey = "confirm.save";
		
		//5 发送一条消息
		String msg = "Hello RabbitMQ Send confirm message!";
		channel.basicPublish(exchangeName, routingKey, null, msg.getBytes());
		
		//6 添加一个确认监听
		channel.addConfirmListener(new ConfirmListener() {
			//失败
			// deliveryTag 消息唯一标签
			@Override
			public void handleNack(long deliveryTag, boolean multiple) throws IOException {
				System.err.println("-------no ack!-----------");
			}

			//成功
			@Override
			public void handleAck(long deliveryTag, boolean multiple) throws IOException {
				System.err.println("-------ack!-----------");
			}
		});		
	}
}

消费者

/**
 * @author niugang
 */
public class Consumer {

	
	public static void main(String[] args) throws Exception {
		
		
		//1 创建ConnectionFactory
		ConnectionFactory connectionFactory = new ConnectionFactory();
		connectionFactory.setHost("localhost");
		connectionFactory.setPort(5672);
		connectionFactory.setVirtualHost("/");
		
		//2 获取C	onnection
		Connection connection = connectionFactory.newConnection();
		
		//3 通过Connection创建一个新的Channel
		Channel channel = connection.createChannel();
		
		String exchangeName = "test_confirm_exchange";
		String routingKey = "confirm.#";
		String queueName = "test_confirm_queue";
		
		//4 声明交换机和队列 然后进行绑定设置, 最后制定路由Key
		channel.exchangeDeclare(exchangeName, "topic", true);
		channel.queueDeclare(queueName, true, false, false, null);
		channel.queueBind(queueName, exchangeName, routingKey);
		
		//5 创建消费者 
		QueueingConsumer queueingConsumer = new QueueingConsumer(channel);
		channel.basicConsume(queueName, true, queueingConsumer);
		
		while(true){
			Delivery delivery = queueingConsumer.nextDelivery();
			String msg = new String(delivery.getBody());
			
			System.err.println("消费端: " + msg);
		}
		
		
	}
}

Return消息机制

  • Return Listener 用于处理一些不可路由的消息。
  • 我们的消息生产者,通过指定一个Exchange和RoutingKey,把消息送达到某一个队列中取,然后我们的消费者监听队列,进行消费处理操作。
  • 但是在某些情况下,如果我们在发送消息的时候,当前的Exchange不存在或者指定的路由key路由不到,这个时候如果我们需要监听这种不可达的消息,就要使用Return Listener

配置

在基础API上有一个关键的配置项

Mandatory:如果为true,则监听器会接收到路由不可达的消息,然后进行后续处理,如果为false,那么broker端自动删除该消息。

流程
RabbitMQ(二) RabbitMQ高级特性
生产者

/**
 * @author niugang
 */
public class Producer {

	public static void main(String[] args) throws Exception {
		
		
		ConnectionFactory connectionFactory = new ConnectionFactory();
		connectionFactory.setHost("localhost");
		connectionFactory.setPort(5672);
		connectionFactory.setVirtualHost("/");
		
		Connection connection = connectionFactory.newConnection();
		Channel channel = connection.createChannel();
		
		String exchange = "test_return_exchange";
		String routingKey = "return.save";
		String routingKeyError = "abc.save";
		
		String msg = "Hello RabbitMQ Return Message";
		
		
		channel.addReturnListener(new ReturnListener() {
			@Override
			public void handleReturn(int replyCode, String replyText, String exchange,
					String routingKey, AMQP.BasicProperties properties, byte[] body) throws IOException {
				
				System.err.println("---------handle  return----------");
				//响应码 312
				System.err.println("replyCode: " + replyCode);
				//NO_ROUTE
				System.err.println("replyText: " + replyText);
				System.err.println("exchange: " + exchange);
				System.err.println("routingKey: " + routingKey);
				System.err.println("properties: " + properties);
				System.err.println("body: " + new String(body));
			}
		});
		
		
		channel.basicPublish(exchange, routingKeyError, true, null, msg.getBytes());
		
		//channel.basicPublish(exchange, routingKeyError, true, null, msg.getBytes());	
	}
}

消费者

/**
 * @author niugang
 */
public class Consumer {
	public static void main(String[] args) throws Exception {
		ConnectionFactory connectionFactory = new ConnectionFactory();
		connectionFactory.setHost("localhost");
		connectionFactory.setPort(5672);
		connectionFactory.setVirtualHost("/");
		
		Connection connection = connectionFactory.newConnection();
		Channel channel = connection.createChannel();
		
		String exchangeName = "test_return_exchange";
		String routingKey = "return.#";
		String queueName = "test_return_queue";
		
		channel.exchangeDeclare(exchangeName, "topic", true, false, null);
		channel.queueDeclare(queueName, true, false, false, null);
		channel.queueBind(queueName, exchangeName, routingKey);	
		QueueingConsumer queueingConsumer = new QueueingConsumer(channel);
		channel.basicConsume(queueName, true, queueingConsumer);
		
		while(true){
			Delivery delivery = queueingConsumer.nextDelivery();
			String msg = new String(delivery.getBody());
			System.err.println("消费者: " + msg);
		}	
	}
}

消费者自定义监听

  • 我们一般就是在代码中编写while循环,进行consumer.nextDelivery方法获取下一条消息,然后进行消费处理!
  • 但是我们使用自定义的Consumer更加的方便,解耦性更加的强,也是在实际工作中最常用的使用方式!

实现方式

自定义类,继承 DefaultConsumer
RabbitMQ(二) RabbitMQ高级特性
生产者

/**
 * @author niugang
 */
public class Producer {

	
	public static void main(String[] args) throws Exception {
		
		ConnectionFactory connectionFactory = new ConnectionFactory();
		connectionFactory.setHost("localhost");
		connectionFactory.setPort(5672);
		connectionFactory.setVirtualHost("/");
		
		Connection connection = connectionFactory.newConnection();
		Channel channel = connection.createChannel();
		
		String exchange = "test_consumer_exchange";
		String routingKey = "consumer.save";
		
		String msg = "Hello RabbitMQ Consumer Message";
		
		for(int i =0; i<5; i ++){
			channel.basicPublish(exchange, routingKey, true, null, msg.getBytes());
		}
		
	}
}

自定义消费者

/**
 * 自定义消费者
 * @author niugang
 */
public class MyConsumer extends DefaultConsumer {


	public MyConsumer(Channel channel) {
		super(channel);
	}

	@Override
	public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {
		System.err.println("-----------consume message----------");
		//消费标签
		System.err.println("consumerTag: " + consumerTag);
		System.err.println("envelope: " + envelope);
		System.err.println("properties: " + properties);
		System.err.println("body: " + new String(body));
	}


}

消费者

/**
 * @author niugang
 */
public class Consumer {

	
	public static void main(String[] args) throws Exception {
		
		
		ConnectionFactory connectionFactory = new ConnectionFactory();
		connectionFactory.setHost("localhost");
		connectionFactory.setPort(5672);
		connectionFactory.setVirtualHost("/");
		
		Connection connection = connectionFactory.newConnection();
		Channel channel = connection.createChannel();
		
		
		String exchangeName = "test_consumer_exchange";
		String routingKey = "consumer.#";
		String queueName = "test_consumer_queue";
		
		channel.exchangeDeclare(exchangeName, "topic", true, false, null);
		channel.queueDeclare(queueName, true, false, false, null);
		channel.queueBind(queueName, exchangeName, routingKey);
		
		channel.basicConsume(queueName, true, new MyConsumer(channel));
		
	
	}
}

消费端限流

什么是消费端的限流

  • 假设一个场景,首先,我们RabbitMQ服务器上有上万条未处理的消息,我们随便打开一个消费者客户端,会出现下面情况:
  • 巨量的消息瞬间全部推送过来,但是我们单个客户端无法同时处理这么多数据;
  • RabbitMQ提供了一种qos(服务质量保证)功能,即在非自动确认消息(autoAck为false)的前提下,如果一定数目的消息(通过基于consume或者channel设置Qos的值)未被确认前,不进行消费新的消息。
  • void BasicQos(uint prefetchSize,ushort prefetchCount,bool global);
  • prefetchSize:0 #这里为0表示不限制
  • prefetchCount: 会告诉RabbitMQ不要同时给一个消费者推送多于N个消息,即一旦有N个消息还没有ack,则该consumer将block掉,直到有消息ack; (prefetchCount等于1即可)
  • global:true\false 是否将上面设置应用于channel
  • 简单来说,就是上面限制是channel级别的还是consumer级别;

生产者

/**
 * @author niugang
 */
public class Producer {

	
	public static void main(String[] args) throws Exception {
		
		ConnectionFactory connectionFactory = new ConnectionFactory();
		connectionFactory.setHost("localhosy");
		connectionFactory.setPort(5672);
		connectionFactory.setVirtualHost("/");
		
		Connection connection = connectionFactory.newConnection();
		Channel channel = connection.createChannel();
		
		String exchange = "test_qos_exchange";
		String routingKey = "qos.save";
		
		String msg = "Hello RabbitMQ QOS Message";
		
		for(int i =0; i<5; i ++){
			channel.basicPublish(exchange, routingKey, true, null, msg.getBytes());
		}
		
	}
}

自定义消费者

public class MyConsumer extends DefaultConsumer {


	private Channel channel ;
	
	public MyConsumer(Channel channel) {
		super(channel);
		this.channel = channel;
	}

	@Override
	public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {
		System.err.println("-----------consume message----------");
		System.err.println("consumerTag: " + consumerTag);
		System.err.println("envelope: " + envelope);
		System.err.println("properties: " + properties);
		System.err.println("body: " + new String(body));
		//ack 注释掉后 控制台只会接收到一条消息
		channel.basicAck(envelope.getDeliveryTag(), false);
		
	}

}

消费者

/**
 * @author niugang
 */
public class Consumer {
	public static void main(String[] args) throws Exception {
		ConnectionFactory connectionFactory = new ConnectionFactory();
		connectionFactory.setHost("localhost");
		connectionFactory.setPort(5672);
		connectionFactory.setVirtualHost("/");
		
		Connection connection = connectionFactory.newConnection();
		Channel channel = connection.createChannel();
		String exchangeName = "test_qos_exchange";
		String queueName = "test_qos_queue";
		String routingKey = "qos.#";
		
		channel.exchangeDeclare(exchangeName, "topic", true, false, null);
		channel.queueDeclare(queueName, true, false, false, null);
		channel.queueBind(queueName, exchangeName, routingKey);
		
		//1 限流方式  第一件事就是 autoAck设置为 false
		//prefetchCount broker 给 消费者 最大推送消息数量
		channel.basicQos(0, 1, false);
		//手工签收
		channel.basicConsume(queueName, false, new MyConsumer(channel));	
	}
}

消息ACK与重回队列

消费端的手工ACK和NACK

  • 消费端进行消费的时候,如果由于业务异常我们可以进行日志的记录,然后进行补偿
  • 如果由于服务器宕机等严重问题,那我们就需要手工进行ACK保障消费端消费成功

消费端的重回队列

  • 消费端重回队列是为了对没有处理成功的消息,把消息重新会递给Broker (requeue属性设置)

  • 一般我们在实际应用中,都会关闭重回队列,也就是设置为false;

生产者

/**
 * ack 测试生产者
 * @author niugang
 */
public class Producer {
	public static void main(String[] args) throws Exception {
		
		ConnectionFactory connectionFactory = new ConnectionFactory();
		connectionFactory.setHost("localhost");
		connectionFactory.setPort(5672);
		connectionFactory.setVirtualHost("/");
		Connection connection = connectionFactory.newConnection();
		Channel channel = connection.createChannel();
		String exchange = "test_ack_exchange";
		String routingKey = "ack.save";
		for(int i =0; i<5; i ++){
			
			Map<String, Object> headers = new HashMap<String, Object>();
			headers.put("num", i);
			//设置消息属性
			AMQP.BasicProperties properties = new AMQP.BasicProperties.Builder()
					.deliveryMode(2).expiration("1000")
					.contentEncoding("UTF-8")
					.headers(headers)
					.build();
			String msg = "Hello RabbitMQ ACK Message " + i;
			channel.basicPublish(exchange, routingKey, true, properties, msg.getBytes());
		}
		
	}
}

自定义消费者

/**
 * 自定义消费者
 * @author niugang
 */
public class MyConsumer extends DefaultConsumer {


	private Channel channel ;
	
	public MyConsumer(Channel channel) {
		super(channel);
		this.channel = channel;
	}

	@Override
	public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {
		System.err.println("-----------consume message----------");
		System.err.println("body: " + new String(body));
		try {
			Thread.sleep(2000);
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
		if((Integer)properties.getHeaders().get("num") == 0) {
			//multiple 是否是批量
			//requeue 重新添加到队列尾部
			channel.basicNack(envelope.getDeliveryTag(), false, true);
		} else {
			channel.basicAck(envelope.getDeliveryTag(), false);
		}
		
	}
}

消费者

/**
 * 消费者
 * @author niugang
 */
public class Consumer {
    public static void main(String[] args) throws Exception {
        ConnectionFactory connectionFactory = new ConnectionFactory();
        connectionFactory.setHost("localhost");
        connectionFactory.setPort(5672);
        connectionFactory.setVirtualHost("/");

        Connection connection = connectionFactory.newConnection();
        Channel channel = connection.createChannel();
        String exchangeName = "test_ack_exchange";
        String queueName = "test_ack_queue";
        String routingKey = "ack.#";
        channel.exchangeDeclare(exchangeName, "topic", true, false, null);
        channel.queueDeclare(queueName, true, false, false, null);
        channel.queueBind(queueName, exchangeName, routingKey);
        // 手工签收 必须要关闭 autoAck = false
        channel.basicConsume(queueName, false, new MyConsumer(channel));

    }
}

TTL队列/消息

TTL

  • TTL是Time To Live的缩写,也就是生存时间
  • RabbitMQ支持消息的过期时间,在消息发送时可以进行指定。
  • RabbitMQ支持队列的过期时间,从消息入队列开始计算,只要超过了队列的超时时间配置,那么消息会自动的删除。

在控制台创建队列
RabbitMQ(二) RabbitMQ高级特性
在控制台创建exchange 并添加binding 然后发送消息,然后在队列页面可以看到消息自动被队列剔除
RabbitMQ(二) RabbitMQ高级特性
原生API设置TTL

AMQP.BasicProperties properties = new AMQP.BasicProperties.Builder()
					.expiration("1000").build();

Spring AMQP设置TTL

MessageProperties messageProperties = new MessageProperties();
 //消息过期时间
messageProperties.setExpiration("1000");
Message stringMessage = new Message("Hello Springboot RabbitMQ".getBytes(), messageProperties);

死信队列

死信队列:DLX ,Dead-Letter-Exchange

  • 利用DLX,当消息在一个队列中变成死信(dead message)之后,它能被重新publish到另一个Exchange,这个Exchange就是DLX;

消息变成死信有以下几种情况

  • 消息被拒绝(basic.reject/basic.nack) 并且requeue=false;
  • 消息TTL过期
  • 队列达到最大长度

死信队列详细解释

DLX也是一个正常的Exchange,和一般的Exchange没有区别,它能在任何的队列上被指定,实际上就是设置某个队列的属性。
当这个队列中有死信时,RabbitMQ就会自动的将这个消息重新发布到设置的Exchange上去,进而被路由到另一个队列。
可以监听这个队列中消息做相应的处理,这个特性可以弥补RabbitMQ3.0以前支持的immediate参数的功能;

死信队列具体设置

step1:首先需要设置死信队列的exchange和queue,然后进行绑定

例如定义如下exchange和queue

  • Exchange:dlx.echange
  • Queue:dlx.queue
  • RoutingKey:#

step2:

然后我们进行正常声明交换机、队列、绑定,只不过我们需要在队列上加上一个参数即可:arguments.put(“x-dead-letter-exchange”,“dlx.exchange”);

这样消息在过期、requeue、队列在达到最大长度时,消息就可以直接路由到死信队列。

RabbitMQ(二) RabbitMQ高级特性
生产者

/**
 * 私信队列 生产端
 *
 * @author niugang
 */
public class Producer {
    public static void main(String[] args) throws Exception {
        ConnectionFactory connectionFactory = new ConnectionFactory();
        connectionFactory.setHost("localhost");
        connectionFactory.setPort(5672);
        connectionFactory.setVirtualHost("/");

        Connection connection = connectionFactory.newConnection();
        Channel channel = connection.createChannel();
        //自定义普通的exchange
        String exchange = "test_dlx_exchange";
        String routingKey = "dlx.save";
        String msg = "Hello RabbitMQ DLX Message";
        for (int i = 0; i < 1; i++) {
            AMQP.BasicProperties properties = new AMQP.BasicProperties.Builder()
                    .deliveryMode(2)
                    .contentEncoding("UTF-8")
                    //过期时间为10s
                    .expiration("10000")
                    .build();
            channel.basicPublish(exchange, routingKey, true, properties, msg.getBytes());
        }

    }
}

自定义消息消费

/**
 * 自定义消息消费
 *
 * @author niugang
 */
public class MyConsumer extends DefaultConsumer {
    public MyConsumer(Channel channel) {
        super(channel);
    }

    @Override
    public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {
        System.err.println("-----------consume message----------");
        System.err.println("consumerTag: " + consumerTag);
        System.err.println("envelope: " + envelope);
        System.err.println("properties: " + properties);
        System.err.println("body: " + new String(body));
    }
}

生产者

/**
 * 死信队列消费端
 *
 * @author niugang
 */
public class Consumer {
    public static void main(String[] args) throws Exception {
        ConnectionFactory connectionFactory = new ConnectionFactory();
        connectionFactory.setHost("localhost");
        connectionFactory.setPort(5672);
        connectionFactory.setVirtualHost("/");

        Connection connection = connectionFactory.newConnection();
        Channel channel = connection.createChannel();

        // 这就是一个普通的交换机 和 队列 以及路由
        String exchangeName = "test_dlx_exchange";
        String routingKey = "dlx.#";
        String queueName = "test_dlx_queue";

        channel.exchangeDeclare(exchangeName, "topic", true, false, null);

        Map<String, Object> agruments = new HashMap<String, Object>(16);
        //设置死信队列exchange  这些具体的参数可以通过rabbitmq控制台查看
        agruments.put("x-dead-letter-exchange", "dlx.exchange");
        //这个agruments属性,要设置到声明队列上
        channel.queueDeclare(queueName, true, false, false, agruments);
        channel.queueBind(queueName, exchangeName, routingKey);

        //要进行死信队列的声明:
        channel.exchangeDeclare("dlx.exchange", "topic", true, false, null);
        channel.queueDeclare("dlx.queue", true, false, false, null);
        channel.queueBind("dlx.queue", "dlx.exchange", "#");

        channel.basicConsume(queueName, true, new MyConsumer(channel));
    }
}

RabbitMQ(二) RabbitMQ高级特性

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