RocketMQ基本知识-蒲公英云

RocketMQ

rocketmq对比kafaka，它支持预定消息、消息跟踪、广播消息等等。
更多参考

启动

启动nameserver

nohup sh bin/mqnamesrv &
tail -f ~/logs/rocketmqlogs/namesrv.log
The Name Server boot success…
启动Broker

nohup sh bin/mqbroker -n localhost:9876 &
tail -f ~/logs/rocketmqlogs/broker.log
The broker[%s, 172.30.30.233:10911] boot success…

关闭

> sh bin/mqshutdown broker
The mqbroker(36695) is running...
Send shutdown request to mqbroker(36695) OK
> sh bin/mqshutdown namesrv
The mqnamesrv(36664) is running...
Send shutdown request to mqnamesrv(36664) OK

发送消息

可以发送的消息有三种：同步发送、异步发送、单向发送
特殊的是单向发送这种模式，这种不等待服务器返回信息，速度快。

下面举一个例子，比如同步发送

<dependency>
        <groupId>org.apache.rocketmq</groupId>
        <artifactId>rocketmq-client</artifactId>
        <version>4.3.0</version>
    </dependency>
public class SyncProducer {
    public static void main(String[] args) throws Exception {
        //Instantiate with a producer group name.
        DefaultMQProducer producer = new
            DefaultMQProducer("please_rename_unique_group_name");
        // Specify name server addresses.
        producer.setNamesrvAddr("localhost:9876");
        //Launch the instance.
        producer.start();
        for (int i = 0; i < 100; i++) {
            //Create a message instance, specifying topic, tag and message body.
            Message msg = new Message("TopicTest" /* Topic */,
                "TagA" /* Tag */,
                ("Hello RocketMQ " +
                    i).getBytes(RemotingHelper.DEFAULT_CHARSET) /* Message body */
            );
            //Call send message to deliver message to one of brokers.
            SendResult sendResult = producer.send(msg);
            System.out.printf("%s%n", sendResult);
        }
        //Shut down once the producer instance is not longer in use.
        producer.shutdown();
    }
}

接受消息

public class Consumer {
    public static void main(String[] args) throws InterruptedException, MQClientException {
        // Instantiate with specified consumer group name.
        DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("please_rename_unique_group_name");
        // Specify name server addresses.
        consumer.setNamesrvAddr("localhost:9876");
        // Subscribe one more more topics to consume.
        consumer.subscribe("TopicTest", "*");
        // Register callback to execute on arrival of messages fetched from brokers.
        consumer.registerMessageListener(new MessageListenerConcurrently() {
            @Override
            public ConsumeConcurrentlyStatus consumeMessage(List<MessageExt> msgs,
                ConsumeConcurrentlyContext context) {
                System.out.printf("%s Receive New Messages: %s %n", Thread.currentThread().getName(), msgs);
                return ConsumeConcurrentlyStatus.CONSUME_SUCCESS;
            }
        });
        //Launch the consumer instance.
        consumer.start();
        System.out.printf("Consumer Started.%n");
    }
}

局部有序消息

全局有序消息：由于一个 topic 只有一个 queue ，即使我们有多个 producer 实例和 consumer 实例也很难提高消息吞吐量。就好比过独木桥，大家只能一个挨着一个过去，效率低下。

局部有序消息：常见做法就是将 order id 进行处理，将 order id 相同的消息发送到 topicB 的同一个 queue，假设我们 topicB 有 2 个 queue，那么我们可以简单的对 id 取余，奇数的发往 queue0，偶数的发往 queue1，消费者按照 queue 去消费时，就能保证 queue0 里面的消息有序消费，queue1 里面的消息有序消费。

创建一个topic，默认有4个queue，我们这里保证了每一个queue是有序的。这种可以提高吞吐。

public class OrderedProducer {
    public static void main(String[] args) throws Exception {
        //Instantiate with a producer group name.
        MQProducer producer = new DefaultMQProducer("example_group_name");
        //Launch the instance.
        producer.start();
        String[] tags = new String[] {
    "TagA", "TagB", "TagC", "TagD", "TagE"};
        for (int i = 0; i < 100; i++) {
            int orderId = i % 10;
            //Create a message instance, specifying topic, tag and message body.
            Message msg = new Message("TopicTestjjj", tags[i % tags.length], "KEY" + i,
                    ("Hello RocketMQ " + i).getBytes(RemotingHelper.DEFAULT_CHARSET));
            SendResult sendResult = producer.send(msg, new MessageQueueSelector() {
            @Override
            public MessageQueue select(List<MessageQueue> mqs, Message msg, Object arg) {
                Integer id = (Integer) arg;
                int index = id % mqs.size();
                return mqs.get(index); //需要发送到哪一个队列
            }
            }, orderId); // orderId会传递到上面的arg里面
            System.out.printf("%s%n", sendResult);
        }
        //server shutdown
        producer.shutdown();
    }
}

处理消息接受

public class OrderedConsumer {
    public static void main(String[] args) throws Exception {
        DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("example_group_name");
        consumer.setConsumeFromWhere(ConsumeFromWhere.CONSUME_FROM_FIRST_OFFSET);
        consumer.subscribe("TopicTest", "TagA || TagC || TagD");
        consumer.registerMessageListener(new MessageListenerOrderly() {
            AtomicLong consumeTimes = new AtomicLong(0);
            @Override
            public ConsumeOrderlyStatus consumeMessage(List<MessageExt> msgs,
                                                       ConsumeOrderlyContext context) {
                context.setAutoCommit(false);
                System.out.printf(Thread.currentThread().getName() + " Receive New Messages: " + msgs + "%n");
                this.consumeTimes.incrementAndGet();
                if ((this.consumeTimes.get() % 2) == 0) {
                    return ConsumeOrderlyStatus.SUCCESS;
                } else if ((this.consumeTimes.get() % 3) == 0) {
                    return ConsumeOrderlyStatus.ROLLBACK;
                } else if ((this.consumeTimes.get() % 4) == 0) {
                    return ConsumeOrderlyStatus.COMMIT;
                } else if ((this.consumeTimes.get() % 5) == 0) {
                    context.setSuspendCurrentQueueTimeMillis(3000);
                    return ConsumeOrderlyStatus.SUSPEND_CURRENT_QUEUE_A_MOMENT;
                }
                return ConsumeOrderlyStatus.SUCCESS;
            }
        });
        consumer.start();
        System.out.printf("Consumer Started.%n");
    }
}

处理消息接受和异常处理
在这里插入图片描述
消息消费的顺序问题：

并发情况下，返回RECONSUME_LATER，表示过一会儿再消费，先去消费其他消息
有序情况下，返回SUSPEND_CURRENT_QUEUE_A_MOMENT，表示等一会儿再消费，无法消费其他消息
可以通过getReconsumeTimes获取重试次数
参考https://www.cnblogs.com/happyflyingpig/p/8207003.html

广播模式

广播正在向主题的所有订阅者发送消息。
如果您希望所有订阅者都收到有关主题的消息，则广播是一个不错的选择。

public class BroadcastProducer {
    public static void main(String[] args) throws Exception {
        DefaultMQProducer producer = new DefaultMQProducer("ProducerGroupName");
        producer.start();
        for (int i = 0; i < 100; i++){
            Message msg = new Message("TopicTest",
                "TagA",
                "OrderID188",
                "Hello world".getBytes(RemotingHelper.DEFAULT_CHARSET));
            SendResult sendResult = producer.send(msg);
            System.out.printf("%s%n", sendResult);
        }
        producer.shutdown();
    }
}
public class BroadcastConsumer {
    public static void main(String[] args) throws Exception {
        DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("example_group_name");
        consumer.setConsumeFromWhere(ConsumeFromWhere.CONSUME_FROM_FIRST_OFFSET);
        //set to broadcast mode
        consumer.setMessageModel(MessageModel.BROADCASTING);
        consumer.subscribe("TopicTest", "TagA || TagC || TagD");
        consumer.registerMessageListener(new MessageListenerConcurrently() {
            @Override
            public ConsumeConcurrentlyStatus consumeMessage(List<MessageExt> msgs,
                ConsumeConcurrentlyContext context) {
                System.out.printf(Thread.currentThread().getName() + " Receive New Messages: " + msgs + "%n");
                return ConsumeConcurrentlyStatus.CONSUME_SUCCESS;
            }
        });
        consumer.start();
        System.out.printf("Broadcast Consumer Started.%n");
    }
}

延迟消息

预定消息与普通消息的不同之处在于，它们将在稍后提供的时间之前传送。

import org.apache.rocketmq.client.producer.DefaultMQProducer;
 import org.apache.rocketmq.common.message.Message;
 public class ScheduledMessageProducer {
     public static void main(String[] args) throws Exception {
         // Instantiate a producer to send scheduled messages
         DefaultMQProducer producer = new DefaultMQProducer("ExampleProducerGroup");
         // Launch producer
         producer.start();
         int totalMessagesToSend = 100;
         for (int i = 0; i < totalMessagesToSend; i++) {
             Message message = new Message("TestTopic", ("Hello scheduled message " + i).getBytes());
             // This message will be delivered to consumer 10 seconds later.
             message.setDelayTimeLevel(3);
             // Send the message
             producer.send(message);
         }
         // Shutdown producer after use.
         producer.shutdown();
     }
 }

批量发送

批量发送应该需要保持同一个主题，大小不超过1mb。

String topic = "BatchTest";
List<Message> messages = new ArrayList<>();
messages.add(new Message(topic, "TagA", "OrderID001", "Hello world 0".getBytes()));
messages.add(new Message(topic, "TagA", "OrderID002", "Hello world 1".getBytes()));
messages.add(new Message(topic, "TagA", "OrderID003", "Hello world 2".getBytes()));
try {
    producer.send(messages);
} catch (Exception e) {
    e.printStackTrace();
    //handle the error
}

详情参考

消息的tag过滤

在大多数情况下，tag是一种简单实用的设计，用于选择所需的消息。
例如：

DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("CID_EXAMPLE");
consumer.subscribe("TOPIC", "TAGA || TAGB || TAGC");

消息的tag这可以有一个，这对于复杂的需求是没办法满足的，不过我们可以使用properties配合sql语法过滤需要的消息。
具体参考

RocketMQ事务

事务状态

三种状态：
（1）TransactionStatus.CommitTransaction：提交事务，它意味着允许消费者使用此消息。
（2）TransactionStatus.RollbackTransaction：回滚事务，表示该消息将被删除而不允许使用。
（3）TransactionStatus.Unknown：中间状态，表示需要MQ检查以确定状态。
import org.apache.rocketmq.client.consumer.DefaultMQPushConsumer;
import org.apache.rocketmq.client.consumer.listener.ConsumeConcurrentlyContext;
import org.apache.rocketmq.client.consumer.listener.ConsumeConcurrentlyStatus;
import org.apache.rocketmq.client.consumer.listener.MessageListenerConcurrently;
import org.apache.rocketmq.common.message.MessageExt;
import java.util.List;
public class TransactionProducer {
    public static void main(String[] args) throws MQClientException, InterruptedException {
        TransactionListener transactionListener = new TransactionListenerImpl();
        TransactionMQProducer producer = new TransactionMQProducer("please_rename_unique_group_name");
        ExecutorService executorService = new ThreadPoolExecutor(2, 5, 100, TimeUnit.SECONDS, new ArrayBlockingQueue<Runnable>(2000), new ThreadFactory() {
            @Override
            public Thread newThread(Runnable r) {
                Thread thread = new Thread(r);
                thread.setName("client-transaction-msg-check-thread");
                return thread;
            }
        });
        producer.setExecutorService(executorService);
        producer.setTransactionListener(transactionListener);
        producer.start();
        String[] tags = new String[] {
    "TagA", "TagB", "TagC", "TagD", "TagE"};
        for (int i = 0; i < 10; i++) {
            try {
                Message msg =
                    new Message("TopicTest1234", tags[i % tags.length], "KEY" + i,
                        ("Hello RocketMQ " + i).getBytes(RemotingHelper.DEFAULT_CHARSET));
                SendResult sendResult = producer.sendMessageInTransaction(msg, null);
                System.out.printf("%s%n", sendResult);
                Thread.sleep(10);
            } catch (MQClientException | UnsupportedEncodingException e) {
                e.printStackTrace();
            }
        }
        for (int i = 0; i < 100000; i++) {
            Thread.sleep(1000);
        }
        producer.shutdown();
    }
}
import ...
   public class TransactionListenerImpl implements TransactionListener {
       private AtomicInteger transactionIndex = new AtomicInteger(0);
       private ConcurrentHashMap<String, Integer> localTrans = new ConcurrentHashMap<>();
       @Override
       public LocalTransactionState executeLocalTransaction(Message msg, Object arg) {
              //这里获取本地事务的业务ID，返回UNKON是为了
              //重试checkLocalTransaction方法
           int value = transactionIndex.getAndIncrement();
           int status = value % 3;
           localTrans.put(msg.getTransactionId(), status);
           return LocalTransactionState.UNKNOW;
       }
       @Override
       public LocalTransactionState checkLocalTransaction(MessageExt msg) {
              //根据本地事务状态判断是否需要回滚
           Integer status = localTrans.get(msg.getTransactionId());
           if (null != status) {
               switch (status) {
                   case 0:
                       return LocalTransactionState.UNKNOW;
                   case 1:
                       return LocalTransactionState.COMMIT_MESSAGE;
                   case 2:
                       return LocalTransactionState.ROLLBACK_MESSAGE;
               }
           }
           return LocalTransactionState.COMMIT_MESSAGE;
       }
   }

事务的处理参考
https://yq.aliyun.com/articles/684259
http://rocketmq.apache.org/docs/transaction-example/

消息日志配置

log4j xml配置

<appender name="mqAppender1" class="org.apache.rocketmq.logappender.log4j.RocketmqLog4jAppender">
    <param name="Tag" value="yourTag" />
    <param name="Topic" value="yourLogTopic" />
    <param name="ProducerGroup" value="yourLogGroup" />
    <param name="NameServerAddress" value="yourRocketmqNameserverAddress"/>
    <layout class="org.apache.log4j.PatternLayout">
        <param name="ConversionPattern" value="%d{yyyy-MM-dd HH:mm:ss}-%p %t %c - %m%n" />
    </layout>
</appender>
<appender name="mqAsyncAppender1" class="org.apache.log4j.AsyncAppender">
    <param name="BufferSize" value="1024" />
    <param name="Blocking" value="false" />
    <appender-ref ref="mqAppender1"/>
</appender>

logback配置

<appender name="mqAppender1" class="org.apache.rocketmq.logappender.logback.RocketmqLogbackAppender">
    <tag>yourTag</tag>
    <topic>yourLogTopic</topic>
    <producerGroup>yourLogGroup</producerGroup>
    <nameServerAddress>yourRocketmqNameserverAddress</nameServerAddress>
    <layout>
        <pattern>%date %p %t - %m%n</pattern>
    </layout>
</appender>
<appender name="mqAsyncAppender1" class="ch.qos.logback.classic.AsyncAppender">
    <queueSize>1024</queueSize>
    <discardingThreshold>80</discardingThreshold>
    <maxFlushTime>2000</maxFlushTime>
    <neverBlock>true</neverBlock>
    <appender-ref ref="mqAppender1"/>
</appender>