RocketMQ introduction and practice

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Introduction to RocketMQ and comparison of mainstream MQ

Mainstream MQ comparison: Kafka, RocketMq, RabbitMq Kafka: a sub-project under Apache, a high-performance distributed Publish/Subscribe message queue system implemented by scala (for the log field)

• Fast persistence: Through disk sequential read and write and zero-copy mechanism, messages can be persisted under O(1) system overhead
• High throughput: a throughput rate of 10w/s can be achieved on an ordinary server
• High accumulation: support for consumers to leave school for a long time under the topic, and the message accumulation is large
• Completely distributed system: Broker, Producer, and Consumer all support distribution natively and automatically, and rely on zookeeper to automatically achieve load balancing
• Support for Hadoop data parallel loading: For log data and offline analysis systems like Hadoop, but requiring real-time processing constraints, this is a viable solution

RocketMq: Formerly known as Metaq, it was renamed RocketMq when 3.0 was released. RocketMq is a distributed, queue model message middleware (normal business)

• Able to guarantee strict message ordering
• Provides rich message pull mode
• Efficient subscriber horizontal scalability
• Real-time message subscription mechanism
• support transaction message
• The stacking capacity of billions of messages is a little lower than that of kafka

RabbitMq: An open source message queue written in Erlang, which supports many protocols: AMQP, XMPP, SMTP, STOMP, making it very heavyweight and suitable for enterprise-level development

• Routing
• Load balance
• data persistence

Download the installation package

Download address: dlcdn.apache.org/rocketmq/4.... Unzip or compile:

> unzip rocketmq-all-4.9.3-source-release.zip   
> cd rocketmq-all-4.9.3/   
> mvn -Prelease-all -DskipTests clean install -U   
> cd distribution/target/rocketmq-4.9.3/rocketmq-4.9.3
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service start

Start the NameServer service

> nohup sh bin/mqnamesrv &
> tail -f ~/logs/rocketmqlogs/namesrv.log
The Name Server boot success...
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start the broker

> nohup sh bin/mqbroker -n localhost:9876 &   
> tail -f ~/logs/rocketmqlogs/broker.log    
The broker[%s, 172.30.30.233:10911] boot success... 
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Sending and reading messages Before sending/receiving messages, we need to tell the client where the name servers are. RocketMQ provides multiple ways to do this. For simplicity we use the environment variable NAMESRV_ADDR

 > export NAMESRV_ADDR=localhost:9876
 > sh bin/tools.sh org.apache.rocketmq.example.quickstart.Producer
 SendResult [sendStatus=SEND_OK, msgId= ...

 > sh bin/tools.sh org.apache.rocketmq.example.quickstart.Consumer
 ConsumeMessageThread_%d Receive New Messages: [MessageExt...
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Note: If the disk of our computer is insufficient (the space used exceeds 90%), we have no way to send a message, which can be solved by increasing the threshold in the startup parameters (file location bin/runbroker.sh)

service shut down

> 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
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RocketMQ installation console

Download the installation package

Download address: github.com/apache/rock…Select tag and download

Compile the installation package

mvn clean install -Dmaven.test.skip=true -U
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start the service

Start command:

java -jar target/rocketmq-console-ng-1.0.0.jar --rocketmq.config.namesrvAddr='localhost:9876' &
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Startup log: After startup, the running effect is as follows:

RockectMQ in action

basic message

push mode

// 推模式
public class PushConsumer {

    public static void main(String[] args) throws InterruptedException, MQClientException {
        DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("CID_JODIE_1");
        consumer.subscribe("TopicTest", "*");
        consumer.setConsumeFromWhere(ConsumeFromWhere.CONSUME_FROM_FIRST_OFFSET);
        //wrong time format 2017_0422_221800
        consumer.setConsumeTimestamp("20181109221800");
        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;
            }
        });
        consumer.start();
        System.out.printf("Consumer Started.%n");
    }
}
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pull mode

// 拉模式
@SuppressWarnings("deprecation")
public class PullConsumer {

    public static void main(String[] args) throws MQClientException {

        DefaultMQPullConsumer consumer = new DefaultMQPullConsumer("please_rename_unique_group_name_5");
        consumer.setNamesrvAddr("127.0.0.1:9876");
        Set<String> topics = new HashSet<>();
        //You would better to register topics,It will use in rebalance when starting
        topics.add("TopicTest");
        consumer.setRegisterTopics(topics);
        consumer.start();

        ExecutorService executors = Executors.newFixedThreadPool(topics.size(), new ThreadFactory() {
            @Override
            public Thread newThread(Runnable r) {
                return new Thread(r, "PullConsumerThread");
            }
        });
        for (String topic : consumer.getRegisterTopics()) {

            executors.execute(new Runnable() {

                public void doSomething(List<MessageExt> msgs) {
                    //do your business

                }

                @Override
                public void run() {
                    while (true) {
                        try {
                            Set<MessageQueue> messageQueues = consumer.fetchMessageQueuesInBalance(topic);
                            if (messageQueues == null || messageQueues.isEmpty()) {
                                Thread.sleep(1000);
                                continue;
                            }
                            PullResult pullResult = null;
                            for (MessageQueue messageQueue : messageQueues) {
                                try {
                                    long offset = this.consumeFromOffset(messageQueue);
                                    pullResult = consumer.pull(messageQueue, "*", offset, 32);
                                    switch (pullResult.getPullStatus()) {
                                        case FOUND:
                                            List<MessageExt> msgs = pullResult.getMsgFoundList();

                                            if (msgs != null && !msgs.isEmpty()) {
                                                this.doSomething(msgs);
                                                //update offset to broker
                                                consumer.updateConsumeOffset(messageQueue, pullResult.getNextBeginOffset());
                                                //print pull tps
                                                this.incPullTPS(topic, pullResult.getMsgFoundList().size());
                                            }
                                            break;
                                        case OFFSET_ILLEGAL:
                                            consumer.updateConsumeOffset(messageQueue, pullResult.getNextBeginOffset());
                                            break;
                                        case NO_NEW_MSG:
                                            Thread.sleep(1);
                                            consumer.updateConsumeOffset(messageQueue, pullResult.getNextBeginOffset());
                                            break;
                                        case NO_MATCHED_MSG:
                                            consumer.updateConsumeOffset(messageQueue, pullResult.getNextBeginOffset());
                                            break;
                                        default:
                                    }
                                } catch (RemotingException e) {
                                    e.printStackTrace();
                                } catch (MQBrokerException e) {
                                    e.printStackTrace();
                                } catch (Exception e) {
                                    e.printStackTrace();
                                }
                            }
                        } catch (MQClientException e) {
                            //reblance error
                            e.printStackTrace();
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        } catch (Exception e) {
                            e.printStackTrace();
                        }
                    }
                }

                public long consumeFromOffset(MessageQueue messageQueue) throws MQClientException {
                    //-1 when started
                    long offset = consumer.getOffsetStore().readOffset(messageQueue, ReadOffsetType.READ_FROM_MEMORY);
                    if (offset < 0) {
                        //query from broker
                        offset = consumer.getOffsetStore().readOffset(messageQueue, ReadOffsetType.READ_FROM_STORE);
                    }
                    if (offset < 0) {
                        //first time start from last offset
                        offset = consumer.maxOffset(messageQueue);
                    }
                    //make sure
                    if (offset < 0) {
                        offset = 0;
                    }
                    return offset;
                }

                public void incPullTPS(String topic, int pullSize) {
                    consumer.getDefaultMQPullConsumerImpl().getRebalanceImpl().getmQClientFactory()
                            .getConsumerStatsManager().incPullTPS(consumer.getConsumerGroup(), topic, pullSize);
                }
            });

        }
//        executors.shutdown();
//        consumer.shutdown();
    }
}

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pull mode litepull

// litepull 拉模式
public class LitePullConsumerAssign {

    public static volatile boolean running = true;

    public static void main(String[] args) throws Exception {
        DefaultLitePullConsumer litePullConsumer = new DefaultLitePullConsumer("please_rename_unique_group_name");
        litePullConsumer.setAutoCommit(false);
        litePullConsumer.start();
        Collection<MessageQueue> mqSet = litePullConsumer.fetchMessageQueues("TopicTest");
        List<MessageQueue> list = new ArrayList<>(mqSet);
        List<MessageQueue> assignList = new ArrayList<>();
        for (int i = 0; i < list.size() / 2; i++) {
            assignList.add(list.get(i));
        }
        litePullConsumer.assign(assignList);
        litePullConsumer.seek(assignList.get(0), 10);
        try {
            while (running) {
                List<MessageExt> messageExts = litePullConsumer.poll();
                System.out.printf("%s %n", messageExts);
                litePullConsumer.commitSync();
            }
        } finally {
            litePullConsumer.shutdown();
        }

    }
}
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sequential message

RocketMQ uses FIFO order to provide ordered messages. The following examples demonstrate sending/receiving of global and partitioned ordered messages.

Message producer:

public class Producer {
    public static void main(String[] args) throws UnsupportedEncodingException {
        try {
            DefaultMQProducer producer = new DefaultMQProducer("please_rename_unique_group_name");
            producer.start();

            String[] tags = new String[] {"TagA", "TagB", "TagC", "TagD", "TagE"};
            for (int i = 0; i < 100; i++) {
                int orderId = i % 10;
                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);
                    }
                }, orderId);

                System.out.printf("%s%n", sendResult);
            }

            producer.shutdown();
        } catch (MQClientException | RemotingException | MQBrokerException | InterruptedException e) {
            e.printStackTrace();
        }
    }
}

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News subscribers:

public class Consumer {

    public static void main(String[] args) throws MQClientException {
        DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("please_rename_unique_group_name_3");

        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(true);
                System.out.printf("%s Receive New Messages: %s %n", Thread.currentThread().getName(), msgs);
                this.consumeTimes.incrementAndGet();
                if ((this.consumeTimes.get() % 2) == 0) {
                    return ConsumeOrderlyStatus.SUCCESS;
                } 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");
    }

}
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broadcast message

Broadcasting is sending a message to all subscribers of a topic. Broadcasting is a good choice if you want all subscribers to receive messages about a topic.

Message producer:

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();
    }
}

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message subscriber

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");
    }
}

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delayed message

Level settings for delayed messages Message subscribers:

public class ScheduledMessageConsumer {
    
    public static void main(String[] args) throws Exception {
        // Instantiate message consumer
        DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("ExampleConsumer");
        // Subscribe topics
        consumer.subscribe("TestTopic", "*");
        // Register message listener
        consumer.registerMessageListener(new MessageListenerConcurrently() {
            @Override
            public ConsumeConcurrentlyStatus consumeMessage(List<MessageExt> messages, ConsumeConcurrentlyContext context) {
                for (MessageExt message : messages) {
                    // Print approximate delay time period
                    System.out.printf("Receive message[msgId=%s %d  ms later]\n", message.getMsgId(),
                            System.currentTimeMillis() - message.getStoreTimestamp());
                }
                return ConsumeConcurrentlyStatus.CONSUME_SUCCESS;
            }
        });
        // Launch consumer
        consumer.start();
        //info:to see the time effect, run the consumer first , it will wait for the msg
        //then start the producer
    }
}
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Message publisher: The delayTimeLevel set for publishing a message corresponds to the previously configured message delay level, starting from 1

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();
    }
    
}
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Bulk message

Bulk messages, limited to a maximum of 1mb each time

public class SimpleBatchProducer {

    public static void main(String[] args) throws Exception {
        DefaultMQProducer producer = new DefaultMQProducer("BatchProducerGroupName");
        producer.start();

        //If you just send messages of no more than 1MiB at a time, it is easy to use batch
        //Messages of the same batch should have: same topic, same waitStoreMsgOK and no schedule support
        String topic = "BatchTest";
        List<Message> messages = new ArrayList<>();
        messages.add(new Message(topic, "Tag", "OrderID001", "Hello world 0".getBytes()));
        messages.add(new Message(topic, "Tag", "OrderID002", "Hello world 1".getBytes()));
        messages.add(new Message(topic, "Tag", "OrderID003", "Hello world 2".getBytes()));

        producer.send(messages);
    }
}
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message filtering

News subscribers:

public class TagFilterConsumer {

    public static void main(String[] args) throws InterruptedException, MQClientException, IOException {

        DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("please_rename_unique_group_name");

        consumer.subscribe("TagFilterTest", "TagA || TagC");

        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;
            }
        });

        consumer.start();

        System.out.printf("Consumer Started.%n");
    }
}

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message publisher

public class TagFilterProducer {

    public static void main(String[] args) throws Exception {

        DefaultMQProducer producer = new DefaultMQProducer("please_rename_unique_group_name");
        producer.start();

        String[] tags = new String[] {"TagA", "TagB", "TagC"};

        for (int i = 0; i < 60; i++) {
            Message msg = new Message("TagFilterTest",
                tags[i % tags.length],
                "Hello world".getBytes(RemotingHelper.DEFAULT_CHARSET));

            SendResult sendResult = producer.send(msg);
            System.out.printf("%s%n", sendResult);
        }

        producer.shutdown();
    }
}
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