RocketMq源码学习—— 生产者创建

RocketMq源码学习小记，生产者创建的源码学习，初步记录大概的创建流程，简单记录一下这个过程中用到的设计模式，后续其他的理解和感受继续补充其中

DefaultMQProducer.java #start()

@Override
public void start() throws MQClientException {
    this.setProducerGroup(withNamespace(this.producerGroup));
    this.defaultMQProducerImpl.start();
    if (this.produceAccumulator != null) {
        this.produceAccumulator.start();
    }
    if (null != traceDispatcher) {
        try {
            traceDispatcher.start(this.getNamesrvAddr(), this.getAccessChannel());
        } catch (MQClientException e) {
            logger.warn("trace dispatcher start failed ", e);
        }
    }
}

跳转 DefaultMQProducerImpl.java # start

public void start(final boolean startFactory) throws MQClientException {
        switch (this.serviceState) {
            case CREATE_JUST:
//                生产者状态置为失败
                this.serviceState = ServiceState.START_FAILED;
                //检查参数
                this.checkConfig();

                if (!this.defaultMQProducer.getProducerGroup().equals(MixAll.CLIENT_INNER_PRODUCER_GROUP)) {
                    this.defaultMQProducer.changeInstanceNameToPID();
                }

                this.mQClientFactory = MQClientManager.getInstance().getOrCreateMQClientInstance(this.defaultMQProducer, rpcHook);

                boolean registerOK = mQClientFactory.registerProducer(this.defaultMQProducer.getProducerGroup(), this);
                if (!registerOK) {
                    this.serviceState = ServiceState.CREATE_JUST;
                    throw new MQClientException("The producer group[" + this.defaultMQProducer.getProducerGroup()
                        + "] has been created before, specify another name please." + FAQUrl.suggestTodo(FAQUrl.GROUP_NAME_DUPLICATE_URL),
                        null);
                }

                if (startFactory) {
                    mQClientFactory.start();
                }

                this.mqFaultStrategy.startDetector();

                log.info("the producer [{}] start OK. sendMessageWithVIPChannel={}", this.defaultMQProducer.getProducerGroup(),
                    this.defaultMQProducer.isSendMessageWithVIPChannel());
                this.serviceState = ServiceState.RUNNING;
                break;
            case RUNNING:
            case START_FAILED:
            case SHUTDOWN_ALREADY:
                throw new MQClientException("The producer service state not OK, maybe started once, "
                    + this.serviceState
                    + FAQUrl.suggestTodo(FAQUrl.CLIENT_SERVICE_NOT_OK),
                    null);
            default:
                break;
        }

        this.mQClientFactory.sendHeartbeatToAllBrokerWithLock();

        RequestFutureHolder.getInstance().startScheduledTask(this);

    }

在这里起始状态是：CREATE_JUST

在这里需要额外来看一个类MQClientManager

它使用了单例模式：

而在这个单例模式中又嵌套了一个工厂模式

/**
 *  clientId =ClientIP@instanceName@unitName@STREAM
*/
private ConcurrentMap<String/* clientId */, MQClientInstance> factoryTable =new ConcurrentHashMap<>(); 

/**
 * 获得或创建一个MQClientInstance
 * @param clientConfig
 * @param rpcHook
 * @return
 */    
public MQClientInstance getOrCreateMQClientInstance(final ClientConfig clientConfig, RPCHook rpcHook) {
    String clientId = clientConfig.buildMQClientId();
    MQClientInstance instance = this.factoryTable.get(clientId);
    if (null == instance) {
        instance =
            new MQClientInstance(clientConfig.cloneClientConfig(),
                this.factoryIndexGenerator.getAndIncrement(), clientId, rpcHook);
        MQClientInstance prev = this.factoryTable.putIfAbsent(clientId, instance);
        if (prev != null) {
            instance = prev;
            log.warn("Returned Previous MQClientInstance for clientId:[{}]", clientId);
        } else {
            log.info("Created new MQClientInstance for clientId:[{}]", clientId);
        }
    }

    return instance;
}

创建 MQClientInstance

public MQClientInstance(ClientConfig clientConfig, int instanceIndex, String clientId, RPCHook rpcHook) {
    this.clientConfig = clientConfig;
    this.nettyClientConfig = new NettyClientConfig();
    this.nettyClientConfig.setClientCallbackExecutorThreads(clientConfig.getClientCallbackExecutorThreads());
    this.nettyClientConfig.setUseTLS(clientConfig.isUseTLS());
    this.nettyClientConfig.setSocksProxyConfig(clientConfig.getSocksProxyConfig());
    ClientRemotingProcessor clientRemotingProcessor = new ClientRemotingProcessor(this);
    this.mQClientAPIImpl = new MQClientAPIImpl(this.nettyClientConfig, clientRemotingProcessor, rpcHook, clientConfig);

    if (this.clientConfig.getNamesrvAddr() != null) {
        this.mQClientAPIImpl.updateNameServerAddressList(this.clientConfig.getNamesrvAddr());
        log.info("user specified name server address: {}", this.clientConfig.getNamesrvAddr());
    }

    this.clientId = clientId;

    this.mQAdminImpl = new MQAdminImpl(this);

    this.pullMessageService = new PullMessageService(this);

    this.rebalanceService = new RebalanceService(this);

    this.defaultMQProducer = new DefaultMQProducer(MixAll.CLIENT_INNER_PRODUCER_GROUP);
    this.defaultMQProducer.resetClientConfig(clientConfig);

    this.consumerStatsManager = new ConsumerStatsManager(this.scheduledExecutorService);

    log.info("Created a new client Instance, InstanceIndex:{}, ClientID:{}, ClientConfig:{}, ClientVersion:{}, SerializerType:{}",
        instanceIndex,
        this.clientId,
        this.clientConfig,
        MQVersion.getVersionDesc(MQVersion.CURRENT_VERSION), RemotingCommand.getSerializeTypeConfigInThisServer());
}

这里是创建流程图