rocketmq源码解析请求处理检查事务状态

最新推荐文章于 2025-03-01 18:09:27 发布

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最新推荐文章于 2025-03-01 18:09:27 发布

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本文链接：https://blog.youkuaiyun.com/qq_23283355/article/details/100063920

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本文深入探讨RocketMQ中请求处理检查事务状态的源码流程，从ClientRemotingProcessor开始，经过MQClientInstance、DefaultMQProducerImpl，直到NettyRemotingClient，详细解析每个关键步骤，帮助理解RocketMQ的事务处理机制。

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说在前面

请求处理检查事务状态，更多源码解析请关注“天河聊架构”微信公众号

源码解析
进入这个方法，检查事务的状态，org.apache.rocketmq.client.impl.ClientRemotingProcessor.checkTransactionState(ChannelHandlerContext, RemotingCommand)

public RemotingCommand checkTransactionState(ChannelHandlerContext ctx,
        RemotingCommand request) throws RemotingCommandException {
        final CheckTransactionStateRequestHeader requestHeader =
            (CheckTransactionStateRequestHeader) request.decodeCommandCustomHeader(CheckTransactionStateRequestHeader.class);
        final ByteBuffer byteBuffer = ByteBuffer.wrap(request.getBody());
        final MessageExt messageExt = MessageDecoder.decode(byteBuffer);
        if (messageExt != null) {
            String transactionId = messageExt.getProperty(MessageConst.PROPERTY_UNIQ_CLIENT_MESSAGE_ID_KEYIDX);
            if (null != transactionId && !"".equals(transactionId)) {
                messageExt.setTransactionId(transactionId);
            }
            final String group = messageExt.getProperty(MessageConst.PROPERTY_PRODUCER_GROUP);
            if (group != null) {
//                按组选择producer
                MQProducerInner producer = this.mqClientFactory.selectProducer(group);
                if (producer != null) {
                    final String addr = RemotingHelper.parseChannelRemoteAddr(ctx.channel());
                    producer.checkTransactionState(addr, messageExt, requestHeader);
                } else {
                    log.debug("checkTransactionState, pick producer by group[{}] failed", group);
                }
            } else {
                log.warn("checkTransactionState, pick producer group failed");
            }
        } else {
            log.warn("checkTransactionState, decode message failed");
        }

        return null;
    }

进入这个方法，按组选择producer，org.apache.rocketmq.client.impl.factory.MQClientInstance.selectProducer(String)

public MQProducerInner selectProducer(final String group) {
        return this.producerTable.get(group);
org.apache.rocketmq.client.impl.producer.DefaultMQProducerImpl.checkTransactionState(String, MessageExt, CheckTransactionStateRequestHeader)    }

往上返回到这个方法，org.apache.rocketmq.client.impl.producer.DefaultMQProducerImpl.checkTransactionState(String, MessageExt, CheckTransactionStateRequestHeader)

@Override
    public void checkTransactionState(final String addr, final MessageExt msg,
        final CheckTransactionStateRequestHeader header) {
        Runnable request = new Runnable() {
            private final String brokerAddr = addr;
            private final MessageExt message = msg;
            private final CheckTransactionStateRequestHeader checkRequestHeader = header;
            private final String group = DefaultMQProducerImpl.this.defaultMQProducer.getProducerGroup();

            @Override
            public void run() {
//                获取事务监听器
                TransactionListener transactionCheckListener = DefaultMQProducerImpl.this.checkListener();
                if (transactionCheckListener != null) {
                    LocalTransactionState localTransactionState = LocalTransactionState.UNKNOW;
                    Throwable exception = null;
                    try {
//                        检查本地事务状态=》
                        localTransactionState = transactionCheckListener.checkLocalTransaction(message);
                    } catch (Throwable e) {
                        log.error("Broker call checkTransactionState, but checkLocalTransactionState exception", e);
                        exception = e;
                    }

//                    处理事务状态=》
                    this.processTransactionS

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