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RocketMQ 消息失败重试 解析——图解、源码级解析

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文章目录

异常消息处理

在这里插入图片描述

使用

Consumer时

会注册

MessageListener

，消费消息的接口会返回处理状态：

  • ConsumeConcurrentlyStatus.CONSUME_SUCCESS：消费成功
  • ConsumeConcurrentlyStatus.REConsume_LATER：等待一段时间后再消费
MessageListener

在

CnsumeMessageConcurrentlyService

中被调用的，上面两个状态会映射到

CMResult

定义的枚举值：

  • CMResult.CR_SUCCESS：消费成功
  • CMResult.CR_LATER：等待一段时间后再消费
  • CMResult.CR_ROLLBACK：事务回滚
  • CMResult.CR_COMMIT：事务提交
  • CMResult.CR_THROW_EXCEPTION：消费异常
  • CMResult.CR_RETURN_NULL：消费结果为null

针对

CMResult.CR_LATER

状态的处理策略为：将该消息发挥Broker，继续等待后续消息。发送回的消息会设置重试的

Topic

，命名规则为：“%RETRY%” + Consumer组名，消息原本的

Topic

会暂存到消息体中，并且会额外设置

delayLevel

及

reconsumeTimes

消息消费的结果会在

CnsumeMessageConcurrentlyService.processConsumeResult

中处理

publicvoidprocessConsumeResult(finalConsumeConcurrentlyStatus status,finalConsumeConcurrentlyContext context,finalConsumeRequest consumeRequest
    ){int ackIndex = context.getAckIndex();// 消息为空，直接返回if(consumeRequest.getMsgs().isEmpty())return;// 计算从consumerequest.msg[0]到consumerequest.msgs[ackIndex]的消息消费成功的数量switch(status){case CONSUME_SUCCESS:if(ackIndex >= consumeRequest.getMsgs().size()){
                    ackIndex = consumeRequest.getMsgs().size()-1;}// 统计成功/失败数量int ok = ackIndex +1;int failed = consumeRequest.getMsgs().size()- ok;this.getConsumerStatsManager().incConsumeOKTPS(consumerGroup, consumeRequest.getMessageQueue().getTopic(), ok);this.getConsumerStatsManager().incConsumeFailedTPS(consumerGroup, consumeRequest.getMessageQueue().getTopic(), failed);break;case RECONSUME_LATER:
                ackIndex =-1;// 统计失败数量this.getConsumerStatsManager().incConsumeFailedTPS(consumerGroup, consumeRequest.getMessageQueue().getTopic(),
                    consumeRequest.getMsgs().size());break;default:break;}// 处理消息失败的消息switch(this.defaultMQPushConsumer.getMessageModel()){// 如果是广播模式，无论是否消费失败，都不回发消息给Broker，只打印Logcase BROADCASTING:for(int i = ackIndex +1; i < consumeRequest.getMsgs().size(); i++){MessageExt msg = consumeRequest.getMsgs().get(i);
                    log.warn("BROADCASTING, the message consume failed, drop it, {}", msg.toString());}break;// 发回失败消息到Brokercase CLUSTERING:List<MessageExt> msgBackFailed =newArrayList<MessageExt>(consumeRequest.getMsgs().size());for(int i = ackIndex +1; i < consumeRequest.getMsgs().size(); i++){MessageExt msg = consumeRequest.getMsgs().get(i);// 回发给Broker的的具体方法boolean result =this.sendMessageBack(msg, context);if(!result){// 重复消费次数 + 1
                        msg.setReconsumeTimes(msg.getReconsumeTimes()+1);
                        msgBackFailed.add(msg);}}// 如果回发给Broker也失败的话，则提交延迟消费请求（稍后在客户端重新消费）if(!msgBackFailed.isEmpty()){
                    consumeRequest.getMsgs().removeAll(msgBackFailed);this.submitConsumeRequestLater(msgBackFailed, consumeRequest.getProcessQueue(), consumeRequest.getMessageQueue());}break;default:break;}// 移除消费成功消息，并返回消费的最新进度long offset = consumeRequest.getProcessQueue().removeMessage(consumeRequest.getMsgs());// 更新最新消费进度，进度更新只能增长 if(offset >=0&&!consumeRequest.getProcessQueue().isDropped()){this.defaultMQPushConsumerImpl.getOffsetStore().updateOffset(consumeRequest.getMessageQueue(), offset,true);}}

Consumer

消费的时候可以设置

consumeMessageBatchMaxSize

来控制传入

MessageListener

的消息数量。RocketMQ认为只要有一条消息消费失败，这一批消息都会发回给Broker，所以设置

consumeMessageBatchMaxSize

这个值时应当注意避免出现消息重复消费的问题。

Broker处理流程

Broker端对应的处理逻辑在

SendMessageProcessor.consumerSendMsgBack

里，对于Consumer发送失败返的消息，Broker会将其放入重试

Topic

中

/**
     * 消费者将消息发回给Broker，可以指定多久后重新消费该消息
     *
     * @param ctx
     * @param request
     * @return
     * @throws RemotingCommandException
     */privateCompletableFuture<RemotingCommand>asyncConsumerSendMsgBack(ChannelHandlerContext ctx,RemotingCommand request)throwsRemotingCommandException{// 初始化响应finalRemotingCommand response =RemotingCommand.createResponseCommand(null);finalConsumerSendMsgBackRequestHeader requestHeader =(ConsumerSendMsgBackRequestHeader)request.decodeCommandCustomHeader(ConsumerSendMsgBackRequestHeader.class);String namespace =NamespaceUtil.getNamespaceFromResource(requestHeader.getGroup());if(this.hasConsumeMessageHook()&&!UtilAll.isBlank(requestHeader.getOriginMsgId())){ConsumeMessageContext context =buildConsumeMessageContext(namespace, requestHeader, request);this.executeConsumeMessageHookAfter(context);}SubscriptionGroupConfig subscriptionGroupConfig =this.brokerController.getSubscriptionGroupManager().findSubscriptionGroupConfig(requestHeader.getGroup());if(null== subscriptionGroupConfig){
            response.setCode(ResponseCode.SUBSCRIPTION_GROUP_NOT_EXIST);
            response.setRemark("subscription group not exist, "+ requestHeader.getGroup()+" "+FAQUrl.suggestTodo(FAQUrl.SUBSCRIPTION_GROUP_NOT_EXIST));returnCompletableFuture.completedFuture(response);}// 检查Broker是否有写入权限if(!PermName.isWriteable(this.brokerController.getBrokerConfig().getBrokerPermission())){
            response.setCode(ResponseCode.NO_PERMISSION);
            response.setRemark("the broker["+this.brokerController.getBrokerConfig().getBrokerIP1()+"] sending message is forbidden");returnCompletableFuture.completedFuture(response);}// 检查重试队列个数是否大于0if(subscriptionGroupConfig.getRetryQueueNums()<=0){
            response.setCode(ResponseCode.SUCCESS);
            response.setRemark(null);returnCompletableFuture.completedFuture(response);}// 计算retry Topic = "%RETRY% + consumeGroup"String newTopic =MixAll.getRetryTopic(requestHeader.getGroup());// 计算队列编号int queueIdInt =Math.abs(this.random.nextInt()%99999999)% subscriptionGroupConfig.getRetryQueueNums();int topicSysFlag =0;if(requestHeader.isUnitMode()){
            topicSysFlag =TopicSysFlag.buildSysFlag(false,true);}// 获取topicConfig，如果获取不到，则在response里进行相应设置TopicConfig topicConfig =this.brokerController.getTopicConfigManager().createTopicInSendMessageBackMethod(
                newTopic,
                subscriptionGroupConfig.getRetryQueueNums(),PermName.PERM_WRITE |PermName.PERM_READ, topicSysFlag);if(null== topicConfig){
            response.setCode(ResponseCode.SYSTEM_ERROR);
            response.setRemark("topic["+ newTopic +"] not exist");returnCompletableFuture.completedFuture(response);}// 不允许写入if(!PermName.isWriteable(topicConfig.getPerm())){
            response.setCode(ResponseCode.NO_PERMISSION);
            response.setRemark(String.format("the topic[%s] sending message is forbidden", newTopic));returnCompletableFuture.completedFuture(response);}// 根据消息的commitLog Offset查询实际的MessageExt（消费失败的实际消息）MessageExt msgExt =this.brokerController.getMessageStore().lookMessageByOffset(requestHeader.getOffset());if(null== msgExt){
            response.setCode(ResponseCode.SYSTEM_ERROR);
            response.setRemark("look message by offset failed, "+ requestHeader.getOffset());returnCompletableFuture.completedFuture(response);}// 设置 PROPERTY_RETRY_TOPIC = 原始消息的Topic，msgInner通过setProperties()方法将原始消息的Properties拷贝过去finalString retryTopic = msgExt.getProperty(MessageConst.PROPERTY_RETRY_TOPIC);if(null== retryTopic){MessageAccessor.putProperty(msgExt,MessageConst.PROPERTY_RETRY_TOPIC, msgExt.getTopic());}// 设置消息不等待存储完成
        msgExt.setWaitStoreMsgOK(false);int delayLevel = requestHeader.getDelayLevel();int maxReconsumeTimes = subscriptionGroupConfig.getRetryMaxTimes();// 3.4.9版本之后可以支持自定义消息的最大消费次数，若未指定，默认为16if(request.getVersion()>=MQVersion.Version.V3_4_9.ordinal()){Integer times = requestHeader.getMaxReconsumeTimes();if(times !=null){
                maxReconsumeTimes = times;}}// 如果超过最大消费次数或delayLevel < 0，则加入私信队列if(msgExt.getReconsumeTimes()>= maxReconsumeTimes
                || delayLevel <0){
            newTopic =MixAll.getDLQTopic(requestHeader.getGroup());
            queueIdInt =Math.abs(this.random.nextInt()%99999999)% DLQ_NUMS_PER_GROUP;

            topicConfig =this.brokerController.getTopicConfigManager().createTopicInSendMessageBackMethod(newTopic,
                    DLQ_NUMS_PER_GROUP,PermName.PERM_WRITE,0);if(null== topicConfig){
                response.setCode(ResponseCode.SYSTEM_ERROR);
                response.setRemark("topic["+ newTopic +"] not exist");returnCompletableFuture.completedFuture(response);}}else{if(0== delayLevel){// 设置延迟级别为重试消费次数 + 3
                delayLevel =3+ msgExt.getReconsumeTimes();}
            msgExt.setDelayTimeLevel(delayLevel);}// 创建MessageExtBrokerInner，除了Topic、QueueId不同外，其他的都是拷贝原始消息的数据MessageExtBrokerInner msgInner =newMessageExtBrokerInner();
        msgInner.setTopic(newTopic);
        msgInner.setBody(msgExt.getBody());
        msgInner.setFlag(msgExt.getFlag());MessageAccessor.setProperties(msgInner, msgExt.getProperties());
        msgInner.setPropertiesString(MessageDecoder.messageProperties2String(msgExt.getProperties()));
        msgInner.setTagsCode(MessageExtBrokerInner.tagsString2tagsCode(null, msgExt.getTags()));

        msgInner.setQueueId(queueIdInt);
        msgInner.setSysFlag(msgExt.getSysFlag());
        msgInner.setBornTimestamp(msgExt.getBornTimestamp());
        msgInner.setBornHost(msgExt.getBornHost());
        msgInner.setStoreHost(msgExt.getStoreHost());
        msgInner.setReconsumeTimes(msgExt.getReconsumeTimes()+1);String originMsgId =MessageAccessor.getOriginMessageId(msgExt);MessageAccessor.setOriginMessageId(msgInner,UtilAll.isBlank(originMsgId)? msgExt.getMsgId(): originMsgId);
        msgInner.setPropertiesString(MessageDecoder.messageProperties2String(msgExt.getProperties()));// 发送消息CompletableFuture<PutMessageResult> putMessageResult =this.brokerController.getMessageStore().asyncPutMessage(msgInner);return putMessageResult.thenApply((r)->{if(r !=null){switch(r.getPutMessageStatus()){case PUT_OK:String backTopic = msgExt.getTopic();String correctTopic = msgExt.getProperty(MessageConst.PROPERTY_RETRY_TOPIC);if(correctTopic !=null){
                            backTopic = correctTopic;}this.brokerController.getBrokerStatsManager().incSendBackNums(requestHeader.getGroup(), backTopic);
                        response.setCode(ResponseCode.SUCCESS);
                        response.setRemark(null);return response;default:break;}
                response.setCode(ResponseCode.SYSTEM_ERROR);
                response.setRemark(r.getPutMessageStatus().name());return response;}
            response.setCode(ResponseCode.SYSTEM_ERROR);
            response.setRemark("putMessageResult is null");return response;});}

重试消息的重新投递逻辑与延迟消息一致，等待

DelayLevel

对应的延时之后，Broker会尝试重新进行消息投递。

关于延迟级别的的配置在

MessageStoreConfig.messageDelay

里，默认配置如下：

this.messageDelayLevel ="1s 5s 10s 30s 1m 2m 3m 4m 5m 6m 7m 8m 9m 10m 20m 30m 1h 2h";

可以主动调整每一个延迟级别对应的时间，但仍然有一些缺陷：

  1. 时间精度不够细，最小粒度是1s
  2. 延迟级别的个数是固定的，无法调整

死信队列

RocketMQ里的消息不能无限次重复消费，当重试次数超过所有延迟级别的个数之后，消息就会进入到死信队列里，死信的Topic命名规则为："%DLQ% " + Consumer组名

// 如果超过最大消费次数或delayLevel < 0，则加入私信队列if(msgExt.getReconsumeTimes()>= maxReconsumeTimes
                || delayLevel <0){
            newTopic =MixAll.getDLQTopic(requestHeader.getGroup());
            queueIdInt =Math.abs(this.random.nextInt()%99999999)% DLQ_NUMS_PER_GROUP;

            topicConfig =this.brokerController.getTopicConfigManager().createTopicInSendMessageBackMethod(newTopic,
                    DLQ_NUMS_PER_GROUP,PermName.PERM_WRITE,0);

进入到死信队列后的消息就不会再被投递了，可以通过接口来查询当前RocketMQ中的死信队列的消息。

标签： 1024程序员节
本文转载自: https://blog.csdn.net/HNU_Csee_wjw/article/details/127502526
版权归原作者 小王曾是少年 所有， 如有侵权，请联系我们删除。
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