基于RocketMQ release-4.9.3，深入的介绍了Broker接收消息源码，以及自动创建Topic的源码。
此前我们学习RocketMQ的Broker接收Producer消息的入口源码：RocketMQ源码(9)—Broker接收消息入口源码，在文章的最后我们到了asyncSendMessage方法。
asyncSendMessage方法用来处理来自producer发送的消息，内部内容非常多，本次我们学习asyncSendMessage方法的整体流程，以及自动创建topic的源码。
该方法是broker处理单条消息的通用入口方法，该方法非常重要，大概步骤为：
/**
* SendMessageProcessor的方法
*
* 处理单条消息
*/
private CompletableFuture<RemotingCommand> asyncSendMessage(ChannelHandlerContext ctx, RemotingCommand request,
SendMessageContext mqtraceContext,
SendMessageRequestHeader requestHeader) {
/*
* 1 创建响应的命令对象，包括自动创建topic的逻辑
*/
final RemotingCommand response = preSend(ctx, request, requestHeader);
//获取响应头
final SendMessageResponseHeader responseHeader = (SendMessageResponseHeader) response.readCustomHeader();
if (response.getCode() != -1) {
return CompletableFuture.completedFuture(response);
}
//获取消息体
final byte[] body = request.getBody();
//获取队列id
int queueIdInt = requestHeader.getQueueId();
//从broker的topicConfigTable缓存中根据topicName获取TopicConfig
TopicConfig topicConfig = this.brokerController.getTopicConfigManager().selectTopicConfig(requestHeader.getTopic());
//如果队列id小于0，则随机选择一个写队列索引作为id
if (queueIdInt < 0) {
queueIdInt = randomQueueId(topicConfig.getWriteQueueNums());
}
//构建消息对象，保存着要存入commitLog的数据
MessageExtBrokerInner msgInner = new MessageExtBrokerInner();
//设置topic
msgInner.setTopic(requestHeader.getTopic());
//设置队列id
msgInner.setQueueId(queueIdInt);
/*
* 2 处理重试和死信队列消息，将会对死信消息替换为死信topic
*/
if (!handleRetryAndDLQ(requestHeader, response, request, msgInner, topicConfig)) {
return CompletableFuture.completedFuture(response);
}
/*
* 设置一系列属性
*/
msgInner.setBody(body);
msgInner.setFlag(requestHeader.getFlag());
Map<String, String> origProps = MessageDecoder.string2messageProperties(requestHeader.getProperties());
//设置到properties属性中
MessageAccessor.setProperties(msgInner, origProps);
msgInner.setBornTimestamp(requestHeader.getBornTimestamp());
msgInner.setBornHost(ctx.channel().remoteAddress());
msgInner.setStoreHost(this.getStoreHost());
msgInner.setReconsumeTimes(requestHeader.getReconsumeTimes() == null ? 0 : requestHeader.getReconsumeTimes());
String clusterName = this.brokerController.getBrokerConfig().getBrokerClusterName();
MessageAccessor.putProperty(msgInner, MessageConst.PROPERTY_CLUSTER, clusterName);
//WAIT属性表示 消息发送时是否等消息存储完成后再返回
if (origProps.containsKey(MessageConst.PROPERTY_WAIT_STORE_MSG_OK)) {
// There is no need to store "WAIT=true", remove it from propertiesString to save 9 bytes for each message.
// It works for most case. In some cases msgInner.setPropertiesString invoked later and replace it.
//不需要存储"WAIT=true"属性，从propertiesString中移除它，为每个消息节省9个字节。
String waitStoreMsgOKValue = origProps.remove(MessageConst.PROPERTY_WAIT_STORE_MSG_OK);
//将没有WAIT属性的origProps存入msgInner的propertiesString属性
msgInner.setPropertiesString(MessageDecoder.messageProperties2String(msgInner.getProperties()));
// Reput to properties, since msgInner.isWaitStoreMsgOK() will be invoked later
//将WAIT属性重新存入origProps集合中，因为msgInner.isWaitStoreMsgOK()稍后将被调用
origProps.put(MessageConst.PROPERTY_WAIT_STORE_MSG_OK, waitStoreMsgOKValue);
} else {
//将没有WAIT属性的origProps存入msgInner的propertiesString属性
msgInner.setPropertiesString(MessageDecoder.messageProperties2String(msgInner.getProperties()));
}
CompletableFuture<PutMessageResult> putMessageResult = null;
/*
* 处理事务消息逻辑
*/
//TRAN_MSG属性值为true，表示为事务消息
String transFlag = origProps.get(MessageConst.PROPERTY_TRANSACTION_PREPARED);
//处理事务消息
if (transFlag != null && Boolean.parseBoolean(transFlag)) {
//判断是否需要拒绝事务消息，如果需要拒绝，则返回NO_PERMISSION异常
if (this.brokerController.getBrokerConfig().isRejectTransactionMessage()) {
response.setCode(ResponseCode.NO_PERMISSION);
response.setRemark(
"the broker[" + this.brokerController.getBrokerConfig().getBrokerIP1()
+ "] sending transaction message is forbidden");
return CompletableFuture.completedFuture(response);
}
//调用asyncPrepareMessage方法以异步的方式处理、存储事务准备消息，底层仍是asyncPutMessage方法
putMessageResult = this.brokerController.getTransactionalMessageService().asyncPrepareMessage(msgInner);
} else {
//不是事务消息，那么调用asyncPutMessage方法处理，存储消息
//以异步方式将消息存储到存储器中，处理器可以处理下一个请求而不是等待结果，当结果完成时，以异步方式通知客户端
putMessageResult = this.brokerController.getMessageStore().asyncPutMessage(msgInner);
}
//处理消息存放的结果
return handlePutMessageResultFuture(putMessageResult, response, request, msgInner, responseHeader, mqtraceContext, ctx, queueIdInt);
}
该方法用于创建响应的命令对象，其中还包括topic的校验，以及自动创建topic的逻辑。
该方法中将会创建一个RemotingCommand对象，并且设置唯一id为请求的id。除此之外还会校验如果当前时间小于该broker的起始服务时间，那么broker会返回一个SYSTEM_ERROR，表示现在broker还不能提供服务。
在最后，会调用msgCheck方法进行一系列的校验，包括自动创建topic的逻辑。
/**
* SendMessageProcessor的方法
*
* 准备响应数据
*/
private RemotingCommand preSend(ChannelHandlerContext ctx, RemotingCommand request,
SendMessageRequestHeader requestHeader) {
//创建响应命令对象
final RemotingCommand response = RemotingCommand.createResponseCommand(SendMessageResponseHeader.class);
//设置唯一id为请求id
response.setOpaque(request.getOpaque());
//添加扩展字段属性"MSG_REGION"、"TRACE_ON"
response.addExtField(MessageConst.PROPERTY_MSG_REGION, this.brokerController.getBrokerConfig().getRegionId());
response.addExtField(MessageConst.PROPERTY_TRACE_SWITCH, String.valueOf(this.brokerController.getBrokerConfig().isTraceOn()));
log.debug("Receive SendMessage request command {}", request);
//获取配置的broker的处理请求的起始服务时间，默认为0
final long startTimestamp = this.brokerController.getBrokerConfig().getStartAcceptSendRequestTimeStamp();
//如果当前时间小于起始时间，那么broker会返回一个SYSTEM_ERROR，表示现在broker还不能提供服务
if (this.brokerController.getMessageStore().now() < startTimestamp) {
response.setCode(ResponseCode.SYSTEM_ERROR);
response.setRemark(String.format("broker unable to service, until %s", UtilAll.timeMillisToHumanString2(startTimestamp)));
return response;
}
//设置code为-1
response.setCode(-1);
/*
* 消息校验，包括自动创建topic的逻辑
*/
super.msgCheck(ctx, requestHeader, response);
if (response.getCode() != -1) {
return response;
}
return response;
}
该方法进行一系列的消息校验，并且会尝试自动创建topic。大概步骤为：
/**
* AbstractSendMessageProcessor的方法
*
* 消息校验，包括自动创建topic的逻辑
*/
protected RemotingCommand msgCheck(final ChannelHandlerContext ctx,
final SendMessageRequestHeader requestHeader, final RemotingCommand response) {
//如果当前broker没有写的权限，那么broker会返回一个NO_PERMISSION异常，sending message is forbidden，禁止向该broker发送消息
if (!PermName.isWriteable(this.brokerController.getBrokerConfig().getBrokerPermission())
&& this.brokerController.getTopicConfigManager().isOrderTopic(requestHeader.getTopic())) {
response.setCode(ResponseCode.NO_PERMISSION);
response.setRemark("the broker[" + this.brokerController.getBrokerConfig().getBrokerIP1()
+ "] sending message is forbidden");
return response;
}
//校验topic不能为空，必须属于合法字符regex: ^[%|a-zA-Z0-9_-]+$，且长度不超过127个字符
if (!TopicValidator.validateTopic(requestHeader.getTopic(), response)) {
return response;
}
//校验如果当前topic是不为允许使用的系统topic，那么抛出异常，默认不能为SCHEDULE_TOPIC_XXXX
if (TopicValidator.isNotAllowedSendTopic(requestHeader.getTopic(), response)) {
return response;
}
//从broker的topicConfigTable缓存中根据topicName获取TopicConfig
TopicConfig topicConfig =
this.brokerController.getTopicConfigManager().selectTopicConfig(requestHeader.getTopic());
//如果不存在该topic信息
if (null == topicConfig) {
int topicSysFlag = 0;
if (requestHeader.isUnitMode()) {
if (requestHeader.getTopic().startsWith(MixAll.RETRY_GROUP_TOPIC_PREFIX)) {
topicSysFlag = TopicSysFlag.buildSysFlag(false, true);
} else {
topicSysFlag = TopicSysFlag.buildSysFlag(true, false);
}
}
log.warn("the topic {} not exist, producer: {}", requestHeader.getTopic(), ctx.channel().remoteAddress());
/*
* 尝试创建普通topic
*/
topicConfig = this.brokerController.getTopicConfigManager().createTopicInSendMessageMethod(
requestHeader.getTopic(),
requestHeader.getDefaultTopic(),
RemotingHelper.parseChannelRemoteAddr(ctx.channel()),
requestHeader.getDefaultTopicQueueNums(), topicSysFlag);
/*
* 尝试创建重试topic
*/
if (null == topicConfig) {
if (requestHeader.getTopic().startsWith(MixAll.RETRY_GROUP_TOPIC_PREFIX)) {
topicConfig =
this.brokerController.getTopicConfigManager().createTopicInSendMessageBackMethod(
requestHeader.getTopic(), 1, PermName.PERM_WRITE | PermName.PERM_READ,
topicSysFlag);
}
}
if (null == topicConfig) {
response.setCode(ResponseCode.TOPIC_NOT_EXIST);
response.setRemark("topic[" + requestHeader.getTopic() + "] not exist, apply first please!"
+ FAQUrl.suggestTodo(FAQUrl.APPLY_TOPIC_URL));
return response;
}
}
//校验queutId 不能大于等于该broker的读或写的最大数量
int queueIdInt = requestHeader.getQueueId();
int idValid = Math.max(topicConfig.getWriteQueueNums(), topicConfig.getReadQueueNums());
if (queueIdInt >= idValid) {
String errorInfo = String.format("request queueId[%d] is illegal, %s Producer: %s",
queueIdInt,
topicConfig.toString(),
RemotingHelper.parseChannelRemoteAddr(ctx.channel()));
log.warn(errorInfo);
response.setCode(ResponseCode.SYSTEM_ERROR);
response.setRemark(errorInfo);
return response;
}
return response;
}
该方法尝试创建一个新的topic，大概步骤为：
/**
* TopicConfigManager的方法
*
* 创建普通topic，并持久化至配置文件 {user.home}/store/config/topics.json中
*
* @param topic 待创建topic
* @param defaultTopic 默认topic，用于作为模板创建新topic
* @param remoteAddress 远程地址
* @param clientDefaultTopicQueueNums 自动创建服务器不存在的topic时，默认创建的队列数，默认为4
* 可通过生产者DefaultMQProducer的defaultTopicQueueNums属性进行配置
* @param topicSysFlag topic标识
* @return topic配置
*/
public TopicConfig createTopicInSendMessageMethod(final String topic, final String defaultTopic,
final String remoteAddress, final int clientDefaultTopicQueueNums, final int topicSysFlag) {
TopicConfig topicConfig = null;
boolean createNew = false;
try {
//需要加锁防止并发创建相同的topic
if (this.topicConfigTableLock.tryLock(LOCK_TIMEOUT_MILLIS, TimeUnit.MILLISECONDS)) {
try {
//再次尝试从topicConfigTable获取topic信息，如果获取到了，那么直接返回
topicConfig = this.topicConfigTable.get(topic);
if (topicConfig != null)
return topicConfig;
//获取默认topic的信息，用于作为模板创建新topic，默认的默认topic实际上就是TBW102，其有8个读写队列，权限为读写并且可继承，即7
TopicConfig defaultTopicConfig = this.topicConfigTable.get(defaultTopic);
if (defaultTopicConfig != null) {
//如果默认topic就是TBW102
if (defaultTopic.equals(TopicValidator.AUTO_CREATE_TOPIC_KEY_TOPIC)) {
//如果broker配置不支持自动创建topic，那么设置权限为可读写，不可继承，即6
if (!this.brokerController.getBrokerConfig().isAutoCreateTopicEnable()) {
defaultTopicConfig.setPerm(PermName.PERM_READ | PermName.PERM_WRITE);
}
}
//如果默认topic配置的权限包括可继承，那么从默认topic继承属性
if (PermName.isInherited(defaultTopicConfig.getPerm())) {
//创建topic配置
topicConfig = new TopicConfig(topic);
//选择默认队列数量与默认topic写队列数中最小的值作为新topic的读写队列数量，默认为4
int queueNums = Math.min(clientDefaultTopicQueueNums, defaultTopicConfig.getWriteQueueNums());
if (queueNums < 0) {
queueNums = 0;
}
topicConfig.setReadQueueNums(queueNums);
topicConfig.setWriteQueueNums(queueNums);
//权限
int perm = defaultTopicConfig.getPerm();
//去掉可继承权限
perm &= ~PermName.PERM_INHERIT;
topicConfig.setPerm(perm);
topicConfig.setTopicSysFlag(topicSysFlag);
topicConfig.setTopicFilterType(defaultTopicConfig.getTopicFilterType());
} else {
log.warn("Create new topic failed, because the default topic[{}] has no perm [{}] producer:[{}]",
defaultTopic, defaultTopicConfig.getPerm(), remoteAddress);
}
} else {
log.warn("Create new topic failed, because the default topic[{}] not exist. producer:[{}]",
defaultTopic, remoteAddress);
}
//如果topic不为null，说明创建了新topic
if (topicConfig != null) {
log.info("Create new topic by default topic:[{}] config:[{}] producer:[{}]",
defaultTopic, topicConfig, remoteAddress);
//将新的topic信息存入topicConfigTable缓存中
this.topicConfigTable.put(topic, topicConfig);
//生成下一个数据版本
this.dataVersion.nextVersion();
//标识位置为true
createNew = true;
/*
* 将topic配置持久化到配置文件 {user.home}/store/config/topics.json中
*/
this.persist();
}
} finally {
//解锁
this.topicConfigTableLock.unlock();
}
}
} catch (InterruptedException e) {
log.error("createTopicInSendMessageMethod exception", e);
}
//如果创建了新topic，那么马上向nameServer注册当前broker的新配置路由信息
if (createNew) {
this.brokerController.registerBrokerAll(false, true, true);
}
return topicConfig;
}
该方法用于自动创建重试topic，其源码和创建普通topic差不多，区别就是重试topic不需要模板topic，默认读写队列数都是1，权限为读写。
/**
* TopicConfigManager的方法
*
* 创建重试topic，并持久化至配置文件 {user.home}/store/config/topics.json中
*
* @param topic 待创建topic
* @param perm 权限
* @param clientDefaultTopicQueueNums 自动创建服务器不存在的topic时，默认创建的队列数，默认为4
* 可通过生产者DefaultMQProducer的defaultTopicQueueNums属性进行配置
* @param topicSysFlag topic标识
* @return topic配置
*/
public TopicConfig createTopicInSendMessageBackMethod(
final String topic,
final int clientDefaultTopicQueueNums,
final int perm,
final int topicSysFlag) {
//尝试获取topic
TopicConfig topicConfig = this.topicConfigTable.get(topic);
//如果存在则直接返回
if (topicConfig != null)
return topicConfig;
boolean createNew = false;
try {
//需要加锁防止并发创建相同的topic
if (this.topicConfigTableLock.tryLock(LOCK_TIMEOUT_MILLIS, TimeUnit.MILLISECONDS)) {
try {
//再次尝试从topicConfigTable获取topic信息，如果获取到了，那么直接返回
topicConfig = this.topicConfigTable.get(topic);
if (topicConfig != null)
return topicConfig;
//创建topic
topicConfig = new TopicConfig(topic);
//重试topic的默认读写队列数量为1
topicConfig.setReadQueueNums(clientDefaultTopicQueueNums);
topicConfig.setWriteQueueNums(clientDefaultTopicQueueNums);
//重试topic的默认权限为读写
topicConfig.setPerm(perm);
topicConfig.setTopicSysFlag(topicSysFlag);
log.info("create new topic {}", topicConfig);
this.topicConfigTable.put(topic, topicConfig);
createNew = true;
//获取下一个版本
this.dataVersion.nextVersion();
//持久化broker信息
this.persist();
} finally {
//解锁
this.topicConfigTableLock.unlock();
}
}
} catch (InterruptedException e) {
log.error("createTopicInSendMessageBackMethod exception", e);
}
if (createNew) {
//注册broker信息
this.brokerController.registerBrokerAll(false, true, true);
}
return topicConfig;
}
之前将Producer发送消息源码的时候，我们的客户端，在发送消息的之前，会先选择一个topic所在的broker地址，如果topic不存在，那么选择默认topic的路由信息中的一个broker进行发送。
当发送到broker之后，会发现没有指定的topic并且如果broker的autoCreateTopicEnable为true，那么将会走刚才的createTopicInSendMessageMethod源码，自动创建topic的方法的最后会马上调用registerBrokerAll方法向nameServer注册当前broker的新配置路由信息。
生产者客户端会定时每30s从nameServer更新路由数据，如果此时有其他的producer的存在，并且刚好从nameServer获取到了这个新的topic的路由信息，假设其他producer也需要向该topic发送信息，由于发现topic路由信息已存在，并且只存在于刚才那一个broker中，此时这些producer都会将该topic的消息发送到这一个broker中来。
这样，接下来所有的Producer都只会向这一个Broker发送消息，其他Broker也就不会再有机会创建新Topic。我们本想要该Topic在每个broker上都被自动创建，但结果仅仅是在一个broker上有该topic的信息，这样就背离了RocketMQ集群的初衷，不能实现压力的分摊。
因此，RocketMQ官方建议生产环境下将broker的autoCreateTopicEnable设置为false，即关闭自动创建topic，全部改为手动在每个broker上创建，这样安全又保险。
当存放消息完毕时，执行后续的操作，即执行handlePutMessageResult方法。
/**
* SendMessageProcessor的方法
*
* 处理消息存放结果
*
* @param putMessageResult 存放结果
* @param response 响应对象
* @param request 请求对象
* @param msgInner 内部消息对象
* @param responseHeader 响应头
* @param sendMessageContext 发送消息上下文
* @param ctx 连接上下文
* @param queueIdInt queueId
* @return
*/
private CompletableFuture<RemotingCommand> handlePutMessageResultFuture(CompletableFuture<PutMessageResult> putMessageResult,
RemotingCommand response,
RemotingCommand request,
MessageExt msgInner,
SendMessageResponseHeader responseHeader,
SendMessageContext sendMessageContext,
ChannelHandlerContext ctx,
int queueIdInt) {
//阻塞，当从存放消息完毕时，执行后续的操作，即执行handlePutMessageResult方法
return putMessageResult.thenApply((r) ->
handlePutMessageResult(r, response, request, msgInner, responseHeader, sendMessageContext, ctx, queueIdInt)
);
}
该方法处理存放消息的结果，并且将响应写回给客户端。
/**
* SendMessageProcessor的方法
*
* 处理存放消息的结果
*
* @param putMessageResult 存放结果
* @param response 响应对象
* @param request 请求对象
* @param msg 内部消息对象
* @param responseHeader 响应头
* @param sendMessageContext 发送消息上下文
* @param ctx 连接上下文
* @param queueIdInt queueId
* @return
*/
private RemotingCommand handlePutMessageResult(PutMessageResult putMessageResult, RemotingCommand response,
RemotingCommand request, MessageExt msg,
SendMessageResponseHeader responseHeader, SendMessageContext sendMessageContext, ChannelHandlerContext ctx,
int queueIdInt) {
//结果为null，那么直接返回系统异常
if (putMessageResult == null) {
response.setCode(ResponseCode.SYSTEM_ERROR);
response.setRemark("store putMessage return null");
return response;
}
boolean sendOK = false;
//解析存放消息状态码，转换为对应的响应码
switch (putMessageResult.getPutMessageStatus()) {
// Success
case PUT_OK:
sendOK = true;
response.setCode(ResponseCode.SUCCESS);
break;
case FLUSH_DISK_TIMEOUT:
response.setCode(ResponseCode.FLUSH_DISK_TIMEOUT);
sendOK = true;
break;
case FLUSH_SLAVE_TIMEOUT:
response.setCode(ResponseCode.FLUSH_SLAVE_TIMEOUT);
sendOK = true;
break;
case SLAVE_NOT_AVAILABLE:
response.setCode(ResponseCode.SLAVE_NOT_AVAILABLE);
sendOK = true;
break;
// Failed
case CREATE_MAPEDFILE_FAILED:
response.setCode(ResponseCode.SYSTEM_ERROR);
response.setRemark("create mapped file failed, server is busy or broken.");
break;
case MESSAGE_ILLEGAL:
case PROPERTIES_SIZE_EXCEEDED:
response.setCode(ResponseCode.MESSAGE_ILLEGAL);
response.setRemark(
"the message is illegal, maybe msg body or properties length not matched. msg body length limit 128k, msg properties length limit 32k.");
break;
case SERVICE_NOT_AVAILABLE:
response.setCode(ResponseCode.SERVICE_NOT_AVAILABLE);
response.setRemark(
"service not available now. It may be caused by one of the following reasons: " +
"the broker's disk is full [" + diskUtil() + "], messages are put to the slave, message store has been shut down, etc.");
break;
case OS_PAGECACHE_BUSY:
response.setCode(ResponseCode.SYSTEM_ERROR);
response.setRemark("[PC_SYNCHRONIZED]broker busy, start flow control for a while");
break;
case LMQ_CONSUME_QUEUE_NUM_EXCEEDED:
response.setCode(ResponseCode.SYSTEM_ERROR);
response.setRemark("[LMQ_CONSUME_QUEUE_NUM_EXCEEDED]broker config enableLmq and enableMultiDispatch, lmq consumeQueue num exceed maxLmqConsumeQueueNum config num, default limit 2w.");
break;
case UNKNOWN_ERROR:
response.setCode(ResponseCode.SYSTEM_ERROR);
response.setRemark("UNKNOWN_ERROR");
break;
default:
response.setCode(ResponseCode.SYSTEM_ERROR);
response.setRemark("UNKNOWN_ERROR DEFAULT");
break;
}
String owner = request.getExtFields().get(BrokerStatsManager.COMMERCIAL_OWNER);
//如果发送成功
if (sendOK) {
//如果topic是SCHEDULE_TOPIC_XXXX，即延迟消息的topic
if (TopicValidator.RMQ_SYS_SCHEDULE_TOPIC.equals(msg.getTopic())) {
//增加统计计数
this.brokerController.getBrokerStatsManager().incQueuePutNums(msg.getTopic(), msg.getQueueId(), putMessageResult.getAppendMessageResult().getMsgNum(), 1);
this.brokerController.getBrokerStatsManager().incQueuePutSize(msg.getTopic(), msg.getQueueId(), putMessageResult.getAppendMessageResult().getWroteBytes());
}
//增加统计计数
this.brokerController.getBrokerStatsManager().incTopicPutNums(msg.getTopic(), putMessageResult.getAppendMessageResult().getMsgNum(), 1);
this.brokerController.getBrokerStatsManager().incTopicPutSize(msg.getTopic(),
putMessageResult.getAppendMessageResult().getWroteBytes());
this.brokerController.getBrokerStatsManager().incBrokerPutNums(putMessageResult.getAppendMessageResult().getMsgNum());
response.setRemark(null);
//设置响应头中的migId，实际上就是broker生成的offsetMsgId属性
responseHeader.setMsgId(putMessageResult.getAppendMessageResult().getMsgId());
//消息队列Id
responseHeader.setQueueId(queueIdInt);
//消息逻辑偏移量
responseHeader.setQueueOffset(putMessageResult.getAppendMessageResult().getLogicsOffset());
//如果不是单向请求，那么将响应写会客户端
doResponse(ctx, request, response);
//如果有发送消息的钩子，那么执行
if (hasSendMessageHook()) {
sendMessageContext.setMsgId(responseHeader.getMsgId());
sendMessageContext.setQueueId(responseHeader.getQueueId());
sendMessageContext.setQueueOffset(responseHeader.getQueueOffset());
int commercialBaseCount = brokerController.getBrokerConfig().getCommercialBaseCount();
int wroteSize = putMessageResult.getAppendMessageResult().getWroteBytes();
int incValue = (int) Math.ceil(wroteSize / BrokerStatsManager.SIZE_PER_COUNT) * commercialBaseCount;
sendMessageContext.setCommercialSendStats(BrokerStatsManager.StatsType.SEND_SUCCESS);
sendMessageContext.setCommercialSendTimes(incValue);
sendMessageContext.setCommercialSendSize(wroteSize);
sendMessageContext.setCommercialOwner(owner);
}
return null;
} else {
//如果有发送消息的钩子，那么执行
if (hasSendMessageHook()) {
int wroteSize = request.getBody().length;
int incValue = (int) Math.ceil(wroteSize / BrokerStatsManager.SIZE_PER_COUNT);
sendMessageContext.setCommercialSendStats(BrokerStatsManager.StatsType.SEND_FAILURE);
sendMessageContext.setCommercialSendTimes(incValue);
sendMessageContext.setCommercialSendSize(wroteSize);
sendMessageContext.setCommercialOwner(owner);
}
}
return response;
}
本次我们学习了asyncSendMessage方法的整体流程，以及自动创建topic的源码，并且我们学习到了autoCreateTopicEnable属性为true，即自动创建topic的一些问题。下一章，我们将学习asyncPutMessage方法，该方法真正的用来存储消息。