RocketMQ源码 — 三、 Producer消息发送过程
Producer
消息发送
producer start
producer启动过程如下图
public void start(final boolean startFactory) throws MQClientException {
switch (this.serviceState) {
case CREATE_JUST:
this.serviceState = ServiceState.START_FAILED;
// check GroupName
this.checkConfig();
// 改变ClientConfig.instanceName为pid
if (!this.defaultMQProducer.getProducerGroup().equals(MixAll.CLIENT_INNER_PRODUCER_GROUP)) {
this.defaultMQProducer.changeInstanceNameToPID();
}
// 初始化mQClientFactory为MQClientInstance，并将该实例加入factoryTable
this.mQClientFactory = MQClientManager.getInstance().getAndCreateMQClientInstance(this.defaultMQProducer, rpcHook);
// 将producer注册到MQClientInstance.producerTbale
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);
}
// 保存topic对应的routeInfo
this.topicPublishInfoTable.put(this.defaultMQProducer.getCreateTopicKey(), new TopicPublishInfo());
if (startFactory) {
// 启动MQClientInstance
mQClientFactory.start();
}
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;
}
// 启动的时候向所有的broker发送heartbeat
this.mQClientFactory.sendHeartbeatToAllBrokerWithLock();
}
消息发送流程
消息发送过程：先由producer封装通过netty发送到broker，然后由broker进行保存，过程如下
============================= producer发送消息 =============================
主要逻辑在DefaultMQProducerImpl.sendDefaultImpl
- 获取topicRouteInfo
DefaultMQProducerImpl.tryToFindTopicPublishInfo
->
MQClientInstance.updateTopicRouteInfoFromNameServer
private final ConcurrentHashMap<String/* group */, MQProducerInner> producerTable：放置所有的producer
updateTopicRouteInfoFromNameServer
- 获取topicRouteInfo
- 然后遍历producerTable，更新所有producer的topicRouteInfo
- 遍历consumerTable，更新所有的consumer的topicSubscribeInfo
- 加入topicRouteTable
->
MQClientAPIImpl.getTopicRouteInfoFromNameServer
通过netty向nameServer发出请求，请求topicRouteInfo
2. 选取一个messageQueue
从messageQueueList取一个MessageQueue
3. netty发送消息
DefaultMQProducer.sendKernelImpl，
============================= broker接收消息 =============================
因为使用netty作为网络通信工具，broker也是先使用netty接收到信息，然后调用注册的processor处理
- parseRequestHeader
利用反射构造requestHeader - 构造SendMessageContext
- 执行beforeHook
- 发送消息
- 构造MessageExtBrokerInner
- 保存消息DefaultMessageStore.putMessage
- CommitLog.putMessage
- 从mapedFileQueue中取出一个mapedFile,appendMessag使用directBuffer的方式写入commitLog
- 同步或者异步刷盘
- 同步双写
- CommitLog.putMessage
- 执行afterHook
issue
broker怎么会使用SendMessageProcessor来处理producer发来的消息？
// 在broker初始化的时候会注册所有的processor，registerProcessor
SendMessageProcessor sendProcessor = new SendMessageProcessor(this);
sendProcessor.registerSendMessageHook(sendMessageHookList)
sendProcessor.registerConsumeMessageHook(consumeMessageHookList);
this.remotingServer.registerProcessor(RequestCode.SEND_MESSAGE, sendProcessor, this.sendMessageExecutor);
this.remotingServer.registerProcessor(RequestCode.SEND_MESSAGE_V2, sendProcessor, this.sendMessageExecutor);
this.remotingServer.registerProcessor(RequestCode.CONSUMER_SEND_MSG_BACK, sendProcessor, this.sendMessageExecutor);
this.fastRemotingServer.registerProcessor(RequestCode.SEND_MESSAGE, sendProcessor, this.sendMessageExecutor);
this.fastRemotingServer.registerProcessor(RequestCode.SEND_MESSAGE_V2, sendProcessor, this.sendMessageExecutor);
this.fastRemotingServer.registerProcessor(RequestCode.CONSUMER_SEND_MSG_BACK, sendProcessor, this.sendMessageExecutor);
broker怎么接收消息并写入文件
- 找到需要写入的mapedFile（最后一个，或者新建一个）
- 使用mapedFile.appendMessage
怎么获取需要写入的mapedFile
见时序图：RocketMQ.asta（Broker收到sendRequest）
mapedFile.appendMessage的过程
见时序图：RocketMQ.asta（Broker收到sendRequest）
消息发送过程中涉及到的类
DefaultMQProducerImpl
topicPublishInfoTable
里面存放topic对应的messageQueue等信息
// topic对应的消息是否有序
private boolean orderTopic = false;
// 有没有routerInfo
private boolean haveTopicRouterInfo = false;
// topic对应的messageQueue
private List<MessageQueue> messageQueueList = new ArrayList<MessageQueue>();
// 消息发往哪一个queue
private volatile ThreadLocalIndex sendWhichQueue = new ThreadLocalIndex(0);
private TopicRouteData topicRouteData;
private final ConcurrentHashMap<String/* topic */, TopicPublishInfo> topicPublishInfoTable = new ConcurrentHashMap<String, TopicPublishInfo>();
put:
- 在producer start的时候会根据当前producer 的topic新建一个TopicPushlishInfo放进去
- 在发送信息之前会获取topic对应的topicPublishInfo，这个时候会去nameServer 查询最新的信息并更新table中所有的记录
defaultMQProducer
private final DefaultMQProducer defaultMQProducer;
发送消息的类，在DefaultMQProducer的构造函数里new DefaultMQProducerImpl传入DefaultMQProducer自身，所以这里DefaultMQProducerImpl.defaultMQProducer默认就是DefaultMQProducer
mQClientFactory
private MQClientInstance mQClientFactory;
MQClientManager是单例，包含两个属性
// 用来生成MQClientInstance的id，每个递增
private AtomicInteger factoryIndexGenerator = new AtomicInteger();
// 包含clientId到MQClientInstance的映射，管理client
private ConcurrentHashMap<String/* clientId */, MQClientInstance> factoryTable =
new ConcurrentHashMap<String, MQClientInstance>();
通过getInstance获取实例之后调用getAndCreateMQClientInstance创建MQClientInstance。
在DefaultMQProducerImpl.start的时候调用mQClientFactory.start启动
MQClientInstance
字段
// 在MQClientManager中new MQCLientInstance的时候，传入DefaultMQProducer，因为DefaultMQProducer继承了ClientConfig
private final ClientConfig clientConfig;
// new 的时候传入，由MQClientManager生成
private final int instanceIndex;
// new的时候传入，由clientConfig.buildMQClientId生成，形式为：ip@instanceName
private final String clientId;
// 每个group对应的MQProducerInner
// 在producer启动的时候注册到这儿
// 在每次发送message的时候从nameServer获取topicRouteData并更新每个producer对应的信息
private final ConcurrentHashMap<String/* group */, MQProducerInner> producerTable = new ConcurrentHashMap<String, MQProducerInner>();
// 每个group对应的MQConsumerInner
// consumer start的时候注册到这儿
// 在每次发送message的时候从nameServer获取topicRouteData并更新每个consumer对应的信息
private final ConcurrentHashMap<String/* group */, MQConsumerInner> consumerTable = new ConcurrentHashMap<String, MQConsumerInner>();
// 每个group对应的adminExtInner，在NameServer 启动的时候会注册DefaultMQAdminExt
private final ConcurrentHashMap<String/* group */, MQAdminExtInner> adminExtTable = new ConcurrentHashMap<String, MQAdminExtInner>();
// topic对应的TopicRouteTable
// 在每次发送message的时候从nameServer获取topicRouteData并更新对应的信息
private final ConcurrentHashMap<String/* Topic */, TopicRouteData> topicRouteTable = new ConcurrentHashMap<String, TopicRouteData>();
// 所有broker的地址
// 在每次发送message的时候从nameServer获取topicRouteData并更新对应的信息
private final ConcurrentHashMap<String/* Broker Name */, HashMap<Long/* brokerId */, String/* address */>> brokerAddrTable =
new ConcurrentHashMap<String, HashMap<Long, String>>();
// 定时任务线程池，包括：fetchNameServerAddr，updateTopicRouteInfoFromNameServer等
private final ScheduledExecutorService scheduledExecutorService = Executors.newSingleThreadScheduledExecutor(new ThreadFactory() {
@Override
public Thread newThread(Runnable r) {
return new Thread(r, "MQClientFactoryScheduledThread");
}
});
// service
private final PullMessageService pullMessageService;
private final RebalanceService rebalanceService;
private final NettyClientConfig nettyClientConfig;
// 用来client远程通信，使用netty
private final MQClientAPIImpl mQClientAPIImpl;
关键方法
public void start() throws MQClientException {
synchronized (this) {
switch (this.serviceState) {
case CREATE_JUST:
this.serviceState = ServiceState.START_FAILED;
// If not specified,looking address from name server
if (null == this.clientConfig.getNamesrvAddr()) {
this.clientConfig.setNamesrvAddr(this.mQClientAPIImpl.fetchNameServerAddr());
}
// Start request-response channel
this.mQClientAPIImpl.start();
// Start various schedule tasks
this.startScheduledTask();
// Start pull service
this.pullMessageService.start();
// Start rebalance service
this.rebalanceService.start();
// Start push service
this.defaultMQProducer.getDefaultMQProducerImpl().start(false);
log.info("the client factory [{}] start OK", this.clientId);
this.serviceState = ServiceState.RUNNING;
break;
case RUNNING:
break;
case SHUTDOWN_ALREADY:
break;
case START_FAILED:
throw new MQClientException("The Factory object[" + this.getClientId() + "] has been created before, and failed.", null);
default:
break;
}
}
}
private void startScheduledTask() {
if (null == this.clientConfig.getNamesrvAddr()) {
this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {
@Override
public void run() {
try {
// 获取nameServer的地址
MQClientInstance.this.mQClientAPIImpl.fetchNameServerAddr();
} catch (Exception e) {
log.error("ScheduledTask fetchNameServerAddr exception", e);
}
}
}, 1000 * 10, 1000 * 60 * 2, TimeUnit.MILLISECONDS);
}
this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {
@Override
public void run() {
try {
// 更新topicRouteData
MQClientInstance.this.updateTopicRouteInfoFromNameServer();
} catch (Exception e) {
log.error("ScheduledTask updateTopicRouteInfoFromNameServer exception", e);
}
}
}, 10, this.clientConfig.getPollNameServerInteval(), TimeUnit.MILLISECONDS);
this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {
@Override
public void run() {
try {
// 清理掉线的broker
MQClientInstance.this.cleanOfflineBroker();
// 给broker发送心跳
MQClientInstance.this.sendHeartbeatToAllBrokerWithLock();
} catch (Exception e) {
log.error("ScheduledTask sendHeartbeatToAllBroker exception", e);
}
}
}, 1000, this.clientConfig.getHeartbeatBrokerInterval(), TimeUnit.MILLISECONDS);
this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {
@Override
public void run() {
try {
// 保存consumerOffset
MQClientInstance.this.persistAllConsumerOffset();
} catch (Exception e) {
log.error("ScheduledTask persistAllConsumerOffset exception", e);
}
}
}, 1000 * 10, this.clientConfig.getPersistConsumerOffsetInterval(), TimeUnit.MILLISECONDS);
this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {
@Override
public void run() {
try {
// 根据processQueueTable的大小决定是否需要增加或者减少threadPool的大小
// 目前尚未实现具体的增加或者减少的逻辑
MQClientInstance.this.adjustThreadPool();
} catch (Exception e) {
log.error("ScheduledTask adjustThreadPool exception", e);
}
}
}, 1, 1, TimeUnit.MINUTES);
}
DefaultMessageStore
字段
private final MessageStoreConfig messageStoreConfig;
// CommitLog
private final CommitLog commitLog;
// topic和queueId唯一确定一个consumeQueue
// put：
// 1. 在getMessage的时候会调用findConsumeQueue，如果consumeQueueTable不存在对应的（topic，queueId），则新建一个加入table
// 2. 在启动的时候load
private final ConcurrentHashMap<String/* topic */, ConcurrentHashMap<Integer/* queueId */, ConsumeQueue>> consumeQueueTable;
/** service */
// 消息刷盘，依次循环consumeQueueTable，将每个consumeQueue中的mapedFileQueue commit
private final FlushConsumeQueueService flushConsumeQueueService;
// 删除过时的commitlog文件
private final CleanCommitLogService cleanCommitLogService;
// 删除consumeQueue文件
private final CleanConsumeQueueService cleanConsumeQueueService;
// 在新建DefaultMessageStore的时候新建new
// 在messageStore start的时候start
// 在run方法中循环取出requestQueue（PriorityBlokingQueue，take的时候是阻塞的）里面的request处理——即新建mapedFile
private final AllocateMapedFileService allocateMapedFileService;
// TODO 暂时还不能理解indexservice
private final IndexService indexService;
// TODO
private final ReputMessageService reputMessageService;
// HA 高可用，同步双写，异步复制
private final HAService haService;
private final ScheduleMessageService scheduleMessageService;
private final StoreStatsService storeStatsService;
关键方法
public void start() throws Exception {
this.flushConsumeQueueService.start();
this.commitLog.start();
this.storeStatsService.start();
if (this.scheduleMessageService != null && SLAVE != messageStoreConfig.getBrokerRole()) {
this.scheduleMessageService.start();
}
if (this.getMessageStoreConfig().isDuplicationEnable()) {
this.reputMessageService.setReputFromOffset(this.commitLog.getConfirmOffset());
} else {
this.reputMessageService.setReputFromOffset(this.commitLog.getMaxOffset());
}
this.reputMessageService.start();
this.haService.start();
this.createTempFile();
this.addScheduleTask();
this.shutdown = false;
}
CommitLog
消息写入内存，保存文件的地方
字段
// 消息文件队列，包含所有保存在磁盘上的文件
private final MapedFileQueue mapedFileQueue;
//
private final DefaultMessageStore defaultMessageStore;
// 消息刷盘
private final FlushCommitLogService flushCommitLogService;
// 添加消息的回调，在doAppend方法中追加消息到内存
private final AppendMessageCallback appendMessageCallback;
// 记录topic对应每个队列的offset
private HashMap<String/* topic-queueid */, Long/* offset */> topicQueueTable = new HashMap<String, Long>(1024);
MapedFileQueue
管理mapedFile，新建、获取、删除mapedFile将消息写入文件
字段
// 每次删除文件个数，作为是否删除的一个参数
private static final int DeleteFilesBatchMax = 10;
// 文件的存储路径
private final String storePath;
// 每个文件的大小
private final int mapedFileSize;
// 所有文件列表
private final List<MapedFile> mapedFiles = new ArrayList<MapedFile>();
// 读锁
private final ReadWriteLock readWriteLock = new ReentrantReadWriteLock();
// 新建mapedFile的地方，将新建mapedFile的 request添加到requesttable和requestQueue中
// 在MessageStore启动的时候会启动AllocateMapedFileService这个线程，执行requestQueue里面的request，新建mapedFile
private final AllocateMapedFileService allocateMapedFileService;
MapedFile
和文件一对一关系
字段
// 保存消息的文件名
private final String fileName;
// 该文件的全局offset，也就是文件名的前缀
private final long fileFromOffset;
// 文件大小
private final int fileSize;
// 文件对象
private final File file;
// 文件映射为的内存
private final MappedByteBuffer mappedByteBuffer;
// 文件写的位置
private final AtomicInteger wrotePostion = new AtomicInteger(0);
// 刷盘之后的位置
private final AtomicInteger committedPosition = new AtomicInteger(0);
// nio阻塞
private FileChannel fileChannel;
private volatile long storeTimestamp = 0;
private boolean firstCreateInQueue = false;
方法
public int commit(final int flushLeastPages) {
// 判断是否需要flush
if (this.isAbleToFlush(flushLeastPages)) {
//判断文件是否被占用，也就是说每次commit的时候不一定成功
if (this.hold()) {
// 如果没有被占用则将内存刷到磁盘上
int value = this.wrotePostion.get();
// 将内存强制写入磁盘
this.mappedByteBuffer.force();
this.committedPosition.set(value);
// 释放占用
this.release();
} else {
// 尝试占用失败，重置committedPosition
log.warn("in commit, hold failed, commit offset = " + this.committedPosition.get());
this.committedPosition.set(this.wrotePostion.get());
}
}
return this.getCommittedPosition();
}
public AppendMessageResult appendMessage(final Object msg, final AppendMessageCallback cb) {
assert msg != null;
assert cb != null;
// file当前position
int currentPos = this.wrotePostion.get();
if (currentPos < this.fileSize) {
// 获取DirectByteBuffer的一个分片，重置了mark，position，limit是剩下的大小，和原来的buffer共享同一块内存
ByteBuffer byteBuffer = this.mappedByteBuffer.slice();
byteBuffer.position(currentPos);
AppendMessageResult result =
cb.doAppend(this.getFileFromOffset(), byteBuffer, this.fileSize - currentPos, msg);
this.wrotePostion.addAndGet(result.getWroteBytes());
this.storeTimestamp = result.getStoreTimestamp();
return result;
}
log.error("MapedFile.appendMessage return null, wrotePostion: " + currentPos + " fileSize: "
+ this.fileSize);
return new AppendMessageResult(AppendMessageStatus.UNKNOWN_ERROR);
}
