大家好，我是烤鸭：
上一篇简单介绍broker的初始化，这一篇介绍 NettyRequestProcessor 的实现(主要是broker里用到的)。
AdminBrokerProcessor、ClientManageProcessor、ConsumerManageProcessor、EndTransactionProcessor
NettyRequestProcessor
/**
* Common remoting command processor
*/
public interface NettyRequestProcessor {
RemotingCommand processRequest(ChannelHandlerContext ctx, RemotingCommand request)
throws Exception;
boolean rejectRequest();
}
先看下哪些是broker里用到的，从包名就能看出来（remoting包下的后边看），接下来一个一个分析。
AdminBrokerProcessor (后台发起的 CURD)
@Override
public RemotingCommand processRequest(ChannelHandlerContext ctx,
RemotingCommand request) throws RemotingCommandException {
switch (request.getCode()) {
case RequestCode.UPDATE_AND_CREATE_TOPIC:
return this.updateAndCreateTopic(ctx, request);
//...
default:
break;
}
return null;
}
ClientManageProcessor
@Override
public RemotingCommand processRequest(ChannelHandlerContext ctx, RemotingCommand request)
throws RemotingCommandException {
switch (request.getCode()) {
case RequestCode.HEART_BEAT:
// 心跳,针对consumer,如果心跳的信息有更新(group和subscribe),会update
return this.heartBeat(ctx, request);
case RequestCode.UNREGISTER_CLIENT:
// 下线,针对 producer和consumer, producer和consumer 下线
return this.unregisterClient(ctx, request);
case RequestCode.CHECK_CLIENT_CONFIG:
// 通过注册的filter校验client的config
return this.checkClientConfig(ctx, request);
default:
break;
}
return null;
}
ConsumerManageProcessor
@Override
public RemotingCommand processRequest(ChannelHandlerContext ctx, RemotingCommand request)
throws RemotingCommandException {
switch (request.getCode()) {
case RequestCode.GET_CONSUMER_LIST_BY_GROUP:
// 根据group获取customer的list
return this.getConsumerListByGroup(ctx, request);
case RequestCode.UPDATE_CONSUMER_OFFSET:
// 更新topic@group对应的queueId和offset(没有就直接put,已存在的话如果要更新的offset<本地offset,记录日志)
return this.updateConsumerOffset(ctx, request);
case RequestCode.QUERY_CONSUMER_OFFSET:
// 根据topic@group、queueId获取offset(如果offset<0,并且在磁盘没有刷到内存,返回0,否则返回 QUERY_NOT_FOUND)
return this.queryConsumerOffset(ctx, request);
default:
break;
}
return null;
}
EndTransactionProcessor
@Override
public RemotingCommand processRequest(ChannelHandlerContext ctx, RemotingCommand request) throws
RemotingCommandException {
final RemotingCommand response = RemotingCommand.createResponseCommand(null);
final EndTransactionRequestHeader requestHeader =
(EndTransactionRequestHeader)request.decodeCommandCustomHeader(EndTransactionRequestHeader.class);
LOGGER.debug("Transaction request:{}", requestHeader);
// salve 不支持事务
if (BrokerRole.SLAVE == brokerController.getMessageStoreConfig().getBrokerRole()) {
response.setCode(ResponseCode.SLAVE_NOT_AVAILABLE);
LOGGER.warn("Message store is slave mode, so end transaction is forbidden. ");
return response;
}
// 来源于事务检查(ClientRemotingProcessor.processRequest)
if (requestHeader.getFromTransactionCheck()) {
switch (requestHeader.getCommitOrRollback()) {
// 非事务类型,直接返回
case MessageSysFlag.TRANSACTION_NOT_TYPE: {
LOGGER.warn("Check producer[{}] transaction state, but it's pending status."
+ "RequestHeader: {} Remark: {}",
RemotingHelper.parseChannelRemoteAddr(ctx.channel()),
requestHeader.toString(),
request.getRemark());
return null;
}
// commit, break 执行执行
case MessageSysFlag.TRANSACTION_COMMIT_TYPE: {
LOGGER.warn("Check producer[{}] transaction state, the producer commit the message."
+ "RequestHeader: {} Remark: {}",
RemotingHelper.parseChannelRemoteAddr(ctx.channel()),
requestHeader.toString(),
request.getRemark());
break;
}
case MessageSysFlag.TRANSACTION_ROLLBACK_TYPE: {
LOGGER.warn("Check producer[{}] transaction state, the producer rollback the message."
+ "RequestHeader: {} Remark: {}",
RemotingHelper.parseChannelRemoteAddr(ctx.channel()),
requestHeader.toString(),
request.getRemark());
break;
}
default:
return null;
}
} else {
switch (requestHeader.getCommitOrRollback()) {
case MessageSysFlag.TRANSACTION_NOT_TYPE: {
LOGGER.warn("The producer[{}] end transaction in sending message, and it's pending status."
+ "RequestHeader: {} Remark: {}",
RemotingHelper.parseChannelRemoteAddr(ctx.channel()),
requestHeader.toString(),
request.getRemark());
return null;
}
case MessageSysFlag.TRANSACTION_COMMIT_TYPE: {
break;
}
case MessageSysFlag.TRANSACTION_ROLLBACK_TYPE: {
LOGGER.warn("The producer[{}] end transaction in sending message, rollback the message."
+ "RequestHeader: {} Remark: {}",
RemotingHelper.parseChannelRemoteAddr(ctx.channel()),
requestHeader.toString(),
request.getRemark());
break;
}
default:
return null;
}
}
OperationResult result = new OperationResult();
// 提交
if (MessageSysFlag.TRANSACTION_COMMIT_TYPE == requestHeader.getCommitOrRollback()) {
// 根据offset从commitlog中获取当前的 halfmessage(半消息)
result = this.brokerController.getTransactionalMessageService().commitMessage(requestHeader);
if (result.getResponseCode() == ResponseCode.SUCCESS) {
// 校验半消息的合法性,group、事务队列的offset、commitlog的offset是否一致
RemotingCommand res = checkPrepareMessage(result.getPrepareMessage(), requestHeader);
if (res.getCode() == ResponseCode.SUCCESS) {
// 根据半消息构建一条事务消息
MessageExtBrokerInner msgInner = endMessageTransaction(result.getPrepareMessage());
msgInner.setSysFlag(MessageSysFlag.resetTransactionValue(msgInner.getSysFlag(), requestHeader.getCommitOrRollback()));
msgInner.setQueueOffset(requestHeader.getTranStateTableOffset());
msgInner.setPreparedTransactionOffset(requestHeader.getCommitLogOffset());
msgInner.setStoreTimestamp(result.getPrepareMessage().getStoreTimestamp());
MessageAccessor.clearProperty(msgInner, MessageConst.PROPERTY_TRANSACTION_PREPARED);
// 发送最终消息,消息刷到commitlog
RemotingCommand sendResult = sendFinalMessage(msgInner);
if (sendResult.getCode() == ResponseCode.SUCCESS) {
// 最终消息发送成功,在commitlog里原msg打一个'd'的标记this.brokerController.getTransactionalMessageService().deletePrepareMessage(result.getPrepareMessage());
}
return sendResult;
}
return res;
}
// 回滚
} else if (MessageSysFlag.TRANSACTION_ROLLBACK_TYPE == requestHeader.getCommitOrRollback()) {
// 流程同提交差不多，半小时获取成功之后，在commitlog里原msg打一个'd'的标记
result = this.brokerController.getTransactionalMessageService().rollbackMessage(requestHeader);
if (result.getResponseCode() == ResponseCode.SUCCESS) {
RemotingCommand res = checkPrepareMessage(result.getPrepareMessage(), requestHeader);
if (res.getCode() == ResponseCode.SUCCESS) {
this.brokerController.getTransactionalMessageService().deletePrepareMessage(result.getPrepareMessage());
}
return res;
}
}
response.setCode(result.getResponseCode());
response.setRemark(result.getResponseRemark());
return response;
}
ForwardRequestProcessor
@Override
public RemotingCommand processRequest(ChannelHandlerContext ctx, RemotingCommand request) {
return null;
}
小结
介绍了4个 processor：
AdminBrokerProcessor：给console台提供的 curd接口
ClientManageProcessor：针对client端的请求，包含 心跳(上线)、下线、配置检查
ConsumerManageProcessor：针对consumer的，包含 获取consumer列表、更新queueId和offset、获取offset
EndTransactionProcessor：提交模式，从commitlog根据offset获取半消息，写入commitlog，原半消息打一个’d’的标记。
回滚模式，从commitlog根据offset获取半消息，原半消息打一个’d’的标记。