1、Seata server注册器
//来自RM分支事务注册
super.registerProcessor(MessageType.TYPE_BRANCH_REGISTER, onRequestProcessor, messageExecutor);
//开启全局事务
super.registerProcessor(MessageType.TYPE_GLOBAL_BEGIN, onRequestProcessor, messageExecutor);
//提交全局事务
super.registerProcessor(MessageType.TYPE_GLOBAL_COMMIT, onRequestProcessor, messageExecutor);
//回滚全局事务
super.registerProcessor(MessageType.TYPE_GLOBAL_ROLLBACK, onRequestProcessor, messageExecutor);
//RM分支事务提交
super.registerProcessor(MessageType.TYPE_BRANCH_COMMIT_RESULT, onResponseProcessor, messageExecutor);
//RM分支事务回滚
super.registerProcessor(MessageType.TYPE_BRANCH_ROLLBACK_RESULT, onResponseProcessor, messageExecutor);
2、DefaultCoordinator协调者
TC开启全局事务
io.seata.server.coordinator.DefaultCoordinator#doGlobalBegin
@Override
public String begin(String applicationId, String transactionServiceGroup, String name, int timeout)throws TransactionException {GlobalSession session = GlobalSession.createGlobalSession(applicationId, transactionServiceGroup, name,timeout);MDC.put(RootContext.MDC_KEY_XID, session.getXid());session.addSessionLifecycleListener(SessionHolder.getRootSessionManager());session.begin();// transaction start eventeventBus.post(new GlobalTransactionEvent(session.getTransactionId(), GlobalTransactionEvent.ROLE_TC,session.getTransactionName(), applicationId, transactionServiceGroup, session.getBeginTime(), null, session.getStatus()));return session.getXid();}
TC提交全局事务
io.seata.server.coordinator.DefaultCore#doGlobalCommit @Overridepublic boolean doGlobalCommit(GlobalSession globalSession, boolean retrying) throws TransactionException {boolean success = true;// start committing eventeventBus.post(new GlobalTransactionEvent(globalSession.getTransactionId(), GlobalTransactionEvent.ROLE_TC,globalSession.getTransactionName(), globalSession.getApplicationId(), globalSession.getTransactionServiceGroup(),globalSession.getBeginTime(), null, globalSession.getStatus()));if (globalSession.isSaga()) {success = getCore(BranchType.SAGA).doGlobalCommit(globalSession, retrying);} else {Boolean result = SessionHelper.forEach(globalSession.getSortedBranches(), branchSession -> {// if not retrying, skip the canBeCommittedAsync branchesif (!retrying && branchSession.canBeCommittedAsync()) {return CONTINUE;}BranchStatus currentStatus = branchSession.getStatus();if (currentStatus == BranchStatus.PhaseOne_Failed) {globalSession.removeBranch(branchSession);return CONTINUE;}try {BranchStatus branchStatus = getCore(branchSession.getBranchType()).branchCommit(globalSession, branchSession);switch (branchStatus) {case PhaseTwo_Committed:globalSession.removeBranch(branchSession);return CONTINUE;case PhaseTwo_CommitFailed_Unretryable:if (globalSession.canBeCommittedAsync()) {LOGGER.error("Committing branch transaction[{}], status: PhaseTwo_CommitFailed_Unretryable, please check the business log.", branchSession.getBranchId());return CONTINUE;} else {SessionHelper.endCommitFailed(globalSession);LOGGER.error("Committing global transaction[{}] finally failed, caused by branch transaction[{}] commit failed.", globalSession.getXid(), branchSession.getBranchId());return false;}default:if (!retrying) {globalSession.queueToRetryCommit();return false;}if (globalSession.canBeCommittedAsync()) {LOGGER.error("Committing branch transaction[{}], status:{} and will retry later",branchSession.getBranchId(), branchStatus);return CONTINUE;} else {LOGGER.error("Committing global transaction[{}] failed, caused by branch transaction[{}] commit failed, will retry later.", globalSession.getXid(), branchSession.getBranchId());return false;}}} catch (Exception ex) {StackTraceLogger.error(LOGGER, ex, "Committing branch transaction exception: {}",new String[] {branchSession.toString()});if (!retrying) {globalSession.queueToRetryCommit();throw new TransactionException(ex);}}return CONTINUE;});// Return if the result is not nullif (result != null) {return result;}//If has branch and not all remaining branches can be committed asynchronously,//do print log and return falseif (globalSession.hasBranch() && !globalSession.canBeCommittedAsync()) {LOGGER.info("Committing global transaction is NOT done, xid = {}.", globalSession.getXid());return false;}}// if it succeeds and there is no branch, retrying=true is the asynchronous state when retrying. EndCommitted is executed to improve concurrency performance, and the global transaction ends..if (success && globalSession.getBranchSessions().isEmpty() && retrying) {SessionHelper.endCommitted(globalSession);// committed eventeventBus.post(new GlobalTransactionEvent(globalSession.getTransactionId(), GlobalTransactionEvent.ROLE_TC,globalSession.getTransactionName(), globalSession.getApplicationId(), globalSession.getTransactionServiceGroup(),globalSession.getBeginTime(), System.currentTimeMillis(), globalSession.getStatus()));LOGGER.info("Committing global transaction is successfully done, xid = {}.", globalSession.getXid());}return success;}@Overridepublic GlobalStatus commit(String xid) throws TransactionException {GlobalSession globalSession = SessionHolder.findGlobalSession(xid);if (globalSession == null) {return GlobalStatus.Finished;}globalSession.addSessionLifecycleListener(SessionHolder.getRootSessionManager());// just lock changeStatusboolean shouldCommit = SessionHolder.lockAndExecute(globalSession, () -> {// Highlight: Firstly, close the session, then no more branch can be registered.globalSession.closeAndClean();if (globalSession.getStatus() == GlobalStatus.Begin) {if (globalSession.canBeCommittedAsync()) {globalSession.asyncCommit();return false;} else {globalSession.changeStatus(GlobalStatus.Committing);return true;}}return false;});if (shouldCommit) {boolean success = doGlobalCommit(globalSession, false);//If successful and all remaining branches can be committed asynchronously, do async commit.if (success && globalSession.hasBranch() && globalSession.canBeCommittedAsync()) {globalSession.asyncCommit();return GlobalStatus.Committed;} else {return globalSession.getStatus();}} else {return globalSession.getStatus() == GlobalStatus.AsyncCommitting ? GlobalStatus.Committed : globalSession.getStatus();}}
TC回滚全局事务
io.seata.server.coordinator.DefaultCoordinator#doGlobalRollback@Overridepublic boolean doGlobalRollback(GlobalSession globalSession, boolean retrying) throws TransactionException {boolean success = true;// start rollback eventeventBus.post(new GlobalTransactionEvent(globalSession.getTransactionId(),GlobalTransactionEvent.ROLE_TC, globalSession.getTransactionName(),globalSession.getApplicationId(),globalSession.getTransactionServiceGroup(), globalSession.getBeginTime(),null, globalSession.getStatus()));if (globalSession.isSaga()) {success = getCore(BranchType.SAGA).doGlobalRollback(globalSession, retrying);} else {Boolean result = SessionHelper.forEach(globalSession.getReverseSortedBranches(), branchSession -> {BranchStatus currentBranchStatus = branchSession.getStatus();if (currentBranchStatus == BranchStatus.PhaseOne_Failed) {globalSession.removeBranch(branchSession);return CONTINUE;}try {BranchStatus branchStatus = branchRollback(globalSession, branchSession);switch (branchStatus) {case PhaseTwo_Rollbacked:globalSession.removeBranch(branchSession);LOGGER.info("Rollback branch transaction successfully, xid = {} branchId = {}", globalSession.getXid(), branchSession.getBranchId());return CONTINUE;case PhaseTwo_RollbackFailed_Unretryable:SessionHelper.endRollbackFailed(globalSession);LOGGER.info("Rollback branch transaction fail and stop retry, xid = {} branchId = {}", globalSession.getXid(), branchSession.getBranchId());return false;default:LOGGER.info("Rollback branch transaction fail and will retry, xid = {} branchId = {}", globalSession.getXid(), branchSession.getBranchId());if (!retrying) {globalSession.queueToRetryRollback();}return false;}} catch (Exception ex) {StackTraceLogger.error(LOGGER, ex,"Rollback branch transaction exception, xid = {} branchId = {} exception = {}",new String[] {globalSession.getXid(), String.valueOf(branchSession.getBranchId()), ex.getMessage()});if (!retrying) {globalSession.queueToRetryRollback();}throw new TransactionException(ex);}});// Return if the result is not nullif (result != null) {return result;}// In db mode, there is a problem of inconsistent data in multiple copies, resulting in new branch// transaction registration when rolling back.// 1. New branch transaction and rollback branch transaction have no data association// 2. New branch transaction has data association with rollback branch transaction// The second query can solve the first problem, and if it is the second problem, it may cause a rollback// failure due to data changes.GlobalSession globalSessionTwice = SessionHolder.findGlobalSession(globalSession.getXid());if (globalSessionTwice != null && globalSessionTwice.hasBranch()) {LOGGER.info("Rollbacking global transaction is NOT done, xid = {}.", globalSession.getXid());return false;}}if (success) {SessionHelper.endRollbacked(globalSession);// rollbacked eventeventBus.post(new GlobalTransactionEvent(globalSession.getTransactionId(),GlobalTransactionEvent.ROLE_TC, globalSession.getTransactionName(),globalSession.getApplicationId(),globalSession.getTransactionServiceGroup(),globalSession.getBeginTime(), System.currentTimeMillis(),globalSession.getStatus()));LOGGER.info("Rollback global transaction successfully, xid = {}.", globalSession.getXid());}return success;}@Overridepublic GlobalStatus rollback(String xid) throws TransactionException {GlobalSession globalSession = SessionHolder.findGlobalSession(xid);if (globalSession == null) {return GlobalStatus.Finished;}globalSession.addSessionLifecycleListener(SessionHolder.getRootSessionManager());// just lock changeStatusboolean shouldRollBack = SessionHolder.lockAndExecute(globalSession, () -> {globalSession.close(); // Highlight: Firstly, close the session, then no more branch can be registered.if (globalSession.getStatus() == GlobalStatus.Begin) {globalSession.changeStatus(GlobalStatus.Rollbacking);return true;}return false;});if (!shouldRollBack) {return globalSession.getStatus();}doGlobalRollback(globalSession, false);return globalSession.getStatus();}
RM注册分支事务到TC
io.seata.server.coordinator.DefaultCoordinator#doBranchRegister
@Overrideprotected void doBranchRegister(BranchRegisterRequest request, BranchRegisterResponse response,RpcContext rpcContext) throws TransactionException {MDC.put(RootContext.MDC_KEY_XID, request.getXid());response.setBranchId(core.branchRegister(request.getBranchType(), request.getResourceId(), rpcContext.getClientId(),request.getXid(), request.getApplicationData(), request.getLockKey()));}
RM提交分支事务到TC
RM回滚分支事务到TC