阿里 Seata 新版本终于解决了 TCC 模式的幂等、悬挂和空回滚问题

@LocalTCC
public interface StorageService {

    /**
     * 扣减库存
     * @param xid 全局xid
     * @param productId 产品id
     * @param count 数量
     * @return
     */
    @TwoPhaseBusinessAction(name = "storageApi", commitMethod = "commit", rollbackMethod = "rollback", useTCCFence = true)
    boolean decrease(String xid, Long productId, Integer count);

    /**
     * 提交事务
     * @param actionContext
     * @return
     */
    boolean commit(BusinessActionContext actionContext);

    /**
     * 回滚事务
     * @param actionContext
     * @return
     */
    boolean rollback(BusinessActionContext actionContext);
}

CREATE TABLE IF NOT EXISTS `tcc_fence_log`
(
    `xid`           VARCHAR(128)  NOT NULL COMMENT 'global id',
    `branch_id`     BIGINT        NOT NULL COMMENT 'branch id',
    `action_name`   VARCHAR(64)   NOT NULL COMMENT 'action name',
    `status`        TINYINT       NOT NULL COMMENT 'status(tried:1;committed:2;rollbacked:3;suspended:4)',
    `gmt_create`    DATETIME(3)   NOT NULL COMMENT 'create time',
    `gmt_modified`  DATETIME(3)   NOT NULL COMMENT 'update time',
    PRIMARY KEY (`xid`, `branch_id`),
    KEY `idx_gmt_modified` (`gmt_modified`),
    KEY `idx_status` (`status`)
) ENGINE = InnoDB
DEFAULT CHARSET = utf8mb4;

@Override
public BranchStatus branchCommit(BranchType branchType, String xid, long branchId, String resourceId,
         String applicationData) throws TransactionException {
 TCCResource tccResource = (TCCResource)tccResourceCache.get(resourceId);
 //省略判断
 Object targetTCCBean = tccResource.getTargetBean();
 Method commitMethod = tccResource.getCommitMethod();
 //省略判断
 try {
  //BusinessActionContext
  BusinessActionContext businessActionContext = getBusinessActionContext(xid, branchId, resourceId,
   applicationData);
  Object[] args = this.getTwoPhaseCommitArgs(tccResource, businessActionContext);
  Object ret;
  boolean result;
  //注解 useTCCFence 属性是否设置为 true
  if (Boolean.TRUE.equals(businessActionContext.getActionContext(Constants.USE_TCC_FENCE))) {
   try {
    result = TCCFenceHandler.commitFence(commitMethod, targetTCCBean, xid, branchId, args);
   } catch (SkipCallbackWrapperException | UndeclaredThrowableException e) {
    throw e.getCause();
   }
  } else {
   //省略逻辑
  }
  LOGGER.info("TCC resource commit result : {}, xid: {}, branchId: {}, resourceId: {}", result, xid, branchId, resourceId);
  return result ? BranchStatus.PhaseTwo_Committed : BranchStatus.PhaseTwo_CommitFailed_Retryable;
 } catch (Throwable t) {
  //省略
  return BranchStatus.PhaseTwo_CommitFailed_Retryable;
 }
}

public static boolean commitFence(Method commitMethod, Object targetTCCBean,
          String xid, Long branchId, Object[] args) {
 return transactionTemplate.execute(status -> {
  try {
   Connection conn = DataSourceUtils.getConnection(dataSource);
   TCCFenceDO tccFenceDO = TCC_FENCE_DAO.queryTCCFenceDO(conn, xid, branchId);
   if (tccFenceDO == null) {
    throw new TCCFenceException(String.format("TCC fence record not exists, commit fence method failed. xid= %s, branchId= %s", xid, branchId),
      FrameworkErrorCode.RecordAlreadyExists);
   }
   if (TCCFenceConstant.STATUS_COMMITTED == tccFenceDO.getStatus()) {
    LOGGER.info("Branch transaction has already committed before. idempotency rejected. xid: {}, branchId: {}, status: {}", xid, branchId, tccFenceDO.getStatus());
    return true;
   }
   if (TCCFenceConstant.STATUS_ROLLBACKED == tccFenceDO.getStatus() || TCCFenceConstant.STATUS_SUSPENDED == tccFenceDO.getStatus()) {
    if (LOGGER.isWarnEnabled()) {
     LOGGER.warn("Branch transaction status is unexpected. xid: {}, branchId: {}, status: {}", xid, branchId, tccFenceDO.getStatus());
    }
    return false;
   }
   return updateStatusAndInvokeTargetMethod(conn, commitMethod, targetTCCBean, xid, branchId, TCCFenceConstant.STATUS_COMMITTED, status, args);
  } catch (Throwable t) {
   status.setRollbackOnly();
   throw new SkipCallbackWrapperException(t);
  }
 });
}

//TCCFenceHandler 类
public static Object prepareFence(String xid, Long branchId, String actionName, Callback<Object> targetCallback) {
 return transactionTemplate.execute(status -> {
  try {
   Connection conn = DataSourceUtils.getConnection(dataSource);
   boolean result = insertTCCFenceLog(conn, xid, branchId, actionName, TCCFenceConstant.STATUS_TRIED);
   LOGGER.info("TCC fence prepare result: {}. xid: {}, branchId: {}", result, xid, branchId);
   if (result) {
    return targetCallback.execute();
   } else {
    throw new TCCFenceException(String.format("Insert tcc fence record error, prepare fence failed. xid= %s, branchId= %s", xid, branchId),
      FrameworkErrorCode.InsertRecordError);
   }
  } catch (TCCFenceException e) {
   //省略
  } catch (Throwable t) {
   //省略
  }
 });
}

//TCCFenceHandler 类
public static boolean rollbackFence(Method rollbackMethod, Object targetTCCBean,
         String xid, Long branchId, Object[] args, String actionName) {
 return transactionTemplate.execute(status -> {
  try {
   Connection conn = DataSourceUtils.getConnection(dataSource);
   TCCFenceDO tccFenceDO = TCC_FENCE_DAO.queryTCCFenceDO(conn, xid, branchId);
   // non_rollback
   if (tccFenceDO == null) {
    //不执行回滚逻辑
    return true;
   } else {
    if (TCCFenceConstant.STATUS_ROLLBACKED == tccFenceDO.getStatus() || TCCFenceConstant.STATUS_SUSPENDED == tccFenceDO.getStatus()) {
     LOGGER.info("Branch transaction had already rollbacked before, idempotency rejected. xid: {}, branchId: {}, status: {}", xid, branchId, tccFenceDO.getStatus());
     return true;
    }
    if (TCCFenceConstant.STATUS_COMMITTED == tccFenceDO.getStatus()) {
     if (LOGGER.isWarnEnabled()) {
      LOGGER.warn("Branch transaction status is unexpected. xid: {}, branchId: {}, status: {}", xid, branchId, tccFenceDO.getStatus());
     }
     return false;
    }
   }
   return updateStatusAndInvokeTargetMethod(conn, rollbackMethod, targetTCCBean, xid, branchId, TCCFenceConstant.STATUS_ROLLBACKED, status, args);
  } catch (Throwable t) {
   status.setRollbackOnly();
   throw new SkipCallbackWrapperException(t);
  }
 });
}

update tcc_fence_log set status = ?, gmt_modified = ?
    where xid = ? and  branch_id = ? and status = ? ;

public static boolean rollbackFence(Method rollbackMethod, Object targetTCCBean,
         String xid, Long branchId, Object[] args, String actionName) {
 return transactionTemplate.execute(status -> {
  try {
   Connection conn = DataSourceUtils.getConnection(dataSource);
   TCCFenceDO tccFenceDO = TCC_FENCE_DAO.queryTCCFenceDO(conn, xid, branchId);
   // non_rollback
   if (tccFenceDO == null) {
       //插入防悬挂记录
    boolean result = insertTCCFenceLog(conn, xid, branchId, actionName, TCCFenceConstant.STATUS_SUSPENDED);
    //省略逻辑
    return true;
   } else {
    //省略逻辑
   }
   return updateStatusAndInvokeTargetMethod(conn, rollbackMethod, targetTCCBean, xid, branchId, TCCFenceConstant.STATUS_ROLLBACKED, status, args);
  } catch (Throwable t) {
   //省略逻辑
  }
 });
}

//TCCFenceHandler 类
public static Object prepareFence(String xid, Long branchId, String actionName, Callback<Object> targetCallback) {
 return transactionTemplate.execute(status -> {
  try {
   Connection conn = DataSourceUtils.getConnection(dataSource);
   boolean result = insertTCCFenceLog(conn, xid, branchId, actionName, TCCFenceConstant.STATUS_TRIED);
   //省略逻辑
  } catch (TCCFenceException e) {
   if (e.getErrcode() == FrameworkErrorCode.DuplicateKeyException) {
    LOGGER.error("Branch transaction has already rollbacked before,prepare fence failed. xid= {},branchId = {}", xid, branchId);
    addToLogCleanQueue(xid, branchId);
   }
   status.setRollbackOnly();
   throw new SkipCallbackWrapperException(e);
  } catch (Throwable t) {
   //省略
  }
 });
}