分布式事务与Seate框架(2)——Seata实践

一、实践准备工作

1、框架介绍

实践主要是以“订单-库存-账户”系统演示,主要的框架图如下,图中各个部分充当的分布式事务角色已标明。

    

分布式事务与Seate框架(2)——Seata实践

  具体流程:

  1)用户登录XXX商品购物系统(假设已有账户),

  2)点击购买某个商品,发起创建订单请求;

  3)检查购买商品的库存量,如果不够则创建订单失败提示库存不足;否则锁定该商品---->减少库存--->创建订单;

  4)订单创建成功后点击付款(或直接付款无需点击,实际上整个Demo中下单之后模拟立马支付,并不会点击付款);

  5)如果购买成功则对账户进行余额进行判断,余额足够则进行减扣,余额不够则进行提示说明

  6)返回购买成功失败提示说明。

2、项目结构

项目结构如下:

分布式事务与Seate框架(2)——Seata实践

分布式事务与Seate框架(2)——Seata实践

mvn package打包运行seata服务,即运行TC服务器(这里只展示单机)

分布式事务与Seate框架(2)——Seata实践

初始化Seata库,导入sql脚本

分布式事务与Seate框架(2)——Seata实践

二、代码实践

这里只展示关键代码,全部代码已提交gituhb:,有需要的小伙伴可以自行获取

1、“订单-库存-账户”服务

订单服务:

    TM(microService):seata-order-service

    RM(DB Resources):jdbc:mysql://127.0.0.1:3306/order

OrderService:


@GlobalTransactional // TM开启全局事务 @Transactional(rollbackFor = Exception.class) public void createOrder(Long productId, BigDecimal price){ // 这里模拟获取的是用户的账户ID // 通过上下文获取userId再获取accountId(单个账户) Long accountId = 1L; // 假设已经获取到了账户ID // 1.rpc调用库存微服务检查库存并减库存操作 Boolean deductStorageSuccess = storageFeignClient.deduct(productId); if (!deductStorageSuccess) { throw new RuntimeException("storage deduct failed!"); } // 2.创建订单 ProductOrder order = ProductOrder.builder() .productId(productId) .accountId(accountId) .payAmount(price) .build(); log.info("create order : {}", order); // 这里为了模拟回滚,所以先对价格的判断放到了创建订单之后,抛出runtime exception if (price.compareTo(BigDecimal.ZERO) < 0) { throw new NumberFormatException("product price must greater than zero!"); } orderMapper.insertSelective(order); // 3.rpc调用账户微服务对余额检查并扣款操作 Boolean deductAccountSuccess = accountFeignClient.deduct(accountId, price); if (!deductAccountSuccess) { throw new RuntimeException("account deduct failed!"); } // 4. 反馈结果 }

OrderController:


/** * 模拟创建订单 * @param productId * @param price * @return */ @PostMapping("/create") public String create(Long productId, BigDecimal price){ try { orderService.createOrder(productId, price); } catch (Exception e) { log.error("order failed: ", e); return "order failed"; } return "order success"; }

调用的Feign:


@FeignClient(name="seata-account-service") public interface AccountFeignClient { @PostMapping("/account/deduct") Boolean deduct(@RequestParam("accountId") Long accountId, @RequestParam("payAmount") BigDecimal payAmount); } @FeignClient(name="seata-storage-service") public interface StorageFeignClient { @PostMapping("/storage/deduct") Boolean deduct(@RequestParam("productId") Long productId); }

库存服务:

    microService:seata-storage-service

    RM(DB Resources):jdbc:mysql://127.0.0.1:3306/storage

StorageService


public Boolean deduct(Long productId){ // 这里先检查有没有库存了, 生产环境下这里是需要for update数据库锁,或者分布式锁 Repo repoFromDB = repoMapper.selectByPrimaryKey(productId); if (repoFromDB == null) { throw new RuntimeException("product not exist!"); } // 对库存减一 int afterCount = repoFromDB.getAmount()-1; // 没有库存剩余了 if (afterCount < 0) { throw new RuntimeException("product storage is no remaining!"); } Repo repo = Repo.builder() .id(productId) .amount(afterCount) .build(); repoMapper.updateAmount(repo); log.info("deduct product[{}] storage, current amount is {}", productId, afterCount); return true; }

StorageController:


/** * 模拟对商品库存减一 * @param productId * @return */ @PostMapping("/deduct") public Boolean deduct(Long productId){ try { storageService.deduct(productId); } catch (Exception e) { return false; } return true; }

账户服务

    microService:seata-account-service

    RM(DB Resources):jdbc:mysql:127.0.0.1/account

AccountService:


public void deduct(Long accountId, BigDecimal payAmount){ // 这里先检查有没有账户存在, 生产环境下这里是需要for update数据库锁,或者分布式锁 UserAccount userAccountFromDB = userAccountMapper.selectByPrimaryKey(accountId); if (userAccountFromDB == null) { throw new RuntimeException("account not exist!"); } // 检查余额是否足够 BigDecimal afterBalance = userAccountFromDB.getBalance().subtract(payAmount); if (afterBalance.compareTo(BigDecimal.ZERO) < 0) { throw new RuntimeException("the balance is not enough!"); } UserAccount userAccount = UserAccount.builder() .id(accountId) .balance(afterBalance) .build(); log.info("deduct account[{}] , current balance is {}", accountId, afterBalance); userAccountMapper.updateBalance(userAccount); }

AccountController:


/** * 模拟账户扣款 * @param accountId * @param payAmount * @return */ @PostMapping("/deduct") public Boolean deduct(Long accountId, BigDecimal payAmount){ try { accountService.deduct(accountId, payAmount); } catch (Exception e) { return false; } return true; }

2、Seata服务器,即TC角色

  首先初始化seata的sql脚本(sql脚本参考官方wiki),并开启seata库,之后开启Seata Server(具体的配置与启动前nacos配置,事务分组等相关概念请参考官方wiki)

    

分布式事务与Seate框架(2)——Seata实践

3、检查Nacos服务与配置列表

  微服务模块启动后快速注册到dev命名空间下的SEATA_GROUP分组,此时TM、RM、TC都已经具备 

分布式事务与Seate框架(2)——Seata实践

       

分布式事务与Seate框架(2)——Seata实践

启动微服务模块后可以看到日志输出,说明启动成功并且已经成功注册


RM will register :jdbc:mysql://127.0.0.1:3306/account
nacos registry, SEATA_GROUP seata-account-service 192.168.99.1:6009 register finished Started SeataAccountApplication in 30.115 seconds (JVM running for 33.158) ....... NettyPool create channel to transactionRole:TMROLE,address:169.254.6.29:8091,msg:< RegisterTMRequest{applicationId='seata-account-service', transactionServiceGroup='my_test_tx_group'} > register TM success. client version:1.4.0, server version:1.4.0,channel:[id: 0xa77dc065, L:/169.254.6.29:52794 - R:/169.254.6.29:8091] register success, cost 4 ms, version:1.4.0,role:TMROLE,channel:[id: 0xa77dc065, L:/169.254.6.29:52794 - R:/169.254.6.29:8091]

三、运行测试

1、模拟购买支付成功情况

运行启动所有的微服务后,在TC Serve的日志可以看到所有的TM、RM都已经注册了

分布式事务与Seate框架(2)——Seata实践

此时productId=1库存还剩998

分布式事务与Seate框架(2)——Seata实践

accountId=1的用户余额还剩1000元

分布式事务与Seate框架(2)——Seata实践

 接下来就是模拟用户购买商品环节,调用http://localhost:6008/order/create,表示用户想买商品ID=1,价格为12.25的商品

分布式事务与Seate框架(2)——Seata实践

清空日志,并发起请求查看日志:


16:10:45.167 INFO --- [rverHandlerThread_1_4_500] i.s.s.coordinator.DefaultCoordinator : Begin new global transaction applicationId: seata-order-service,transactionServiceGroup: my_test_tx_group, transactionName: createOrder(java.lang.Long, java.math.BigDecimal),timeout:60000,xid:169.254.6.29:8091:136139747123908608 16:10:45.964 INFO --- [ batchLoggerPrint_1_1] i.s.c.r.p.server.BatchLogHandler : SeataMergeMessage xid=169.254.6.29:8091:136139747123908608,branchType=AT,resourceId=jdbc:mysql://127.0.0.1:3306/storage,lockKey=repo:1 ,clientIp:169.254.6.29,vgroup:my_test_tx_group 16:10:46.086 INFO --- [rverHandlerThread_1_5_500] i.seata.server.coordinator.AbstractCore : Register branch successfully, xid = 169.254.6.29:8091:136139747123908608, branchId = 136139750928142336, resourceId = jdbc:mysql://127.0.0.1:3306/storage ,lockKeys = repo:1 16:10:46.788 INFO --- [ batchLoggerPrint_1_1] i.s.c.r.p.server.BatchLogHandler : SeataMergeMessage xid=169.254.6.29:8091:136139747123908608,branchType=AT,resourceId=jdbc:mysql://127.0.0.1:3306/account,lockKey=user_account:1 ,clientIp:169.254.6.29,vgroup:my_test_tx_group 16:10:46.918 INFO --- [rverHandlerThread_1_6_500] i.seata.server.coordinator.AbstractCore : Register branch successfully, xid = 169.254.6.29:8091:136139747123908608, branchId = 136139754342305793, resourceId = jdbc:mysql://127.0.0.1:3306/account ,lockKeys = user_account:1 16:10:47.015 INFO --- [ batchLoggerPrint_1_1] i.s.c.r.p.server.BatchLogHandler : xid=169.254.6.29:8091:136139747123908608,branchType=AT,resourceId=jdbc:mysql://127.0.0.1:3306/order,lockKey=product_order:6,clientIp:169.254.6.29,vgroup:my_test_tx_group 16:10:47.073 INFO --- [rverHandlerThread_1_7_500] i.seata.server.coordinator.AbstractCore : Register branch successfully, xid = 169.254.6.29:8091:136139747123908608, branchId = 136139755294412801, resourceId = jdbc:mysql://127.0.0.1:3306/order ,lockKeys = product_order:6 16:10:47.184 INFO --- [ batchLoggerPrint_1_1] i.s.c.r.p.server.BatchLogHandler : xid=169.254.6.29:8091:136139747123908608,extraData=null,clientIp:169.254.6.29,vgroup:my_test_tx_group 16:10:48.084 INFO --- [ AsyncCommitting_1_1] io.seata.server.coordinator.DefaultCore : Committing global transaction is successfully done, xid = 169.254.6.29:8091:136139747123908608. 16:10:53.908 INFO --- [ TxTimeoutCheck_1_1] i.s.s.coordinator.DefaultCoordinator : Global transaction[169.254.6.29:8091:136139530647490560] is timeout and will be rollback. 16:10:54.947 INFO --- [ RetryRollbacking_1_1] io.seata.server.coordinator.DefaultCore : Rollback global transaction successfully, xid = 169.254.6.29:8091:136139530647490560.

从日志中我们可以看到:

1)全局事务XID已经生成,各个分支注册成功,

2)branchId也已经生成并在全局事务XID下,资源已被锁住

3)全局事务提交成功

查看此时的库存与余额,都已经进行了减扣

分布式事务与Seate框架(2)——Seata实践

分布式事务与Seate框架(2)——Seata实践

2、模拟库存不足情况

修改productId=1的商品库存为0:

分布式事务与Seate框架(2)——Seata实践

再次发起请求,查看TC Server日志,可以查出明显发生了全局事务的回滚


16:20:24.258 INFO --- [verHandlerThread_1_12_500] i.s.s.coordinator.DefaultCoordinator : Begin new global transaction applicationId: seata-order-service,transactionServiceGroup: my_test_tx_group, transactionName: createOrder(java.lang.Long, java.math.BigDecimal),timeout:60000,xid:169.254.6.29:8091:136142176250875904 16:20:24.279 INFO --- [ batchLoggerPrint_1_1] i.s.c.r.p.server.BatchLogHandler : xid=169.254.6.29:8091:136142176250875904,extraData=null,clientIp:169.254.6.29,vgroup:my_test_tx_group 16:20:24.420 INFO --- [verHandlerThread_1_13_500] io.seata.server.coordinator.DefaultCore : Rollback global transaction successfully, xid = 169.254.6.29:8091:136142176250875904.

查看库存与余额情况,库存仍然是0,余额仍然是987.75

3、模拟余额不足情况

修改accountId=1的账户余额小于12.25

分布式事务与Seate框架(2)——Seata实践

再次发起请求,查看日志


16:27:41.811 INFO --- [verHandlerThread_1_14_500] i.s.s.coordinator.DefaultCoordinator : Begin new global transaction applicationId: seata-order-service,transactionServiceGroup: my_test_tx_group, transactionName: createOrder(java.lang.Long, java.math.BigDecimal),timeout:60000,xid:169.254.6.29:8091:136144011456008192 16:27:41.836 INFO --- [ batchLoggerPrint_1_1] i.s.c.r.p.server.BatchLogHandler : SeataMergeMessage xid=169.254.6.29:8091:136144011456008192,branchType=AT,resourceId=jdbc:mysql://127.0.0.1:3306/storage,lockKey=repo:1 ,clientIp:169.254.6.29,vgroup:my_test_tx_group 16:27:41.889 INFO --- [verHandlerThread_1_15_500] i.seata.server.coordinator.AbstractCore : Register branch successfully, xid = 169.254.6.29:8091:136144011456008192, branchId = 136144011762192385, resourceId = jdbc:mysql://127.0.0.1:3306/storage ,lockKeys = repo:1 16:27:42.088 INFO --- [ batchLoggerPrint_1_1] i.s.c.r.p.server.BatchLogHandler : xid=169.254.6.29:8091:136144011456008192,extraData=null,clientIp:169.254.6.29,vgroup:my_test_tx_group 16:27:42.632 INFO --- [verHandlerThread_1_16_500] io.seata.server.coordinator.DefaultCore : Rollback branch transaction successfully, xid = 169.254.6.29:8091:136144011456008192 branchId = 136144011762192385 16:27:42.754 INFO --- [verHandlerThread_1_16_500] io.seata.server.coordinator.DefaultCore : Rollback global transaction successfully, xid = 169.254.6.29:8091:136144011456008192.

不同于库存不足的情况的是,这里库存服务分支事务是先注册TC Server的,因为有异常的并不是库存服务,需要注意的是因为我模拟的是下单之后立马支付,支付失败的话订单也是不会存在,实际生活中应该是订单显示“支付失败”。

查看库存与余额情况,库存仍然是997,余额仍然是10.75

分布式事务与Seate框架(2)——Seata实践

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