SpringCloud Alibaba Seata 处理分布式事务
文章目录
- SpringCloud Alibaba Seata 处理分布式事务
- 一、Seata 介绍
- 二、Seata 的下载和安装
- 三、Seata 使用
一、Seata 介绍
在分布式之后，单体应用被拆分成微服务应用，原来的三个模块被拆分成三个独立的应用，分别使用三个独立的数据源，业务操作需要调用三个服务来实现。此时每个服务内部的数据一致性由本地事务来保证，但是全局的数据一致性没发保证。
一句话：一次业务操作需要跨多个数据源或需要跨多个系统进行远程调用，就会产生分布式事务问题。
而 Seata 可以帮我们解决这种问题。
Seata 是一款开源的分布式事务解决方案，致力于在微服务架构下提供高性能和简单易用的分布式事务服务。
Seata 官网
分布式事务处理过程的一ID+ 三组件模型：
- ID ：Transaction ID XID ,全局唯一事务的ID。不同的数据库，但是他们拥有相同的ID，表示他们为一组。
三组件模型：
- Transaction Coordinator（TC）：事务协调器，维护全局事务的运行状态，服务协调并驱动全局事务的提价和回滚。
- Transaction Manager （TM）：控制全局事务的边界，负责开启一个全局事务，并最终发起全局提价或全局回滚的决议。
- Resource Manager （RM）： 控制分支事务，负责分支种族侧，状态汇报，并接受事务协调器的指令，驱动分支（本地）事务的提交和回滚。
处理过程：
- TM 向 TC 申请开启一个全局事务，全局事务创建成功并生成一个全局唯一的XID
- XID 在微服务调用链路的上下文中传播
- RM 向 TC 注册分支事务，将其纳入XID 对应全局事务的管辖
- TM 向 TC 发起针对 XID 的全局提交或回滚决议
- TC 调度 XID 下管辖的全部分支事务完成提交或回滚请求
自动补偿/反向补偿：
如果有微服务 A、B、C 现在 A中分别去调用 B 和 C，未了确保 B 和 C 的调用同时成功或者同时失败，那么就要用分布式事务。假设先调用 B ，在调用 C ，B调用完之后，事务就提交了，然后调用 C ，C 出错了，现在要回滚。此时 B 需要回滚，但是 B 的回滚并不是我们传统意义上所说的回滚，而是通过一条更新 SQL，将 B 中的数据复原，这个过程就叫反向补偿。
二、Seata 的下载和安装
修改conf目录下的file.conf配置文件。
新建seata数据库，并执行下面sql
-- -------------------------------- The script used when storeMode is 'db' --------------------------------
-- the table to store GlobalSession data
CREATE TABLE IF NOT EXISTS `global_table`
(
`xid` VARCHAR(128) NOT NULL,
`transaction_id` BIGINT,
`status` TINYINT NOT NULL,
`application_id` VARCHAR(32),
`transaction_service_group` VARCHAR(32),
`transaction_name` VARCHAR(128),
`timeout` INT,
`begin_time` BIGINT,
`application_data` VARCHAR(2000),
`gmt_create` DATETIME,
`gmt_modified` DATETIME,
PRIMARY KEY (`xid`),
KEY `idx_gmt_modified_status` (`gmt_modified`, `status`),
KEY `idx_transaction_id` (`transaction_id`)
) ENGINE = InnoDB
DEFAULT CHARSET = utf8;
-- the table to store BranchSession data
CREATE TABLE IF NOT EXISTS `branch_table`
(
`branch_id` BIGINT NOT NULL,
`xid` VARCHAR(128) NOT NULL,
`transaction_id` BIGINT,
`resource_group_id` VARCHAR(32),
`resource_id` VARCHAR(256),
`branch_type` VARCHAR(8),
`status` TINYINT,
`client_id` VARCHAR(64),
`application_data` VARCHAR(2000),
`gmt_create` DATETIME(6),
`gmt_modified` DATETIME(6),
PRIMARY KEY (`branch_id`),
KEY `idx_xid` (`xid`)
) ENGINE = InnoDB
DEFAULT CHARSET = utf8;
-- the table to store lock data
CREATE TABLE IF NOT EXISTS `lock_table`
(
`row_key` VARCHAR(128) NOT NULL,
`xid` VARCHAR(128),
`transaction_id` BIGINT,
`branch_id` BIGINT NOT NULL,
`resource_id` VARCHAR(256),
`table_name` VARCHAR(32),
`pk` VARCHAR(36),
`status` TINYINT NOT NULL DEFAULT '0' COMMENT '0:locked ,1:rollbacking',
`gmt_create` DATETIME,
`gmt_modified` DATETIME,
PRIMARY KEY (`row_key`),
KEY `idx_status` (`status`),
KEY `idx_branch_id` (`branch_id`)
) ENGINE = InnoDB
DEFAULT CHARSET = utf8;
CREATE TABLE IF NOT EXISTS `distributed_lock`
(
`lock_key` CHAR(20) NOT NULL,
`lock_value` VARCHAR(20) NOT NULL,
`expire` BIGINT,
primary key (`lock_key`)
) ENGINE = InnoDB
DEFAULT CHARSET = utf8mb4;
INSERT INTO `distributed_lock` (lock_key, lock_value, expire) VALUES ('AsyncCommitting', ' ', 0);
INSERT INTO `distributed_lock` (lock_key, lock_value, expire) VALUES ('RetryCommitting', ' ', 0);
INSERT INTO `distributed_lock` (lock_key, lock_value, expire) VALUES ('RetryRollbacking', ' ', 0);
INSERT INTO `distributed_lock` (lock_key, lock_value, expire) VALUES ('TxTimeoutCheck', ' ', 0);修改conf目录下的registry.conf配置文件。
先启动 Nacos ，在启动Seata
三、Seata 使用
业务说明：
- 新建三个数据库，执行如下sql
CREATE DATABASE seata_order;
CREATE DATABASE seata_storage;
CREATE DATABASE seata_account;- 创建三张对应表以及各自的回滚日志表
/*
Navicat Premium Data Transfer
Source Server : localhost
Source Server Type : MySQL
Source Server Version : 80020
Source Host : 127.0.0.1:3306
Source Schema : seata_account
Target Server Type : MySQL
Target Server Version : 80020
File Encoding : 65001
Date: 15/05/2020 18:54:52
*/
SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;
-- ----------------------------
-- Table structure for t_account
-- ----------------------------
DROP TABLE IF EXISTS `t_account`;
CREATE TABLE `t_account` (
`id` bigint(0) NOT NULL AUTO_INCREMENT COMMENT 'id',
`user_id` bigint(0) NULL DEFAULT NULL COMMENT '用户id',
`total` decimal(10, 0) NULL DEFAULT NULL COMMENT '总额度',
`used` decimal(10, 0) NULL DEFAULT NULL COMMENT '已用余额',
`residue` decimal(10, 0) NULL DEFAULT 0 COMMENT '剩余可用额度',
PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 2 CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic;
-- ----------------------------
-- Records of t_account
-- ----------------------------
INSERT INTO `t_account` VALUES (1, 1, 1000, 200, 800);
-- ----------------------------
-- Table structure for undo_log
-- ----------------------------
DROP TABLE IF EXISTS `undo_log`;
CREATE TABLE `undo_log` (
`id` bigint(0) NOT NULL AUTO_INCREMENT,
`branch_id` bigint(0) NOT NULL,
`xid` varchar(100) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL,
`context` varchar(128) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL,
`rollback_info` longblob NOT NULL,
`log_status` int(0) NOT NULL,
`log_created` datetime(0) NOT NULL,
`log_modified` datetime(0) NOT NULL,
`ext` varchar(100) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
PRIMARY KEY (`id`) USING BTREE,
UNIQUE INDEX `ux_undo_log`(`xid`, `branch_id`) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 1 CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic;
SET FOREIGN_KEY_CHECKS = 1;/*
Navicat Premium Data Transfer
Source Server : localhost
Source Server Type : MySQL
Source Server Version : 80020
Source Host : 127.0.0.1:3306
Source Schema : seata_order
Target Server Type : MySQL
Target Server Version : 80020
File Encoding : 65001
Date: 15/05/2020 18:54:59
*/
SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;
-- ----------------------------
-- Table structure for t_order
-- ----------------------------
DROP TABLE IF EXISTS `t_order`;
CREATE TABLE `t_order` (
`id` bigint(0) NOT NULL AUTO_INCREMENT,
`user_id` bigint(0) NULL DEFAULT NULL COMMENT '用户id',
`product_id` bigint(0) NULL DEFAULT NULL COMMENT '产品id',
`count` int(0) NULL DEFAULT NULL COMMENT '数量',
`money` decimal(11, 0) NULL DEFAULT NULL COMMENT '金额',
`status` int(0) NULL DEFAULT NULL COMMENT '订单状态：0：创建中; 1：已完结',
PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 7 CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic;
-- ----------------------------
-- Records of t_order
-- ----------------------------
INSERT INTO `t_order` VALUES (8, 1, 1, 10, 100, 1);
INSERT INTO `t_order` VALUES (9, 1, 1, 10, 100, 0);
-- ----------------------------
-- Table structure for undo_log
-- ----------------------------
DROP TABLE IF EXISTS `undo_log`;
CREATE TABLE `undo_log` (
`id` bigint(0) NOT NULL AUTO_INCREMENT,
`branch_id` bigint(0) NOT NULL,
`xid` varchar(100) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL,
`context` varchar(128) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL,
`rollback_info` longblob NOT NULL,
`log_status` int(0) NOT NULL,
`log_created` datetime(0) NOT NULL,
`log_modified` datetime(0) NOT NULL,
`ext` varchar(100) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
PRIMARY KEY (`id`) USING BTREE,
UNIQUE INDEX `ux_undo_log`(`xid`, `branch_id`) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 1 CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic;
SET FOREIGN_KEY_CHECKS = 1;/*
Navicat Premium Data Transfer
Source Server : localhost
Source Server Type : MySQL
Source Server Version : 80020
Source Host : 127.0.0.1:3306
Source Schema : seata_storage
Target Server Type : MySQL
Target Server Version : 80020
File Encoding : 65001
Date: 15/05/2020 18:55:06
*/
SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;
-- ----------------------------
-- Table structure for t_storage
-- ----------------------------
DROP TABLE IF EXISTS `t_storage`;
CREATE TABLE `t_storage` (
`id` bigint(0) NOT NULL AUTO_INCREMENT,
`product_id` bigint(0) NULL DEFAULT NULL COMMENT '产品id',
`total` int(0) NULL DEFAULT NULL COMMENT '总库存',
`used` int(0) NULL DEFAULT NULL COMMENT '已用库存',
`residue` int(0) NULL DEFAULT NULL COMMENT '剩余库存',
PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 2 CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic;
-- ----------------------------
-- Records of t_storage
-- ----------------------------
INSERT INTO `t_storage` VALUES (1, 1, 100, 20, 80);
-- ----------------------------
-- Table structure for undo_log
-- ----------------------------
DROP TABLE IF EXISTS `undo_log`;
CREATE TABLE `undo_log` (
`id` bigint(0) NOT NULL AUTO_INCREMENT,
`branch_id` bigint(0) NOT NULL,
`xid` varchar(100) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL,
`context` varchar(128) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL,
`rollback_info` longblob NOT NULL,
`log_status` int(0) NOT NULL,
`log_created` datetime(0) NOT NULL,
`log_modified` datetime(0) NOT NULL,
`ext` varchar(100) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
PRIMARY KEY (`id`) USING BTREE,
UNIQUE INDEX `ux_undo_log`(`xid`, `branch_id`) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 1 CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic;
SET FOREIGN_KEY_CHECKS = 1;订单模块
- pom
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<parent>
<artifactId>cloud2021</artifactId>
<groupId>com.atguigu.springcloud</groupId>
<version>1.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>seata-order-service</artifactId>
<dependencies>
<dependency>
<groupId>com.alibaba.cloud</groupId>
<artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
</dependency>
<dependency>
<groupId>com.alibaba.cloud</groupId>
<artifactId>spring-cloud-starter-alibaba-seata</artifactId>
<exclusions>
<exclusion>
<artifactId>seata-all</artifactId>
<groupId>io.seata</groupId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>io.seata</groupId>
<artifactId>seata-all</artifactId>
<version>1.4.0</version>
</dependency>
<dependency>
<groupId>com.alibaba.cloud</groupId>
<artifactId>spring-cloud-starter-alibaba-sentinel</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-openfeign</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
<scope>runtime</scope>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
<scope>runtime</scope>
<optional>true</optional>
</dependency>
<dependency> <!--引入自己定义的api通用包，可以使用payment支持Entity-->
<groupId>com.atguigu.springcloud</groupId>
<artifactId>cloud-api-commons</artifactId>
<version>1.0-SNAPSHOT</version>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
</dependency>
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>2.0.0</version>
</dependency>
</dependencies>
</project>- yml
server:
port: 2001
spring:
application:
name: seata-order-service
cloud:
alibaba:
seata:
tx-service-group: fsp_tx_group # 自动以事务组的名称需要和seata-server中的对应
nacos:
discovery:
server-addr: 114.55.56.149:8849 # 配置Nacos地址
datasource:
driver-class-name: com.mysql.jdbc.Driver
url: jdbc:mysql://localhost:3306/seata_order
username: root
password: root
feign:
hystrix:
enabled: false
logging:
level:
io:
seata: info
mybatis:
mapper-locations: classpath:mapper/*.xml- 主启动类
package com.atguigu.springcloud.alibaba;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.openfeign.EnableFeignClients;
/**
* exclude = DataSourceAutoConfiguration.class 取消数据源的自动创建,
* 读取自定义的DataSourceProxyConfig.class类，使用Seata对数据源进行代理
* <p/>
*
* @EnableDiscoveryClient 该注解用于向使用consul或者zookeeper作为注册中心时注册服务
* @date 2020/12/18 16:05
* @description 支付服务
*/
@EnableDiscoveryClient
@EnableFeignClients
@SpringBootApplication(exclude = DataSourceAutoConfiguration.class)
public class SeataOrderService2001Application {
public static void main(String[] args) {
SpringApplication.run(SeataOrderService2001Application.class, args);
System.out.println("启动成功");
}
}- 业务类
package com.atguigu.springcloud.alibaba.service.impl;
import com.atguigu.springcloud.alibaba.dao.OrderDao;
import com.atguigu.springcloud.alibaba.domain.Order;
import com.atguigu.springcloud.alibaba.service.AccountService;
import com.atguigu.springcloud.alibaba.service.OrderService;
import com.atguigu.springcloud.alibaba.service.StorageService;
import io.seata.spring.annotation.GlobalTransactional;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;
import javax.annotation.Resource;
/**
* @auther zzyy
* @create 2020-02-26 15:20
*/
@Service
@Slf4j
public class OrderServiceImpl implements OrderService {
@Resource
private OrderDao orderDao;
@Resource
private StorageService storageService;
@Resource
private AccountService accountService;
/**
* 创建订单->调用库存服务扣减库存->调用账户服务扣减账户余额->修改订单状态
* 简单说：下订单->扣库存->减余额->改状态
* 注释掉 @GlobalTransactional 的时候，需要注意下方这个方法里面手动模拟了延时，也需要注释掉
* com.atguigu.springcloud.alibaba.service.impl.AccountServiceImpl#decrease(java.lang.Long, java.math.BigDecimal)
*/
@Override
@GlobalTransactional(name = "fsp-create-order", rollbackFor = Exception.class)
public void create(Order order) {
log.info("----->开始新建订单");
//1 新建订单
orderDao.create(order);
//2 扣减库存
log.info("----->订单微服务开始调用库存，做扣减Count");
storageService.decrease(order.getProductId(), order.getCount());
log.info("----->订单微服务开始调用库存，做扣减end");
//3 扣减账户
log.info("----->订单微服务开始调用账户，做扣减Money");
accountService.decrease(order.getUserId(), order.getMoney());
log.info("----->订单微服务开始调用账户，做扣减end");
//4 修改订单状态，从零到1,1代表已经完成
log.info("----->修改订单状态开始");
orderDao.update(order.getUserId(), 0);
log.info("----->修改订单状态结束");
log.info("----->下订单结束了，O(∩_∩)O哈哈~");
}
}package com.atguigu.springcloud.alibaba.service;
import com.atguigu.springcloud.alibaba.domain.CommonResult;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestParam;
/**
* @auther zzyy
* @create 2020-02-26 15:22
*/
@FeignClient(value = "seata-storage-service")
public interface StorageService {
@PostMapping(value = "/storage/decrease")
CommonResult decrease(@RequestParam("productId") Long productId, @RequestParam("count") Integer count);
}可以发现这里 OrderServiceImpl 类中通过 storageService.decrease方法，然后通过 openFign 远程调用其他的微服务。像这种服务与服务的调用，我们是无法通过 @Transactional（本地服务回滚） 回滚俩个服务里面的动作的。我们可以通过Seata中的 @GlobalTransactional 注解实现多个服务的回滚。
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