分布式事务Seata

安装Seata

使用docker安装seata前提，client端（业务端）需要新增表undo_log，具体根据数据库类型来
数据库类型
MySQL为：

-- for AT mode you must to init this sql for you business database. the seata server not need it.
CREATE TABLE IF NOT EXISTS `undo_log`
(
    `branch_id`     BIGINT       NOT NULL COMMENT 'branch transaction id',
    `xid`           VARCHAR(128) NOT NULL COMMENT 'global transaction id',
    `context`       VARCHAR(128) NOT NULL COMMENT 'undo_log context,such as serialization',
    `rollback_info` LONGBLOB     NOT NULL COMMENT 'rollback info',
    `log_status`    INT(11)      NOT NULL COMMENT '0:normal status,1:defense status',
    `log_created`   DATETIME(6)  NOT NULL COMMENT 'create datetime',
    `log_modified`  DATETIME(6)  NOT NULL COMMENT 'modify datetime',
    UNIQUE KEY `ux_undo_log` (`xid`, `branch_id`)
) ENGINE = InnoDB
  AUTO_INCREMENT = 1
  DEFAULT CHARSET = utf8mb4 COMMENT ='AT transaction mode undo table';

seata-server端 需要新建数据库seata（这里名字要跟seata-server application.yml配置文件中store的db保持一致） 并创建下面4张表

根据数据库类型来
MySQL为：

-- -------------------------------- 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_status_gmt_modified` (`status` , `gmt_modified`),
    KEY `idx_transaction_id` (`transaction_id`)
) ENGINE = InnoDB
  DEFAULT CHARSET = utf8mb4;

-- 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 = utf8mb4;

-- 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`),
    KEY `idx_xid_and_branch_id` (`xid` , `branch_id`)
) ENGINE = InnoDB
  DEFAULT CHARSET = utf8mb4;

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);

下载镜像：

docker pull seataio/seata-server:1.5.2

docker run --name seata-server -p 8091:8091 -p 7091:7091 -d seataio/seata-server:1.5.2

将容器内部resources文件夹拷贝出来并修改：

mkdir /home/seata/resources -p
docker cp seata-server:/seata-server/resources /home/seata/
cd /home/seata/resources
vim application.yml

参考application.example.yml修改application.yml的 config，registry，store具体如下：

seata:
  config:
    # support: nacos, consul, apollo, zk, etcd3
    type: nacos
    nacos:
     server-addr: 192.168.233.128:8848
     namespace:
     group: SEATA_GROUP
     username: nacos
     password: nacos

  registry:
    # support: nacos, eureka, redis, zk, consul, etcd3, sofa
    type: nacos
    nacos:
      application: seata-server
      server-addr: 192.168.233.128:8848
      group: SEATA_GROUP
      namespace:
      cluster: default
      username: nacos
      password: nacos
  store:
    # support: file 、 db 、 redis
    mode: db
    db:
      datasource: druid
      db-type: mysql
      driver-class-name: com.mysql.jdbc.Driver
      url: jdbc:mysql://127.0.0.1:3306/seata?rewriteBatchedStatements=true
      user: root
      password: root
      min-conn: 5
      max-conn: 100
      global-table: global_table
      branch-table: branch_table
      lock-table: lock_table
      distributed-lock-table: distributed_lock
      query-limit: 100
      max-wait: 5000

重新挂载配置文件，需要先移除容器再使用挂在配置启动容器：

docker stop seata-server
docker rm seata-server
docker run --name seata-server -p 8091:8091 -p 7091:7091 -v /home/seata/resources:/seata-server/resources -d seataio/seata-server:1.5.2

查看seata启动控制台 docker logs seata-server
至此，nacos上就会注册seata服务

业务端使用seata控制全局事务

依赖

        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-seata</artifactId>
            <exclusions>
                <exclusion>
                    <groupId>io.seata</groupId>
                    <artifactId>seata-spring-boot-starter</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>io.seata</groupId>
            <artifactId>seata-spring-boot-starter</artifactId>
            <version>1.5.2</version>
        </dependency>

所有微服务配置文件需要添加

seata:
  enabled: true
  tx-service-group: imooc_tx_group
  service:
    vgroup-mapping:
      imooc_tx_group: SEATA_GROUP
    grouplist:
      SEATA_GROUP: 192.168.233.128:8091
  config:
    nacos:
      server-addr: 192.168.233.128:8848
      username: nacos
      password: nacos
  registry:
    nacos:
      server-addr: 192.168.233.128:8848
      username: nacos
      password: nacos

调用方serviceImpl方法上添加 @GlobalTransactional，并且一旦远程调用失败，则手动回滚全局事务

        // 发起远程调用，初始化用户简历，新增一条空记录
        GraceJSONResult graceJSONResult = workMicroServiceFeign.init(user.getId());
        if (graceJSONResult.getStatus() != 200) {
            // 如果调用状态不是200，则手动回滚全局事务
            String xid = RootContext.getXID();
            if (StringUtils.isNotBlank(xid)) {
                try {
                    GlobalTransactionContext.reload(xid).rollback();
                } catch (TransactionException e) {
                    e.printStackTrace();
                } finally {
                    GraceException.display(ResponseStatusEnum.USER_REGISTER_ERROR);
                }
            }
        }

或者使用切面来控制全局事务

package com.imooc.api;

import io.seata.core.context.RootContext;
import io.seata.core.exception.TransactionException;
import io.seata.tm.api.GlobalTransaction;
import io.seata.tm.api.GlobalTransactionContext;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.StringUtils;
import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.AfterThrowing;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.springframework.stereotype.Component;

@Slf4j
@Component
@Aspect
public class SeataTransactionAspect {

    /**
     * 调用service之前，手动加入或者创建全局事务
     * @param joinPoint
     * @throws TransactionException
     */
    @Before("execution(* com.imooc.service.impl..*.*(..))")
    public void beginTransaction(JoinPoint joinPoint) throws TransactionException {
        log.info("手动开启全局事务");
        // 手动开启全局事务
        GlobalTransaction gt = GlobalTransactionContext.getCurrentOrCreate();
        gt.begin();
    }

    /**
     * 捕获异常，则手动回滚全局事务
     * @param throwable
     * @throws Throwable
     */
    @AfterThrowing(
            throwing = "throwable",
            pointcut = "execution(* com.imooc.service.impl..*.*(..))"
    )
    public void seataRollback(Throwable throwable) throws Throwable {

        log.info("捕获到异常信息，则回滚，异常信息为：" + throwable.getMessage());

        // 从当前线程获得xid
        String xid = RootContext.getXID();
        if (StringUtils.isNotBlank(xid)) {
            GlobalTransactionContext.reload(xid).rollback();
        }
    }

}