微服务之分布式事务Seata

Seata AT模式(全自动事务,只需配置即可)

服务端搭建

分布式事务/seata-server-1.3.zip

Seata Server 配置

 Seata Server - TC全局事务协调器

介绍了 AT 事务的三个角色：TC（事务协调器）、TM（事务管理器）和RM（资源管理器），其中 TM 和 RM 是嵌入在业务应用中的，而 TC 则是一个独立服务。

配置 registry.conf配置文件--注册

选择eureka并设置合适的路径及服务名称

Seata 支持多款注册中心服务：nacos 、eureka、redis、zk、consul、etcd3、sofa。

我们项目中要使用 eureka 注册中心，eureka服务的连接地址、注册的服务名，这需要在 registry.conf 文件中进行配置：

registry {
  # file 、nacos 、eureka、redis、zk、consul、etcd3、sofa
  # 这里选择 eureka 注册配置
  type = "eureka"

  nacos {
	......
  }

  # eureka的注册配置
  eureka {
    # 注册中心地址
    serviceUrl = "http://localhost:8761/eureka"
    # 注册的服务ID
    application = "seata-server"
    weight = "1"
  }
  
  redis {
	......
  }
  ......

 配置 registry.conf配置文件--配置

设置为最简单的本地配置--file.conf

Seata 需要存储全局事务信息、分支事务信息、全局锁信息，这些数据存储到什么位置？

针对存储位置的配置，支持放在配置中心，或者也可以放在本地文件。Seata Server 支持的配置中心服务有：nacos 、apollo、zk、consul、etcd3。

这里我们选择最简单的，使用本地文件，这需要在 registry.conf 配置文件中来指定：

......

config {
  # file、nacos 、apollo、zk、consul、etcd3
  # 在这里选择使用本地文件来保存配置
  type = "file"


......

  etcd3 {
    serverAddr = "http://localhost:2379"
  }
  
  file {
    # 在这里设置配置文件的文件名
    name = "file.conf"
  }
}

 配置file.conf配置文件

file.conf 中对事务信息的存储位置进行配置，存储位置支持：file、db、redis。

这里我们选择数据库作为存储位置，这需要在 file.conf 中进行配置：

注意数据库中需要有对应的表在git中有source.sql文件

store {
  ## store mode: file、db、redis
  # 这里选择数据库存储
  mode = "db"

  ## file store property
  file {
  	......
  }

  # 数据库存储
  db {
    ## the implement of javax.sql.DataSource, such as DruidDataSource(druid)/BasicDataSource(dbcp)/HikariDataSource(hikari) etc.
    datasource = "druid"
    ## mysql/oracle/postgresql/h2/oceanbase etc.
    dbType = "mysql"
    driverClassName = "com.mysql.jdbc.Driver"

	# 数据库连接配置
    url = "jdbc:mysql://127.0.0.1:3306/seata?useUnicode=true&characterEncoding=UTF-8&serverTimezone=GMT%2B8"
    user = "root"
    password = "root"
    minConn = 5
    maxConn = 30

	# 事务日志表表名设置
    globalTable = "global_table"
    branchTable = "branch_table"
    lockTable = "lock_table"

    queryLimit = 100
    maxWait = 5000
  }

  ## redis store property
  redis {
  	......
  }
}

启动参数设置

启动文件：seata-server.bat

用文本编辑器打开文件，找到文件中这一行：

%JAVACMD% %JAVA_OPTS% -server -Xmx2048m -Xms2048m -Xmn1024m -Xss512k -XX:Sur......

 看到 Seata Server 默认使用 2G 内存，测试环境我们可以把内存调低：

%JAVACMD% %JAVA_OPTS% -server -Xmx256m -Xms256m -Xmn128m -Xss512k -XX:Sur......

 启动 Seata Server

双击 seata-server.bat 启动 Seata Server。

查看 Eureka 注册中心 Seata Server 的注册信息：

 应用服务添加 Seata AT 事务

 

1.添加依赖

    4.0.0
    
        org.springframework.boot
        spring-boot-starter-parent
        2.3.2.RELEASE
         
    
    cn.tedu
    order-parent
    1.0-SNAPSHOT
    pom
    order-parent


    
        1.3.0
        2.0.0.RELEASE
    

    


		
        
          com.alibaba.cloud
          spring-cloud-alibaba-seata
          ${spring-cloud-alibaba-seata.version}
          
            
              seata-all
              io.seata
            
          
        
        
          io.seata
          seata-all
          ${seata.version}
        
    

2.在application.yml中 添加对应的tc事务组

spring:
  ......
  
  cloud:
    alibaba:
      seata:
        tx-service-group: order_tx_group

......

 3.添加registry.conf文件

需要从注册中心获得 TC 的地址，这里配置注册中心的地址。

TC 在注册中心注册的服务ID在下面 file.conf 中指定。

registry {
  # file 、nacos 、eureka、redis、zk、consul、etcd3、sofa
  type = "eureka"

  nacos {
    serverAddr = "localhost"
    namespace = ""
    cluster = "default"
  }
  eureka {
    serviceUrl = "http://localhost:8761/eureka"
    # application = "default"
    # weight = "1"
  }
  redis {
    serverAddr = "localhost:6379"
    db = "0"
    password = ""
    cluster = "default"
    timeout = "0"
  }
  zk {
    cluster = "default"
    serverAddr = "127.0.0.1:2181"
    session.timeout = 6000
    connect.timeout = 2000
    username = ""
    password = ""
  }
  consul {
    cluster = "default"
    serverAddr = "127.0.0.1:8500"
  }
  etcd3 {
    cluster = "default"
    serverAddr = "http://localhost:2379"
  }
  sofa {
    serverAddr = "127.0.0.1:9603"
    application = "default"
    region = "DEFAULT_ZONE"
    datacenter = "DefaultDataCenter"
    cluster = "default"
    group = "SEATA_GROUP"
    addressWaitTime = "3000"
  }
  file {
    name = "file.conf"
  }
}

config {
  # file、nacos 、apollo、zk、consul、etcd3、springCloudConfig
  type = "file"

  nacos {
    serverAddr = "localhost"
    namespace = ""
    group = "SEATA_GROUP"
  }
  consul {
    serverAddr = "127.0.0.1:8500"
  }
  apollo {
    app.id = "seata-server"
    apollo.meta = "http://192.168.1.204:8801"
    namespace = "application"
  }
  zk {
    serverAddr = "127.0.0.1:2181"
    session.timeout = 6000
    connect.timeout = 2000
    username = ""
    password = ""
  }
  etcd3 {
    serverAddr = "http://localhost:2379"
  }
  file {
    name = "file.conf"
  }
}

 4.添加file.conf文件

在这里我们指定 TC 的服务ID seata-server：

vgroupMapping.order_tx_group = "seata-server"

order_tx_group 对应 application.yml 中注册的事务组名。

transport {
  # tcp udt unix-domain-socket
  type = "TCP"
  #NIO NATIVE
  server = "NIO"
  #enable heartbeat
  heartbeat = true
  # the client batch send request enable
  enableClientBatchSendRequest = true
  #thread factory for netty
  threadFactory {
    bossThreadPrefix = "NettyBoss"
    workerThreadPrefix = "NettyServerNIOWorker"
    serverExecutorThread-prefix = "NettyServerBizHandler"
    shareBossWorker = false
    clientSelectorThreadPrefix = "NettyClientSelector"
    clientSelectorThreadSize = 1
    clientWorkerThreadPrefix = "NettyClientWorkerThread"
    # netty boss thread size,will not be used for UDT
    bossThreadSize = 1
    #auto default pin or 8
    workerThreadSize = "default"
  }
  shutdown {
    # when destroy server, wait seconds
    wait = 3
  }
  serialization = "seata"
  compressor = "none"
}
service {
  #transaction service group mapping
  # order_tx_group 与 yml 中的 “tx-service-group: order_tx_group” 配置一致
  # “seata-server” 与 TC 服务器的注册名一致
  # 从eureka获取seata-server的地址，再向seata-server注册自己，设置group
  vgroupMapping.order_tx_group = "seata-server"
  #only support when registry.type=file, please don't set multiple addresses
  order_tx_group.grouplist = "127.0.0.1:8091"
  #degrade, current not support
  enableDegrade = false
  #disable seata
  disableGlobalTransaction = false
}

client {
  rm {
    asyncCommitBufferLimit = 10000
    lock {
      retryInterval = 10
      retryTimes = 30
      retryPolicyBranchRollbackOnConflict = true
    }
    reportRetryCount = 5
    tableMetaCheckEnable = false
    reportSuccessEnable = false
  }
  tm {
    commitRetryCount = 5
    rollbackRetryCount = 5
  }
  undo {
    dataValidation = true
    logSerialization = "jackson"
    logTable = "undo_log"
  }
  log {
    exceptionRate = 100
  }
}

5.创建 seata 数据源代理

Seata AT 事务对业务代码无侵入，全自动化处理全局事务，其功能是靠 Seata 的数据源代理工具实现的。

这里我们创建 Seata 的数据源代理，并排除 Spring 默认的数据源

package cn.tedu.order;

import com.alibaba.druid.pool.DruidDataSource;
import io.seata.rm.datasource.DataSourceProxy;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;

import javax.sql.DataSource;

@Configuration
public class DatasourceConfiguration {
    @Bean
    @ConfigurationProperties(prefix = "spring.datasource")
    public DataSource druidDataSource(){
        DruidDataSource druidDataSource = new DruidDataSource();
        return druidDataSource;
    }

    @Primary
    @Bean("dataSource")
    public DataSourceProxy dataSource(DataSource druidDataSource){
        return new DataSourceProxy(druidDataSource);
    }
}

6.主程序中排除Springboot 的默认数据源

package cn.tedu.order;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;
import org.springframework.cloud.openfeign.EnableFeignClients;

@EnableFeignClients
@MapperScan("cn.tedu.order.mapper")
@SpringBootApplication(exclude = DataSourceAutoConfiguration.class)
public class OrderApplication {

    public static void main(String[] args) {
        SpringApplication.run(OrderApplication.class, args);
    }

}

 7.在业务中加入注解全局注解和局部注解

package cn.tedu.order.service;

import cn.tedu.order.entity.Order;
import cn.tedu.order.feign.AccountClient;
import cn.tedu.order.feign.EasyIdClient;
import cn.tedu.order.feign.StorageClient;
import cn.tedu.order.mapper.OrderMapper;
import io.seata.spring.annotation.GlobalTransactional;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

@Service
public class OrderServiceImpl implements OrderService {
    @Autowired
    private OrderMapper orderMapper;
    @Autowired
    private EasyIdClient easyIdClient;
    @Autowired
    private StorageClient storageClient;
    @Autowired
    private AccountClient accountClient;

    @GlobalTransactional //开启全局事务,旨在第一个模块添加
    @Transactional  //开启本地本地事务
    @Override
    public void create(Order order) {
        // TODO: 从全局唯一id发号器获得id，这里暂时随机产生一个 orderId
        //Long orderId = Long.valueOf(new Random().nextInt(Integer.MAX_VALUE));
        //long orderId = Math.abs(new Random().nextLong());

        String s = easyIdClient.nextId("order_business");
        Long orderId = Long.valueOf(s);
        order.setId(orderId);
        orderMapper.create(order);
        // TODO: 调用storage，修改库存
        storageClient.decrease(order.getProductId(),order.getCount());
        // TODO: 调用account，修改账户余额
        accountClient.decrease(order.getUserId(),order.getMoney());
    }
}

 8.测试事务结果

观察控制台，看到全局事务和订单的分支事务已经启动，并可以看到全局事务ID（XID）和分支事务ID（Branch ID）：

 

事务回滚截图: