分布式事务Seata-AT模式，在已有springcloud+eureka+feign+mybatis项目基础上如何整合Seata

之前已经详细介绍过Seata的几种模式，今天用一个Demo来说明在现有springcloud+eureka+feign+mybatis项目基础上如何整合Seata，以官方demo为例
首先下载一下官方的Demo,地址：https://github.com/seata/seata-samples
然后下载Seata的server端，地址：https://github.com/seata/seata/releases

seata-samples项目下载好之后项目结构如下，然后我们要用的是springcloud-eureka-feign-mybatis-seata，demo里已经都加好了配置文件，我们逐步说一下都需要那些配置：

接下来是具体步骤：

1.修改seata-server的配置信息：

seata-server中，/conf目录下，有两个配置文件,需要结合自己的情况来修改：

1.1.file.conf

里面有事务组配置，锁配置，事务日志存储等相关配置信息，由于此demo使用db存储事务信息，我们这里要修改store中的配置：

transport {
  # tcp udt unix-domain-socket
  type = "TCP"
  #NIO NATIVE
  server = "NIO"
  #enable heartbeat
  heartbeat = true
  # the client batch send request enable
  enableClientBatchSendRequest = false
  #thread factory for netty
  threadFactory {
    bossThreadPrefix = "NettyBoss"
    workerThreadPrefix = "NettyServerNIOWorker"
    serverExecutorThreadPrefix = "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 configuration, only used in client side
service {
  #transaction service group mapping
  vgroupMapping.ydc_tx_group = "default" //注意，修改这里，ydc_tx_group 为自定义事务组名称，需保持server和client一致，否则报错
  #only support when registry.type=file, please don't set multiple addresses
  default.grouplist = "127.0.0.1:8091"
  #degrade, current not support
  enableDegrade = false
  #disable seata
  disableGlobalTransaction = false
}
#client transaction configuration, only used in client side
client {
  rm {
    asyncCommitBufferLimit = 10000
    lock {
      retryInterval = 10
      retryTimes = 30
      retryPolicyBranchRollbackOnConflict = true
    }
    reportRetryCount = 5
    tableMetaCheckEnable = false
    reportSuccessEnable = false
    sqlParserType = druid
  }
  tm {
    commitRetryCount = 5
    rollbackRetryCount = 5
  }
  undo {
    dataValidation = true
    logSerialization = "jackson"
    logTable = "undo_log"
  }
  log {
    exceptionRate = 100
  }
}
## transaction log store, only used in seata-server
store {
  ## store mode: file、db
  mode = "db"  //注意：修改这里，表明事务信息使用db存储

  ## file store property  // 当mode = "db"此部分配置不生效
  file {
    ## store location dir
    dir = "sessionStore"
    # branch session size , if exceeded first try compress lockkey, still exceeded throws exceptions
    maxBranchSessionSize = 16384
    # globe session size , if exceeded throws exceptions
    maxGlobalSessionSize = 512
    # file buffer size , if exceeded allocate new buffer
    fileWriteBufferCacheSize = 16384
    # when recover batch read size
    sessionReloadReadSize = 100
    # async, sync
    flushDiskMode = async
  }

  ## database store property // 当mode = "db"事务日志会存储在这里配置的数据库里
  db {
    ## the implement of javax.sql.DataSource, such as DruidDataSource(druid)/BasicDataSource(dbcp) etc.
    datasource = "dbcp"
    ## mysql/oracle/h2/oceanbase etc.
    dbType = "mysql"
    driverClassName = "com.mysql.jdbc.Driver"
    url = "jdbc:mysql://192.168.1.151:3306/seata" //注意，修改这里
    user = "test" //注意，修改这里
    password = "test" //注意，修改这里
    minConn = 1
    maxConn = 10
    globalTable = "global_table"
    branchTable = "branch_table"
    lockTable = "lock_table"
    queryLimit = 100
  }
}
## server configuration, only used in server side
server {
  recovery {
    #schedule committing retry period in milliseconds
    committingRetryPeriod = 1000
    #schedule asyn committing retry period in milliseconds
    asynCommittingRetryPeriod = 1000
    #schedule rollbacking retry period in milliseconds
    rollbackingRetryPeriod = 1000
    #schedule timeout retry period in milliseconds
    timeoutRetryPeriod = 1000
  }
  undo {
    logSaveDays = 7
    #schedule delete expired undo_log in milliseconds
    logDeletePeriod = 86400000
  }
  #unit ms,s,m,h,d represents milliseconds, seconds, minutes, hours, days, default permanent
  maxCommitRetryTimeout = "-1"
  maxRollbackRetryTimeout = "-1"
  rollbackRetryTimeoutUnlockEnable = false
}

## metrics configuration, only used in server side
metrics {
  enabled = false
  registryType = "compact"
  # multi exporters use comma divided
  exporterList = "prometheus"
  exporterPrometheusPort = 9898
}

1.2.registry.conf

registry{}中是注册中心相关配置，config{}中是配置中心相关配置。seata中，注册中心和配置中心是分开实现的，是两个东西。

我们这里用eureka作注册中心，所以，只用修改registry{}中的：

registry {
  # file 、nacos 、eureka、redis、zk、consul、etcd3、sofa
  type = "eureka"  //注意，修改这里，指明注册中心使用什么

  nacos {
    serverAddr = "localhost"
    namespace = ""
    cluster = "default"
  }
  eureka {
    serviceUrl = "http://192.168.1.151:9020/eureka/"  //注意，修改这里
    application = "default"  
    weight = "1"
  }
  redis {
    serverAddr = "localhost:6379"
    db = "0"
  }
  zk {
    cluster = "default"
    serverAddr = "127.0.0.1:2181"
    session.timeout = 6000
    connect.timeout = 2000
  }
  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"
  }
}

其他的配置可以暂时使用默认值。

2.client端相关配置

因为是在现有项目基础上整合seata,springcloud的一些核心配置就不赘述，这里只说明使用seata需要的额外配置，以demo中的order服务为例：

2.1.application.properties

#添加配置 这个是事务组名称，server和client都要保持一致
spring.cloud.alibaba.seata.tx-service-group = ydc_tx_group

2.2.file.conf

正常我们需要新建这个配置文件，文件内容如下：

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
  vgroupMapping.ydc_tx_group = "default" //注意，修改这里，保持和application.properties中的事务组名称一致
  #only support when registry.type=file, please don't set multiple addresses
  default.grouplist = "127.0.0.1:8091" //这个配置如注释所述，只有在registry.type=file时才会生效
  #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
  }
}

2.3.registry.conf

同上，也需要新建配置文件，内容如下：

registry {
  # file 、nacos 、eureka、redis、zk、consul、etcd3、sofa
  type = "eureka" //注意，修改这里，我们使用的是eureka做注册中心

  nacos {
    serverAddr = "localhost"
    namespace = ""
    cluster = "default"
  }
  eureka {
    serviceUrl = "http://192.168.1.151:9020/eureka/" //注意，修改这里
    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"
  }
}

其他使用默认值就好

3.pom.xml添加依赖

		<dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.0.27</version>
        </dependency>
        <dependency>
            <groupId>io.seata</groupId>
            <artifactId>seata-all</artifactId>
            <version>1.1.0</version>
        </dependency>
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-alibaba-seata</artifactId>
            <version>2.1.0.RELEASE</version>
            <exclusions>
                <exclusion>
                    <artifactId>seata-all</artifactId>
                    <groupId>io.seata</groupId>
                </exclusion>
            </exclusions>
        </dependency>

4.数据源代理

这个是要特别注意的地方，seata对数据源做了代理和接管，在每个参与分布式事务的服务中，都要做如下配置：

import com.alibaba.druid.pool.DruidDataSource;
import io.seata.rm.datasource.DataSourceProxy;
import javax.sql.DataSource;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.transaction.SpringManagedTransactionFactory;
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 org.springframework.core.io.support.PathMatchingResourcePatternResolver;
/**
 * 数据源代理
 * @author wangzhongxiang
 */
@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);
    }

    @Bean
    public SqlSessionFactory sqlSessionFactory(DataSourceProxy dataSourceProxy)throws Exception{
        SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
        sqlSessionFactoryBean.setDataSource(dataSourceProxy);
        sqlSessionFactoryBean.setMapperLocations(new PathMatchingResourcePatternResolver()
        .getResources("classpath*:/mapper/*.xml"));
        sqlSessionFactoryBean.setTransactionFactory(new SpringManagedTransactionFactory());
        return sqlSessionFactoryBean.getObject();
    }

}

5.创建数据库表

因为这里我们使用的是db模式存储事务日志，所以要创建三张seata-server所需表：
global_table，branch_table，lock_table
sql如下：

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,
    `gmt_modified`      DATETIME,
    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(96),
    `transaction_id` BIGINT,
    `branch_id`      BIGINT       NOT NULL,
    `resource_id`    VARCHAR(256),
    `table_name`     VARCHAR(32),
    `pk`             VARCHAR(36),
    `gmt_create`     DATETIME,
    `gmt_modified`   DATETIME,
    PRIMARY KEY (`row_key`),
    KEY `idx_branch_id` (`branch_id`)
) ENGINE = InnoDB
  DEFAULT CHARSET = utf8;

以及每个业务库中还要创建undo_log表
sql如下：

CREATE TABLE `undo_log` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT COMMENT 'increment id',
  `branch_id` bigint(20) NOT NULL COMMENT 'branch transaction id',
  `xid` varchar(100) 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 NOT NULL COMMENT 'create datetime',
  `log_modified` datetime NOT NULL COMMENT 'modify datetime',
  PRIMARY KEY (`id`),
  UNIQUE KEY `ux_undo_log` (`xid`,`branch_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COMMENT='AT transaction mode undo table';

使用本demo还需要执行各个服务下的业务sql

6.客户端使用

在需要开启分布式事务的方法上添加注解

@GlobalTransactional(name = "ydc-create-order",rollbackFor = Exception.class)

7.启动测试

然后启动测试即可，先启动eureka再启动seata-server
windows下执行/bin/seata-server.bat即可。

之后启动order,storage,account服务;

客户端有输出如下log说明有注册到seata-server上：

2020-04-13 15:10:17.459  INFO 15716 --- [           main] i.s.c.r.netty.NettyClientChannelManager  : will connect to 192.168.1.151:18091
2020-04-13 15:10:17.459  INFO 15716 --- [           main] io.seata.core.rpc.netty.RmRpcClient      : RM will register :jdbc:mysql://127.0.0.1:3306/seata-account
2020-04-13 15:10:17.463  INFO 15716 --- [           main] i.s.core.rpc.netty.NettyPoolableFactory  : NettyPool create channel to transactionRole:RMROLE,address:192.168.1.151:18091,msg:< RegisterRMRequest{resourceIds='jdbc:mysql://127.0.0.1:3306/seata-account', applicationId='account-server', transactionServiceGroup='ydc_tx_group'} >

服务端对应会输出如下log:

2020-04-13 14:44:02.908 INFO [ServerHandlerThread_1_500]io.seata.core.rpc.DefaultServerMessageListenerImpl.onRegRmMessage:122 -rm register success,message:RegisterRMRequest{resourceIds='jdbc:mysql://127.0.0.1:3306/seata-account', applicationId='account-server', transactionServiceGroup='ydc_tx_group'},channel:[id: 0x50d8cfa3, L:/192.168.1.151:18091 - R:/192.168.1.192:62019]
2020-04-13 14:44:56.734 INFO [NettyServerNIOWorker_1_16]io.seata.core.rpc.DefaultServerMessageListenerImpl.onRegTmMessage:138 -checkAuth for client:192.168.1.192:62047,vgroup:ydc_tx_group,applicationId:account-server

至此springcloud+eureka+feign+mybatis项目基础上如何整合Seata完成