Seata的简单使用

Seata的简单使用

本文只介绍Seata的简单使用,没有涉及其原理.

 

1.在本地搭建一个TC服务(事务协调者).

1.1 下载seata的安装包

官网(https://github.com/seata/seata/releases)

  往下滑滑,找到你想要的版本和格式下载即可.我这里使用的是seata-server-1.1.0.zip,解压即可使用.

 

1.2 配置

打开解压目录下的conf/registry.conf文件如下

registry {
  # file 、nacos 、eureka、redis、zk、consul、etcd3、sofa
  # 可以把seata-server理解为一个服务,它需要把自己注册到某个注册中心上去,方便使用seata的服务来找到自己
    #在这里就是指定注册中心的类型,由于我们项目用的是eureka,所以这里我选择eureka,即这一堆配置就下面一个eureka生效了
    #这里默认的是file,即文件,选了文件就可以不用搭注册中心,直接从文件里读取服务列表
    #复制之后一定要改一改
  type = "eureka"  

  nacos {
    serverAddr = "localhost"
    namespace = ""
    cluster = "default"
  }
  eureka { #"只有我生效啦"
    serviceUrl = "http://localhost:10086/eureka"  #eureka地址
    application = "seata_tc_server"		#在eureka里显示的名字
    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"
  }
}

config {
    #在这里选择配置中心,这里我们选择file
  # file、nacos 、apollo、zk、consul、etcd3
  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
  }
  etcd3 {
    serverAddr = "http://localhost:2379"
  }
  file {
      #由于选择了file,所以这里生效了
    name = "file.conf"
  }
}

所以接下来看一下file.conf文件

## transaction log store, only used in seata-server
store {
  ## store mode: file、db
    #选择配置中心的存储模式,由于选择file存到文件里(性能高)会变为二进制流不好观察,所以选择数据库
     #复制之后一定要改一改
  mode = "db"

  ## file store property
  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
  db {
      #选择了数据库必定要做出一些配置,数据库里一定要有这3张表
    ## 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://192.168.206.99:3306/seata"
    user = "root"
    password = "root"
    minConn = 1
    maxConn = 10
    globalTable = "global_table"
    branchTable = "branch_table"
    lockTable = "lock_table"
    queryLimit = 100
  }
}

建表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;

1.3 启动

如果是linux环境(要有JRE),执行seata-server.sh

如果是windows环境,执行seata-server.bat

 

 

2 改造微服务

只要是需要用到seata(分布式事务)的服务,都要做类似的配置.

 

2.1 引入依赖

我这里是springboot项目,所以我先在父pom中声明了.如下

    <properties>    
        <alibaba.seata.version>2.1.0.RELEASE</alibaba.seata.version>
        <seata.version>1.1.0</seata.version>
    </properties>

    <dependencyManagement>
        <dependencies>
            <!--seata-->
            <dependency>
                <groupId>com.alibaba.cloud</groupId>
                <artifactId>spring-cloud-alibaba-seata</artifactId>
                <version>${alibaba.seata.version}</version>
                <exclusions>
                    <exclusion>
                        <artifactId>seata-all</artifactId>
                        <groupId>io.seata</groupId>
                    </exclusion>
                </exclusions>
            </dependency>
            <dependency>
                <artifactId>seata-all</artifactId>
                <groupId>io.seata</groupId>
                <version>${seata.version}</version>
            </dependency>
        </dependencies>
    </dependencyManagement>

接下来只要在需要seata的微服务里添加依赖就好了.

<dependency>
    <groupId>com.alibaba.cloud</groupId>
    <artifactId>spring-cloud-alibaba-seata</artifactId>
</dependency>
<dependency>
    <groupId>io.seata</groupId>
    <artifactId>seata-all</artifactId>
</dependency>

 

2.2 添加配置

spring:
  cloud:
    alibaba:
      seata:
        tx-service-group: test_tx_group # 定义事务组的名称

 

2.3 在resources目录下添加2个文件file.confregistry.conf

registry.conf和前面的一样,直接复制过来就好.

file.conf里的内容不同了,新的内容如下:

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 {
#这里注意,等号前后都是配置,前面是yml里配置的事务组,后面是register.conf里定义的seata-server
vgroupMapping.test_tx_group = "seata_tc_server"
#only support when registry.type=file, please don't set multiple addresses
seata_tc_server.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
}
}

配置解读:

  • transport:与TC交互的一些配置

    • heartbeat:client和server通信心跳检测开关

    • enableClientBatchSendRequest:客户端事务消息请求是否批量合并发送

  • service:TC的地址配置,用于获取TC的地址

    • vgroupMapping.test_tx_group = "seata_tc_server"

      • test_tx_group:是事务组名称,要与application.yml中配置一致,

      • seata_tc_server:是TC服务端集群的名称,将来通过注册中心获取TC地址

      • enableDegrade:服务降级开关,默认关闭。如果开启,当业务重试多次失败后会放弃全局事务

      • disableGlobalTransaction:全局事务开关,默认false。false为开启,true为关闭

    • default.grouplist:这个当注册中心为file的时候,才用到

  • client:客户端配置

    • rm:资源管理器配

      • asynCommitBufferLimit:二阶段提交默认是异步执行,这里指定异步队列的大小

      • lock:全局锁配置

        • retryInterval:校验或占用全局锁重试间隔,默认10,单位毫秒

        • retryTimes:校验或占用全局锁重试次数,默认30次

        • retryPolicyBranchRollbackOnConflict:分支事务与其它全局回滚事务冲突时锁策略,默认true,优先释放本地锁让回滚成功

      • reportRetryCount:一阶段结果上报TC失败后重试次数,默认5次

    • tm:事务管理器配置

      • commitRetryCount:一阶段全局提交结果上报TC重试次数,默认1

      • rollbackRetryCount:一阶段全局回滚结果上报TC重试次数,默认1

    • undo:undo_log的配置

      • dataValidation:是否开启二阶段回滚镜像校验,默认true

      • logSerialization:undo序列化方式,默认Jackson

      • logTable:自定义undo表名,默认是undo_log

    • log:日志配置

      • exceptionRate:出现回滚异常时的日志记录频率,默认100,百分之一概率。回滚失败基本是脏数据,无需输出堆栈占用硬盘空间

 

 

2.4 代理DataSource

由于在一阶段是通过拦截sql分析语义来生成回滚策略,原来的数据源已经不够用了,得换个牛逼的.在服务里新建一个配置类.

  • 如果是使用的是mybatis

import io.seata.rm.datasource.DataSourceProxy;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import javax.sql.DataSource;

@Configuration
public class DataSourceProxyConfig {

    @Bean
    public SqlSessionFactory sqlSessionFactoryBean(DataSource dataSource) throws Exception {
        // 因为使用的是mybatis,这里定义SqlSessionFactoryBean
        SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
        // 配置数据源代理
        sqlSessionFactoryBean.setDataSource(new DataSourceProxy(dataSource));
        return sqlSessionFactoryBean.getObject();
    }
}

  

如果使用的是mybatis-plus

 

import com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean;
import io.seata.rm.datasource.DataSourceProxy;
import org.apache.ibatis.session.SqlSessionFactory;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import javax.sql.DataSource;

@Configuration
public class DataSourceProxyConfig {

    @Bean
    public SqlSessionFactory sqlSessionFactoryBean(DataSource dataSource) throws Exception {
        // 订单服务中引入了mybatis-plus,所以要使用特殊的SqlSessionFactoryBean
        MybatisSqlSessionFactoryBean sqlSessionFactoryBean = new MybatisSqlSessionFactoryBean();
        // 代理数据源
        sqlSessionFactoryBean.setDataSource(new DataSourceProxy(dataSource));
        // 生成SqlSessionFactory
        return sqlSessionFactoryBean.getObject();
    }
}

 

2.5 加上注解

给事务发起者的方法上加上@GlobalTransactional即可,其它的参与者只要加@Transactional就好了.

 

 

3.踩坑记录

1.由于更换了数据源,不知道为什么我在yml里给mybatis配置的驼峰映射失效了,导致我查到的数据缺少了某些字段.不知道这个问题在mybatis-plus中会不会出现.

解决办法:单独给数据源配置映射规则就好了.所以我把上面的配置类加了一个设置,修改后的代码如下.

import io.seata.rm.datasource.DataSourceProxy;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import javax.sql.DataSource;

@Configuration
public class DataSourceProxyConfig {

    @Bean
    public SqlSessionFactory sqlSessionFactoryBean(DataSource dataSource) throws Exception {
        // 因为使用的是mybatis,这里定义SqlSessionFactoryBean
        SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
        // 配置数据源代理
        sqlSessionFactoryBean.setDataSource(new DataSourceProxy(dataSource));
        SqlSessionFactory object = sqlSessionFactoryBean.getObject();
        assert object != null;
     // 单独给数据源设置驼峰映射 object.getConfiguration().setMapUnderscoreToCamelCase(
true); return object; } }

 

posted @ 2020-11-28 23:00  重生之我是程序员  阅读(7650)  评论(0编辑  收藏  举报