一、分布式事务问题二、Seata简介三、Seata的部署
3.1 Seata Server端配置
3.1.1 修改配置文件3.1.2 MySQL 数据库配置3.1.3 启动Seata Server端 3.2 Seata Client 客户端配置
3.2.1 业务前置准备3.2.2 创建undo_log表3.2.3 Seata Client配置文件3.2.4 pom.xml文件3.2.5 application.yml文件3.2.6 业务代码编写：加@GlobalTransactional3.2.7 config代码编写3.2.8 主启动类 3.3 测试
一、分布式事务问题一次业务操作需要跨多个数据源或者需要跨多个系统进行远程调用，就会产生分布式事务问题。
举例：
用户购买商品的业务逻辑。整个业务逻辑由3个微服务提供支持：
仓储服务：对给定的商品扣除仓储数量。订单服务：根据采购需求创建订单。帐户服务：从用户帐户中扣除余额。
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完成。此时每个服务内部的数据一致性由本地事务来保证，但是全局数据一致性问题是无法保证的。
二、Seata简介Seata官网地址：http://seata.io/zh-cn/
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 将为用户提供了 AT、TCC、SAGA 和 XA 事务模式，为用户打造一站式的分布式解决方案。
Seata术语：
TC (Transaction Coordinator) - 事务协调者
维护全局和分支事务的状态，驱动全局事务提交或回滚。
TM (Transaction Manager) - 事务管理器
定义全局事务的范围：开始全局事务、提交或回滚全局事务。
RM (Resource Manager) - 资源管理器
管理分支事务处理的资源，与TC交谈以注册分支事务和报告分支事务的状态，并驱动分支事务提交或回滚。
Seata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者回滚请求
Seata的版本选择： Spring Cloud Alibaba与Spring Boot、Spring Cloud版本对应关系
官网版本说明
本次使用：Seata 1.2.0
3.1 Seata Server端配置官方配置文档：Seata部署指南
下载seata-server-1.2.0和seata-1.2.0源码
seate-server下载： https://seata.io/zh-cn/blog/download.htmlseata-1.2.0源码下载： https://github.com/seata/seata/releases 3.1.1 修改配置文件
解压后，进入 conf 目录开始参数的配置。我们修改 file.conf 和 registry.conf 这两个文件。
1、进入conf文件夹，修改file.conf文件
2、修改registry.conf文件
如果config设置成了file，则不需要网上的设置nacos的配置
3.1.2 MySQL 数据库配置我们先创建数据库seata（数据库要与file.conf中db设置那里对应），数据库的建表语句在README文件的server连接中
让后执行mysql.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(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;
3.1.3 启动Seata Server端
3.2 Seata Client 客户端配置
3.2.1 业务前置准备
业务场景：用户购买商品的业务逻辑。整个业务逻辑由3个微服务提供支持：
用户A购买商品，调用 A服务 创建订单完成，调用 B服务 扣减库存，然后调用 C服务 扣减账户余额。每个服务内部的数据一致性由本地事务来保证，多个服务调用来完成业务，全局事务数据一致性则由 Seata 来保证。
订单服务A：根据采购需求创建订单。
仓储服务B：对给定的商品扣除仓储数量。
帐户服务C：从用户帐户中扣除余额。
**业务数据库准备：**配置三个业务分别对应各自的数据库。
A服务 对应数据库：seata_order ；表：t_orderB服务 对应数据库：seata_storage ；表：t_storageC服务 对应数据库：seata_account ；表：t_account
建表语句：
# 创建seata_order数据库
CREATE DATAbase seata_order;
# 创建t_order表
CREATE TABLE seata_order.t_order(
`id` BIGINT(11) NOT NULL AUTO_INCREMENT PRIMARY KEY,
`user_id` BIGINT(11) DEFAULT NULL COMMENT '用户id',
`product_id` BIGINT(11) DEFAULT NULL COMMENT '产品id',
`count` INT(11) DEFAULT NULL COMMENT '数量',
`money` DECIMAL(11,0) DEFAULT NULL COMMENT '金额',
`status` INT(1) DEFAULT NULL COMMENT '订单状态：0：创建中; 1：已完结'
) ENGINE=INNODB AUTO_INCREMENT=7 DEFAULT CHARSET=utf8;
# 创建seata_storage数据库
CREATE DATAbase seata_storage;
# 创建t_storage表
CREATE TABLE seata_storage.t_storage(
`id` BIGINT(11) NOT NULL AUTO_INCREMENT PRIMARY KEY,
`product_id` BIGINT(11) DEFAULT NULL COMMENT '产品id',
`total` INT(11) DEFAULT NULL COMMENT '总库存',
`used` INT(11) DEFAULT NULL COMMENT '已用库存',
`residue` INT(11) DEFAULT NULL COMMENT '剩余库存'
) ENGINE=INNODB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8;
# 插入一条数据
INSERT INTO seata_storage.t_storage(`id`,`product_id`,`total`,`used`,`residue`)
VALUES('1','1','100','0','100');
# 创建seata_account数据库
CREATE DATAbase seata_account;
# 创建t_account表
CREATE TABLE seata_account.t_account(
`id` BIGINT(11) NOT NULL AUTO_INCREMENT PRIMARY KEY COMMENT 'id',
`user_id` BIGINT(11) DEFAULT NULL COMMENT '用户id',
`total` DECIMAL(10,0) DEFAULT NULL COMMENT '总额度',
`used` DECIMAL(10,0) DEFAULT NULL COMMENT '已用余额',
`residue` DECIMAL(10,0) DEFAULT '0' COMMENT '剩余可用额度'
) ENGINE=INNODB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8;
# 插入一条数据
INSERT INTO seata_account.t_account(`id`,`user_id`,`total`,`used`,`residue`) VALUES('1','1','1000','0','1000');
3.2.2 创建undo_log表
按照上述3库分别建对应的回滚日志表，建表文件在README_ZH文件中的client中
undo_log表建表语句如下：
-- 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`
(
`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
AUTO_INCREMENT = 1
DEFAULT CHARSET = utf8 COMMENT ='AT transaction mode undo table';
完成图示：
3.2.3 Seata Client配置文件以下配置以seata-order-service2001为例
项目结构：
配置文件的编写参考README_ZH文件中的client中：
1、file.conf，修改这一处
transport {
# tcp, unix-domain-socket
type = "TCP"
#NIO, NATIVE
server = "NIO"
#enable heartbeat
heartbeat = true
# the tm client batch send request enable
enableTmClientBatchSendRequest = false
# the rm client batch send request enable
enableRmClientBatchSendRequest = true
# the rm client rpc request timeout
rpcRmRequestTimeout = 2000
# the tm client rpc request timeout
rpcTmRequestTimeout = 10000
# the tc client rpc request timeout
rpcTcRequestTimeout = 5000
#thread factory for netty
threadFactory {
bossThreadPrefix = "NettyBoss"
workerThreadPrefix = "NettyServerNIOWorker"
serverExecutorThread-prefix = "NettyServerBizHandler"
shareBossWorker = false
clientSelectorThreadPrefix = "NettyClientSelector"
clientSelectorThreadSize = 1
clientWorkerThreadPrefix = "NettyClientWorkerThread"
# netty boss thread size
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.my_test_tx_group = "default"
#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 {
rm {
asyncCommitBufferLimit = 10000
lock {
retryInterval = 10
retryTimes = 30
retryPolicyBranchRollbackonConflict = true
}
reportRetryCount = 5
tablemetaCheckEnable = false
tablemetaCheckerInterval = 60000
reportSuccessEnable = false
sagaBranchRegisterEnable = false
sagaJsonParser = "fastjson"
sagaRetryPersistModeUpdate = false
sagaCompensatePersistModeUpdate = false
tccActionInterceptorOrder = -2147482648 #Ordered.HIGHEST_PRECEDENCE + 1000
}
tm {
commitRetryCount = 5
rollbackRetryCount = 5
defaultGlobalTransactionTimeout = 60000
degradeCheck = false
degradeCheckPeriod = 2000
degradeCheckAllowTimes = 10
interceptorOrder = -2147482648 #Ordered.HIGHEST_PRECEDENCE + 1000
}
undo {
dataValidation = true
onlyCareUpdateColumns = true
logSerialization = "jackson"
logTable = "undo_log"
compress {
enable = true
# allow zip, gzip, deflater, 7z, lz4, bzip2, zstd default is zip
type = zip
# if rollback info size > threshold, then will be compress
# allow k m g t
threshold = 64k
}
}
loadBalance {
type = "RandomLoadBalance"
virtualNodes = 10
}
}
log {
exceptionRate = 100
}
tcc {
fence {
# tcc fence log table name
logTableName = tcc_fence_log
# tcc fence log clean period
cleanPeriod = 1h
}
}
2、registry.conf，修改这一处
registry {
# file 、nacos 、eureka、redis、zk、consul、etcd3、sofa、custom
type = "nacos"
nacos {
application = "seata-server"
serverAddr = "127.0.0.1:8848"
namespace = ""
username = ""
password = ""
##if use MSE Nacos with auth, mutex with username/password attribute
#accessKey = ""
#secretKey = ""
}
eureka {
serviceUrl = "http://localhost:8761/eureka"
weight = "1"
}
redis {
serverAddr = "localhost:6379"
db = "0"
password = ""
timeout = "0"
}
zk {
serverAddr = "127.0.0.1:2181"
sessionTimeout = 6000
connectTimeout = 2000
username = ""
password = ""
}
consul {
serverAddr = "127.0.0.1:8500"
aclToken = ""
}
etcd3 {
serverAddr = "http://localhost:2379"
}
sofa {
serverAddr = "127.0.0.1:9603"
region = "DEFAULT_ZONE"
datacenter = "DefaultDataCenter"
group = "SEATA_GROUP"
addressWaitTime = "3000"
}
file {
name = "file.conf"
}
custom {
name = ""
}
}
config {
# file、nacos 、apollo、zk、consul、etcd3、springCloudConfig、custom
type = "file"
nacos {
serverAddr = "127.0.0.1:8848"
namespace = ""
group = "SEATA_GROUP"
username = ""
password = ""
##if use MSE Nacos with auth, mutex with username/password attribute
#accessKey = ""
#secretKey = ""
dataId = "seata.properties"
}
consul {
serverAddr = "127.0.0.1:8500"
key = "seata.properties"
aclToken = ""
}
apollo {
appId = "seata-server"
apollometa = "http://192.168.1.204:8801"
namespace = "application"
apolloAccesskeySecret = ""
}
zk {
serverAddr = "127.0.0.1:2181"
sessionTimeout = 6000
connectTimeout = 2000
username = ""
password = ""
nodePath = "/seata/seata.properties"
}
etcd3 {
serverAddr = "http://localhost:2379"
key = "seata.properties"
}
file {
name = "file.conf"
}
custom {
name = ""
}
}
3.2.4 pom.xml文件
3.2.5 application.yml文件com.alibaba.cloud spring-cloud-starter-alibaba-nacos-discovery com.alibaba.cloud spring-cloud-starter-alibaba-seata seata-all io.seata io.seata seata-all 1.2.0 org.springframework.cloud spring-cloud-starter-openfeign org.springframework.boot spring-boot-starter-web org.springframework.boot spring-boot-starter-actuator mysql mysql-connector-java 5.1.37 com.alibaba druid-spring-boot-starter 1.1.10 org.mybatis.spring.boot mybatis-spring-boot-starter 2.0.0 org.springframework.boot spring-boot-starter-test test org.projectlombok lombok true
server:
port: 2001
spring:
application:
name: seata-order-service
cloud:
alibaba:
seata:
# 自定义事务组名称需要与seata-server中的对应
tx-service-group: my_test_tx_group #因为seata的file.conf文件中没有service模块，事务组名默认为my_test_tx_group
#service要与tx-service-group对齐，vgroupMapping和grouplist在service的下一级，my_test_tx_group在再下一级
service:
vgroupMapping:
#要和tx-service-group的值一致
my_test_tx_group: default
grouplist:
# seata seaver的 地址配置，此处可以集群配置是个数组
default: 127.0.0.1:8091
nacos:
discovery:
server-addr: localhost:8848
datasource:
driver-class-name: com.mysql.jdbc.Driver
url: jdbc:mysql://localhost:3306/seata_order?useUnicode=true&characterEncoding=UTF-8&useSSL=false&serverTimezone=GMT%2B8
username: root
password: root
feign:
hystrix:
enabled: false
logging:
level:
io:
seata:
mybatis:
mapperLocations: classpath:mapper/*.xml
3.2.6 业务代码编写：加@GlobalTransactional
dao层、mapper层、controller层代码省略
业务代码使用OpenFeign 的方式进行服务间的调用，来实现一个简单的业务功能。AT模式只用一个 @GlobalTransactional 注解即可实现分布式事务。name 属性为事务唯一性表示，可以随意定义。rollbackFor 属性为指定Exception异常才进行事务回滚。
OrderServiceImpl.java
@Service
@Slf4j
public class OrderServiceImpl implements OrderService {
@Resource
private OrderDao orderDao;
@Resource
private StorageService storageService;
@Resource
private AccountService accountService;
@Override
@GlobalTransactional(name = "fsp-create-order",rollbackFor = Exception.class)
public void create(Order order) {
log.info("------->下单开始");
//本应用创建订单
orderDao.create(order);
//远程调用库存服务扣减库存
log.info("------->order-service中扣减库存开始");
storageService.decrease(order.getProductId(),order.getCount());
log.info("------->order-service中扣减库存结束");
//远程调用账户服务扣减余额
log.info("------->order-service中扣减余额开始");
accountService.decrease(order.getUserId(),order.getMoney());
log.info("------->order-service中扣减余额结束");
//修改订单状态为已完成
log.info("------->order-service中修改订单状态开始");
orderDao.update(order.getUserId(),0);
log.info("------->order-service中修改订单状态结束");
log.info("------->下单结束");
}
}
3.2.7 config代码编写
1、MybatisConfig.java
@Configuration
@MapperScan({"com.zb.springcloud.dao"})
public class MyBatisConfig {
}
2、DataSourceProxyConfig.java
package com.zb.springcloud.config;
import com.alibaba.druid.pool.DruidDataSource;
import io.seata.rm.datasource.DataSourceProxy;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.transaction.SpringManagedTransactionFactory;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import javax.sql.DataSource;
@Configuration
public class DataSourceProxyConfig {
@Value("${mybatis.mapperLocations}")
private String mapperLocations;
@Bean
@ConfigurationProperties(prefix = "spring.datasource")
public DataSource druidDataSource(){
return new DruidDataSource();
}
@Bean
public DataSourceProxy dataSourceProxy(DataSource dataSource) {
return new DataSourceProxy(dataSource);
}
@Bean
public SqlSessionFactory sqlSessionFactoryBean(DataSourceProxy dataSourceProxy) throws Exception {
SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
sqlSessionFactoryBean.setDataSource(dataSourceProxy);
sqlSessionFactoryBean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources(mapperLocations));
sqlSessionFactoryBean.setTransactionFactory(new SpringManagedTransactionFactory());
return sqlSessionFactoryBean.getObject();
}
}
3.2.8 主启动类
@EnableDiscoveryClient
@EnableFeignClients
@SpringBootApplication(exclude = DataSourceAutoConfiguration.class)//取消数据源的自动创建
public class SeataOrderMainApp2001 {
public static void main(String[] args)
{
SpringApplication.run(SeataOrderMainApp2001.class, args);
}
}
3.3 测试
分别启三个服务，可以看到在项目启动过程中，Seata Sever 服务端会有相对应提示
发送请求 http://localhost:2001/order/create?userId=1&productId=1&count=10&money=100 来模拟下单请求。发送多次请求，可以看到下单都成功了，Seata Server 端也有事务在进行处理的过程。（此时数据库中，因为事务处理完成，并没有任何数据）
参考博客：
Spring Cloud Alibabaseata 分布式事务解决方案简介
SpringCloud 整合Seata 解决分布式事务
