主要示例为官网的例子,把官网关于springcloud集成eureka的模块独立出来了,排除一些其他示例项目的干扰,我们先看seata的概念:
Seata 是一款开源的分布式事务解决方案,致力于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。 —— 引用自 SEATA 官方文档
接下来来看集成seata要做些什么工作:
1、引入seata相关包。
<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>
</dependency>
2、配置yml,registry.conf 及 file.conf信息,其中registry.conf 及 file.conf对于后续要运行的seata server的配置也是一样的,也就是说seata server和被管理的事务项目工程都使用相同的配置,它们三个放在同一位置下:
具体配置信息如下所示:
yml:
logging.level.io.seata: debug
spring.cloud.alibaba.seata.tx-service-group: my_test_tx_group
registry.conf,特别注意registry.eureka.application的值,要与file.conf的server.vgroupMapping.my_test_tx_group保持一致:
registry {
# 注册方式,如file 、nacos 、eureka、redis、zk、consul、etcd3、sofa,我们这里选择eureka
type = "eureka"
nacos {
serverAddr = "localhost"
namespace = ""
cluster = "default"
}
eureka {
# 要注册的eureka地址,这里为本地
serviceUrl = "http://localhost:8761/eureka"
# 要连接的seata server的服务名
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 {
# 配置文件读取方式,可选file、nacos 、apollo、zk、consul、etcd3、springCloudConfig,这里我们选择本地文件的方式file,就会读取file.conf文件。
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"
}
}
file.conf,特别注意server下的vgroupMapping.xxx配置后面的xxx要与yml配置中的spring.cloud.alibaba.seata.tx-service-group一致,配置的值要与regiester.conf里的registry节点下的eureka下的application保持一致:
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 {
#此处的vgroupMapping.xxx配置后面的xxx要与yml配置中的spring.cloud.alibaba.seata.tx-service-group一致,配置的值要与regiester.conf里的registry节点下的eureka下的application保持一致。
vgroupMapping.my_test_tx_group = "default"
#当注册类型为file文件时配置,不要输入多个地址,此处的地址为seata server的监听地址(seata server也有相同配置)
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
reportSuccessEnable = false
}
tm {
commitRetryCount = 5
rollbackRetryCount = 5
}
undo {
dataValidation = true
logSerialization = "jackson"
logTable = "undo_log"
}
log {
exceptionRate = 100
}
}
3、在各服务数据库中增加 undo_log 表
建表语句可从 SEATA 发布版中获得,如
https://github.com/seata/seata/blob/v1.0.0/script/client/at/db/mysql.sql
我这版用的是:
CREATE TABLE `undo_log` (
`id` bigint(20) NOT NULL AUTO_INCREMENT,
`branch_id` bigint(20) NOT NULL,
`xid` varchar(100) NOT NULL,
`context` varchar(128) NOT NULL,
`rollback_info` longblob NOT NULL,
`log_status` int(11) NOT NULL,
`log_created` datetime NOT NULL,
`log_modified` datetime NOT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `ux_undo_log` (`xid`,`branch_id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;
4、添加全局事务注解在 controller 或者 service 上,标记 @GlobalTransactional 注解。
接下来我们使用springcloud-eureka-seata例子来看一下实际效果,具体代码最后会贴出来:
1、首先先执行一下业务脚本sql:
CREATE TABLE `account_tbl` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`user_id` varchar(255) DEFAULT NULL,
`money` int(11) DEFAULT '0',
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;
CREATE TABLE `storage_tbl` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`commodity_code` varchar(255) DEFAULT NULL,
`count` int(11) DEFAULT '0',
PRIMARY KEY (`id`),
UNIQUE KEY `commodity_code` (`commodity_code`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;
CREATE TABLE `order_tbl` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`user_id` varchar(255) DEFAULT NULL,
`commodity_code` varchar(255) DEFAULT NULL,
`count` int(11) DEFAULT '0',
`money` int(11) DEFAULT '0',
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;
CREATE TABLE `undo_log` (
`id` bigint(20) NOT NULL AUTO_INCREMENT,
`branch_id` bigint(20) NOT NULL,
`xid` varchar(100) NOT NULL,
`context` varchar(128) NOT NULL,
`rollback_info` longblob NOT NULL,
`log_status` int(11) NOT NULL,
`log_created` datetime NOT NULL,
`log_modified` datetime NOT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `ux_undo_log` (`xid`,`branch_id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;
2、启动eureka
3、下载seata server,下载地址下载后修改seata\conf下的file.conf、registry.conf配置为上面讲到的配置,然后进入seata\bin,双击seata-server.bat启动server服务:
看到这信息则表示启动无报错,再看eureka是否已注册成功:
注册成功!
4、再依次启动工程中的剩余四个模块,order、account、storage、business,启动后如下图所示:
准备工作已经就绪,接下来对例子说明一下,此例子主要模拟下单减库存的操作,拥有账户表,订单表,库存表三张表,并在business模块的controller里提供了两个接口,
一个为正常下单接口,每次扣取30库存:
另一个为模拟全局事务回滚,一次性扣取9999库存:
而purchase方法的下单逻辑为
1、先减库存
2、再创建订单信息(先下单,再扣用户账户钱)
3、校验用户账户是否没钱,库存是否不够,一旦两个条件任意一个满足,则抛出异常让@GlobalTransactional注解修饰的purchase方法感知,从而让全局事务进行回滚。相关代码如下所示:
下面测试一下:
先调用正常扣取接口:http://localhost:8084/purchase/commit
得到结果:
用户账户表
扣除前:
扣扣除后
订单表
扣除前:无
扣除后
库存表
扣除前:
扣除后
再调用模拟全局事务回滚的接口:http://localhost:8084/purchase/rollback
,发现结果还是跟调用前一样,表示事务回滚成功!
具体代码例子:github地址