seata分布式事务讲解，SpringBoot项目整合seata全流程和常见错误解决
在项目中，常用的@Transactional事务注解属于本地事务，在分布式系统中，只能控制住自己服务的回滚，控制不了其它服务的回滚。
聊聊本地分布式事务
一个请求链路中包含多个服务，某一个服务出现了异常，所有服务对数据库的操作都必须回滚，这样才不会出现什么问题。
Spring Cloud Alibaba Seata 分布式事务
Seata控制分布式事务
1、每一个微服务对应的数据库必须先创建undo_log表
-- 注意此处0.3.0+ 增加唯一索引 ux_undo_log
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,
`ext` VARCHAR(100) DEFAULT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `ux_undo_log` (`xid`,`branch_id`)
) ENGINE=INNODB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;2、安装事务协调器：seata-server：Releases · seata/seata · GitHub
3、Spring Boot整合Spring Cloud Alibaba seata
首先导入maven依赖
com.alibaba.cloud spring-cloud-starter-alibaba-seata
然后查看导入的seata依赖是什么版本
去 Releases · seata/seata · GitHub 下载对应版本
下载完成后解压
registry.conf：注册中心相关配置
registry {
# file 、nacos 、eureka、redis、zk、consul、etcd3、sofa 指定注册中心
type = "nacos"
nacos {
serverAddr = "localhost:8848"
namespace = "public"
cluster = "default"
}
eureka {
serviceUrl = "http://localhost:1001/eureka"
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"
}
}
config {
# file、nacos 、apollo、zk、consul、etcd3 指定seata的配置都在哪里
type = "file"
nacos {
serverAddr = "localhost"
namespace = "public"
cluster = "default"
}
consul {
serverAddr = "127.0.0.1:8500"
}
apollo {
app.id = "seata-server"
apollo.meta = "http://192.168.1.204:8801"
}
zk {
serverAddr = "127.0.0.1:2181"
session.timeout = 6000
connect.timeout = 2000
}
etcd3 {
serverAddr = "http://localhost:2379"
}
file {
name = "file.conf"
}
}
file.conf ：事务日志存储位置
transport {
# tcp udt unix-domain-socket
type = "TCP"
#NIO NATIVE
server = "NIO"
#enable heartbeat
heartbeat = true
#thread factory for netty
thread-factory {
boss-thread-prefix = "NettyBoss"
worker-thread-prefix = "NettyServerNIOWorker"
server-executor-thread-prefix = "NettyServerBizHandler"
share-boss-worker = false
client-selector-thread-prefix = "NettyClientSelector"
client-selector-thread-size = 1
client-worker-thread-prefix = "NettyClientWorkerThread"
# netty boss thread size,will not be used for UDT
boss-thread-size = 1
#auto default pin or 8
worker-thread-size = 8
}
shutdown {
# when destroy server, wait seconds
wait = 3
}
serialization = "seata"
compressor = "none"
}
service {
#vgroup->rgroup
vgroup_mapping.my_test_tx_group = "default"
#only support single node
default.grouplist = "127.0.0.1:8091"
#degrade current not support
enableDegrade = false
#disable
disable = false
#unit ms,s,m,h,d represents milliseconds, seconds, minutes, hours, days, default permanent
max.commit.retry.timeout = "-1"
max.rollback.retry.timeout = "-1"
}
client {
async.commit.buffer.limit = 10000
lock {
retry.internal = 10
retry.times = 30
}
report.retry.count = 5
}
## transaction log store 事务日志存储在哪里
store {
## store mode: file、db
mode = "file"
## file store
file {
dir = "sessionStore"
# branch session size , if exceeded first try compress lockkey, still exceeded throws exceptions
max-branch-session-size = 16384
# globe session size , if exceeded throws exceptions
max-global-session-size = 512
# file buffer size , if exceeded allocate new buffer
file-write-buffer-cache-size = 16384
# when recover batch read size
session.reload.read_size = 100
# async, sync
flush-disk-mode = async
}
## database store
db {
## the implement of javax.sql.DataSource, such as DruidDataSource(druid)/BasicDataSource(dbcp) etc.
datasource = "dbcp"
## mysql/oracle/h2/oceanbase etc.
db-type = "mysql"
url = "jdbc:mysql://127.0.0.1:3306/seata"
user = "root"
password = "123456"
min-conn = 1
max-conn = 3
global.table = "global_table"
branch.table = "branch_table"
lock-table = "lock_table"
query-limit = 100
}
}
lock {
## the lock store mode: local、remote
mode = "remote"
local {
## store locks in user's database
}
remote {
## store locks in the seata's server
}
}
recovery {
committing-retry-delay = 30
asyn-committing-retry-delay = 30
rollbacking-retry-delay = 30
timeout-retry-delay = 30
}
transaction {
undo.data.validation = true
undo.log.serialization = "jackson"
}
## metrics settings
metrics {
enabled = false
registry-type = "compact"
# multi exporters use comma divided
exporter-list = "prometheus"
exporter-prometheus-port = 9898
}运行seata
nacos上seata服务上线，表示启动成功
可以开始撸分布式事务代码了，但是撸代码之前还要配置一些东西
所有想要用到分布式事务的微服务都要使用seata DataSourceProxy代理自己的数据源
将MySeataConfig.class放在各个服务中
@Configuration
public class MySeataConfig {
@Autowired
DataSourceProperties dataSourceProperties;
@Bean
public DataSource dataSource(DataSourceProperties dataSourceProperties){
HikariDataSource dataSource = dataSourceProperties.initializeDataSourceBuilder().type(HikariDataSource.class).build();
if(StringUtils.hasText(dataSourceProperties.getName())){
dataSource.setPoolName(dataSourceProperties.getName());
}
return new DataSourceProxy(dataSource);
}
}
将file.conf和registry.conf复制到各个服务的resources下
file.conf
transport {
# tcp udt unix-domain-socket
type = "TCP"
#NIO NATIVE
server = "NIO"
#enable heartbeat
heartbeat = true
#thread factory for netty
thread-factory {
boss-thread-prefix = "NettyBoss"
worker-thread-prefix = "NettyServerNIOWorker"
server-executor-thread-prefix = "NettyServerBizHandler"
share-boss-worker = false
client-selector-thread-prefix = "NettyClientSelector"
client-selector-thread-size = 1
client-worker-thread-prefix = "NettyClientWorkerThread"
# netty boss thread size,will not be used for UDT
boss-thread-size = 1
#auto default pin or 8
worker-thread-size = 8
}
shutdown {
# when destroy server, wait seconds
wait = 3
}
serialization = "seata"
compressor = "none"
}
service {
#vgroup->rgroup
vgroup_mapping.gulimall-order-fescar-service-group = "default"
#only support single node
default.grouplist = "127.0.0.1:8091"
#degrade current not support
enableDegrade = false
#disable
disable = false
#unit ms,s,m,h,d represents milliseconds, seconds, minutes, hours, days, default permanent
max.commit.retry.timeout = "-1"
max.rollback.retry.timeout = "-1"
}
client {
async.commit.buffer.limit = 10000
lock {
retry.internal = 10
retry.times = 30
}
report.retry.count = 5
}
## transaction log store 事务日志存储在哪里
store {
## store mode: file、db
mode = "file"
## file store
file {
dir = "sessionStore"
# branch session size , if exceeded first try compress lockkey, still exceeded throws exceptions
max-branch-session-size = 16384
# globe session size , if exceeded throws exceptions
max-global-session-size = 512
# file buffer size , if exceeded allocate new buffer
file-write-buffer-cache-size = 16384
# when recover batch read size
session.reload.read_size = 100
# async, sync
flush-disk-mode = async
}
## database store
db {
## the implement of javax.sql.DataSource, such as DruidDataSource(druid)/BasicDataSource(dbcp) etc.
datasource = "dbcp"
## mysql/oracle/h2/oceanbase etc.
db-type = "mysql"
url = "jdbc:mysql://127.0.0.1:3306/seata"
user = "root"
password = "123456"
min-conn = 1
max-conn = 3
global.table = "global_table"
branch.table = "branch_table"
lock-table = "lock_table"
query-limit = 100
}
}
lock {
## the lock store mode: local、remote
mode = "remote"
local {
## store locks in user's database
}
remote {
## store locks in the seata's server
}
}
recovery {
committing-retry-delay = 30
asyn-committing-retry-delay = 30
rollbacking-retry-delay = 30
timeout-retry-delay = 30
}
transaction {
undo.data.validation = true
undo.log.serialization = "jackson"
}
## metrics settings
metrics {
enabled = false
registry-type = "compact"
# multi exporters use comma divided
exporter-list = "prometheus"
exporter-prometheus-port = 9898
}
registry.conf
registry {
# file 、nacos 、eureka、redis、zk、consul、etcd3、sofa 指定注册中心
type = "nacos"
nacos {
application = "seata-server"
serverAddr = "localhost:8848"
namespace = "public"
cluster = "default"
}
eureka {
serviceUrl = "http://localhost:1001/eureka"
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"
}
}
config {
# file、nacos 、apollo、zk、consul、etcd3 指定seata的配置都在哪里
type = "file"
nacos {
serverAddr = "localhost"
namespace = "public"
cluster = "default"
}
consul {
serverAddr = "127.0.0.1:8500"
}
apollo {
app.id = "seata-server"
apollo.meta = "http://192.168.1.204:8801"
}
zk {
serverAddr = "127.0.0.1:2181"
session.timeout = 6000
connect.timeout = 2000
}
etcd3 {
serverAddr = "http://localhost:2379"
}
file {
name = "file.conf"
}
}
file.conf里需要更改一个配置
启动类要加上@EnableAspectJAutoProxy(exposeProxy = true)
@EnableAspectJAutoProxy(exposeProxy = true)
@MapperScan("com.atguigu.gulimall.order.dao")
@EnableRabbit
@SpringBootApplication
@EnableRedisHttpSession
@EnableFeignClients(basePackages = "com.atguigu.gulimall.order.feign")
@EnableDiscoveryClient
public class GulimallOrderApplication {
public static void main(String[] args) {
SpringApplication.run(GulimallOrderApplication.class, args);
}
@Bean
public Logger.Level logger(){
return Logger.Level.FULL;
}
}
开始撸代码了，给分布式大事务入口处标注@GlobalTransactional全局事务注解
order服务的下单接口submitOrder 标上@GlobalTransactional全局事务注解
每一个远程的小事务用 @Transactional即可
仓库服务的锁定库存接口orderLockStock使用@Transactional事务注解
手动制造错误抛出异常
总结
业务场景是订单服务去库存服务中锁定对应订单的商品库存，库存锁定成功了，但是order服务报错了，这时候是需要库存服务和order服务都要回滚的，经过测试确实回滚成功了，seata真牛！
bug总结
在整合当中出现了几个bug，解决花了很多时间，很痛苦，在这里记录一下
问题一：
seata 0.7.1 不能使用MyBatis-Plus的saveBatch只能遍历一个List一个一个save到表中，这应该知识 0.7.1的Bug，后续高版本应该解决了
问题二：
报错信息：io.seata.common.exception.FrameworkException: can not connect to services-server.
registry.conf文件中，如果使用nacos作为注册中心，那么要将application的名称也加上去，seata默认的名称是seata-server，填写seata-server即可。不填会报错服务注册不到seata中
问题三：
seata版本对应问题，如下图
