Seata分布式事务框架Sample
前言
阿里官方给出了seata-sample地址,官方自己也对Sample提供了很多类型,可以查看学习。 我这里选择演示SpringBoot+MyBatis。
该聚合工程共包括5个module:
- sbm-account-service
- sbm-business-service
- sbm-common-service
- sbm-order-service
- sbm-storage-service
不同Module之间的服务通信使用Rest方式通信。
准备工作
创建数据库
在sql/all_in_one_sql里是演示中需要的sql脚本,共创建了3个schema: db_account, db_order, db_storage, 分别演示三个不同的数据库,每个schema里都有一张undo_log表。
启动Seata-Server
Seata-Server扮演TM的角色,在官网下载http://seata.io/zh-cn/blog/download.html,最新版本为1.4.2。
/conf/registry.conf 中有两个大的节点registry - 注册中心配置选项,config - 配置中心配置选项。
# 注册中心配置
registry {
# file 、nacos 、eureka、redis、zk、consul、etcd3、sofa
type = "file"
nacos {
application = "seata-server"
serverAddr = "127.0.0.1:8848"
group = "SEATA_GROUP"
namespace = ""
cluster = "default"
username = ""
password = ""
}
eureka {
serviceUrl = "http://localhost:8761/eureka"
application = "default"
weight = "1"
}
redis {
serverAddr = "localhost:6379"
db = 0
password = ""
cluster = "default"
timeout = 0
}
zk {
cluster = "default"
serverAddr = "127.0.0.1:2181"
sessionTimeout = 6000
connectTimeout = 2000
username = ""
password = ""
}
consul {
cluster = "default"
serverAddr = "127.0.0.1:8500"
aclToken = ""
}
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"
}
}
# 配置中心配置
config {
# file、nacos 、apollo、zk、consul、etcd3
type = "file"
nacos {
serverAddr = "127.0.0.1:8848"
namespace = ""
group = "SEATA_GROUP"
username = ""
password = ""
dataId = "seataServer.properties"
}
consul {
serverAddr = "127.0.0.1:8500"
aclToken = ""
}
apollo {
appId = "seata-server"
## apolloConfigService will cover apolloMeta
apolloMeta = "http://192.168.1.204:8801"
apolloConfigService = "http://192.168.1.204:8080"
namespace = "application"
apolloAccesskeySecret = ""
cluster = "seata"
}
zk {
serverAddr = "127.0.0.1:2181"
sessionTimeout = 6000
connectTimeout = 2000
username = ""
password = ""
nodePath = "/seata/seata.properties"
}
etcd3 {
serverAddr = "http://localhost:2379"
}
file {
name = "file.conf"
}
}
/conf/file.conf - 只有当registry.conf下 config.type=file时才加载file.config中的参数。config.type等于其他值的话则不需要file.config。 seata-server也提供了file.conf.example, 详细的参数介绍也可以查看http://seata.io/zh-cn/docs/user/configurations.html。
## transaction log store, only used in seata-server
store {
## store mode: file、db、redis
mode = "file"
## rsa decryption public key
publicKey = ""
## 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 {
## the implement of javax.sql.DataSource, such as DruidDataSource(druid)/BasicDataSource(dbcp)/HikariDataSource(hikari) etc.
datasource = "druid"
## mysql/oracle/postgresql/h2/oceanbase etc.
dbType = "mysql"
driverClassName = "com.mysql.jdbc.Driver"
## if using mysql to store the data, recommend add rewriteBatchedStatements=true in jdbc connection param
url = "jdbc:mysql://127.0.0.1:3306/seata?rewriteBatchedStatements=true"
user = "mysql"
password = "mysql"
minConn = 5
maxConn = 100
globalTable = "global_table"
branchTable = "branch_table"
lockTable = "lock_table"
queryLimit = 100
maxWait = 5000
}
## redis store property
redis {
## redis mode: single、sentinel
mode = "single"
## single mode property
single {
host = "127.0.0.1"
port = "6379"
}
## sentinel mode property
sentinel {
masterName = ""
## such as "10.28.235.65:26379,10.28.235.65:26380,10.28.235.65:26381"
sentinelHosts = ""
}
password = ""
database = "0"
minConn = 1
maxConn = 10
maxTotal = 100
queryLimit = 100
}
}
启动服务./bin/seata-server.bat ,默认打开了8091端口。
启动Sample服务
依此启动account-service,business-service,order-service,storage-service。business-service作为业务逻辑的入口分别调用order-service和storage-service。这里就看到了关键注解GlobalTransactional。
4个服务的默认端口分别是8081,8082, 8083,8084。
BusinessService
@Service
public class BusinessService {
private static final Logger LOGGER = LoggerFactory.getLogger(BusinessService.class);
@Autowired
private StorageClient storageClient;
@Autowired
private OrderClient orderClient;
/**
* 减库存,下订单
*
* @param userId
* @param commodityCode
* @param orderCount
*/
@GlobalTransactional
public void purchase(String userId, String commodityCode, int orderCount) {
LOGGER.info("purchase begin ... xid: " + RootContext.getXID());
storageClient.deduct(commodityCode, orderCount);
orderClient.create(userId, commodityCode, orderCount);
}
}
OrderClient
@Slf4j
@Component
public class OrderClient {
@Autowired
private RestTemplate restTemplate;
public void create(String userId, String commodityCode, int orderCount) {
String url = "http://127.0.0.1:8082/api/order/debit?userId=" + userId + "&commodityCode=" + commodityCode + "&count=" + orderCount;
try {
restTemplate.getForEntity(url, Void.class);
} catch (Exception e) {
log.error("create url {} ,error:", url);
throw new RuntimeException();
}
}
}
StorageClient
@Slf4j
@Component
public class StorageClient {
@Autowired
private RestTemplate restTemplate;
public void deduct(String commodityCode, int orderCount) {
System.out.println("business to storage " + RootContext.getXID());
String url = "http://127.0.0.1:8081/api/storage/deduct?commodityCode=" + commodityCode + "&count=" + orderCount;
try {
restTemplate.getForEntity(url, Void.class);
} catch (Exception e) {
log.error("deduct url {} ,error:", url, e);
throw new RuntimeException();
}
}
}
运行Sample
模拟正常事务提交
运行Sample前,我们先查看下当前三个服务数据库的数据。
db_account.account_tbl
db_storage.storage_tbl
业务接口在business-service/BusinessController里,我们先来执行下购买下单正常的提交流程。
执行接口http://localhost:8094/api/business/purchase/commit/, 执行后,seata-server控制台上会显示全局事务执行的具体日志和执行成功的日志。
执行后我们再查看下数据库。
db_account.account_tbl。 user_id对应1001的账户减去了5元(9995)。
db_storage.storage_tbl
db_order.order_tbl
模拟全局事务回滚
执行接口http://localhost:8084/api/business/purchase/rollback, 这里我们想查看undo_log表的数据,则在BusinessSerivce#purchase断点。
db_storage.undo_log
undo_log里最重要的是关注beforeImage和afterImage节点。
全局事务回滚后,undo_log表会清空数据。
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