seata 项目结构
项目结构
seata 的代码开源在 github https://github.com/seata 。除了主代码 seata ，还有一些其它的项目，如 seata-samples / website 等等。git
seata 主项目使用 maven 进行管理，划分为多个模块，运行 mvn compile 从编译结果里面可看到github
[INFO] Seata Parent POM 1.0.0-SNAPSHOT .................... SUCCESS [ 25.687 s] [INFO] seata-common 1.0.0-SNAPSHOT ........................ SUCCESS [ 3.319 s] [INFO] seata-config 1.0.0-SNAPSHOT ........................ SUCCESS [ 0.238 s] [INFO] seata-config-core 1.0.0-SNAPSHOT ................... SUCCESS [ 0.668 s] [INFO] seata-config-custom 1.0.0-SNAPSHOT ................. SUCCESS [ 0.321 s] [INFO] seata-config-apollo 1.0.0-SNAPSHOT ................. SUCCESS [ 0.535 s] [INFO] seata-config-nacos 1.0.0-SNAPSHOT .................. SUCCESS [ 0.536 s] [INFO] seata-config-zk 1.0.0-SNAPSHOT ..................... SUCCESS [ 0.426 s] [INFO] seata-config-consul 1.0.0-SNAPSHOT ................. SUCCESS [ 0.354 s] [INFO] seata-config-etcd3 1.0.0-SNAPSHOT .................. SUCCESS [ 1.071 s] [INFO] seata-config-spring-cloud 1.0.0-SNAPSHOT ........... SUCCESS [ 0.346 s] [INFO] seata-discovery 1.0.0-SNAPSHOT ..................... SUCCESS [ 0.241 s] [INFO] seata-discovery-core 1.0.0-SNAPSHOT ................ SUCCESS [ 0.427 s] [INFO] seata-core 1.0.0-SNAPSHOT .......................... SUCCESS [ 2.591 s] [INFO] seata-discovery-custom 1.0.0-SNAPSHOT .............. SUCCESS [ 0.314 s] [INFO] seata-discovery-consul 1.0.0-SNAPSHOT .............. SUCCESS [ 0.339 s] [INFO] seata-discovery-eureka 1.0.0-SNAPSHOT .............. SUCCESS [ 0.497 s] [INFO] seata-discovery-nacos 1.0.0-SNAPSHOT ............... SUCCESS [ 0.499 s] [INFO] seata-discovery-redis 1.0.0-SNAPSHOT ............... SUCCESS [ 0.399 s] [INFO] seata-discovery-sofa 1.0.0-SNAPSHOT ................ SUCCESS [ 0.677 s] [INFO] seata-discovery-zk 1.0.0-SNAPSHOT .................. SUCCESS [ 0.400 s] [INFO] seata-discovery-etcd3 1.0.0-SNAPSHOT ............... SUCCESS [ 0.489 s] [INFO] seata-tm 1.0.0-SNAPSHOT ............................ SUCCESS [ 0.750 s] [INFO] seata-dubbo 1.0.0-SNAPSHOT ......................... SUCCESS [ 0.295 s] [INFO] seata-dubbo-alibaba 1.0.0-SNAPSHOT ................. SUCCESS [ 0.397 s] [INFO] seata-sofa-rpc 1.0.0-SNAPSHOT ...................... SUCCESS [ 0.543 s] [INFO] seata-motan 1.0.0-SNAPSHOT ......................... SUCCESS [ 0.333 s] [INFO] seata-rm 1.0.0-SNAPSHOT ............................ SUCCESS [ 0.386 s] [INFO] seata-rm-datasource 1.0.0-SNAPSHOT ................. SUCCESS [ 9.087 s] [INFO] seata-tcc 1.0.0-SNAPSHOT ........................... SUCCESS [ 0.481 s] [INFO] seata-codec 1.0.0-SNAPSHOT ......................... SUCCESS [ 0.249 s] [INFO] seata-codec-seata 1.0.0-SNAPSHOT ................... SUCCESS [ 0.796 s] [INFO] seata-codec-protobuf 1.0.0-SNAPSHOT ................ SUCCESS [ 15.332 s] [INFO] seata-codec-kryo 1.0.0-SNAPSHOT .................... SUCCESS [ 1.254 s] [INFO] seata-codec-all 1.0.0-SNAPSHOT ..................... SUCCESS [ 0.416 s] [INFO] seata-spring 1.0.0-SNAPSHOT ........................ SUCCESS [ 1.515 s] [INFO] seata-grpc 1.0.0-SNAPSHOT .......................... SUCCESS [ 1.825 s] [INFO] seata-codec-hessian ................................ SUCCESS [ 0.546 s] [INFO] seata-compressor 1.0.0-SNAPSHOT .................... SUCCESS [ 0.278 s] [INFO] seata-compressor-gzip 1.0.0-SNAPSHOT ............... SUCCESS [ 0.606 s] [INFO] seata-saga 1.0.0-SNAPSHOT .......................... SUCCESS [ 0.477 s] [INFO] seata-saga-processctrl 1.0.0-SNAPSHOT .............. SUCCESS [ 0.804 s] [INFO] seata-saga-statelang 1.0.0-SNAPSHOT ................ SUCCESS [ 0.797 s] [INFO] seata-saga-engine 1.0.0-SNAPSHOT ................... SUCCESS [ 1.305 s] [INFO] seata-saga-rm 1.0.0-SNAPSHOT ....................... SUCCESS [ 0.305 s] [INFO] seata-saga-tm 1.0.0-SNAPSHOT ....................... SUCCESS [ 0.396 s] [INFO] seata-saga-engine-store 1.0.0-SNAPSHOT ............. SUCCESS [ 0.616 s] [INFO] Seata All-in-one 1.0.0-SNAPSHOT .................... SUCCESS [ 2.015 s] [INFO] Seata bom 1.0.0-SNAPSHOT ........................... SUCCESS [ 0.001 s] [INFO] seata-config-all 1.0.0-SNAPSHOT .................... SUCCESS [ 0.173 s] [INFO] seata-discovery-all 1.0.0-SNAPSHOT ................. SUCCESS [ 0.175 s] [INFO] seata-compressor-all 1.0.0-SNAPSHOT ................ SUCCESS [ 0.175 s] [INFO] seata-metrics 1.0.0-SNAPSHOT ....................... SUCCESS [ 0.151 s] [INFO] seata-metrics-api 1.0.0-SNAPSHOT ................... SUCCESS [ 0.260 s] [INFO] seata-metrics-core 1.0.0-SNAPSHOT .................. SUCCESS [ 0.316 s] [INFO] seata-metrics-registry-compact 1.0.0-SNAPSHOT ...... SUCCESS [ 0.350 s] [INFO] seata-metrics-exporter-prometheus 1.0.0-SNAPSHOT ... SUCCESS [ 0.313 s] [INFO] seata-metrics-all 1.0.0-SNAPSHOT ................... SUCCESS [ 0.179 s] [INFO] seata-server 1.0.0-SNAPSHOT ........................ SUCCESS [ 1.347 s] [INFO] seata-distribution 1.0.0-SNAPSHOT .................. SUCCESS [ 0.195 s] [INFO] seata-test 1.0.0-SNAPSHOT .......................... SUCCESS [ 0.246 s] [INFO] seata-spring-boot-starter 1.0.0-SNAPSHOT ........... SUCCESS [ 1.059 s]
当前的 seata 一共有 62 个模块。除了 parent、all 这几个类型为 pom 的模块，其它 jar 模块可分为如下的几类：web
seata-common 包含 seata 的基本模型 seata-config seata 与其它技术集成的配置 seata-core 核心功能逻辑模块 seata-discovery seata 服务注册与发现的相关功能，支持 nacos、eureka、zookeeper 等服务发现方案 seata-tm tm 模块 seata-rm rm 模块 seata-tcc tcc 事务 seata-codec 消息编解码 seata-compressor 消息压缩 seata-saga saga 事务 seata-metrics 度量 seata-server seata 的服务器 seata-spring 与 spring 集成的模块 seata-distribution seata 发布相关 rpc 的模块 seata-grpc、seata-sofa-rpc（蚂蚁金服）、seata-motan（微博）等等
seata 提供了框架接口，很是容易与其它的微服务框架进行对接，目前已支持的 spring cloud 和 dubbo 。redis
编程模式
在开始学习 seata 的源代码前，能够先下载 seata-examples 里面的示例项目看看具体的应用，挑选其中两三个认真看看就能够。通常来讲，集成 seata 须要如下的步骤:spring
1. 配置 seata 服务器，重点是会话存储方式、与微服务的集成方式 2. 每一个微服务都配置客户端，在项目中用对应的方法集成 seata 3. 在全局事务的入口方法处，使用 `@GlobalTransactional` 标记一个全局事务，此事务会传播到它调用的全部的后续服务
@GlobalTransactional 是 seata-spring 提供的注解，标注了此注册的方法，在启动时被 seata-spring 的 GlobalTransactionScanner 扫描到，而后进行代理。编程
在 springcloud-eureka-seata 示例，bussiness 子项目的 BusinessService 为全局事务的入口，代码为：json
/**
* 减库存，下订单
*
* @param userId
* @param commodityCode
* @param orderCount
*/
@GlobalTransactional
public void purchase(String userId, String commodityCode, int orderCount) {
storageFeignClient.deduct(commodityCode, orderCount);
orderFeignClient.create(userId, commodityCode, orderCount);
if (!validData()) {
throw new RuntimeException("帐户或库存不足,执行回滚");
}
}
这里使用了 2 个服务的 feign 接口进行调用，若是查看各自的服务，都不须要标注 @GlobalTransactional，如仓储控制器的入口api
@RestController
public class StorageController {
@Autowired
private StorageService storageService;
@RequestMapping(value = "/deduct", produces = "application/json")
public Boolean deduct(String commodityCode, Integer count) {
storageService.deduct(commodityCode, count);
return true;
}
}
编程模式比较简单，其它都靠 seata-server 这个 TC 来协调。服务器