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关于seata:Seata-分布式事务系列二-Dubbo分布式事务

jiezi

在后面一篇咱们介绍了 Seata 分布式事务系列一: Seata 服务端搭建.

这一篇咱们应用 Seata 进行一个 Dubbo 微服务分布式事务的示例. 本示例蕴含 4 个我的项目:

  • API Rest 服务, 对立对外的业务模块, 这里示例一个购物服务 purchase(). 其 Dubbo 身份为服务消费者.
  • Account 账户微服务, 下单前需扣除账户余额. 其 Dubbo 身份为服务提供者.
  • Order 订单微服务, 创立订单. 其 Dubbo 身份为服务消费者 + 提供者.
  • Inventory 库存微服务, 创立订单前需扣除商品库存. 其 Dubbo 身份为服务提供者.

四者之间的调用关系如下图所示:

一. API 服务

API 模块为一个一般的 SpringBoot Web Restful API 服务, 为 Dubbo 服务消费者. 在 purchase() 中, 启动全局事务.

1.1 maven 依赖

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.5.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <groupId>fun.faceless.dubboshop.api</groupId>
    <artifactId>parent</artifactId>
    <packaging>pom</packaging>
    <version>1.0.0-SNAPSHOT</version>
    <name>api-center</name>
    <description>dubboshop api center</description>

    <properties>
        <java.version>1.8</java.version>
        <spring-boot.version>2.1.5.RELEASE</spring-boot.version>
        <spring.version>5.1.7.RELEASE</spring.version>
        <dubbo.version>2.7.7</dubbo.version>
    </properties>


    <dependencyManagement>
        <dependencies>
            <!-- springboot related -->
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
                <version>${spring-boot.version}</version>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-devtools</artifactId>
                <version>${spring-boot.version}</version>
                <scope>runtime</scope>
            </dependency>

            <!-- db data -->
            <!-- 对应 mybatis 3.5.5，从 3.5.0 开始反对 mapper 返回 Optional -->
            <dependency>
                <groupId>org.mybatis.spring.boot</groupId>
                <artifactId>mybatis-spring-boot-starter</artifactId>
                <version>2.1.3</version>
            </dependency>
            <!-- https://mvnrepository.com/artifact/org.mybatis.dynamic-sql/mybatis-dynamic-sql -->
            <dependency>
                <groupId>org.mybatis.dynamic-sql</groupId>
                <artifactId>mybatis-dynamic-sql</artifactId>
                <version>1.1.4</version>
            </dependency>
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <version>8.0.16</version>
            </dependency>
            <dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>druid</artifactId>
                <version>1.0.29</version>
            </dependency>

            <!-- Redis -->
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-data-redis</artifactId>
                <version>${spring-boot.version}</version>
            </dependency>
            <dependency>
                <groupId>org.apache.commons</groupId>
                <artifactId>commons-pool2</artifactId>
                <version>2.6.2</version>
            </dependency>
            <!--jackson 依赖 -->
            <dependency>
                <groupId>com.fasterxml.jackson.core</groupId>
                <artifactId>jackson-core</artifactId>
                <version>2.9.5</version>
            </dependency>
            <dependency>
                <groupId>com.fasterxml.jackson.core</groupId>
                <artifactId>jackson-databind</artifactId>
                <version>2.9.5</version>
            </dependency>

            <!-- rocketmq -->
            <!--<dependency>
                <groupId>org.apache.rocketmq</groupId>
                <artifactId>rocketmq-client</artifactId>
                <version>4.7.0</version>
            </dependency>-->
            <dependency>
                <groupId>org.apache.rocketmq</groupId>
                <artifactId>rocketmq-spring-boot-starter</artifactId>
                <version>2.1.0</version>
            </dependency>

            <!-- caching -->
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-cache</artifactId>
                <version>${spring-boot.version}</version>
            </dependency>
            <dependency>
                <groupId>org.ehcache</groupId>
                <version>3.6.3</version>
                <artifactId>ehcache</artifactId>
            </dependency>
            <dependency>
                <groupId>javax.cache</groupId>
                <artifactId>cache-api</artifactId>
                <version>1.1.0</version>
            </dependency>

            <!-- Seata -->
            <dependency>
                <groupId>io.seata</groupId>
                <artifactId>seata-spring-boot-starter</artifactId>
                <version>1.3.0</version>
            </dependency>

            <!-- Dubbo dependencies -->
            <dependency>
                <groupId>org.apache.dubbo</groupId>
                <artifactId>dubbo-bom</artifactId>
                <version>${dubbo.version}</version>
                <type>pom</type>
            </dependency>
            <dependency>
                <groupId>org.apache.dubbo</groupId>
                <artifactId>dubbo</artifactId>
                <version>${dubbo.version}</version>
                <exclusions>
                    <exclusion>
                        <groupId>org.apache.thrift</groupId>
                        <artifactId>libthrift</artifactId>
                    </exclusion>
                </exclusions>
            </dependency>
            <dependency>
                <groupId>org.apache.dubbo</groupId>
                <artifactId>dubbo-spring-boot-starter</artifactId>
                <version>${dubbo.version}</version>
            </dependency>
            <dependency>
                <groupId>org.apache.dubbo</groupId>
                <artifactId>dubbo-metadata-report-zookeeper</artifactId>
                <version>${dubbo.version}</version>
            </dependency>

            <!-- dubbo REST protocal -->
            <dependency>
                <groupId>org.apache.dubbo</groupId>
                <artifactId>dubbo-rpc-rest</artifactId>
                <version>${dubbo.version}</version>
            </dependency>
            <dependency>
                <groupId>org.apache.tomcat.embed</groupId>
                <artifactId>tomcat-embed-core</artifactId>
                <version>8.5.32</version>
            </dependency>

            <!-- Zookeeper dependencies-->
            <dependency>
                <groupId>org.apache.dubbo</groupId>
                <artifactId>dubbo-dependencies-zookeeper</artifactId>
                <version>2.7.1</version>
                <type>pom</type>
                <exclusions>
                    <exclusion>
                        <artifactId>log4j</artifactId>
                        <groupId>log4j</groupId>
                    </exclusion>
                    <exclusion>
                        <artifactId>slf4j-log4j12</artifactId>
                        <groupId>org.slf4j</groupId>
                    </exclusion>
                </exclusions>
            </dependency>

            <!-- inter-project modules -->
            <dependency>
                <groupId>fun.faceless.dubboshop</groupId>
                <artifactId>comms</artifactId>
                <version>1.0.0-SNAPSHOT</version>
            </dependency>
            <dependency>
                <groupId>fun.faceless.dubboshop.inventory</groupId>
                <artifactId>dubboapi</artifactId>
                <version>1.0.0-SNAPSHOT</version>
            </dependency>
            <dependency>
                <groupId>fun.faceless.dubboshop.account</groupId>
                <artifactId>dubboapi</artifactId>
                <version>1.0.0-SNAPSHOT</version>
            </dependency>
            <dependency>
                <groupId>fun.faceless.dubboshop.order</groupId>
                <artifactId>dubboapi</artifactId>
                <version>1.0.0-SNAPSHOT</version>
            </dependency>

            <!-- other dependencies -->
            <dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
                <version>1.18.8</version>
                <optional>true</optional>
            </dependency>

            <!-- testing related -->
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-test</artifactId>
                <version>${spring-boot.version}</version>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <dependencies>
        <!-- 将下面通过 dependencyManagement 指定版本号的依赖依据须要放到这里... -->
    </dependencies>

1.2 我的项目配置文件

在 application.yaml中配置 seata:

spring:
  # 这里省略 spring 相干的惯例配置...
  
dubbo:
  # 注册核心配置
  registry:
    id: dubboshop-registry
    address: zookeeper://<your_zk_host>:2181
    group: dubbo
    simplified: true
  metadata-report:
    address: zookeeper://<your_zk_host>:2181
    group: dubbo
  application:
    name: dubboshop-api
    id: dubboshop-api
    logger: slf4j

# 这里 seata 未应用注册核心. 如果应用过
seata:
  application-id: dubboshop-api         # Seata 利用编号，tx-service-group: dubboshop-api-group # Seata 事务组编号，用于 TC 集群名
  # Seata 服务配置项，对应 ServiceProperties 类
  service:
    # 虚构组和分组的映射
    vgroup-mapping:
      dubboshop-api-group: default      # 这里 dubboshop-api-group 对应下面 tx-service-group 的值.
    # 分组和 Seata 服务的映射. 不实用 Nacos 注册核心时, 配置 grouplist, 否则不须要该项.
    grouplist:
      default: <your_seata_server_host>:8091

1.3 业务代码

我的项目启动WebApplication:

@SpringBootApplication
@RestController
@ComponentScan("fun.faceless.dubboshop.api")
public class WebApplication {public static void main(String[] args) {SpringApplication.run(WebApplication.class, args);
    }

    @GetMapping("/")
    public String home() {return String.format("<html>Welcome to %s</html>", "DubboShopApiCenter");
    }
}

业务代码, 这里为了不便, 事务间接放在了 OrderController 中, 没有独自去写一个 Service 了.

@RestController
@RequestMapping("/api")
@Slf4j
public class OrderController {

    // 在 dubbo 2.7.x 中, cluster="failfast" 存在 bug, 无奈失常失效, 所以须要设置 retries=0.
    @Reference(protocol = "dubbo", cluster="failfast", retries=0)
    OrderProvider orderProvider;

    @Reference(protocol = "dubbo", cluster="failfast", retries=0)
    AccountCreditProvider accountCreditProvider;

    private String dubboConfigCenterAddr = "yyadmin:2181";

    @PostMapping(value = "purchase")
    @GlobalTransactional  // 留神这里启动全局事务
    public Result purchase(@RequestParam int userId, @RequestParam int goodsId, @RequestParam int goodsNum) {log.info("以后 XID: {}", RootContext.getXID());

        int unitCredit = 10;
        int creditAmount = goodsNum * unitCredit;
        accountCreditProvider.debit(userId, creditAmount);
        orderProvider.createOrder(userId, goodsId, goodsNum);
        return Result.succ("Order created successfully.");
    }
}

二. 其余微服务

其余微服务指 Account, Inventory, Order 3 个微服务项目. 三者的配置和形式都根本一样, 外围就是在相干 Service 上应用 @Transactional 进行本地事务管理. 此外, 能够通过 RootContext获取全局事务 ID: xid.

2.1 Maven 依赖

微服务项目的 dubbo 和 seata 无关依赖跟 api 我的项目的依赖基本一致. 能够间接参考下面.

2.2 我的项目配置

各微服务项目 dubbo 和 seata 无关的配置也基本一致. 只不过这三者作为微服务提供者, dubbo 相干的会多一些 protocol 配置. 这里以 Order 我的项目为例:

# ========= Dubbo Provider ==============
dubbo:
  # 配置核心, see: http://dubbo.apache.org/zh-cn/docs/user/configuration/config-center.html
  config-center:
    address: zookeeper://<your_zk_host>:2181
    group: dubbo
  # 注册核心配置
  registry:
    id: dubboshop-registry
    address: zookeeper://<your_zk_host>:2181
    group: dubbo
    simplified: true
    check: true
  metadata-report:
    address: zookeeper://<your_zk_host>:2181
    group: dubbo
  application:
    name: dubboshop-order
    id: dubboshop-order
    logger: slf4j
  # 示例多 Protocol, 这里反对 dubbo 和 rest 两种 Protocols.
  protocols:
    dubbo:
      name: dubbo
      server: netty4
      port: 20884
      accesslog: true
    rest:
      name: rest
      server: tomcat
      port: 8084
      accesslog: true
  scan:
    # dubbo 服务提供者实现类所在包
    base-packages: fun.faceless.dubboshop.order.dubboprovider


# Seata 配置项，对应 SeataProperties 类
seata:
  application-id: dubboshop-order           # Seata 利用编号，默认为 ${spring.application.name}
  tx-service-group: dubboshop-order-group   # Seata 事务组编号，用于 TC 集群名
  # Seata 服务配置项，对应 ServiceProperties 类
  service:
    # 虚构组和分组的映射
    vgroup-mapping:
      dubboshop-order-group: default        # 这里 dubboshop-order-group 对应 下面 tx-service-group 的值.
    # 分组和 Seata 服务的映射. 不实用 Nacos 注册核心时, 配置 grouplist, 否则不须要该项.
    grouplist:
      default: <your_seata_server_host>:8091

# 本来纯 dubbo 服务不须要配置 server.port, 不过 Seata 会主动启动 SpringBoot Web, 须要配置一个端口. 留神如果是同一主机上启动这几个服务, 这个端口取不同的值. 否则会报端口占用异样.
server:
  port: 28084

2.3 业务代码

@Slf4j
@Service(cluster="failfast", retries=0, timeout = 2000)
public class OrderProviderImpl implements OrderProvider {

    // 本地长久化 DAO
    @Autowired
    private OrderDao orderDao;

    // Dubbo 调用 InventoryProvider
    @Reference(protocol="dubbo", cluster="failfast", retries=0, timeout = 1500)
    private InventoryProvider inventoryProvider;

    /**
     * 调用 Dubbo 服务, 扣除库存. 而后提交数据库, 创立一个新订单.
     *
     * @param userId
     * @param goodsId
     * @param orderCount
     * @return 返回受影响的记录行数
     */
    @Override
    @Transactional      // <- 留神这里须要本地事务
    public int createOrder(int userId, int goodsId, int orderCount) {log.info("以后 XID: {}", RootContext.getXID());

        Result debitResult = inventoryProvider.deduce(goodsId, orderCount);
        return this.saveOrder(userId, goodsId, orderCount);
    }

    private int saveOrder(int userId, int goodsId, int orderCount) {Order order = new Order();
        order.setUserId(userId);
        order.setState((short) 10);
        order.setGoodsInfo(prepareNewGoodsInfo(goodsId, orderCount));
        int recordsAffected = orderDao.createOrder(order);

        return recordsAffected;
    }
    // 省略其余业务代码
}
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