LCN分布式事务框架原理和多模式下的实战使用

Bertha 。 2022-12-27 06:23 95阅读 0赞

LCN分布式事务框架原理和多模式下的实战使用，基础Dubbo框架为例：

# LCN框架 原理 #

## 背景 ##

LCN 名称是由早期版本的 LCN 框架命名，在设计框架之初的1.0~2.0的版本时框架设计的步骤是如下，各取其首字母得来的 LCN 命名。

*  锁定事务单元（Lock）
 *  确认事务模块状态（ Confirm）
 *  通知事务（ Notify）

## 框架定位 ##

LCN 并不生产事务，LCN 只是本地事务的协调工。TX-LCN 定位于一款事务协调性框架，框架其本身并不操作事务，而是基于对事务的协调从而达到事务一致性的效果。

## 事务控制原理 ##

TX-LCN由两大模块组成， TxClient、 TxManager，支持3PC、TCC等事务模式。

TxClient 作为模块的依赖框架，提供 TX-LCN 的标准支持， TxManager 作为分布式事务的控制方。事务发起方或者参与方都由 TxClient 来控制。

通过代理 Connection 的方式实现对本地事务的操作，然后在由 TxManager 统一协调控制事务。当本地事务提交回滚或者关闭连接时将会执行假操作，该代理的连接将由 LCN 连接池管理。

## 原理图 ##

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L25hbmRhbzE1OA_size_16_color_FFFFFF_t_70][]

一、LCN框架3PC模式，实战Dubbo微服务，集成zookeeber、redis等，详情看配置：

1、服务端事务管理器的微服务引入jar

<?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">
        <parent>
            <artifactId>trans-lcn</artifactId>
            <groupId>com.enjoy</groupId>
            <version>1.0</version>
        </parent>
        <modelVersion>4.0.0</modelVersion>
    
        <artifactId>lcn-tm</artifactId>
    
        <properties>
            <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
            <maven.compiler.source>1.7</maven.compiler.source>
            <maven.compiler.target>1.7</maven.compiler.target>
        </properties>
    
        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-data-redis</artifactId>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-jdbc</artifactId>
                <exclusions>
                    <exclusion>
                        <groupId>org.apache.tomcat</groupId>
                        <artifactId>tomcat-jdbc</artifactId>
                    </exclusion>
                </exclusions>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>
            
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <version>5.1.6</version>
            </dependency>
            
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-jdbc</artifactId>
                <exclusions>
                    <exclusion>
                        <groupId>org.apache.tomcat</groupId>
                        <artifactId>tomcat-jdbc</artifactId>
                    </exclusion>
                </exclusions>
            </dependency>
            
            <dependency>
                <groupId>com.codingapi.txlcn</groupId>
                <artifactId>txlcn-tm</artifactId>
                <version>5.0.2.RELEASE</version>
            </dependency>
        </dependencies>
        <dependencyManagement>
            <dependencies>
                <dependency>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-dependencies</artifactId>
                    <version>2.1.0.RELEASE</version>
                    <type>pom</type>
                    <scope>import</scope>
                </dependency>
            </dependencies>
        </dependencyManagement>
        <build>
            <plugins>
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                    <version>2.2.0.RELEASE</version>
                </plugin>
            </plugins>
        </build>
    </project>

2、application.yml 配置文件设置：

spring.application.name=tm-manager
    server.port=7970
    
    spring.datasource.driver-class-name=com.mysql.jdbc.Driver
    spring.datasource.url=jdbc:mysql://10.130.166.2466:305199/ZIPKIN?useUnicode=true&characterEncoding=UTF-8&allowMultiQueries=true
    spring.datasource.username=mysql
    spring.datasource.password=mysql
    
    # TxManager Host Ip
    tx-lcn.manager.host=127.0.0.1
    # TxClient连接请求端口
    tx-lcn.manager.port=8070
    # 心跳检测时间(ms)
    tx-lcn.manager.heart-time=15000
    # 分布式事务执行总时间
    tx-lcn.manager.dtx-time=30000
    #参数延迟删除时间单位ms
    tx-lcn.message.netty.attr-delay-time=10000
    tx-lcn.manager.concurrent-level=128
    # 开启日志
    tx-lcn.logger.enabled=true
    logging.level.com.codingapi=debug
    #redis 主机
    spring.redis.host=127.0.0.1
    #redis 端口
    spring.redis.port=6379
    #redis 密码
    #spring.redis.password=123456

3、服务端启动类注解配置：@EnableTransactionManagerServer ，

import com.codingapi.txlcn.tm.config.EnableTransactionManagerServer;
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    
    @SpringBootApplication
    @EnableTransactionManagerServer
    public class TmManager {
    
        public static void main(String[] args) {
            SpringApplication.run(TmManager.class, args);
        }
    
    }

4、启动类上加 : @EnableDistributedTransaction 注解

然后就可以启动了。

二、客户端服务发现方的创建：

1、微服务jar包的引入：

<?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">
        <parent>
            <artifactId>trans-lcn</artifactId>
            <groupId>com.enjoy</groupId>
            <version>1.0</version>
        </parent>
        <modelVersion>4.0.0</modelVersion>
    
        <artifactId>lcn-busi</artifactId>
    
        <properties>
            <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
            <maven.compiler.source>1.7</maven.compiler.source>
            <maven.compiler.target>1.7</maven.compiler.target>
        </properties>
    
        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>
            
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <version>5.1.6</version>
            </dependency>
            
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-jdbc</artifactId>
                <exclusions>
                    <exclusion>
                        <groupId>org.apache.tomcat</groupId>
                        <artifactId>tomcat-jdbc</artifactId>
                    </exclusion>
                </exclusions>
            </dependency>
            
            <dependency>
                <groupId>io.springfox</groupId>
                <artifactId>springfox-swagger2</artifactId>
                <version>2.6.1</version>
            </dependency>
            <dependency>
                <groupId>io.springfox</groupId>
                <artifactId>springfox-swagger-ui</artifactId>
                <version>2.6.1</version>
            </dependency>
            
            <dependency>
                <groupId>com.codingapi.txlcn</groupId>
                <artifactId>txlcn-tc</artifactId>
                <version>5.0.2.RELEASE</version>
            </dependency>
            <dependency>
                <groupId>com.codingapi.txlcn</groupId>
                <artifactId>txlcn-txmsg-netty</artifactId>
                <version>5.0.2.RELEASE</version>
            </dependency>
            
            <dependency>
                <groupId>org.apache.zookeeper</groupId>
                <artifactId>zookeeper</artifactId>
                <version>3.4.11</version>
                <exclusions>
                    <exclusion>
                        <groupId>*</groupId>
                        <artifactId>*</artifactId>
                    </exclusion>
                </exclusions>
            </dependency>
            <dependency>
                <groupId>com.101tec</groupId>
                <artifactId>zkclient</artifactId>
                <version>0.10</version>
                <exclusions>
                    <exclusion>
                        <groupId>org.slf4j</groupId>
                        <artifactId>slf4j-log4j12</artifactId>
                    </exclusion>
                </exclusions>
            </dependency>
            <dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>dubbo</artifactId>
                <version>2.6.2</version>
                <exclusions>
                    <exclusion>
                        <groupId>org.springframework</groupId>
                        <artifactId>*</artifactId>
                    </exclusion>
                </exclusions>
            </dependency>
        </dependencies>
        <dependencyManagement>
            <dependencies>
                <dependency>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-dependencies</artifactId>
                    <version>2.1.0.RELEASE</version>
                    <type>pom</type>
                    <scope>import</scope>
                </dependency>
            </dependencies>
        </dependencyManagement>
        <build>
            <plugins>
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                    <version>2.2.0.RELEASE</version>
                </plugin>
            </plugins>
        </build>
    </project>

2、application.yml文件配置：

server:
      port: 8090
    spring:
      application:
        name: lcn-busi
      datasource:
        username: mysql
        password: mysql
        driver-class-name: com.mysql.jdbc.Driver
        url: jdbc:mysql://10.130.16.2466:305199/ZIPKIN?useUnicode=true&characterEncoding=UTF-8&allowMultiQueries=true
    
    tx-lcn:
      client:
        manager-address: 127.0.0.1:8070
    
    zookeeper:
      url: zookeeper://192.168.0.128:2181
    
    dubbo:
      name: lcn-busi
      port: 20880

3、controller层核心代码：

import com.enjoy.service.TransferService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    @RestController
    public class AccountController {
    
        @Autowired
        private TransferService transferService;
    
        @GetMapping("/transfer")
        public String transfer(int money){
            return transferService.transfer(money);
        }
    
    }

4、微服务业务层接口加上注解 @LcnTransaction，

import com.codingapi.txlcn.tc.annotation.LcnTransaction;
    import com.enjoy.service.TransferService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.jdbc.core.JdbcTemplate;
    import org.springframework.web.client.RestTemplate;
    
    import static com.codingapi.txlcn.tracing.TracingContext.tracing;
    
    @org.springframework.stereotype.Service
    public class RestTransferService implements TransferService {
        private RestTemplate restTemplate =new RestTemplate();
    
        @Autowired
        private JdbcTemplate jdbcTemplate;
    
        @LcnTransaction   //lcn子事务 groupid 传递过去
        public String transfer(int money) {
            String appList = tracing().appMapString();
            String groupId = tracing().groupId();
            String lcn_param = "&appList="+appList+"&groupId="+groupId;
    
            int resultUser = jdbcTemplate.update("INSERT INTO bank_c(money,user_name)VALUES (?,?)",-money,"james");
            String url = "http://localhost:5003/receive?money={money}"+lcn_param;
            String resultGood = restTemplate.postForObject(url, "money", String.class, money);
            if (money > 20){
                throw new RuntimeException("money too large");
            }
            return resultUser+"-";
        }
    }

或者用DUBBO配置的实现类：此处只能有一个实现类，因为初始化对象是单例的，否则启动报错。

import com.alibaba.dubbo.config.annotation.Reference;
    import com.codingapi.txlcn.tc.annotation.LcnTransaction;
    import com.codingapi.txlcn.tracing.TracingContext;
    import com.enjoy.service.ReceiveService;
    import com.enjoy.service.TransferService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.jdbc.core.JdbcTemplate;
    
    @org.springframework.stereotype.Service
    public class DubboTransferService implements TransferService{
        @Autowired
        private JdbcTemplate jdbcTemplate;
    
        @Reference//dubbo模式的依赖注入
        private ReceiveService receiveService;
    
        @LcnTransaction
        public String transfer(int money) {
            int resultUser = jdbcTemplate.update("INSERT INTO bank_c(money,user_name)VALUES (?,?)",-money,"james");
    
            System.out.println(TracingContext.tracing().groupId());
            receiveService.receiveMoney(money);//一样隐藏地传递了groupid
            if (money > 20){
                throw new RuntimeException("money too large");
            }
            return resultUser+"-";
        }
    
    }

二、客户端服务提供方的创建：

1、pom文件

<?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">
        <parent>
            <artifactId>trans-lcn</artifactId>
            <groupId>com.enjoy</groupId>
            <version>1.0</version>
        </parent>
        <modelVersion>4.0.0</modelVersion>
    
        <artifactId>lcn-service</artifactId>
    
        <properties>
            <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
            <maven.compiler.source>1.7</maven.compiler.source>
            <maven.compiler.target>1.7</maven.compiler.target>
        </properties>
    
        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>
            
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <version>5.1.6</version>
            </dependency>
            
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-jdbc</artifactId>
                <exclusions>
                    <exclusion>
                        <groupId>org.apache.tomcat</groupId>
                        <artifactId>tomcat-jdbc</artifactId>
                    </exclusion>
                </exclusions>
            </dependency>
            
            <dependency>
                <groupId>io.springfox</groupId>
                <artifactId>springfox-swagger2</artifactId>
                <version>2.6.1</version>
            </dependency>
            <dependency>
                <groupId>io.springfox</groupId>
                <artifactId>springfox-swagger-ui</artifactId>
                <version>2.6.1</version>
            </dependency>
            
            <dependency>
                <groupId>com.codingapi.txlcn</groupId>
                <artifactId>txlcn-tc</artifactId>
                <version>5.0.2.RELEASE</version>
            </dependency>
            <dependency>
                <groupId>com.codingapi.txlcn</groupId>
                <artifactId>txlcn-txmsg-netty</artifactId>
                <version>5.0.2.RELEASE</version>
            </dependency>
            
            <dependency>
                <groupId>org.apache.zookeeper</groupId>
                <artifactId>zookeeper</artifactId>
                <version>3.4.11</version>
                <exclusions>
                    <exclusion>
                        <groupId>*</groupId>
                        <artifactId>*</artifactId>
                    </exclusion>
                </exclusions>
            </dependency>
            <dependency>
                <groupId>com.101tec</groupId>
                <artifactId>zkclient</artifactId>
                <version>0.10</version>
                <exclusions>
                    <exclusion>
                        <groupId>org.slf4j</groupId>
                        <artifactId>slf4j-log4j12</artifactId>
                    </exclusion>
                </exclusions>
            </dependency>
            <dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>dubbo</artifactId>
                <version>2.6.2</version>
                <exclusions>
                    <exclusion>
                        <groupId>org.springframework</groupId>
                        <artifactId>*</artifactId>
                    </exclusion>
                </exclusions>
            </dependency>
        </dependencies>
        <dependencyManagement>
            <dependencies>
                <dependency>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-dependencies</artifactId>
                    <version>2.1.0.RELEASE</version>
                    <type>pom</type>
                    <scope>import</scope>
                </dependency>
            </dependencies>
        </dependencyManagement>
        <build>
            <plugins>
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                    <version>2.2.0.RELEASE</version>
                </plugin>
            </plugins>
        </build>
    </project>

2、applaication.yml配置：

server:
      port: 5003
    spring:
      application:
        name: lcn-service
      datasource:
        username: mysql
        password: mysql
        driver-class-name: com.mysql.jdbc.Driver
        url: jdbc:mysql://10.130.166.2466:305199/ZIPKIN?useUnicode=true&characterEncoding=UTF-8&allowMultiQueries=true
    tx-lcn:
      client:
        manager-address: 127.0.0.1:8070
    #注册中心
    zookeeper:
      url: zookeeper://127.0.0.1:2181
    #Dubbo相关配置
    dubbo:
      name: lcn-service
      port: 20881

3、controller层核心代码：

import com.codingapi.txlcn.common.util.Maps;
    import com.codingapi.txlcn.tracing.TracingConstants;
    import com.codingapi.txlcn.tracing.TracingContext;
    import com.enjoy.service.ReceiveService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.web.bind.annotation.PostMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    import javax.servlet.http.HttpServletRequest;
    
    @RestController
    public class ReceiveController {
    
        @Autowired
        private ReceiveService receiveService;
    
        @PostMapping("/receive")
        public String receive(HttpServletRequest request) {
            //事务组的获取
            String groupId = request.getParameter("groupId");
            String appList = request.getParameter("appList");
            TracingContext.tracing().init(Maps.newHashMap(TracingConstants.GROUP_ID, groupId, TracingConstants.APP_MAP, appList));
    
            int money = Integer.parseInt(request.getParameter("money"));
            receiveService.receiveMoney(money);
            return "success";
        }
    }

4、server业务层核心代码：

import com.codingapi.txlcn.tc.annotation.LcnTransaction;
    import com.codingapi.txlcn.tracing.TracingContext;
    import com.enjoy.service.ReceiveService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.jdbc.core.JdbcTemplate;
    
    @com.alibaba.dubbo.config.annotation.Service
    public class LcnReceiveServiceImpl implements ReceiveService {
    
        @Autowired
        private JdbcTemplate jdbcTemplate;
    
        //3pc事务
        @LcnTransaction
        public void receiveMoney(int money) {
            int resultUser = jdbcTemplate.update("INSERT INTO bank_b(money,user_name)VALUES (?,?)",money,"peter");
            System.out.println(TracingContext.tracing().groupId());
        }
    }

5、启动类上加 : @EnableDistributedTransaction 注解，启动此客户端

三、LCN框架提供的TCC模式：

# TCC 原理 #

前面的 LCN 依赖包，其实也实现了 TCC 事务。

TCC其实就是采用的补偿机制，其核心思想是：针对每个操作，都要注册一个与其业务逻辑对应的确认和补偿（撤销）操作。

其将整个业务逻辑的每个分支显式的分成了 Try、 Confirm、 Cancel 三个操作。Try 部分完成业务的准备工作， Confirm 部分完成业务的提交， Cancel 部分完成事务的回滚。

## 原理图： ##

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L25hbmRhbzE1OA_size_16_color_FFFFFF_t_70 1][]

1、基础配置就是 客户端服务提供方的，即都一样，只有server业务层接口实现的内容不同：

import com.codingapi.txlcn.tc.annotation.TccTransaction;
    import com.codingapi.txlcn.tracing.TracingContext;
    import com.enjoy.service.ReceiveService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.jdbc.core.JdbcTemplate;
    
    import static com.codingapi.txlcn.tracing.TracingContext.tracing;
    
    @com.alibaba.dubbo.config.annotation.Service
    public class TccReceiveServiceImpl implements ReceiveService {
    
        @Autowired
        private JdbcTemplate jdbcTemplate;
    
        //try   不再是数据操作
        //lcn子事务   当前事务上下文中有了groupId，则加入，没有则新建一个
        @TccTransaction(confirmMethod = "confirm", cancelMethod = "cancel", executeClass = TccReceiveServiceImpl.class)
        public void receiveMoney(int money) {
            String groupId = TracingContext.tracing().groupId();
            int resultUser = jdbcTemplate.update("INSERT INTO bank_b(money,user_name,status)VALUES (?,?,?)",money,"peter",groupId);
        }
    
        //确认接口
        public void confirm(int money) {
            String groupId = TracingContext.tracing().groupId();
            int resultUser = jdbcTemplate.update("UPDATE bank_b SET status = 1 WHERE status = ?", tracing().groupId());
        }
    
        //取消回滚接口
        public void cancel(int money) {
            String groupId = TracingContext.tracing().groupId();
            int resultUser = jdbcTemplate.update("INSERT INTO bank_b(money,user_name,status)VALUES (?,?,?)",-money,"peter",groupId);
        }
    }

2、到此就可以测试了。三个服务启动后访问：[http://localhost:8090/transfer?money=12][http_localhost_8090_transfer_money_12]

**优点** ：跟  2PC  比起来，实现以及流程相对简单了一些，但数据的一致性比  2PC  也要差一些。

**缺点** ： TCC  属于应用层的一种补偿方式，所以需要程序员在实现的时候多写很多补偿的代码，而且补偿的时候也有可能失败，在一些场景中，一些 业务流程可能用 TCC  不太好定义及处理。

到此，LCN框架原理和实战分享暂时告一段落，以后有机会分析一下源码，敬请期待！

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L25hbmRhbzE1OA_size_16_color_FFFFFF_t_70]: /images/20221120/051b8c7118f4484faa8f2c6f27bcb54e.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L25hbmRhbzE1OA_size_16_color_FFFFFF_t_70 1]: /images/20221120/9c04cd0e62ba445e8a468e13ee3e2f4d.png
[http_localhost_8090_transfer_money_12]: http://localhost:8090/transfer?money=12