轻服务是反微服务吗？-- 微服务的轻量化

1. 背景

• 对外交付项目多为微服务架构，全量部署需要占用较多的内存资源。
• 私有化交付时，客户对投入的硬件成本有预算限制，前期太多的硬件投入影响客户体验，不利于成单。

2.目标

• 不改变目前SAAS环境微服务部署架构，避免SAAS环境出现性能问题，进而影响系统的稳定性。
• 私有化交付项目通过部署、打包等技术，将多个微服务部署到一个JVM进程或整合为一个单体项目，进而缩减硬件成本。
• 只针对SpringBoot项目做改造。

3.【Docker】融合部署

3.1 docker单容器多应用

3.2 dockerfile改造

• 端口映射改造

  一个docker容器同时映射多个应用服务端口

• 应用jar文件包含改造

  一个docker镜像需将多个springboot jar文件打包进去

• ENTRYPOINT启动脚本改造

  ENTRYPOINT启动脚本需包含多个应用的启动过程

4.【Tomcat】融合部署

4.1 Tomcat单实例多应用

4.2 原微服务应用改造

• 修改pom 为war

原：
<artifactId>web-provider</artifactId>
<name>web-provider</name>
<packaging>jar</packaging>

新：
<artifactId>web-provider</artifactId>
<name>web-provider</name>
<packaging>war</packaging>

• 排除SpringBoot内嵌容器tomcat

pom新增坐标：

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-tomcat</artifactId>
    <scope>provided</scope>
</dependency>

• 排除三方组件，减少war包大小

调整spring-boot-maven-plugin插件只把业务代码及依赖的业务组件打包进war中：

<plugin>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-maven-plugin</artifactId>
    <configuration>
        <includes>        
            <include> <!-- 根据实际情况修改，<includes>下可以包含多个<include> -->
                <groupId>com.lw.micro</groupId> <!-- 业务组件groupId -->
                <artifactId>web-provider-api</artifactId><!-- 业务组件artifactId -->
            </include>
        </includes>
    </configuration>
</plugin>

• 改造启动类

原启动类继承SpringBootServletInitializer并实现configure方法：

@ComponentScan
@SpringBootApplication
@EnableFeignClients({"com.web.provider.api"})
public class Application extends SpringBootServletInitializer{
   public static void main(String[] args) {
      SpringApplication.run(Application.class, args);
   }

   @Override
   protected SpringApplicationBuilder configure(SpringApplicationBuilder builder) {
      return builder.sources(Application.class);
   }
}

4.3抽取全量三方组件

• 新建项目为pom
• 中需包含各个微服务war包共享的全量三方组件
• 利用maven-dependency-plugin插件将依赖组件抽取到指定目录中

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-dependency-plugin</artifactId>
    <executions>
        <execution>
            <id>copy-dependencies</id>
            <phase>package</phase>
            <goals>
                <goal>copy-dependencies</goal>
            </goals>
            <configuration>
                <outputDirectory>${project.build.directory}/lib</outputDirectory><!-- 依赖包输出目录 -->
                <excludeTransitive>false</excludeTransitive>
                <stripVersion>false</stripVersion>
                <includeScope>runtime</includeScope>
                <excludeGroupIds>com.lw.micro</excludeGroupIds><!-- 需要排除的业务组件groupId，多个以逗号分割 -->
            </configuration>
        </execution>
    </executions>
</plugin>

4.4 Tomcat部署

4.4.1 tomcat配置

4.4.1.1server.xml配置

• 根据实际情况修改

<?xml version="1.0" encoding="UTF-8"?>
<Server port="8005" shutdown="SHUTDOWN">
  <Listener className="org.apache.catalina.startup.VersionLoggerListener" />
  <Listener className="org.apache.catalina.core.AprLifecycleListener" SSLEngine="on" />
  <!-- Prevent memory leaks due to use of particular java/javax APIs-->
  <Listener className="org.apache.catalina.core.JreMemoryLeakPreventionListener" />
  <Listener className="org.apache.catalina.mbeans.GlobalResourcesLifecycleListener" />
  <Listener className="org.apache.catalina.core.ThreadLocalLeakPreventionListener" />

  <!-- Global JNDI resources
       Documentation at /docs/jndi-resources-howto.html
  -->
  <GlobalNamingResources>
    <!-- Editable user database that can also be used by
         UserDatabaseRealm to authenticate users
    -->
    <Resource name="UserDatabase" auth="Container"
              type="org.apache.catalina.UserDatabase"
              description="User database that can be updated and saved"
              factory="org.apache.catalina.users.MemoryUserDatabaseFactory"
              pathname="conf/tomcat-users.xml" />
  </GlobalNamingResources>

  <Service name="lw-micro-demo">
    <Connector port="8280" protocol="HTTP/1.1"
               connectionTimeout="20000"
               redirectPort="8243"
               maxParameterCount="1000"
               />
    <Engine name="lw-micro-demo" defaultHost="www.demo.com">
      <Realm className="org.apache.catalina.realm.LockOutRealm">
        <Realm className="org.apache.catalina.realm.UserDatabaseRealm"
               resourceName="UserDatabase"/>
      </Realm>
      <Host name="www.demo.com"  appBase="webapps"
            unpackWARs="true" autoDeploy="false" deployOnStartup="false">
        <Context path="web-provider" docBase="web-provider"/>
        <Context path="web-consumer" docBase="web-consumer"/>
        <Valve className="org.apache.catalina.valves.AccessLogValve" directory="logs"
               prefix="localhost_access_log" suffix=".txt"
               pattern="%h %l %u %t &quot;%r&quot; %s %b" />

      </Host>
    </Engine>
  </Service>  
</Server> 

4.4.1.2 catalina.properties配置

• 根据实际情况修改

<?xml version="1.0" encoding="UTF-8"?>
<Server port="8005" shutdown="SHUTDOWN">
  <Listener className="org.apache.catalina.startup.VersionLoggerListener" />

  <Listener className="org.apache.catalina.core.AprLifecycleListener" SSLEngine="on" />

    
  <Listener className="org.apache.catalina.core.JreMemoryLeakPreventionListener" />
  <Listener className="org.apache.catalina.mbeans.GlobalResourcesLifecycleListener" />
  <Listener className="org.apache.catalina.core.ThreadLocalLeakPreventionListener" />

  <GlobalNamingResources>
    <!-- Editable user database that can also be used by
         UserDatabaseRealm to authenticate users
    -->
    <Resource name="UserDatabase" auth="Container"
              type="org.apache.catalina.UserDatabase"
              description="User database that can be updated and saved"
              factory="org.apache.catalina.users.MemoryUserDatabaseFactory"
              pathname="conf/tomcat-users.xml" />
  </GlobalNamingResources>
  <Service name="lw-micro-demo">
    <Connector port="8280" protocol="HTTP/1.1"
               connectionTimeout="20000"
               redirectPort="8243"
               maxParameterCount="1000"
               />
    <Engine name="lw-micro-demo" defaultHost="www.demo.com">
      <Realm className="org.apache.catalina.realm.LockOutRealm">
        <Realm className="org.apache.catalina.realm.UserDatabaseRealm"
               resourceName="UserDatabase"/>
      </Realm>
      <Host name="www.demo.com"  appBase="webapps"
            unpackWARs="true" autoDeploy="false" deployOnStartup="false">
        <Context path="web-provider" docBase="web-provider"/>
        <Context path="web-consumer" docBase="web-consumer"/>
        <Valve className="org.apache.catalina.valves.AccessLogValve" directory="logs"
               prefix="localhost_access_log" suffix=".txt"
               pattern="%h %l %u %t &quot;%r&quot; %s %b" />
      </Host>
    </Engine>
  </Service>  
</Server>

4.4.2 部署目录

1、war包部署目录为webapps 2、webapps目录为默认自带目录

1、各个war包共享三方组件部署目录为shared

2、shared目录为catalina.properties中shared.loader自定义目录，需自建

5【Maven】融合打包

5.1 打包方案

5.2 原微服务应用改造

• 修改SpringBoot打包类型为普通jar包

注释SpringBoot打包插件：
<!--            <plugin>-->
<!--                <groupId>org.springframework.boot</groupId>-->
<!--                <artifactId>spring-boot-maven-plugin</artifactId>-->
<!--                <configuration>-->
<!--                    <fork>false</fork>-->
<!--                </configuration>-->
<!--            </plugin>-->

• 命名冲突改造

  1. 包名冲突改造
  2. IOC容器Bean类名冲突改造 禁用如下配置解决Bean类名冲突问题spring.main.allow-bean-definition-overriding: true

• 数据源配置改造

  1. 单数据源，抽取各个微服务的数据源到公共包中，各个微服务依赖公共包，配置类及配置项key不需要调整

  2. 多数据源，需要按照各个微服务的命名区分配置类及配置项key，以保障集成为单体时不冲突，如：

     • 配置项key

           当前配置
          druid.datasource.url
          druid.datasource.username
          druid.datasource.password
       
          # 改后配置
          xxx.druid.datasource.url
          xxx.druid.datasource.username
          xxx.druid.datasource.password

     • 配置类

        @Configuration
        @Slf4j
        @MapperScan(basePackages = {"com.xxx.dao"}, sqlSessionFactoryRef = "xxxSqlSessionFactory")
        public class XXXDataSourceConfiguration extends DruidDataSoureConfiguration {
            @Value("com.alibaba.druid.pool.DruidDataSource")
            private Class<? extends DataSource> dataSourceType;
     
            @Bean(name = "xxxDataSource")
            @ConfigurationProperties(prefix = "xxx.druid.datasource")
            public DataSource dataSource() {
                DataSource dataSource = DataSourceBuilder.create().type(dataSourceType).build();
                return buildDataSourcePool(dataSource);
            }
     
            @Bean(name = "xxxSqlSessionFactory")
            public SqlSessionFactory sqlSessionFactory(@Qualifier("xxxDataSource") DataSource dataSource) throws Exception {
                SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
                bean.setDataSource(dataSource);
                bean.setMapperLocations(resolveMapperLocations());
                return bean.getObject();
            }
     
            @Bean(name = "xxxTransactionManager")
            public DataSourceTransactionManager transactionManager(@Qualifier("xxxDataSource") DataSource dataSource) {
                return new DataSourceTransactionManager(dataSource);
            }
     
            @Bean(name = "xxxSqlSessionTemplate")
            public SqlSessionTemplate sqlSessionTemplate(@Qualifier("xxxSqlSessionFactory") SqlSessionFactory sqlSessionFactory) {
                return new SqlSessionTemplate(sqlSessionFactory);
            }
     
            private Resource[] resolveMapperLocations() {
                ResourcePatternResolver resourcePatternResolver = new PathMatchingResourcePatternResolver();
                List<String> mapperLocations = new ArrayList<>();
                mapperLocations.add("classpath*:com/xxx/dao/**/*.xml");
     
                List<Resource> resources = new ArrayList<>();
                if (CollectionUtils.isNotEmpty(mapperLocations)) {
                    for (String mapperLocation : mapperLocations) {
                        try {
                            Resource[] mappers = resourcePatternResolver.getResources(mapperLocation);
                            resources.addAll(Arrays.asList(mappers));
                        } catch (IOException e) {
                            log.error("resourcePatternResolver getResources error", e);
                        }
                    }
                }
     
                return resources.toArray(new Resource[resources.size()]);
            }
        ```

• HTTP客户端改造

  • 建议HTTP客户端统一改造为OpenFeign
  • 建议OpenFeign接口类按单一职责定义
  • HTTP客户端情况

5.3 新建单体项目

• 新建一个SpringBoot项目，打包插件为spring-boot-maven-plugin
• 添加原各个微服务普通jar组件依赖

<dependencies>
    <dependency>
        <groupId>com.lw.micro</groupId>
        <artifactId>web-provider</artifactId>
        <version>${project.parent.version}</version>
    </dependency>
    <dependency>
        <groupId>com.lw.micro</groupId>
        <artifactId>web-consumer</artifactId>
        <version>${project.parent.version}</version>
    </dependency>
</dependencies>

• 添加原各个微服务application.yml配置项（删除重复项）
• 启动类增加@ComponentScan、@MapperScan注解

@MapperScan(basePackages = {
      "com.web.provider.dao",
      "com.web.consumer.dao"
})
@ComponentScan({
      "com.web.provider.*",
      "com.web.consumer.*"
})
@SpringBootApplication
public class Application{
   public static void main(String[] args) {
      SpringApplication.run(Application.class, args);
   }
}

• 合并mybatis-plus.mapper-locations配置

mybatis-plus:
  mapper-locations: classpath*:com/web/provider/**/mapping/*.xml,classpath*:com/web/consumer/**/mapping/*.xml

• OpenFeign本地调用改造

1、新建的单体项目启动类@EnableFeignClients注解只指定依赖的外部服务接口
@MapperScan(basePackages = {
      "com.web.provider.dao",
      "com.web.consumer.dao"
})
@ComponentScan({
      "com.web.provider.*",
      "com.web.consumer.*"
})
@EnableFeignClients(basePackages = {
    "依赖的外部服务接口"
})
@SpringBootApplication
public class Application{
   public static void main(String[] args) {
      SpringApplication.run(Application.class, args);
   }
}

2、新建的单体项目对应Controller类实现@FeignClient注解的接口
@FeignClient(name="web-provider", url = "${web.provider.url}")
public interface ProviderTestApi{

    @GetMapping("/provider-test/getTest")
    Response getTest();

}

@RestController
@RequestMapping("/provider-test")
@Slf4j
public class ProviderTestController implements ProviderTestApi{
    @Autowired
    private IProviderTestService providerTestService;

    @Override
    @GetMapping("/getTest")
    public Response getTest() {
        log.info("remote obj addr={}",this.toString());
        Test test = providerTestService.getById(1);
        log.info(test.toString());
        return Response.ok("调用provider成功");
    }

}

6 方案选型

6.1 微服务拆分方式

*备注：较少冲突*

*备注：较多冲突*

6.2 方案选型

• 方案对比

方案	优点	缺点	适用场景	ffff	改造Demo
【Maven】融合打包	1. 全部SpringBoot部署 2. 部署运维方案一致	1. 命名冲突较多时改造成本高 2. http客户端需要改造	1. 各个微服务包名及类名有少量冲突2. 改造风险可控3. 改造成本可控	具体见5.2~5.3	xxx
【Tomcat】融合部署	1. 不涉及命名冲突改造。2.不涉及http客户端改造	1. SaaS SpringBoot部署，OP Tomcat部署 2. 部署运维方案不一致	1. 各个微服务包名及类名有大量冲突 2.改造风险高。3.改造成本高。4.缩减JVM内存部署资源	具体见4.2~4.3	xxx
【Docker】融合部署	1. 无需代码变动2. 需要部署的镜像减少，部署运维过程简化	1. JVM内存资源未明显缩减	1. 各个微服务包名及类名有大量冲突	具体见3.2

• 改造难度

  Maven】融合打包>【Tomcat】融合部署>【Docker】融合部署

• 改造收益

【Maven】融合打包>【Tomcat】融合部署>【Docker】融合部署

6.3 代码分支维护