浅谈Spring Cloud Netflix-Ribbon灰度方案之Zuul网关灰度

Eureka默认集成了Ribbon，所以Ribbon的灰度实现原理就是借助服务注册到Eureka中的eureka.instance.metadata-map的内容来进行匹配的。

Zuul网关的灰度实现也是借助了一个Ribbon的插件来实现，相对比较简单。

项目环境说明：有两个eureka的服务端(eureka-server)，有两个相同的后端服务(service-sms)，有一个网关服务(cloud-zuul)。

1、网关的依赖：

<?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 https://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>2.3.9.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.kevin</groupId>
    <artifactId>cloud-zuul</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>cloud-zuul</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Hoxton.SR10</spring-cloud.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-zuul</artifactId>
            <version>2.2.7.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>io.jmnarloch</groupId>
            <artifactId>ribbon-discovery-filter-spring-cloud-starter</artifactId>
            <version>2.1.0</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-redis</artifactId>
            <version>2.2.7.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.1.2</version>
        </dependency>

        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.21</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.48</version>
        </dependency>
    </dependencies>
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <excludes>
                        <exclude>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok</artifactId>
                        </exclude>
                    </excludes>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

这里我们用到的就是io.jmnarloch.ribbon-discovery-filter-spring-cloud-starter 这个插件包。需要注意的是，这个包引入之后，eureka-client自身带的ribbon很多功能就被覆盖了，而且不能再自定义IRule规则。因为这个包里面会生成一个metadataAwareRule的IRule，因为spring默认是单例，所以如果再自定义IRule会出现冲突运行时报错。

2、配置application.yaml

server:
  port: 9100
spring:
  application:
    name: cloud-zuul
  datasource:
    type: com.alibaba.druid.pool.DruidDataSource
    driver-class-name: com.mysql.jdbc.Driver
    url: jdbc:mysql://localhost:3306/test?characterEncoding=UTF-8&serverTimezone=Asia/Shanghai
    username: root
    password: root
    dbcp2:
      initial-size: 5
      min-idle: 5
      max-total: 10
      max-wait-millis: 1000
      validation-query: select 1
      test-while-idle: true
      test-on-borrow: false
      test-on-return: false

eureka:
  client:
    service-url:
      defaultZone: http://eureka-7900:7900/eureka/
mybatis:
  mapper-locations: classpath:mapper/*.xml

说明： 我的eureka服务端是部署在域名eureka-7900端口7900。

3、springboot启动类中添加@EnableZuulProxy

@SpringBootApplication
@EnableZuulProxy
public class CloudZuulApplication {

    public static void main(String[] args) {
        SpringApplication.run(CloudZuulApplication.class, args);
    }
}

4、添加灰度过滤器

import com.kevin.dao.CommonGrayRuleDao;
import com.kevin.entity.CommonGrayRule;
import com.netflix.zuul.ZuulFilter;
import com.netflix.zuul.context.RequestContext;
import com.netflix.zuul.exception.ZuulException;
import io.jmnarloch.spring.cloud.ribbon.support.RibbonFilterContextHolder;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.netflix.zuul.filters.support.FilterConstants;
import org.springframework.stereotype.Component;
import javax.servlet.http.HttpServletRequest;

//加入spring的管理
@Component
public class GrayFilter extends ZuulFilter {
    @Override
    public String filterType() {
        return FilterConstants.ROUTE_TYPE;
    }

    @Override
    public int filterOrder() {
        return 0;
    }

    @Override
    public boolean shouldFilter() {
        //必须返回true，否则过滤器不起作用
        return true;
    }

    @SuppressWarnings("SpringJavaInjectionPointsAutowiringInspection")
    @Autowired
    private CommonGrayRuleDao commonGrayRuleDao;

    @Override
    public Object run() throws ZuulException {
        //模拟从数据库中获取灰度规则配置，此处根据id获取的，实际项目中可以从数据库查处所有放到缓存
        CommonGrayRule commonGrayRule = commonGrayRuleDao.selectByPrimaryKey(1);

        RequestContext currentContext = RequestContext.getCurrentContext();
        HttpServletRequest request = currentContext.getRequest();
        int userId = Integer.parseInt(request.getHeader("userId"));
        //从head中拿出userid，根据数据库中规则进行匹配，如果灰度规则中有这个用户就走灰度v1版本，此处模拟的是根据
        //某一个具体的id获取的值，实际根据情况来定，实际情况中灰度规则也不一定是根据用户来
        if(commonGrayRule.getId() == userId){
            //核心代码就这么一行，实现了灰度，这里的version与要访问的服务的metadata-map中的key和value进行对应
            RibbonFilterContextHolder.getCurrentContext().add("version","v1");
        }

        return null;
    }
}

至此通过网关访问service-sms服务就可以了。如果head中添加version就可以指定到具体服务上。

事前说明：两个service-sms服务的application.yaml文件如下：

spring:
  profiles: sms1
  application:
    name: service-sms
server:
  port: 8001
eureka:
  client:
    service-url:
      defaultZone: http://eureka-7900:7900/eureka/
  instance:
    metadata-map:
      version: v1

---
spring:
  profiles: sms2
  application:
    name: service-sms
server:
  port: 8002
eureka:
  client:
    service-url:
      defaultZone: http://eureka-7900:7900/eureka/
  instance:
    metadata-map:
      version: v2

因为本机测试，所以使用的是profiles进行区分。

可以看到一个metadata-map设置的是version: v1 ，另一个是version: v2。

当我们数据库添加一条用户id是1的数据时，我们通过网关访问服务的时候，head里面添加userId为1的内容，那么这个用户为1的请求就会一直走sms1这个服务，否则会在sms1和sms2中轮询切换。

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