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: 9100spring: 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@EnableZuulProxypublic 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@Componentpublic 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-smsserver: port: 8001eureka: client: service-url: defaultZone: http://eureka-7900:7900/eureka/ instance: metadata-map: version: v1 ---spring: profiles: sms2 application: name: service-smsserver: port: 8002eureka: 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。
以上就是浅谈Spring Cloud Netflix-Ribbon灰度方案之Zuul网关灰度的详细内容，更多关于Ribbon灰度方案之Zuul网关灰度的资料请关注其它相关文章！
去旅行不在于记忆，而在于当时的那份心情。
