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。
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编程网其它相关文章！
