[Java知识库]基于nacos netflix loadbalancer灰度发布策略

一,实现原理

利用nacos元数据，给服务发起方和被调用方定义标签。相同标签的优先调用。

二，实现场景

假设 A,B两个服务，各存在4个节点，且版本都是V1

A1(V1) ?B1(V1)

A2(V1)? B2(V1)

A3(V1)? B3(V1)

A4(V1)? B4(V1)

更新版本后

A1(V2)? B1(V2)

A2(V1)? B2(V1)

A3(V1)? B3(V1)

A4(V1)? B4(V1)

更新后V2的相互调用，V1的相互调用。

三，关键代码

参考NacosRule类 ，更复杂的情况可以依例扩展

pom.xml

<dependencies>
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-configuration-processor</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>
    </dependencies>

GrayConstant.java

package com.rutron.canary;

/**
 * @author liwenchao
 */
public class GrayConstant {

    public static final String GRAY_TAG = "version";

}

CanaryBalancerRule.java

package com.rutron.canary;

import com.alibaba.cloud.nacos.NacosDiscoveryProperties;
import com.alibaba.cloud.nacos.NacosServiceManager;
import com.alibaba.cloud.nacos.ribbon.ExtendBalancer;
import com.alibaba.cloud.nacos.ribbon.NacosServer;
import com.alibaba.nacos.api.naming.NamingService;
import com.alibaba.nacos.api.naming.pojo.Instance;
import com.netflix.client.config.IClientConfig;
import com.netflix.loadbalancer.AbstractLoadBalancerRule;
import com.netflix.loadbalancer.DynamicServerListLoadBalancer;
import com.netflix.loadbalancer.Server;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.StringUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.util.CollectionUtils;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;

/**
 * @author liwenchao
 */
@Slf4j
public class CanaryBalancerRule extends AbstractLoadBalancerRule {

    @Autowired
    private NacosDiscoveryProperties nacosDiscoveryProperties;

    @Autowired
    private NacosServiceManager nacosServiceManager;

    public CanaryBalancerRule() {

    }

    @Override
    public void initWithNiwsConfig(IClientConfig iClientConfig) {

    }

    @Override
    public Server choose(Object key) {
        try {
            String clusterName = this.nacosDiscoveryProperties.getClusterName();
            String group = this.nacosDiscoveryProperties.getGroup();
            Map<String, String> ribbonAttributes = this.nacosDiscoveryProperties.getMetadata();
            DynamicServerListLoadBalancer loadBalancer = (DynamicServerListLoadBalancer) getLoadBalancer();
            String serviceName = loadBalancer.getName();
            NamingService namingService = this.nacosServiceManager.getNamingService(this.nacosDiscoveryProperties.getNacosProperties());
            List<Instance> allInstances = namingService.selectInstances(serviceName, group, true);
            List<Instance> grayInstances = new ArrayList<>();
            List<Instance> noneGrayInstances = new ArrayList<>();
            Instance toBeChooseInstance;
            if (CollectionUtils.isEmpty(allInstances)) {
                log.warn("no instance in service {}", serviceName);
                return null;
            } else {
                if (StringUtils.isNotBlank(clusterName)) {
                    for (Instance instance : allInstances) {
                        Map<String, String> metadata = instance.getMetadata();
                        //当前服务的灰度标签和被调用的服务的灰度标签比,相同则灰色
                        if (!ribbonAttributes.containsKey(GrayConstant.GRAY_TAG) || !metadata.containsKey(GrayConstant.GRAY_TAG)) {
                            noneGrayInstances.add(instance);
                        } else if (ribbonAttributes.get(GrayConstant.GRAY_TAG).trim().equalsIgnoreCase(metadata.get(GrayConstant.GRAY_TAG).trim())) {
                            grayInstances.add(instance);
                        } else if (!StringUtils.isBlank(metadata.get(GrayConstant.GRAY_TAG))) {
                            noneGrayInstances.add(instance);
                        }
                    }
                }
                if (grayInstances.size() > 0) {
                    toBeChooseInstance = ExtendBalancer.getHostByRandomWeight2(grayInstances);
                    return new NacosServer(toBeChooseInstance);
                }
                if (noneGrayInstances.size() > 0) {
                    toBeChooseInstance = ExtendBalancer.getHostByRandomWeight2(noneGrayInstances);
                } else {
                    toBeChooseInstance = ExtendBalancer.getHostByRandomWeight2(allInstances);
                }
                return new NacosServer(toBeChooseInstance);
            }
        } catch (Exception e) {
            log.warn("NacosRule error", e);
            return null;
        }
    }
}

RibbonAutoConfiguration.java

package com.rutron.canary;

import com.netflix.loadbalancer.IRule;
import org.springframework.context.annotation.Bean;

/**
 * @author liwenchao
 */
public class RibbonAutoConfiguration {

    /**
     * 全局配置指定负载均衡策略
     */
    @Bean
    public IRule canaryBalancerRule() {
        return new CanaryBalancerRule();
    }
}

spring.factories

org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
  com.rutron.canary.RibbonAutoConfiguration

?调用者和被调用者添加元数据

{

????"preserved.register.source": "SPRING_CLOUD",

????"version":"v2"

}