聊聊如何基于eureka元数据扩展namespace功能@慕课网原创_慕课网

前言

最近朋友部门接手供方微服务项目过来运维，那套微服务的技术栈是springcloud Netflix，和朋友部门的微服务技术栈刚好匹配。当时朋友部门的想法，既然都是同一套技术体系，那些基础服务治理组件比如注册中心之类，就共用同一套。然而在落地实施的过程中，发现供方提供的微服务项目服务有些serviceId和朋友部门他们已有服务serviceId名字竟然一模一样。这样就有问题了，eureka服务发现是通过serviceId识别

朋友部门的策略是将供方微服务项目serviceId改掉，比如原本serviceId是user，就改成xxx-user。然而调整后，发现供方微服务某些微服务会报错，后面了解到供方仅提供应用层代码，有些核心代码库他们是不提供的。朋友他们部门也考虑要不就替换自己已有服务的serviceId，后边发现可行性也不大，因为朋友他们微服务也对其他部门输出了一些能力，如果改动，就得通知相关方进行改动，这边会涉及到一些沟通成本等非技术性因素。

后边朋友就和我交流了一下方案。首先问题点的本质是serviceId一样引起的吗？乍看一下，好像是这样。我们换个角度考虑这个问题，是不是也可以说是因为隔离性做得不够好导致。于是我就跟朋友说，如果把eureka切换成nacos，对你部门的切换成本大不大。朋友说代码层虽然仅需切换jar和配置即可实现，但是因为版本原因，如果切换，他们也只能用到nacos 1版本的能力。其次他部门对注册中心的性能要求也不高，但对注册中心的稳定性要求比较高，如果切换，他们需要做很多测试方面的工作，仅仅只是因为这个隔离性，他更倾向部署多个eureka。

聊到后面朋友就在吐槽eureka，为啥不能像nacos或者k8s那样搞个namespace来做隔离。基于朋友这个想法，我就跟他说，我帮你扩展一下，让eureka也拥有仿nacos namespace的能力

实现思路

注: 本文以朋友他们公司的微服务版本springcloud Hoxton.SR3来讲解

实现的核心逻辑：利用注册中心都有的元数据，即metaMap，以及配合注册中心具备的服务发现能力进行扩展

核心实现逻辑

1、元数据扩展

a、新建扩展配置类

@ConfigurationProperties(prefix = "eureka.instance.ext")
@Data
@AllArgsConstructor
@NoArgsConstructor
public class EurekaInstanceProperties {

    private String namespace = Constant.META_INFO_DEAFULT_NAMESPACE;

    private String group = Constant.META_INFO_DEAFULT_GROUP;

    private boolean loadBalanceAllowCross;

}

b、元数据扩展填充

public class EurekaInstanceSmartInitializingSingleton implements SmartInitializingSingleton, ApplicationContextAware {


    private ApplicationContext applicationContext;

    @Override
    public void afterSingletonsInstantiated() {
        EurekaInstanceProperties eurekaInstanceProperties = applicationContext.getBean(EurekaInstanceProperties.class);
        EurekaInstanceConfigBean bean = applicationContext.getBean(EurekaInstanceConfigBean.class);
        Map<String, String> metadataMap = bean.getMetadataMap();
        metadataMap.put(Constant.META_INFO_KEY_NAMESPACE,eurekaInstanceProperties.getNamespace());
        metadataMap.put(Constant.META_INFO_KEY_GROUP,eurekaInstanceProperties.getGroup());

    }

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        this.applicationContext = applicationContext;
    }
}

2、eureka服务端面板改造

a、status.ftlh页面逻辑改造

在项目eureka服务端的src/main/resource目录下新建/templates/eureka文件夹，将eureka原本有的status.ftlh拷贝过来，因为我们要对这个status.ftlh进行改造。而status.ftlh原本位置是放在

在status.ftlh添加如下内容

b、微调EurekaController内容

EurekaController是eureka服务用来面板展示的控制器，可以在eureka的服务端的项目建一个EurekaController一模一样的类，形如

注：也可以自己自定义一个controller，反正这个controller就是用来页面渲染用的

对如下方法进行微调

org.springframework.cloud.netflix.eureka.server.EurekaController#populateApps

微调内容如下

	for (InstanceInfo info : app.getInstances()) {
				String id = info.getId();
				String url = info.getStatusPageUrl();
				Map<String, String> metadata = info.getMetadata();
				String group = StringUtils.isEmpty(metadata.get("group")) ? "default" : metadata.get("group");
				String namespace = StringUtils.isEmpty(metadata.get("namespace")) ? "default" : metadata.get("namespace");
				String metaInfo = url + "_" + namespace + "_" + group;
			
				List<Pair<String, String>> list = instancesByStatus
						.computeIfAbsent(status, k -> new ArrayList<>());
				list.add(new Pair<>(id, metaInfo));
			}
		
			for (Map.Entry<InstanceInfo.InstanceStatus, List<Pair<String, String>>> entry : instancesByStatus
					.entrySet()) {
				List<Pair<String, String>> value = entry.getValue();
				InstanceInfo.InstanceStatus status = entry.getKey();
				LinkedHashMap<String, Object> instanceData = new LinkedHashMap<>();
		

				for (Pair<String, String> p : value) {
					LinkedHashMap<String, Object> instance = new LinkedHashMap<>();
					instances.add(instance);
					instance.put("id", p.first());
					String metaInfo = p.second();
					String[] metaInfoArr = metaInfo.split("_");
					String url = metaInfoArr[0];
					instance.put("url", url);
					String namespace = metaInfoArr[1];
					instance.put("namespace", namespace);
					String group = metaInfoArr[2];
					instance.put("group", group);
					boolean isHref = url != null && url.startsWith("http");
					instance.put("isHref", isHref);
				
		}
		model.put("apps", apps);

c、改造后的面板展示

注：在eureka的客户端需配形如下配置

3、服务发现改造

a、重写com.netflix.loadbalancer.ServerList

参照eureka的服务发现配置类

	@Bean
	@ConditionalOnMissingBean
	public ServerList<?> ribbonServerList(IClientConfig config,
			Provider<EurekaClient> eurekaClientProvider) {
		if (this.propertiesFactory.isSet(ServerList.class, serviceId)) {
			return this.propertiesFactory.get(ServerList.class, config, serviceId);
		}
		DiscoveryEnabledNIWSServerList discoveryServerList = new DiscoveryEnabledNIWSServerList(
				config, eurekaClientProvider);
		DomainExtractingServerList serverList = new DomainExtractingServerList(
				discoveryServerList, config, this.approximateZoneFromHostname);
		return serverList;
	}

我们可以发现我们仅需改造DiscoveryEnabledNIWSServerList即可

@Slf4j
public class CustomDiscoveryEnabledNIWSServerList extends DiscoveryEnabledNIWSServerList {

    private final Provider<EurekaClient> eurekaClientProvider;
    private final EurekaInstanceProperties eurekaInstanceProperties;

    public CustomDiscoveryEnabledNIWSServerList(IClientConfig clientConfig, Provider<EurekaClient> eurekaClientProvider,EurekaInstanceProperties eurekaInstanceProperties) {
        this.eurekaClientProvider = eurekaClientProvider;
        this.eurekaInstanceProperties = eurekaInstanceProperties;
        initWithNiwsConfig(clientConfig);
    }

    @Override
    public List<DiscoveryEnabledServer> getInitialListOfServers(){
        List<DiscoveryEnabledServer> initialListOfServers = super.getInitialListOfServers();

        return selectListOfServersByMetaInfo(initialListOfServers);

    }

    @Override
    public List<DiscoveryEnabledServer> getUpdatedListOfServers(){
        List<DiscoveryEnabledServer> updatedListOfServers = super.getUpdatedListOfServers();
        return selectListOfServersByMetaInfo(updatedListOfServers);

    }

    private List<DiscoveryEnabledServer> selectListOfServersByMetaInfo(List<DiscoveryEnabledServer> discoveryEnabledServerList){
        List<DiscoveryEnabledServer> discoveryEnabledServersByMetaInfo = new ArrayList<>();
        if(!CollectionUtils.isEmpty(discoveryEnabledServerList)){
            for (DiscoveryEnabledServer discoveryEnabledServer : discoveryEnabledServerList) {
                Map<String, String> metadata = discoveryEnabledServer.getInstanceInfo().getMetadata();
                String namespace = metadata.get(Constant.META_INFO_KEY_NAMESPACE);
                String group = metadata.get(Constant.META_INFO_KEY_GROUP);
                if(eurekaInstanceProperties.getNamespace().equals(namespace) &&
                        eurekaInstanceProperties.getGroup().equals(group)){
                    discoveryEnabledServersByMetaInfo.add(discoveryEnabledServer);
                }

            }
        }

        if(CollectionUtils.isEmpty(discoveryEnabledServersByMetaInfo) &&
                eurekaInstanceProperties.isLoadBalanceAllowCross()){
            log.warn("not found enabledServerList in namespace : 【{}】 and group : 【{}】. will select default enabledServerList by isLoadBalanceAllowCross is {}",eurekaInstanceProperties.getNamespace(),eurekaInstanceProperties.getGroup(),eurekaInstanceProperties.isLoadBalanceAllowCross());
            return discoveryEnabledServerList;
        }

        return discoveryEnabledServersByMetaInfo;
    }


}

b、配置我们重写后的ServerList

@Configuration
public class EurekaClientAutoConfiguration extends EurekaRibbonClientConfiguration{

    @Value("${ribbon.eureka.approximateZoneFromHostname:false}")
    private boolean approximateZoneFromHostname = false;

    @RibbonClientName
    private String serviceId = "client";;


    @Autowired
    private PropertiesFactory propertiesFactory;



    @Bean
    @Primary
    public ServerList<?> ribbonServerList(IClientConfig config,
                                    Provider<EurekaClient> eurekaClientProvider, EurekaInstanceProperties properties) {
        if (this.propertiesFactory.isSet(ServerList.class, serviceId)) {
            return this.propertiesFactory.get(ServerList.class, config, serviceId);
        }
        DiscoveryEnabledNIWSServerList discoveryServerList = new CustomDiscoveryEnabledNIWSServerList(
                config, eurekaClientProvider,properties);
        DomainExtractingServerList serverList = new DomainExtractingServerList(
                discoveryServerList, config, this.approximateZoneFromHostname);
        return serverList;
    }
}

c、修改ribbionclient的默认配置

@Configuration(proxyBeanMethods = false)
@EnableConfigurationProperties
@ConditionalOnRibbonAndEurekaEnabled
@AutoConfigureAfter(RibbonAutoConfiguration.class)
@RibbonClients(defaultConfiguration = EurekaClientAutoConfiguration.class)
public class RibbonEurekaAutoConfiguration {

}

测试

示例服务：网关、消费者服务、提供者服务、eureka

相关的eureka配置内容如下

1、网关：

网关占用端口：8000

eureka:
  instance:
    instance-id: ${spring.application.name}:${spring.cloud.client.ip-address}:${spring.application.instance_id:${server.port}}
    prefer-ip-address: ${PREFER_IP:true}  #是否选择IP注册
 #   ip-address: ${IP_ADDRESS:localhost}   #指定IP地址注册
    lease-renewal-interval-in-seconds: 5  #续约更新时间间隔（默认30秒）,使得eureka及时剔除无效服务
    lease-expiration-duration-in-seconds: 10 #续约到期时间（默认90秒）
    hostname: ${HOSTNAME:${spring.application.name}}
    ext:
      namespace: dev
      group: lybgeek

  client:
    service-url:
      defaultZone: ${EUREKA_CLIENT_SERVICEURL_DEFAULTZONE:http://localhost:8761/eureka/}
      #缩短延迟向服务端注册的时间、默认40s
    initial-instance-info-replication-interval-seconds: 10
    #提高Eureka-Client端拉取Server注册信息的频率,默认30s
    registry-fetch-interval-seconds: 5

2、消费者

消费者1： 占用端口：6614

eureka:
  instance:
    instance-id: ${spring.application.name}:${spring.cloud.client.ip-address}:${spring.application.instance_id:${server.port}}
    prefer-ip-address: ${PREFER_IP:true}  #是否选择IP注册
 #   ip-address: ${IP_ADDRESS:localhost}   #指定IP地址注册
    lease-renewal-interval-in-seconds: 5  #续约更新时间间隔（默认30秒）,使得eureka及时剔除无效服务
    lease-expiration-duration-in-seconds: 10 #续约到期时间（默认90秒）
    hostname: ${HOSTNAME:${spring.application.name}}
    ext:
      group: lybgeek
      namespace: dev
  client:
    service-url:
      defaultZone: ${EUREKA_CLIENT_SERVICEURL_DEFAULTZONE:http://localhost:8761/eureka/}
      #缩短延迟向服务端注册的时间、默认40s
    initial-instance-info-replication-interval-seconds: 10
    #提高Eureka-Client端拉取Server注册信息的频率,默认30s
    registry-fetch-interval-seconds: 5

消费者2： 占用端口：6613

eureka:
  instance:
    instance-id: ${spring.application.name}:${spring.cloud.client.ip-address}:${spring.application.instance_id:${server.port}}
    prefer-ip-address: ${PREFER_IP:true}  #是否选择IP注册
 #   ip-address: ${IP_ADDRESS:localhost}   #指定IP地址注册
    lease-renewal-interval-in-seconds: 5  #续约更新时间间隔（默认30秒）,使得eureka及时剔除无效服务
    lease-expiration-duration-in-seconds: 10 #续约到期时间（默认90秒）
    hostname: ${HOSTNAME:${spring.application.name}}
    ext:
      group: lybgeek6613
      namespace: dev
  client:
    service-url:
      defaultZone: ${EUREKA_CLIENT_SERVICEURL_DEFAULTZONE:http://localhost:8761/eureka/}
      #缩短延迟向服务端注册的时间、默认40s
    initial-instance-info-replication-interval-seconds: 10
    #提高Eureka-Client端拉取Server注册信息的频率,默认30s
    registry-fetch-interval-seconds: 5

控制层示例

@RestController
@RequestMapping("instance")
public class InstanceInfoController {

    @InstancePort
    private String port;

    @InstanceName
    private String instanceName;

    @Autowired
    private InstanceServiceFeign instanceServiceFeign;

    @GetMapping("list")
    public List<InstanceInfo> list(){
        List<InstanceInfo> instanceInfos = new ArrayList<>();
        InstanceInfo comsumeInstanceInfo = InstanceInfo.builder()
                .port(port).name(instanceName).build();
        instanceInfos.add(comsumeInstanceInfo);
        InstanceInfo providerInstanceInfo = null;
        try {
            providerInstanceInfo = instanceServiceFeign.getInstanceInfo();
            instanceInfos.add(providerInstanceInfo);
        } catch (Exception e) {
            e.printStackTrace();
        }


        return instanceInfos;

    }
}

3、提供者

提供者1： 占用端口:6605

eureka:
  instance:
    instance-id: ${spring.application.name}:${spring.cloud.client.ip-address}:${spring.application.instance_id:${server.port}}
    prefer-ip-address: ${PREFER_IP:true}  #是否选择IP注册
 #   ip-address: ${IP_ADDRESS:localhost}   #指定IP地址注册
    lease-renewal-interval-in-seconds: 5  #续约更新时间间隔（默认30秒）,使得eureka及时剔除无效服务
    lease-expiration-duration-in-seconds: 10 #续约到期时间（默认90秒）
    hostname: ${HOSTNAME:${spring.application.name}}
    ext:
      namespace: dev
      group: lybgeek
  client:
    service-url:
      defaultZone: ${EUREKA_CLIENT_SERVICEURL_DEFAULTZONE:http://localhost:8761/eureka/}
      #缩短延迟向服务端注册的时间、默认40s
    initial-instance-info-replication-interval-seconds: 10
    #提高Eureka-Client端拉取Server注册信息的频率,默认30s
    registry-fetch-interval-seconds: 5

提供者2： 占用端口:6604

eureka:
  instance:
    instance-id: ${spring.application.name}:${spring.cloud.client.ip-address}:${spring.application.instance_id:${server.port}}
    prefer-ip-address: ${PREFER_IP:true}  #是否选择IP注册
 #   ip-address: ${IP_ADDRESS:localhost}   #指定IP地址注册
    lease-renewal-interval-in-seconds: 5  #续约更新时间间隔（默认30秒）,使得eureka及时剔除无效服务
    lease-expiration-duration-in-seconds: 10 #续约到期时间（默认90秒）
    hostname: ${HOSTNAME:${spring.application.name}}
    ext:
      namespace: dev
      group: lybgeek6613
  client:
    service-url:
      defaultZone: ${EUREKA_CLIENT_SERVICEURL_DEFAULTZONE:http://localhost:8761/eureka/}
      #缩短延迟向服务端注册的时间、默认40s
    initial-instance-info-replication-interval-seconds: 10
    #提高Eureka-Client端拉取Server注册信息的频率,默认30s
    registry-fetch-interval-seconds: 5

控制层示例

@RestController
@RequestMapping(InstanceServiceFeign.PATH)
public class InstanceServiceFeignImpl implements InstanceServiceFeign {

    @InstancePort
    private String port;

    @InstanceName
    private String instanceName;


    @Override
    public InstanceInfo getInstanceInfo() {
        return InstanceInfo.builder()
                .name(instanceName).port(port).build();
    }
}

访问eureka面板

通过网关访问会发现不管访问多少次，网关只能命中namespace为dev、group为lybgeek的服务，说明隔离效果生效

当我们的服务和其他服务不属于同个namespace或者group时，可以通过配置load-balance-allow-cross: true，实现跨namespace和group访问。配置形如下

eureka:
  instance:
    instance-id: ${spring.application.name}:${spring.cloud.client.ip-address}:${spring.application.instance_id:${server.port}}
    prefer-ip-address: ${PREFER_IP:true}  #是否选择IP注册
 #   ip-address: ${IP_ADDRESS:localhost}   #指定IP地址注册
    lease-renewal-interval-in-seconds: 5  #续约更新时间间隔（默认30秒）,使得eureka及时剔除无效服务
    lease-expiration-duration-in-seconds: 10 #续约到期时间（默认90秒）
    hostname: ${HOSTNAME:${spring.application.name}}
    ext:
      namespace: dev
      group: lybgeek123
      load-balance-allow-cross: true

我们再通过网关访问一下

观察控制台，会发现出现警告

总结

本文主要是仿造nacos的一些思路，对eureka进行扩展。其实注册中心的功能大同小异，尤其集成springcloud后，基本上都有固定套路了。本文只是实现eureka 服务发现隔离的一种方式，也可以通过eureka本身的zone和region，通过自定义负载均衡策略来实现。最后eureka instance其实也有namespace的属性，只是在springcloud集成，被忽略了

demo链接

https://github.com/lyb-geek/springboot-cloud-metadata-ext