Eureka元数据

获取元数据信息

从Eureka Server获取

元数据举例

<application>
   <name>SERVICE-SMS</name>
   <instance>
   <instanceId>30.136.133.11:service-sms:8002</instanceId>
   <hostName>30.136.133.11</hostName>
   <app>SERVICE-SMS</app>
   <ipAddr>30.136.133.11</ipAddr>
   <status>UP</status>
   <overriddenstatus>UNKNOWN</overriddenstatus>
   <port enabled="true">8002</port>
   <securePort enabled="false">443</securePort>
   <countryId>1</countryId>
   <dataCenterInfo class="com.netflix.appinfo.InstanceInfo$DefaultDataCenterInfo">
   <name>MyOwn</name>
   </dataCenterInfo>
   <leaseInfo>
   <renewalIntervalInSecs>1</renewalIntervalInSecs>
   <durationInSecs>1</durationInSecs>
   <registrationTimestamp>1579673388471</registrationTimestamp>
   <lastRenewalTimestamp>1579673470319</lastRenewalTimestamp>
   <evictionTimestamp>0</evictionTimestamp>
   <serviceUpTimestamp>1579673387755</serviceUpTimestamp>
   </leaseInfo>
   <metadata>
   <user.password>root</user.password>
   <management.port>8002</management.port>
   <jmx.port>62449</jmx.port>
   <user.name>root</user.name>
   </metadata>
   <homePageUrl>http://30.136.133.11:8002/</homePageUrl>
   <statusPageUrl>http://30.136.133.11:8002/actuator/info</statusPageUrl>
   <healthCheckUrl>http://30.136.133.11:8002/actuator/health</healthCheckUrl>
   <vipAddress>service-sms</vipAddress>
   <secureVipAddress>service-sms</secureVipAddress>
   <isCoordinatingDiscoveryServer>false</isCoordinatingDiscoveryServer>
   <lastUpdatedTimestamp>1579673388471</lastUpdatedTimestamp>
   <lastDirtyTimestamp>1579673387301</lastDirtyTimestamp>
   <actionType>ADDED</actionType>
   </instance>
   </application>

手写获取元数据

在一个eureka client（api-listen-order）中，写一个controller

import org.springframework.cloud.client.discovery.DiscoveryClient;

@RestController
@RequestMapping("/service-instance")
public class ServiceInstanceController {
    
    @Autowired
    private DiscoveryClient discoveryClient;
    
    @GetMapping("/query-by-application-name/{applicationName}")
    public List<ServiceInstance> getInstance(@PathVariable String applicationName){
        
        return discoveryClient.getInstances(applicationName);
        
    }

}

• 启动eureka（7900）单节点
• 启动api-listen-order

自己开发

• http://localhost:8084/service-instance/query-by-application-name/api-listen-order
• http://localhost:8084/service-instance/query-by-application-name/service-sms
• 结果看到一堆json信息
• 表示api-listen-order在eureka server中的实例信息

标准元数据和自定义元数据

标准元数据：主机名，ip，端口，健康检查等信息

会被发布到注册表中，用于服务间调用

自定义元数据

eureka.instance.metadata-map

自定义key:自定义value，可以直接在application.properites文件中配置

远程客户端访问。自定义属性。

api-listen-order中ServiceInstanceController，读取instance信息

启动eureka，api-listen-order,

http://localhost:8084/service-instance/query-by-application-name/api-listen-order

{
       "host": "127.0.0.1",
       "port": 8084,
       "metadata": {
           "yueyi": "2019",
           "user.password": "root",
           "management.port": "8084",
           "jmx.port": "61378",
           "user.name": "root"
       },
       "secure": false,
       "uri": "http://127.0.0.1:8084",
       "instanceId": "api-listen-order:30.136.133.11:port",
       "serviceId": "API-LISTEN-ORDER",
       "instanceInfo": {
           "instanceId": "api-listen-order:30.136.133.11:port",
           "app": "API-LISTEN-ORDER",
           "appGroupName": null,
           "ipAddr": "127.0.0.1",
           "sid": "na",
           "homePageUrl": "http://127.0.0.1:8084/",
           "statusPageUrl": "http://127.0.0.1:8084/actuator/info",
           "healthCheckUrl": "http://127.0.0.1:8084/actuator/health",
           "secureHealthCheckUrl": null,
           "vipAddress": "api-listen-order",
           "secureVipAddress": "api-listen-order",
           "countryId": 1,
           "dataCenterInfo": {
               "@class": "com.netflix.appinfo.InstanceInfo$DefaultDataCenterInfo",
               "name": "MyOwn"
           },
           "hostName": "127.0.0.1",
           "status": "UP",
           "overriddenStatus": "UNKNOWN",
           "leaseInfo": {
               "renewalIntervalInSecs": 1,
               "durationInSecs": 1,
               "registrationTimestamp": 1579489514655,
               "lastRenewalTimestamp": 1579489524146,
               "evictionTimestamp": 0,
               "serviceUpTimestamp": 1579489514147
           },
           "isCoordinatingDiscoveryServer": false,
           "metadata": {
               "yueyi": "2019",
               "user.password": "root",
               "management.port": "8084",
               "jmx.port": "61378",
               "user.name": "root"
           },
           "lastUpdatedTimestamp": 1579489514655,
           "lastDirtyTimestamp": 1579489514111,
           "actionType": "ADDED",
           "asgName": null
       },
       "scheme": null
   }

自定义元数据，可以结合ribbon 分发规则使用

网关做分发规则选择服务时，可以作为依据

灰度发布，有用，例子

   client端：
   eureka:
     instance:
       metadataMap:
         tag: pre-prd

调用方   

List<ServiceInstance> instances =  discoveryClient.getInstances(applicationName);
for (ServiceInstance serviceInstance : instances) {
   Map<String, String> metadata = serviceInstance.getMetadata();
   String metaValue = metadata.get("yueyi");
   log.info("元数据："+metaValue);
}

获取到元数据

• 分发的时候，根据app客户端传过来的参数：比如加tag=pre,只分发到pre-prd的eureka client。
• 在新发布的app版本带tag参数，就可以实现灰度测试