关于Spring Cloud Eureka对服务的监控(上线,下线,续约等)

项目上要求要监听各个服务宕机后的信息,发现以前没有做个,于是想了一下,猜想eureka注册中心肯定会提供这类的方法,上网一查,果然发现eureka提供了5的监听器

EurekaInstanceCanceledEvent 服务下线事件
EurekaInstanceRegisteredEvent 服务注册事件
EurekaInstanceRenewedEvent 服务续约事件
EurekaRegistryAvailableEvent Eureka注册中心启动事件
EurekaServerStartedEvent Eureka Server启动事件

那接下来就好说了

第一步 : 引入maven依赖

略: 就是基本的依赖

第二步 : 监听服务

在网上查询了部分资料之后,发现部分的博客缺少一些东西,会对新手有很多的误导,在这里给出一个详细的步骤

Eureka服务端的配置

server:
  port: 8081
eureka:
  instance:
    hostname: localhost
  client:
    registerWithEureka: false
    fetchRegistry: false
    serviceUrl:
      defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/
  server:
      #关闭自我保护
      enable-self-preservation: false
      #清理间隔
      eviction-interval-timer-in-ms: 5000

服务配置这里的 关闭自我保护和清理间隔一定要打开 (虽然我也不知道为什么)

启动类

package com.lh;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;

/**
 * Created by 龙浩 on 2018/7/9.
 */
@SpringBootApplication
@EnableEurekaServer
public class app {
    public static void main(String[] args){
        SpringApplication.run(app.class,args);
    }
}

服务监听类

package com.lh.event;

import com.netflix.appinfo.InstanceInfo;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.cloud.netflix.eureka.server.event.*;
import org.springframework.context.event.EventListener;
import org.springframework.stereotype.Component;


/**
 * Created by 龙浩 on 2018/7/23.
 */
@Component
public class EurekaStateListener {

    private final static Logger logger = LoggerFactory.getLogger(EurekaStateListener.class);

    @EventListener
    public void listen(EurekaInstanceCanceledEvent  event) {
        logger.info("服务{}已下线", event.getAppName());
        logger.info("server地址信息{}", event.getServerId());
    }

    @EventListener
    public void listen(EurekaInstanceRegisteredEvent event) {
        InstanceInfo instanceInfo = event.getInstanceInfo();
        logger.info("服务{}进行注册", instanceInfo.getAppName()+ instanceInfo.getHostName() +"  "+ instanceInfo.getIPAddr() +"  "+ instanceInfo.getPort());
    }

    @EventListener
    public void listen(EurekaInstanceRenewedEvent event) {
        logger.info("服务{}进行续约", event.getServerId() +"  "+ event.getAppName());
    }

    @EventListener
    public void listen(EurekaRegistryAvailableEvent event) {
        logger.info("注册中心启动,{}", System.currentTimeMillis());
    }

    @EventListener
    public void listen(EurekaServerStartedEvent event) {
        logger.info("注册中心服务端启动,{}", System.currentTimeMillis());
    }

}

这里只是简单的记录,实际项目还是要做大量的通知

第三步 : 客户端

客户端配置

spring:
  application:
    name: member
eureka:
  instance:
    # 每间隔1s，向服务端发送一次心跳，证明自己依然”存活“
    lease-renewal-interval-in-seconds: 1
    # 告诉服务端，如果我2s之内没有给你发心跳，就代表我“死”了，将我踢出掉。
    lease-expiration-duration-in-seconds: 2
  client:
    serviceUrl:
      defaultZone: http://localhost:8081/eureka/
server:
  port: 8082

这里的instance配置一定要写,很多新手忘记写这个导致服务下线无法被监听,因为服务下线后eureka没有将该服务踢出

启动类

package com.lh;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;

/**
 * Created by 龙浩 on 2018/7/9.
 */
@SpringBootApplication
@EnableEurekaClient
public class MemberApp {

    public static void main(String[] args){
        SpringApplication.run(MemberApp.class, args);
    }
}

第四步 : 测试

启动服务端,打印如下信息

2018-07-24 09:39:49.590  INFO 16524 --- [      Thread-13] com.lh.event.EurekaStateListener         : 注册中心启动,1532396389590
2018-07-24 09:39:49.591  INFO 16524 --- [      Thread-13] com.lh.event.EurekaStateListener         : 注册中心服务端启动,1532396389591
2018-07-24 09:39:49.631  INFO 16524 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat started on port(s): 8081 (http)
2018-07-24 09:39:49.632  INFO 16524 --- [           main] .s.c.n.e.s.EurekaAutoServiceRegistration : Updating port to 8081
2018-07-24 09:39:49.635  INFO 16524 --- [           main] com.lh.app                               : Started app in 6.512 seconds (JVM running for 7.16)

启动客户端 服务端控制台继续打印如下信息

2018-07-24 09:41:04.656  INFO 16524 --- [nio-8081-exec-2] com.lh.event.EurekaStateListener         : 服务MEMBERDESKTOP-SHDQ5I0  192.168.0.103  8082进行注册
2018-07-24 09:41:04.670  INFO 16524 --- [nio-8081-exec-2] c.n.e.registry.AbstractInstanceRegistry  : Registered instance MEMBER/DESKTOP-SHDQ5I0:member:8082 with status UP (replication=false)
2018-07-24 09:41:05.541  INFO 16524 --- [nio-8081-exec-3] com.lh.event.EurekaStateListener         : 服务DESKTOP-SHDQ5I0:member:8082  MEMBER进行续约
2018-07-24 09:41:06.551  INFO 16524 --- [nio-8081-exec-4] com.lh.event.EurekaStateListener         : 服务DESKTOP-SHDQ5I0:member:8082  MEMBER进行续约
2018-07-24 09:41:07.562  INFO 16524 --- [nio-8081-exec-5] com.lh.event.EurekaStateListener         : 服务DESKTOP-SHDQ5I0:member:8082  MEMBER进行续约
2018-07-24 09:41:08.571  INFO 16524 --- [nio-8081-exec-6] com.lh.event.EurekaStateListener         : 服务DESKTOP-SHDQ5I0:member:8082  MEMBER进行续约

关闭客户端 服务端控制台打印如下信息

2018-07-24 09:41:59.599  INFO 16524 --- [a-EvictionTimer] com.lh.event.EurekaStateListener         : 服务MEMBER已下线
2018-07-24 09:41:59.600  INFO 16524 --- [a-EvictionTimer] com.lh.event.EurekaStateListener         : server地址信息DESKTOP-SHDQ5I0:member:8082
2018-07-24 09:41:59.601  INFO 16524 --- [a-EvictionTimer] c.n.e.registry.AbstractInstanceRegistry  : Cancelled instance MEMBER/DESKTOP-SHDQ5I0:member:8082 (replication=false)