Eureka 的 Application Service client的注冊以及执行演示样例
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1. Eureka 服务器启动
本文 demo 要求 Eureka Server 已经部署好，并已经启动。关于架设步骤參考博客《Linux 下 Eureka 服务器的部署》。
Eureka 服务器启动以后，能够通过 http://serverIP:8080/eureka/ 或者 http://serverIP:8080/eureka/v2/apps/ 浏览已注冊到 Eureka 的 Application Service。
比方作者在开发环境 PC 訪问服务器端的 http://serverIP:8080/eureka/v2/apps/。页面返回结果例如以下：
<applications> <versions__delta>1</versions__delta> <apps__hashcode>UP_1_</apps__hashcode> <application> <name>EUREKA</name> <instance> <hostName>localhost.localdomain</hostName> <app>EUREKA</app> <ipAddr>127.0.0.1</ipAddr> <status>UP</status> <overriddenstatus>UNKNOWN</overriddenstatus> <port enabled="true">8080</port> <securePort enabled="false">443</securePort> <countryId>1</countryId> <dataCenterInfo class="com.netflix.appinfo.InstanceInfo$DefaultDataCenterInfo"> <name>MyOwn</name> </dataCenterInfo> <leaseInfo> <renewalIntervalInSecs>30</renewalIntervalInSecs> <durationInSecs>90</durationInSecs> <registrationTimestamp>1404789864122</registrationTimestamp> <lastRenewalTimestamp>1404798147096</lastRenewalTimestamp> <evictionTimestamp>0</evictionTimestamp> <serviceUpTimestamp>1404789841811</serviceUpTimestamp> </leaseInfo> <metadata class="java.util.Collections$EmptyMap" /> <appGroupName>UNKNOWN</appGroupName> <homePageUrl>http://localhost.localdomain:8080/</homePageUrl> <statusPageUrl>http://localhost.localdomain:8080/Status</statusPageUrl> <healthCheckUrl>http://localhost.localdomain:8080/healthcheck</healthCheckUrl> <vipAddress>eureka.mydomain.net</vipAddress> <isCoordinatingDiscoveryServer>true</isCoordinatingDiscoveryServer> <lastUpdatedTimestamp>1404789864122</lastUpdatedTimestamp> <lastDirtyTimestamp>1404789841863</lastDirtyTimestamp> <actionType>ADDED</actionType> </instance> </application> </applications>
apps__hashcode 是 1，能够看出眼下仅仅有一个 Application Service 注冊到了 Eureka Server，这个名为 Eureka 的 Application Service 仅仅有一个实例，就是这台 Eureka Server 它自己 - localhost.localdomain。为何 Eureka Server 自己也是一个 Application Service 呢？这也是 Eureka 架构健壮性 feature 之中的一个。Eureka Server 之间也会相互注冊，并且还会将注冊到自己的 Application Service 注冊给其它 Eureka Server，避免了一台 Eureka Server 宕机所造成的区域性服务瘫痪。
2. Application Service 配置文件的编写
我们的负载均衡服务器就用官方提供 demo 里的 sampleservice 下的 sample-eureka-service.properties 就可以，当然还要依据实际情况修正一下。比方把 eureka.name 改为我们自己定义的 Application 名以区分开其它服务，把 eureka.port(本服务将会执行并侍服请求的端口)改为我们的 Service 服务器开放的侍服端口 1935，eureka.serviceUrl.default(默认情况下本服务将要注冊到的 Eureka 服务器)：http://serverIP:8080/eureka/v2/：
###Eureka Client configuration for Sample Eureka Service #Properties based configuration for eureka client. The properties specified here is mostly what the users #need to change. All of these can be specified as a java system property with -D option (eg)-Deureka.region=us-east-1 #For additional tuning options refer <url to go here> #Region where eureka is deployed -For AWS specify one of the AWS regions, for other datacenters specify a arbitrary string #indicating the region.This is normally specified as a -D option (eg) -Deureka.region=us-east-1 eureka.region=default #Name of the application to be identified by other services eureka.name=sampleservice #Virtual host name by which the clients identifies this service eureka.vipAddress=sampleservice.mydomain.net #The port where the service will be running and serving requests eureka.port=1935 #For eureka clients running in eureka server, it needs to connect to servers in other zones eureka.preferSameZone=false #Change this if you want to use a DNS based lookup for determining other eureka servers. For example #of specifying the DNS entries, check the eureka-client-test.properties, eureka-client-prod.properties eureka.shouldUseDns=false eureka.us-east-1.availabilityZones=default eureka.serviceUrl.default=http://serverIP:8080/eureka/v2/
3. 日志配置
就用官方提供 demo 里的 sampleservice 下的 log4j.properties 就可以，当然还要依据实际须要修正一下，比方给 com.defonds.wms.module.server 包的输出级别设置为 DEBUG(log4j.properties 追加 log4j.logger.com.defonds.wms.module.server=DEBUG)。以方便我们研发期跟踪调试。
log4j.rootCategory=INFO,stdout log4j.appender.stdout=org.apache.log4j.ConsoleAppender log4j.appender.stdout.layout=org.apache.log4j.PatternLayout log4j.appender.stdout.layout.ConversionPattern=%d %-5p %C:%L [%t] [%M] %m%n
4. Application Service 启动时注冊 Eureka
我们希望每台负载均衡服务器在启动时就注冊给 Eureka，以及时承担负载。注冊代码例如以下所看到的：
private static final DynamicPropertyFactory configInstance = com.netflix.config.DynamicPropertyFactory.getInstance();
private static final Logger logger = LoggerFactory.getLogger(SampleEurekaService.class);
public void registerWithEureka() {
// Register with Eureka
DiscoveryManager.getInstance().initComponent(
new MyDataCenterInstanceConfig(),
new DefaultEurekaClientConfig());
ApplicationInfoManager.getInstance().setInstanceStatus(
InstanceStatus.UP);
}第一句载入本地配置文件，initComponent 句依据配置初始化这台 Eureka Application Service。并且注冊到 Eureka Server，setInstanceStatus 句指示本台 Application Service 已启动。准备好侍服网络请求。
5. Application Service 侍服网络请求
Application Service 的 Eureka Server 初始化以及注冊是异步的。须要一段时间。我们想要在确认初始化并注冊成功之后，提供一个 Socket 服务，以供网络请求。demo 须要。这个服务是一次性的，仅仅提供一次 Socket 侍服。
侍服完一次请求后，本 Socket 服务就关闭，并将自己从 Eureka Server 取消注冊。
String vipAddress = configInstance.getStringProperty(
"eureka.vipAddress", "sampleservice.mydomain.net").get();
InstanceInfo nextServerInfo = null;
while (nextServerInfo == null) {
try {
nextServerInfo = DiscoveryManager.getInstance()
.getDiscoveryClient()
.getNextServerFromEureka(vipAddress, false);
} catch (Throwable e) {
System.out
.println("Waiting for service to register with eureka..");
try {
Thread.sleep(10000);
} catch (InterruptedException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
}
}
System.out.println("Service started and ready to process requests..");
try {
ServerSocket serverSocket = new ServerSocket(configInstance
.getIntProperty("eureka.port", 8010).get());
final Socket s = serverSocket.accept();
System.out
.println("Client got connected..Processing request from the client");
processRequest(s);
} catch (IOException e) {
e.printStackTrace();
}Socket 侍服 processRequest 方法具体例如以下：
private void processRequest(final Socket s) {
try {
BufferedReader rd = new BufferedReader(new InputStreamReader(
s.getInputStream()));
String line = rd.readLine();
if (line != null) {
System.out.println("Received the request from the client.");
}
PrintStream out = new PrintStream(s.getOutputStream());
System.out.println("Sending the response to the client...");
out.println("Reponse at " + new Date());
} catch (Throwable e) {
System.err.println("Error processing requests");
} finally {
if (s != null) {
try {
s.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
} 6. Application Service 关闭时取消注冊
就像 Spring 管理的对象。初始化、销毁都统一管理起来一样。我们希望本台 Application Service 实例在关闭时也能将自身占用的系统资源释放出来(比方任务列表的线程关闭)，并且取消掉 Eureka 服务器的注冊。
public void unRegisterWithEureka() {
// Un register from eureka.
DiscoveryManager.getInstance().shutdownComponent();
}7. 执行 demo
如今我们把完整的 Application Service 整理一下。
/*
* Copyright 2012 Netflix, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.netflix.eureka;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Date;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.netflix.appinfo.ApplicationInfoManager;
import com.netflix.appinfo.InstanceInfo;
import com.netflix.appinfo.InstanceInfo.InstanceStatus;
import com.netflix.appinfo.MyDataCenterInstanceConfig;
import com.netflix.config.DynamicPropertyFactory;
import com.netflix.discovery.DefaultEurekaClientConfig;
import com.netflix.discovery.DiscoveryManager;
/**
* Sample Eureka service that registers with Eureka to receive and process
* requests.
*
* <p>
* This example just receives one request and exits once it receives the request
* after processing it.
* </p>
*
* @author Karthik Ranganathan
*
*/
public class SampleEurekaService {
private static final DynamicPropertyFactory configInstance = com.netflix.config.DynamicPropertyFactory
.getInstance();
private static final Logger logger = LoggerFactory
.getLogger(SampleEurekaService.class);
public void registerWithEureka() {
// Register with Eureka
DiscoveryManager.getInstance().initComponent(
new MyDataCenterInstanceConfig(),
new DefaultEurekaClientConfig());
ApplicationInfoManager.getInstance().setInstanceStatus(
InstanceStatus.UP);
String vipAddress = configInstance.getStringProperty(
"eureka.vipAddress", "sampleservice.mydomain.net").get();
InstanceInfo nextServerInfo = null;
while (nextServerInfo == null) {
try {
nextServerInfo = DiscoveryManager.getInstance()
.getDiscoveryClient()
.getNextServerFromEureka(vipAddress, false);
} catch (Throwable e) {
System.out
.println("Waiting for service to register with eureka..");
try {
Thread.sleep(10000);
} catch (InterruptedException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
}
}
System.out.println("Service started and ready to process requests..");
try {
ServerSocket serverSocket = new ServerSocket(configInstance
.getIntProperty("eureka.port", 8010).get());
final Socket s = serverSocket.accept();
System.out
.println("Client got connected..Processing request from the client");
processRequest(s);
} catch (IOException e) {
e.printStackTrace();
}
this.unRegisterWithEureka();
System.out.println("Shutting down server.Demo over.");
}
public void unRegisterWithEureka() {
// Un register from eureka.
DiscoveryManager.getInstance().shutdownComponent();
}
private void processRequest(final Socket s) {
try {
BufferedReader rd = new BufferedReader(new InputStreamReader(
s.getInputStream()));
String line = rd.readLine();
if (line != null) {
System.out.println("Received the request from the client.");
}
PrintStream out = new PrintStream(s.getOutputStream());
System.out.println("Sending the response to the client...");
out.println("Reponse at " + new Date());
} catch (Throwable e) {
System.err.println("Error processing requests");
} finally {
if (s != null) {
try {
s.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
public static void main(String args[]) {
SampleEurekaService sampleEurekaService = new SampleEurekaService();
sampleEurekaService.registerWithEureka();
}
}非常明显我们的 SampleEurekaService 类须要非常多依赖包，这些包都在 eureka-server-1.1.134.war 包里的 WEB-INF/lib 文件夹下，直接拷贝进我们 demo 的 CLASSPATH。不用一个个去找了，还避免了版本号冲突所带来的不必要麻烦。eureka-client-1.1.134.jar 能够去 http://mvnrepository.com/artifact/com.netflix.eureka/eureka-client/1.1.134 下载，或者直接 maven 依赖导入：
<dependency> <groupId>com.netflix.eureka</groupId> <artifactId>eureka-client</artifactId> <version>1.1.134</version> </dependency>
类完毕了、环境配置好了。接下来把第二、三步写好的 sample-eureka-service.properties、log4j.properties 也拷贝进 CLASSPATH。接下来就能够执行 demo 了。直接 run SampleEurekaService，发现报下面错误：
2014-07-07 17:01:50,141 WARN com.netflix.config.sources.URLConfigurationSource:120 [main] [<init>] No URLs will be polled as dynamic configuration sources.
2014-07-07 17:01:50,144 INFO com.netflix.config.sources.URLConfigurationSource:121 [main] [<init>] To enable URLs as dynamic configuration sources, define System property archaius.configurationSource.additionalUrls or make config.properties available on classpath.
2014-07-07 17:01:50,178 INFO com.netflix.config.DynamicPropertyFactory:281 [main] [getInstance] DynamicPropertyFactory is initialized with configuration sources: [email protected]
2014-07-07 17:01:58,982 WARN com.netflix.appinfo.PropertiesInstanceConfig:349 [main] [init] Cannot find the properties specified : eureka-client. This may be okay if there are other environment specific properties or the configuration is installed with a different mechanism.
2014-07-07 17:02:00,140 WARN com.netflix.discovery.DefaultEurekaClientConfig:95 [main] [init] Cannot find the properties specified : eureka-client. This may be okay if there are other environment specific properties or the configuration is installed with a different mechanism.
2014-07-07 17:02:03,559 INFO com.netflix.appinfo.providers.EurekaConfigBasedInstanceInfoProvider:79 [main] [get] Setting initial instance status as: STARTING
Exception in thread "main" java.lang.RuntimeException: Failed to initialize DiscoveryClient!
at com.netflix.discovery.DiscoveryClient.<init>(DiscoveryClient.java:235)
at com.netflix.discovery.DiscoveryClient.<init>(DiscoveryClient.java:169)
at com.netflix.discovery.DiscoveryManager.initComponent(DiscoveryManager.java:84)
at com.netflix.eureka.SampleEurekaService.registerWithEureka(SampleEurekaService.java:60)
at com.netflix.eureka.SampleEurekaService.main(SampleEurekaService.java:139)
Caused by: java.lang.IllegalArgumentException: DiscoveryClient: invalid serviceUrl specified!
at com.netflix.discovery.DiscoveryClient.getEurekaServiceUrlsFromConfig(DiscoveryClient.java:574)
at com.netflix.discovery.DiscoveryClient.getDiscoveryServiceUrls(DiscoveryClient.java:1180)
at com.netflix.discovery.DiscoveryClient.<init>(DiscoveryClient.java:186)
... 4 more
原来 Archaius 不认 sample-eureka-service.properties。没有把我们的配置成功载入。Archaius 的官方说，Archaius 在默认情况下(就是不指定 properties 文件的情况下)会在应用的 classpath 中寻找一个名为 config.properties 的文件并读取其内容作为配置属性。
好吧。我们把 sample-eureka-service.properties 重命名为 config.properties，然后又一次执行 SampleEurekaService。
这次执行成功了，没有再报错。
訪问服务器端的 http://serverIP:8080/eureka/v2/apps/。显演示样例如以下页面信息：
<applications> <versions__delta>1</versions__delta> <apps__hashcode>UP_2_</apps__hashcode> <application> <name>SAMPLESERVICE</name> <instance> <hostName>defonds-win7</hostName> <app>SAMPLESERVICE</app> <ipAddr>172.21.40.134</ipAddr> <status>UP</status> <overriddenstatus>UNKNOWN</overriddenstatus> <port enabled="true">1935</port> <securePort enabled="false">443</securePort> <countryId>1</countryId> <dataCenterInfo class="com.netflix.appinfo.InstanceInfo$DefaultDataCenterInfo"> <name>MyOwn</name> </dataCenterInfo> <leaseInfo> <renewalIntervalInSecs>30</renewalIntervalInSecs> <durationInSecs>90</durationInSecs> <registrationTimestamp>1404812488643</registrationTimestamp> <lastRenewalTimestamp>1404812609036</lastRenewalTimestamp> <evictionTimestamp>0</evictionTimestamp> <serviceUpTimestamp>1404812458545</serviceUpTimestamp> </leaseInfo> <metadata class="java.util.Collections$EmptyMap" /> <appGroupName>UNKNOWN</appGroupName> <homePageUrl>http://defonds-win7:1935/</homePageUrl> <statusPageUrl>http://defonds-win7:1935/Status</statusPageUrl> <healthCheckUrl>http://defonds-win7:1935/healthcheck</healthCheckUrl> <vipAddress>sampleservice.mydomain.net</vipAddress> <isCoordinatingDiscoveryServer>false</isCoordinatingDiscoveryServer> <lastUpdatedTimestamp>1404812488643</lastUpdatedTimestamp> <lastDirtyTimestamp>1404812513644</lastDirtyTimestamp> <actionType>ADDED</actionType> </instance> </application> <application> <name>EUREKA</name> <instance> <hostName>localhost.localdomain</hostName> <app>EUREKA</app> <ipAddr>127.0.0.1</ipAddr> <status>UP</status> <overriddenstatus>UNKNOWN</overriddenstatus> <port enabled="true">8080</port> <securePort enabled="false">443</securePort> <countryId>1</countryId> <dataCenterInfo class="com.netflix.appinfo.InstanceInfo$DefaultDataCenterInfo"> <name>MyOwn</name> </dataCenterInfo> <leaseInfo> <renewalIntervalInSecs>30</renewalIntervalInSecs> <durationInSecs>90</durationInSecs> <registrationTimestamp>1404812408111</registrationTimestamp> <lastRenewalTimestamp>1404812618042</lastRenewalTimestamp> <evictionTimestamp>0</evictionTimestamp> <serviceUpTimestamp>1404812385938</serviceUpTimestamp> </leaseInfo> <metadata class="java.util.Collections$EmptyMap" /> <appGroupName>UNKNOWN</appGroupName> <homePageUrl>http://localhost.localdomain:8080/</homePageUrl> <statusPageUrl>http://localhost.localdomain:8080/Status </statusPageUrl> <healthCheckUrl>http://localhost.localdomain:8080/healthcheck </healthCheckUrl> <vipAddress>eureka.mydomain.net</vipAddress> <isCoordinatingDiscoveryServer>true</isCoordinatingDiscoveryServer> <lastUpdatedTimestamp>1404812408111</lastUpdatedTimestamp> <lastDirtyTimestamp>1404812385985</lastDirtyTimestamp> <actionType>ADDED</actionType> </instance> </application> </applications>
apps__hashcode 变成 2 了。
能够看出多了一个 defonds-win7 名字的 instance，它的 IP 地址正是我执行 demo 的 PC 地址 172.21.40.134。訪问 http://serverIP:8080/eureka/ 也能够看到该 instance：
证明我们的 Application Service 已经成功注冊到该台 Eureka Server。
我们等待 Eureka Server 心跳訪问该 Application Service。或者自己手工訪问该 Application Service，以达成该服务器关闭条件，将其关闭。Application Service 成功取消注冊。
完整的 demo log 例如以下：
2014-07-08 10:06:54,124 INFO com.netflix.config.sources.URLConfigurationSource:125 [main] [<init>] URLs to be used as dynamic configuration source: [file:/D:/javaprojects/test/bin/config.properties]
2014-07-08 10:06:54,259 INFO com.netflix.config.DynamicPropertyFactory:281 [main] [getInstance] DynamicPropertyFactory is initialized with configuration sources: [email protected]
2014-07-08 10:08:32,464 WARN com.netflix.appinfo.PropertiesInstanceConfig:349 [main] [init] Cannot find the properties specified : eureka-client. This may be okay if there are other environment specific properties or the configuration is installed with a different mechanism.
2014-07-08 10:08:35,592 WARN com.netflix.discovery.DefaultEurekaClientConfig:95 [main] [init] Cannot find the properties specified : eureka-client. This may be okay if there are other environment specific properties or the configuration is installed with a different mechanism.
2014-07-08 10:08:45,835 INFO com.netflix.appinfo.providers.EurekaConfigBasedInstanceInfoProvider:79 [main] [get] Setting initial instance status as: STARTING
2014-07-08 10:08:46,331 WARN com.netflix.discovery.DiscoveryClient:1339 [main] [getZoneOffset] DISCOVERY: Could not pick a zone based on preferred zone settings. My zone - defaultZone, preferSameZone- false. Defaulting to defaultZone
2014-07-08 10:08:49,276 INFO com.netflix.discovery.DiscoveryClient:646 [main] [fetchRegistry] Disable delta property : false
2014-07-08 10:08:49,277 INFO com.netflix.discovery.DiscoveryClient:647 [main] [fetchRegistry] Single vip registry refresh property : null
2014-07-08 10:08:49,277 INFO com.netflix.discovery.DiscoveryClient:648 [main] [fetchRegistry] Force full registry fetch : false
2014-07-08 10:08:49,277 INFO com.netflix.discovery.DiscoveryClient:649 [main] [fetchRegistry] Application is null : false
2014-07-08 10:08:49,277 INFO com.netflix.discovery.DiscoveryClient:650 [main] [fetchRegistry] Registered Applications size is zero : true
2014-07-08 10:08:49,278 INFO com.netflix.discovery.DiscoveryClient:652 [main] [fetchRegistry] Application version is -1: true
2014-07-08 10:08:49,705 INFO com.netflix.discovery.DiscoveryClient:992 [main] [makeRemoteCall] Finished a call to service url http://serverIP:8080/eureka/v2/ and url path apps/ with status code 200.
2014-07-08 10:08:49,706 INFO com.netflix.discovery.DiscoveryClient:758 [main] [getAndStoreFullRegistry] Getting all instance registry info from the eureka server
2014-07-08 10:08:50,501 INFO com.netflix.discovery.DiscoveryClient:765 [main] [getAndStoreFullRegistry] The response status is 200
2014-07-08 10:08:50,504 INFO com.netflix.discovery.DiscoveryClient:1056 [main] [initScheduledTasks] Starting heartbeat executor: renew interval is: 30
2014-07-08 10:09:20,508 INFO com.netflix.discovery.DiscoveryClient:992 [DiscoveryClient-2] [makeRemoteCall] Finished a call to service url http://serverIP:8080/eureka/v2/ and url path apps/delta with status code 200.
2014-07-08 10:09:20,535 INFO com.netflix.discovery.DiscoveryClient$CacheRefreshThread:1542 [DiscoveryClient-2] [run] Completed cache refresh task for discovery. All Apps hash code is Local region apps hashcode: UP_1_, is fetching remote regions? false
2014-07-08 10:09:20,582 INFO com.netflix.discovery.DiscoveryClient:992 [DiscoveryClient-3] [makeRemoteCall] Finished a call to service url http://serverIP:8080/eureka/v2/ and url path apps/SAMPLESERVICE/defonds-win7 with status code 404.
2014-07-08 10:09:20,599 INFO com.netflix.discovery.DiscoveryClient$HeartbeatThread:1415 [DiscoveryClient-3] [run] DiscoveryClient_SAMPLESERVICE/defonds-win7 - Re-registering apps/SAMPLESERVICE
2014-07-08 10:09:20,600 INFO com.netflix.discovery.DiscoveryClient:509 [DiscoveryClient-3] [register] DiscoveryClient_SAMPLESERVICE/defonds-win7: registering service...
2014-07-08 10:09:20,648 INFO com.netflix.discovery.DiscoveryClient:992 [DiscoveryClient-3] [makeRemoteCall] Finished a call to service url http://serverIP:8080/eureka/v2/ and url path apps/SAMPLESERVICE with status code 204.
2014-07-08 10:09:20,649 INFO com.netflix.discovery.DiscoveryClient:514 [DiscoveryClient-3] [register] DiscoveryClient_SAMPLESERVICE/defonds-win7 - registration status: 204
Waiting for service to register with eureka..
2014-07-08 10:09:30,513 INFO com.netflix.discovery.DiscoveryClient$InstanceInfoReplicator:1476 [DiscoveryClient-2] [run] DiscoveryClient_SAMPLESERVICE/defonds-win7 - retransmit instance info with status UP
2014-07-08 10:09:30,514 INFO com.netflix.discovery.DiscoveryClient:509 [DiscoveryClient-2] [register] DiscoveryClient_SAMPLESERVICE/defonds-win7: registering service...
2014-07-08 10:09:30,561 INFO com.netflix.discovery.DiscoveryClient:992 [DiscoveryClient-2] [makeRemoteCall] Finished a call to service url http://serverIP:8080/eureka/v2/ and url path apps/SAMPLESERVICE with status code 204.
2014-07-08 10:09:30,562 INFO com.netflix.discovery.DiscoveryClient:514 [DiscoveryClient-2] [register] DiscoveryClient_SAMPLESERVICE/defonds-win7 - registration status: 204
2014-07-08 10:09:50,540 INFO com.netflix.discovery.DiscoveryClient:992 [DiscoveryClient-1] [makeRemoteCall] Finished a call to service url http://serverIP:8080/eureka/v2/ and url path apps/delta with status code 200.
2014-07-08 10:09:50,543 INFO com.netflix.discovery.DiscoveryClient$CacheRefreshThread:1542 [DiscoveryClient-1] [run] Completed cache refresh task for discovery. All Apps hash code is Local region apps hashcode: UP_2_, is fetching remote regions?
false
2014-07-08 10:09:50,654 INFO com.netflix.discovery.DiscoveryClient:992 [DiscoveryClient-1] [makeRemoteCall] Finished a call to service url http://serverIP:8080/eureka/v2/ and url path apps/SAMPLESERVICE/defonds-win7 with status code 404.
2014-07-08 10:09:50,654 INFO com.netflix.discovery.DiscoveryClient$HeartbeatThread:1415 [DiscoveryClient-1] [run] DiscoveryClient_SAMPLESERVICE/defonds-win7 - Re-registering apps/SAMPLESERVICE
2014-07-08 10:09:50,654 INFO com.netflix.discovery.DiscoveryClient:509 [DiscoveryClient-1] [register] DiscoveryClient_SAMPLESERVICE/defonds-win7: registering service...
2014-07-08 10:09:50,674 INFO com.netflix.discovery.DiscoveryClient:992 [DiscoveryClient-1] [makeRemoteCall] Finished a call to service url http://serverIP:8080/eureka/v2/ and url path apps/SAMPLESERVICE with status code 204.
2014-07-08 10:09:50,674 INFO com.netflix.discovery.DiscoveryClient:514 [DiscoveryClient-1] [register] DiscoveryClient_SAMPLESERVICE/defonds-win7 - registration status: 204
Service started and ready to process requests..
2014-07-08 10:10:20,548 INFO com.netflix.discovery.DiscoveryClient:992 [DiscoveryClient-2] [makeRemoteCall] Finished a call to service url http://serverIP:8080/eureka/v2/ and url path apps/delta with status code 200.
2014-07-08 10:10:20,551 INFO com.netflix.discovery.DiscoveryClient$CacheRefreshThread:1542 [DiscoveryClient-2] [run] Completed cache refresh task for discovery. All Apps hash code is Local region apps hashcode: UP_2_, is fetching remote regions? false
2014-07-08 10:10:20,678 INFO com.netflix.discovery.DiscoveryClient:992 [DiscoveryClient-1] [makeRemoteCall] Finished a call to service url http://serverIP:8080/eureka/v2/ and url path apps/SAMPLESERVICE/defonds-win7 with status code 200.
2014-07-08 10:10:50,556 INFO com.netflix.discovery.DiscoveryClient:992 [DiscoveryClient-1] [makeRemoteCall] Finished a call to service url http://serverIP:8080/eureka/v2/ and url path apps/delta with status code 200.
2014-07-08 10:10:50,559 INFO com.netflix.discovery.DiscoveryClient$CacheRefreshThread:1542 [DiscoveryClient-1] [run] Completed cache refresh task for discovery. All Apps hash code is Local region apps hashcode: UP_2_, is fetching remote regions?
false
2014-07-08 10:10:50,681 INFO com.netflix.discovery.DiscoveryClient:992 [DiscoveryClient-0] [makeRemoteCall] Finished a call to service url http://serverIP:8080/eureka/v2/ and url path apps/SAMPLESERVICE/defonds-win7 with status code 200.
2014-07-08 10:11:20,563 INFO com.netflix.discovery.DiscoveryClient:992 [DiscoveryClient-1] [makeRemoteCall] Finished a call to service url http://serverIP:8080/eureka/v2/ and url path apps/delta with status code 200.
2014-07-08 10:11:20,566 INFO com.netflix.discovery.DiscoveryClient$CacheRefreshThread:1542 [DiscoveryClient-1] [run] Completed cache refresh task for discovery. All Apps hash code is Local region apps hashcode: UP_2_, is fetching remote regions?
false
2014-07-08 10:11:20,684 INFO com.netflix.discovery.DiscoveryClient:992 [DiscoveryClient-1] [makeRemoteCall] Finished a call to service url http://serverIP:8080/eureka/v2/ and url path apps/SAMPLESERVICE/defonds-win7 with status code 200.
2014-07-08 10:11:50,570 INFO com.netflix.discovery.DiscoveryClient:992 [DiscoveryClient-2] [makeRemoteCall] Finished a call to service url http://serverIP:8080/eureka/v2/ and url path apps/delta with status code 200.
2014-07-08 10:11:50,573 INFO com.netflix.discovery.DiscoveryClient$CacheRefreshThread:1542 [DiscoveryClient-2] [run] Completed cache refresh task for discovery. All Apps hash code is Local region apps hashcode: UP_2_, is fetching remote regions? false
2014-07-08 10:11:50,687 INFO com.netflix.discovery.DiscoveryClient:992 [DiscoveryClient-1] [makeRemoteCall] Finished a call to service url http://serverIP:8080/eureka/v2/ and url path apps/SAMPLESERVICE/defonds-win7 with status code 200.
2014-07-08 10:12:20,579 INFO com.netflix.discovery.DiscoveryClient:992 [DiscoveryClient-0] [makeRemoteCall] Finished a call to service url http://serverIP:8080/eureka/v2/ and url path apps/delta with status code 200.
2014-07-08 10:12:20,582 INFO com.netflix.discovery.DiscoveryClient$CacheRefreshThread:1542 [DiscoveryClient-0] [run] Completed cache refresh task for discovery. All Apps hash code is Local region apps hashcode: UP_2_, is fetching remote regions?
false
2014-07-08 10:12:20,691 INFO com.netflix.discovery.DiscoveryClient:992 [DiscoveryClient-0] [makeRemoteCall] Finished a call to service url http://serverIP:8080/eureka/v2/ and url path apps/SAMPLESERVICE/defonds-win7 with status code 200.
Client got connected..Processing request from the client
Received the request from the client.
Sending the response to the client...
2014-07-08 10:12:27,188 INFO com.netflix.discovery.DiscoveryClient:992 [main] [makeRemoteCall] Finished a call to service url http://serverIP:8080/eureka/v2/ and url path apps/SAMPLESERVICE/defonds-win7 with status code 200.
2014-07-08 10:12:27,189 INFO com.netflix.discovery.DiscoveryClient:603 [main] [unregister] DiscoveryClient_SAMPLESERVICE/defonds-win7 - deregister status: 200
Shutting down server.Demo over.
麻雀虽小五脏俱全，样例非常easy，但却完整地展现了一个 Application Service 客户端的 Eureka 生命周期。
參考资料
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