问题：
带ribbon的Spring cloud不会忽略停机的服务器
姜淇
我在使用eureka进行客户端负载平衡时遵循了spring指南：
https://spring.io/guides/gs/client-side-load-balancing/
但是当我关闭了3个服务器实例中的任何一个后，我得到了一个连接拒绝异常。客户端仍然试图向这些服务器发送请求，而不是忽略未通过ping的服务器。当这些服务器被ping时，我会得到一个异常，当客户端试图向这些服务器发送请求时，也会得到同样的异常。看起来功能区正在对配置中列出的所有服务器执行某种盲目循环，并且忽略了我关闭的服务器。
应用yml
spring:
application:
name: user
server:
port: 8888
say-hello:
ribbon:
eureka:
enabled: false
listOfServers: localhost:8090,localhost:9092,localhost:9999
ServerListRefreshInterval: 15000
SayHelloConfiguration.java
package hello;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import com.netflix.client.config.IClientConfig;
import com.netflix.loadbalancer.IPing;
import com.netflix.loadbalancer.IRule;
import com.netflix.loadbalancer.PingUrl;
import com.netflix.loadbalancer.AvailabilityFilteringRule;
public class SayHelloConfiguration {
@Autowired
IClientConfig ribbonClientConfig;
@Bean
public IPing ribbonPing(IClientConfig config) {
return new PingUrl();
}
@Bean
public IRule ribbonRule(IClientConfig config) {
return new AvailabilityFilteringRule();
}
}
用户应用程序。JAVA
package hello;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.cloud.netflix.ribbon.RibbonClient;
@SpringBootApplication
@RestController
@RibbonClient(name = "say-hello", configuration = SayHelloConfiguration.class)
public class UserApplication {
@LoadBalanced
@Bean
RestTemplate restTemplate(){
return new RestTemplate();
}
@Autowired
RestTemplate restTemplate;
@RequestMapping("/hi")
public String hi(@RequestParam(value="name", defaultValue="Artaban") String name) {
String greeting = this.restTemplate.getForObject("http://say-hello/greeting", String.class);
return String.format("%s, %s!", greeting, name);
}
public static void main(String[] args) {
SpringApplication.run(UserApplication.class, args);
}
}
pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>hello</groupId>
<artifactId>user</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>jar</packaging>
<name>user</name>
<description>Demo project for Spring Boot</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.2.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-ribbon</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>Camden.SR5</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
<repositories>
<repository>
<id>spring-snapshots</id>
<name>Spring Snapshots</name>
<url>https://repo.spring.io/snapshot</url>
<snapshots>
<enabled>true</enabled>
</snapshots>
</repository>
<repository>
<id>spring-milestones</id>
<name>Spring Milestones</name>
<url>https://repo.spring.io/milestone</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</repository>
</repositories>
</project>
这是我在关闭服务器时遇到的例外情况：
java.net.ConnectException: Connection refused: connect
at java.net.DualStackPlainSocketImpl.connect0(Native Method)
at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:79)
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
at java.net.Socket.connect(Socket.java:589)
at org.apache.http.conn.scheme.PlainSocketFactory.connectSocket(PlainSocketFactory.java:121)
at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:180)
at org.apache.http.impl.conn.ManagedClientConnectionImpl.open(ManagedClientConnectionImpl.java:326)
at org.apache.http.impl.client.DefaultRequestDirector.tryConnect(DefaultRequestDirector.java:610)
at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:445)
at org.apache.http.impl.client.AbstractHttpClient.doExecute(AbstractHttpClient.java:835)
at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:83)
at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:108)
at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:56)
at com.netflix.loadbalancer.PingUrl.isAlive(PingUrl.java:126)
at com.netflix.loadbalancer.BaseLoadBalancer$SerialPingStrategy.pingServers(BaseLoadBalancer.java:927)
at com.netflix.loadbalancer.BaseLoadBalancer$Pinger.runPinger(BaseLoadBalancer.java:676)
at com.netflix.loadbalancer.BaseLoadBalancer$PingTask.run(BaseLoadBalancer.java:629)
at java.util.TimerThread.mainLoop(Timer.java:555)
at java.util.TimerThread.run(Timer.java:505)
这是客户端应用程序向关闭的服务器发送请求时遇到的例外情况：
java.net.ConnectException: Connection refused: connect
at java.net.DualStackPlainSocketImpl.connect0(Native Method) ~[na:1.8.0_101]
at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:79) ~[na:1.8.0_101]
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350) ~[na:1.8.0_101]
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206) ~[na:1.8.0_101]
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188) ~[na:1.8.0_101]
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172) ~[na:1.8.0_101]
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392) ~[na:1.8.0_101]
at java.net.Socket.connect(Socket.java:589) ~[na:1.8.0_101]
at java.net.Socket.connect(Socket.java:538) ~[na:1.8.0_101]
at sun.net.NetworkClient.doConnect(NetworkClient.java:180) ~[na:1.8.0_101]
at sun.net.www.http.HttpClient.openServer(HttpClient.java:432) ~[na:1.8.0_101]
at sun.net.www.http.HttpClient.openServer(HttpClient.java:527) ~[na:1.8.0_101]
at sun.net.www.http.HttpClient.<init>(HttpClient.java:211) ~[na:1.8.0_101]
at sun.net.www.http.HttpClient.New(HttpClient.java:308) ~[na:1.8.0_101]
at sun.net.www.http.HttpClient.New(HttpClient.java:326) ~[na:1.8.0_101]
at sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(HttpURLConnection.java:1169) ~[na:1.8.0_101]
at sun.net.www.protocol.http.HttpURLConnection.plainConnect0(HttpURLConnection.java:1105) ~[na:1.8.0_101]
at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:999) ~[na:1.8.0_101]
at sun.net.www.protocol.http.HttpURLConnection.connect(HttpURLConnection.java:933) ~[na:1.8.0_101]
at org.springframework.http.client.SimpleBufferingClientHttpRequest.executeInternal(SimpleBufferingClientHttpRequest.java:78) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.http.client.AbstractBufferingClientHttpRequest.executeInternal(AbstractBufferingClientHttpRequest.java:48) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.http.client.AbstractClientHttpRequest.execute(AbstractClientHttpRequest.java:53) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.http.client.InterceptingClientHttpRequest$InterceptingRequestExecution.execute(InterceptingClientHttpRequest.java:99) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.cloud.client.loadbalancer.LoadBalancerRequestFactory$1.apply(LoadBalancerRequestFactory.java:63) ~[spring-cloud-commons-1.1.7.RELEASE.jar:1.1.7.RELEASE]
at org.springframework.cloud.client.loadbalancer.LoadBalancerRequestFactory$1.apply(LoadBalancerRequestFactory.java:52) ~[spring-cloud-commons-1.1.7.RELEASE.jar:1.1.7.RELEASE]
at org.springframework.cloud.netflix.ribbon.RibbonLoadBalancerClient.execute(RibbonLoadBalancerClient.java:98) ~[spring-cloud-netflix-core-1.2.5.RELEASE.jar:1.2.5.RELEASE]
at org.springframework.cloud.client.loadbalancer.RetryLoadBalancerInterceptor$1.doWithRetry(RetryLoadBalancerInterceptor.java:88) ~[spring-cloud-commons-1.1.7.RELEASE.jar:1.1.7.RELEASE]
at org.springframework.cloud.client.loadbalancer.RetryLoadBalancerInterceptor$1.doWithRetry(RetryLoadBalancerInterceptor.java:76) ~[spring-cloud-commons-1.1.7.RELEASE.jar:1.1.7.RELEASE]
at org.springframework.retry.support.RetryTemplate.doExecute(RetryTemplate.java:286) ~[spring-retry-1.2.0.RELEASE.jar:na]
at org.springframework.retry.support.RetryTemplate.execute(RetryTemplate.java:163) ~[spring-retry-1.2.0.RELEASE.jar:na]
at org.springframework.cloud.client.loadbalancer.RetryLoadBalancerInterceptor.intercept(RetryLoadBalancerInterceptor.java:76) ~[spring-cloud-commons-1.1.7.RELEASE.jar:1.1.7.RELEASE]
at org.springframework.http.client.InterceptingClientHttpRequest$InterceptingRequestExecution.execute(InterceptingClientHttpRequest.java:86) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.http.client.InterceptingClientHttpRequest.executeInternal(InterceptingClientHttpRequest.java:70) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.http.client.AbstractBufferingClientHttpRequest.executeInternal(AbstractBufferingClientHttpRequest.java:48) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.http.client.AbstractClientHttpRequest.execute(AbstractClientHttpRequest.java:53) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:652) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:613) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.web.client.RestTemplate.getForObject(RestTemplate.java:287) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at hello.UserApplication.hi(UserApplication.java:31) ~[classes/:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_101]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_101]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_101]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_101]
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:133) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:116) ~[spring-webmvc-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827) ~[spring-webmvc-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738) ~[spring-webmvc-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85) ~[spring-webmvc-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:963) ~[spring-webmvc-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:897) ~[spring-webmvc-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970) ~[spring-webmvc-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861) ~[spring-webmvc-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:622) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846) ~[spring-webmvc-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:230) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) ~[tomcat-embed-websocket-8.5.11.jar:8.5.11]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:105) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:81) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:474) [tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) [tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79) [tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) [tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:349) [tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:783) [tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:798) [tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1434) [tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-8.5.11.jar:8.5.11]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [na:1.8.0_101]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [na:1.8.0_101]
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-8.5.11.jar:8.5.11]
at java.lang.Thread.run(Thread.java:745) [na:1.8.0_101]
我错过了什么？预期的行为是，在ping未能关闭服务器后，客户端应用程序将忽略这些服务器，不再向它们发送请求。
谢啦
共有3个答案
锺离飞鸣
如本教程所述，这是一个简化的示例：
Ribbon中的负载均衡器通常从Netflix Eureka服务注册表获取服务器列表。。。为了简单起见，我们跳过了Eureka
您的应用程序不能知道您的服务器不再可用。这是服务注册中心（例如eureka）的工作，它可以处理通过心跳机制发现哪些服务是死的还是活的...
尤钱明
如果下一台服务器不存在，您可以告诉ribbon重试该服务器：
say-hello:
ribbon:
MaxAutoRetriesNextServer: 1
这也适用于使用eureka。因为服务注册表会删除延迟的服务器，如果它们没有崩溃，也没有取消注册。
此外，您需要添加以下依赖项：
<dependency>
<groupId>org.springframework.retry</groupId>
<artifactId>spring-retry</artifactId>
</dependency>
施英哲
好的，所以我遇到了这个问题，这是我试图解决它的方法。不确定这是否是理想的方法，但这似乎足以满足我现在的需求。
IPing实现仅帮助确定服务器是活的还是死的。它不会将服务器从可用服务器列表中删除。
根据这里的Javadoc，Ribbon似乎将何时将服务器标记为不健康的决定留给了客户机。这似乎是一个安全的选择。如果服务器在1次ping和3次ping失败时被标记为不可用，并且ping时是否有退避，所有这些都取决于您手头的应用程序类型，因此只有客户端可以做出安全的选择。
然而，对于如何在Spring Cloud Netflix的上下文中向负载平衡器添加ServerStatusChangeListener，目前还没有明确的指示。因此，我认为如果我们有这种能力，那将是调用BaseLoadBalancer的正确位置。在监听器中标记ServerDown（服务器）。春云大师的（@Spencergib）在这里很重要。
接下来是我如何实施我的解决方案。除了IPing，我还配置了一个IRule，并从com扩展了我的规则。netflix。负载平衡器。可用性过滤器程序。由于此规则会筛选出发生电路故障的服务器，因此在将其作为所选服务器返回之前，您唯一需要添加的是检查服务器本身是否处于活动状态。
@Configuration
public class MyLoadBalancerConfig {
@Bean
public IRule ribbonRule(IClientConfig config) {
return new AvailabilityBasedServerSelectionRule();
}
@Bean
public IPing ribbonPing() {
return server -> {
try {
// TODO: ping your server to decide if health check has passed or not
Thread.sleep(2000);
} catch (InterruptedException e) {
e.printStackTrace();
}
return true;
};
}
@Bean
public ServerList<Server> ribbonServerList(IClientConfig config) {
return new ServerList<Server>() {
@Override
public List<Server> getInitialListOfServers() {
Server server1 = new Server("server1");
Server server2 = new Server("server2");
return new ArrayList<>(Arrays.asList(server1, server2));
}
@Override
public List<Server> getUpdatedListOfServers() {
Server server3 = new Server("server3");
Server server4 = new Server("server4");
return new ArrayList<>(Arrays.asList(server3, server4));
}
};
}
}
和
public class AvailabilityBasedServerSelectionRule extends AvailabilityFilteringRule {
@Override
public Server choose(Object key) {
Server chosenServer = super.choose(key);
int count = 1;
List<Server> reachableServers = this.getLoadBalancer().getReachableServers();
List<Server> allServers = this.getLoadBalancer().getAllServers();
if(reachableServers.size() > 0) {
while(!reachableServers.contains(chosenServer) && count++ < allServers.size()) {
chosenServer = super.choose(key);
}
}
System.out.println("chosenServer.isAlive() = " + chosenServer.isAlive());
return chosenServer;
}
}
因此，AvailabilityBasedServerSelectionRule始终返回处于活动状态且未断开电路的服务器。我还没有发现这种解决方法有任何问题。我会更新这篇文章，如果我发现任何，因为我继续这个方法。祝你好运
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