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本文主要研究一下EurekaRibbonClientConfiguration

EurekaRibbonClientConfiguration

spring-cloud-netflix-eureka-client-2.0.0.RELEASE-sources.jar!/org/springframework/cloud/netflix/ribbon/eureka/EurekaRibbonClientConfiguration.java

/*** Preprocessor that configures defaults for eureka-discovered ribbon clients. Such as:* <code>@zone</code>, NIWSServerListClassName, DeploymentContextBasedVipAddresses,* NFLoadBalancerRuleClassName, NIWSServerListFilterClassName and more** @author Spencer Gibb* @author Dave Syer* @author Ryan Baxter*/
@Configuration
public class EurekaRibbonClientConfiguration {private static final Log log = LogFactory.getLog(EurekaRibbonClientConfiguration.class);@Value("${ribbon.eureka.approximateZoneFromHostname:false}")private boolean approximateZoneFromHostname = false;@RibbonClientNameprivate String serviceId = "client";@Autowired(required = false)private EurekaClientConfig clientConfig;@Autowired(required = false)private EurekaInstanceConfig eurekaConfig;@Autowiredprivate PropertiesFactory propertiesFactory;public EurekaRibbonClientConfiguration() {}public EurekaRibbonClientConfiguration(EurekaClientConfig clientConfig,String serviceId, EurekaInstanceConfig eurekaConfig,boolean approximateZoneFromHostname) {this.clientConfig = clientConfig;this.serviceId = serviceId;this.eurekaConfig = eurekaConfig;this.approximateZoneFromHostname = approximateZoneFromHostname;}@Bean@ConditionalOnMissingBeanpublic IPing ribbonPing(IClientConfig config) {if (this.propertiesFactory.isSet(IPing.class, serviceId)) {return this.propertiesFactory.get(IPing.class, config, serviceId);}NIWSDiscoveryPing ping = new NIWSDiscoveryPing();ping.initWithNiwsConfig(config);return ping;}@Bean@ConditionalOnMissingBeanpublic 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;}@Beanpublic ServerIntrospector serverIntrospector() {return new EurekaServerIntrospector();}@PostConstructpublic void preprocess() {String zone = ConfigurationManager.getDeploymentContext().getValue(ContextKey.zone);if (this.clientConfig != null && StringUtils.isEmpty(zone)) {if (this.approximateZoneFromHostname && this.eurekaConfig != null) {String approxZone = ZoneUtils.extractApproximateZone(this.eurekaConfig.getHostName(false));log.debug("Setting Zone To " + approxZone);ConfigurationManager.getDeploymentContext().setValue(ContextKey.zone,approxZone);}else {String availabilityZone = this.eurekaConfig == null ? null: this.eurekaConfig.getMetadataMap().get("zone");if (availabilityZone == null) {String[] zones = this.clientConfig.getAvailabilityZones(this.clientConfig.getRegion());// Pick the first one from the regions we want to connect toavailabilityZone = zones != null && zones.length > 0 ? zones[0]: null;}if (availabilityZone != null) {// You can set this with archaius.deployment.* (maybe requires// custom deployment context)?ConfigurationManager.getDeploymentContext().setValue(ContextKey.zone,availabilityZone);}}}RibbonUtils.initializeRibbonDefaults(serviceId);}}

• 创建了NIWSDiscoveryPing、DomainExtractingServerList、EurekaServerIntrospector
• 初始化之后调用RibbonUtils.initializeRibbonDefaults(serviceId)

NIWSDiscoveryPing

ribbon-eureka-2.2.5-sources.jar!/com/netflix/niws/loadbalancer/NIWSDiscoveryPing.java

/*** "Ping" Discovery Client* i.e. we dont do a real "ping". We just assume that the server is up if Discovery Client says so* @author stonse**/
public class NIWSDiscoveryPing extends AbstractLoadBalancerPing {BaseLoadBalancer lb = null; public NIWSDiscoveryPing() {}public BaseLoadBalancer getLb() {return lb;}/*** Non IPing interface method - only set this if you care about the "newServers Feature"* @param lb*/public void setLb(BaseLoadBalancer lb) {this.lb = lb;}public boolean isAlive(Server server) {boolean isAlive = true;if (server!=null && server instanceof DiscoveryEnabledServer){DiscoveryEnabledServer dServer = (DiscoveryEnabledServer)server;             InstanceInfo instanceInfo = dServer.getInstanceInfo();if (instanceInfo!=null){                    InstanceStatus status = instanceInfo.getStatus();if (status!=null){isAlive = status.equals(InstanceStatus.UP);}}}return isAlive;}@Overridepublic void initWithNiwsConfig(IClientConfig clientConfig) {}}

• NIWSDiscoveryPing通过获取实例的eureka状态来判断是否健康

DomainExtractingServerList

spring-cloud-netflix-eureka-client-2.0.0.RELEASE-sources.jar!/org/springframework/cloud/netflix/ribbon/eureka/DomainExtractingServerList.java

public class DomainExtractingServerList implements ServerList<DiscoveryEnabledServer> {private ServerList<DiscoveryEnabledServer> list;private final RibbonProperties ribbon;private boolean approximateZoneFromHostname;public DomainExtractingServerList(ServerList<DiscoveryEnabledServer> list,IClientConfig clientConfig, boolean approximateZoneFromHostname) {this.list = list;this.ribbon = RibbonProperties.from(clientConfig);this.approximateZoneFromHostname = approximateZoneFromHostname;}@Overridepublic List<DiscoveryEnabledServer> getInitialListOfServers() {List<DiscoveryEnabledServer> servers = setZones(this.list.getInitialListOfServers());return servers;}@Overridepublic List<DiscoveryEnabledServer> getUpdatedListOfServers() {List<DiscoveryEnabledServer> servers = setZones(this.list.getUpdatedListOfServers());return servers;}private List<DiscoveryEnabledServer> setZones(List<DiscoveryEnabledServer> servers) {List<DiscoveryEnabledServer> result = new ArrayList<>();boolean isSecure = this.ribbon.isSecure(true);boolean shouldUseIpAddr = this.ribbon.isUseIPAddrForServer();for (DiscoveryEnabledServer server : servers) {result.add(new DomainExtractingServer(server, isSecure, shouldUseIpAddr,this.approximateZoneFromHostname));}return result;}}class DomainExtractingServer extends DiscoveryEnabledServer {private String id;@Overridepublic String getId() {return id;}@Overridepublic void setId(String id) {this.id = id;}public DomainExtractingServer(DiscoveryEnabledServer server, boolean useSecurePort,boolean useIpAddr, boolean approximateZoneFromHostname) {// host and port are set in super()super(server.getInstanceInfo(), useSecurePort, useIpAddr);if (server.getInstanceInfo().getMetadata().containsKey("zone")) {setZone(server.getInstanceInfo().getMetadata().get("zone"));}else if (approximateZoneFromHostname) {setZone(ZoneUtils.extractApproximateZone(server.getHost()));}else {setZone(server.getZone());}setId(extractId(server));setAlive(server.isAlive());setReadyToServe(server.isReadyToServe());}private String extractId(Server server) {if (server instanceof DiscoveryEnabledServer) {DiscoveryEnabledServer enabled = (DiscoveryEnabledServer) server;InstanceInfo instance = enabled.getInstanceInfo();if (instance.getMetadata().containsKey("instanceId")) {return instance.getHostName()+":"+instance.getMetadata().get("instanceId");}}return super.getId();}
}

• getInitialListOfServers及getUpdatedListOfServers都调用了setZones从eureka的metadata读取zone

EurekaServerIntrospector

spring-cloud-netflix-eureka-client-2.0.0.RELEASE-sources.jar!/org/springframework/cloud/netflix/ribbon/eureka/EurekaServerIntrospector.java

public class EurekaServerIntrospector extends DefaultServerIntrospector {@Overridepublic boolean isSecure(Server server) {if (server instanceof DiscoveryEnabledServer) {DiscoveryEnabledServer discoveryServer = (DiscoveryEnabledServer) server;return discoveryServer.getInstanceInfo().isPortEnabled(InstanceInfo.PortType.SECURE);}return super.isSecure(server);}@Overridepublic Map<String, String> getMetadata(Server server) {if (server instanceof DiscoveryEnabledServer) {DiscoveryEnabledServer discoveryServer = (DiscoveryEnabledServer) server;return discoveryServer.getInstanceInfo().getMetadata();}return super.getMetadata(server);}
}

• 这里从eureka的instanceInfo获取metadata

小结

EurekaRibbonClientConfiguration主要是给ribbon配置eureka相关的特性，主要是NIWSDiscoveryPing、DomainExtractingServerList、EurekaServerIntrospector这几个：

• 其中NIWSDiscoveryPing通过eureka中instance的状态来判断是否ping的通
• DomainExtractingServerList提供getInitialListOfServers以及getUpdatedListOfServers方法
• EurekaServerIntrospector主要是通过instanceInfo获取metadata

doc

• 16.5 Using Ribbon with Eureka