聊聊NacosRibbonClientConfiguration

最新推荐文章于 2024-04-01 21:20:44 发布

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原文链接：https://my.oschina.net/go4it/blog/3081397

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#java

本文深入探讨了NacosRibbonClientConfiguration组件如何在Spring Cloud Alibaba中创建NacosServerList，实现服务发现与负载均衡。NacosServerList继承自Netflix Ribbon的AbstractServerList，通过Nacos的NamingService获取服务实例信息。

序

本文主要研究一下NacosRibbonClientConfiguration

NacosRibbonClientConfiguration

spring-cloud-alibaba-0.9.0.RELEASE/spring-cloud-alibaba-nacos-discovery/src/main/java/org/springframework/cloud/alibaba/nacos/ribbon/NacosRibbonClientConfiguration.java

@Configuration
@ConditionalOnRibbonNacos
public class NacosRibbonClientConfiguration {

	@Bean
	@ConditionalOnMissingBean
	public ServerList<?> ribbonServerList(IClientConfig config, NacosDiscoveryProperties nacosDiscoveryProperties) {
		NacosServerList serverList = new NacosServerList(nacosDiscoveryProperties);
		serverList.initWithNiwsConfig(config);
		return serverList;
	}
}

NacosRibbonClientConfiguration会创建NacosServerList

NacosServerList

spring-cloud-alibaba-0.9.0.RELEASE/spring-cloud-alibaba-nacos-discovery/src/main/java/org/springframework/cloud/alibaba/nacos/ribbon/NacosServerList.java

public class NacosServerList extends AbstractServerList<NacosServer> {

	private NacosDiscoveryProperties discoveryProperties;

	private String serviceId;

	public NacosServerList(NacosDiscoveryProperties discoveryProperties) {
		this.discoveryProperties = discoveryProperties;
	}

	@Override
	public List<NacosServer> getInitialListOfServers() {
		return getServers();
	}

	@Override
	public List<NacosServer> getUpdatedListOfServers() {
		return getServers();
	}

	private List<NacosServer> getServers() {
		try {
			List<Instance> instances = discoveryProperties.namingServiceInstance()
					.selectInstances(serviceId, true);
			return instancesToServerList(instances);
		}
		catch (Exception e) {
			throw new IllegalStateException(
					"Can not get service instances from nacos, serviceId=" + serviceId,
					e);
		}
	}

	private List<NacosServer> instancesToServerList(List<Instance> instances) {
		List<NacosServer> result = new ArrayList<>();
		if (null == instances) {
			return result;
		}
		for (Instance instance : instances) {
			result.add(new NacosServer(instance));
		}

		return result;
	}

	public String getServiceId() {
		return serviceId;
	}

	@Override
	public void initWithNiwsConfig(IClientConfig iClientConfig) {
		this.serviceId = iClientConfig.getClientName();
	}
}

NacosServerList继承了com.netflix.loadbalancer.AbstractServerList，其getInitialListOfServers及getUpdatedListOfServers方法都是调用了getServers；getServers方法则是通过NamingService.selectInstances来获取服务实例信息

NacosServer

spring-cloud-alibaba-0.9.0.RELEASE/spring-cloud-alibaba-nacos-discovery/src/main/java/org/springframework/cloud/alibaba/nacos/ribbon/NacosServer.java

public class NacosServer extends Server {

	private final MetaInfo metaInfo;
	private final Instance instance;
	private final Map<String, String> metadata;

	public NacosServer(final Instance instance) {
		super(instance.getIp(), instance.getPort());
		this.instance = instance;
		this.metaInfo = new MetaInfo() {
			@Override
			public String getAppName() {
				return instance.getServiceName();
			}

			@Override
			public String getServerGroup() {
				return null;
			}

			@Override
			public String getServiceIdForDiscovery() {
				return null;
			}

			@Override
			public String getInstanceId() {
				return instance.getInstanceId();
			}
		};
		this.metadata = instance.getMetadata();
	}

	@Override
	public MetaInfo getMetaInfo() {
		return metaInfo;
	}

	public Instance getInstance() {
		return instance;
	}

	public Map<String, String> getMetadata() {
		return metadata;
	}
}

NacosServer继承了com.netflix.loadbalancer.Server；它主要有metaInfo、instance、metadata三个属性

小结

NacosRibbonClientConfiguration会创建NacosServerList；NacosServerList继承了com.netflix.loadbalancer.AbstractServerList，其getInitialListOfServers及getUpdatedListOfServers方法都是调用了getServers；getServers方法则是通过NamingService.selectInstances来获取服务实例信息