聊聊nacos的NacosDiscoveryAutoConfiguration

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本文主要研究一下 nacos 的 NacosDiscoveryAutoConfiguration

NacosDiscoveryAutoConfiguration

nacos-spring-boot-project/nacos-discovery-spring-boot-autoconfigure/src/main/java/com/alibaba/boot/nacos/discovery/autoconfigure/NacosDiscoveryAutoConfiguration.java

@ConditionalOnProperty(name = NacosDiscoveryConstants.ENABLED, matchIfMissing = true)
@ConditionalOnMissingBean(name = DISCOVERY_GLOBAL_NACOS_PROPERTIES_BEAN_NAME)
@EnableNacosDiscovery
@EnableConfigurationProperties(value = NacosDiscoveryProperties.class)
@ConditionalOnClass(name = "org.springframework.boot.context.properties.bind.Binder")
public class NacosDiscoveryAutoConfiguration {

    @Bean
    public NacosDiscoveryAutoRegister discoveryAutoRegister() {return new NacosDiscoveryAutoRegister();
    }

}

• NacosDiscoveryAutoConfiguration 注册了 NacosDiscoveryAutoRegister

NacosDiscoveryAutoRegister

nacos-spring-boot-project/nacos-discovery-spring-boot-autoconfigure/src/main/java/com/alibaba/boot/nacos/discovery/autoconfigure/NacosDiscoveryAutoRegister.java

@Component
public class NacosDiscoveryAutoRegister implements ApplicationListener<WebServerInitializedEvent> {private static final Logger logger = LoggerFactory.getLogger(NacosDiscoveryAutoRegister.class);

    @NacosInjected
    private NamingService namingService;

    @Autowired
    private NacosDiscoveryProperties discoveryProperties;

    @Value("${spring.application.name:spring.application.name}")
    private String applicationName;

    @Override
    public void onApplicationEvent(WebServerInitializedEvent event) {if (!discoveryProperties.isAutoRegister()) {return;}

        Register register = discoveryProperties.getRegister();

        if (StringUtils.isEmpty(register.getIp())) {register.setIp(NetUtils.localIP());
        }

        if (register.getPort() == 0) {register.setPort(event.getWebServer().getPort());
        }

        register.getMetadata().put("preserved.register.source", "SPRING_BOOT");

        register.setInstanceId("");
        String serviceName = StringUtils.isEmpty(register.getServiceName()) ? applicationName : register.getServiceName();

        try {namingService.registerInstance(serviceName, register.getGroupName(), register);
            logger.info("Finished auto register service : {}, ip : {}, port : {}", register.getServiceName(), register.getIp(), register.getPort());
        } catch (NacosException e) {throw new AutoRegisterException(e);
        }
    }

}

• NacosDiscoveryAutoRegister 实现了 ApplicationListener 接口，它会在接收到 WebServerInitializedEvent 时通过 namingService.registerInstance(serviceName, register.getGroupName(), register) 来注册实例，若出现 NacosException 则会被转义为 AutoRegisterException

NacosDiscoveryAutoDeregister

nacos-spring-boot-project/nacos-discovery-spring-boot-autoconfigure/src/main/java/com/alibaba/boot/nacos/discovery/autoconfigure/NacosDiscoveryAutoDeregister.java

@Component
public class NacosDiscoveryAutoDeregister implements ApplicationListener<ContextClosedEvent> {private static final Logger logger = LoggerFactory.getLogger(NacosDiscoveryAutoRegister.class);

    @NacosInjected
    private NamingService namingService;

    private final NacosDiscoveryProperties discoveryProperties;
    private final WebServer webServer;

    @Value("${spring.application.name:spring.application.name}")
    private String applicationName;

    public NacosDiscoveryAutoDeregister(NacosDiscoveryProperties discoveryProperties, WebServer webServer) {
        this.discoveryProperties = discoveryProperties;
        this.webServer = webServer;
    }

    @Override
    public void onApplicationEvent(ContextClosedEvent event) {if (!discoveryProperties.isAutoRegister()) {return;}

        Register register = discoveryProperties.getRegister();

        if (StringUtils.isEmpty(register.getIp())) {register.setIp(NetUtils.localIP());
        }

        if (register.getPort() == 0) {register.setPort(webServer.getPort());
        }

        String serviceName = StringUtils.isEmpty(register.getServiceName()) ? applicationName : register.getServiceName();

        try {namingService.deregisterInstance(serviceName, register.getGroupName(), register);
            logger.info("Finished auto deregister service : {}, ip : {}, port : {}", register.getServiceName(), register.getIp(), register.getPort());
        } catch (NacosException e) {throw new AutoDeregisterException(e);
        }
    }
}

• NacosDiscoveryAutoDeregister 实现了 ApplicationListener 接口，它会在接收到 ContextClosedEvent 时通过 namingService.deregisterInstance(serviceName, register.getGroupName(), register) 来注销实例，若出现 NacosException 则会被转义为 AutoDeregisterException

小结

• NacosDiscoveryAutoConfiguration 注册了 NacosDiscoveryAutoRegister
• NacosDiscoveryAutoRegister 实现了 ApplicationListener 接口，它会在接收到 WebServerInitializedEvent 时通过 namingService.registerInstance(serviceName, register.getGroupName(), register) 来注册实例，若出现 NacosException 则会被转义为 AutoRegisterException
• NacosDiscoveryAutoDeregister 实现了 ApplicationListener 接口，它会在接收到 ContextClosedEvent 时通过 namingService.deregisterInstance(serviceName, register.getGroupName(), register) 来注销实例，若出现 NacosException 则会被转义为 AutoDeregisterException

doc

• NacosDiscoveryAutoConfiguration