序

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();
    }

}
複製程式碼

• NacosDiscoveryAutoConfiguration註冊了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);
        }
    }

}
複製程式碼

• NacosDiscoveryAutoRegister實現了ApplicationListener介面，它會在接收到WebServerInitializedEvent時通過namingService.registerInstance(serviceName,register)來註冊例項，若出現NacosException則會被轉義為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);
            logger.info("Finished auto deregister service : {},register.getPort());
        } catch (NacosException e) {
            throw new AutoDeregisterException(e);
        }
    }
}
複製程式碼

• NacosDiscoveryAutoDeregister實現了ApplicationListener介面，它會在接收到ContextClosedEvent時通過namingService.deregisterInstance(serviceName,register)來登出例項，若出現NacosException則會被轉義為AutoDeregisterException

小結

• NacosDiscoveryAutoConfiguration註冊了NacosDiscoveryAutoRegister
• NacosDiscoveryAutoRegister實現了ApplicationListener介面，它會在接收到WebServerInitializedEvent時通過namingService.registerInstance(serviceName,register)來註冊例項，若出現NacosException則會被轉義為AutoRegisterException
• NacosDiscoveryAutoDeregister實現了ApplicationListener介面，它會在接收到ContextClosedEvent時通過namingService.deregisterInstance(serviceName,register)來登出例項，若出現NacosException則會被轉義為AutoDeregisterException

doc

• NacosDiscoveryAutoConfiguration