序
本文主要研究一下SpringCloudRegistryFactory
SpringCloudRegistryFactory
spring-cloud-alibaba-2.1.0.RELEASE/spring-cloud-alibaba-dubbo/src/main/java/com/alibaba/cloud/dubbo/registry/SpringCloudRegistryFactory.java
public class SpringCloudRegistryFactory implements RegistryFactory {
public static String PROTOCOL = "spring-cloud";
public static String ADDRESS = "localhost";
private static String SERVICES_LOOKUP_SCHEDULER_THREAD_NAME_PREFIX = getProperty(
"dubbo.services.lookup.scheduler.thread.name.prefix ",
"dubbo-services-lookup-");
private static ConfigurableApplicationContext applicationContext;
private DiscoveryClient discoveryClient;
private DubboServiceMetadataRepository dubboServiceMetadataRepository;
private DubboMetadataServiceProxy dubboMetadataConfigServiceProxy;
private JSONUtils jsonUtils;
private volatile boolean initialized = false;
public SpringCloudRegistryFactory() {
}
public static void setApplicationContext(
ConfigurableApplicationContext applicationContext) {
SpringCloudRegistryFactory.applicationContext = applicationContext;
}
protected void init() {
if (initialized || applicationContext == null) {
return;
}
this.discoveryClient = applicationContext.getBean(DiscoveryClient.class);
this.dubboServiceMetadataRepository = applicationContext
.getBean(DubboServiceMetadataRepository.class);
this.dubboMetadataConfigServiceProxy = applicationContext
.getBean(DubboMetadataServiceProxy.class);
this.jsonUtils = applicationContext.getBean(JSONUtils.class);
}
@Override
public Registry getRegistry(URL url) {
init();
return new SpringCloudRegistry(url, discoveryClient,
dubboServiceMetadataRepository, dubboMetadataConfigServiceProxy,
jsonUtils, applicationContext);
}
}- SpringCloudRegistryFactory实现了RegistryFactory接口，其getRegistry方法首先调用init方法，然后创建并返回SpringCloudRegistry；init方法会从spring容器中获取DiscoveryClient、DubboServiceMetadataRepository、DubboMetadataServiceProxy、JSONUtils
SpringCloudRegistry
spring-cloud-alibaba-2.1.0.RELEASE/spring-cloud-alibaba-dubbo/src/main/java/com/alibaba/cloud/dubbo/registry/SpringCloudRegistry.java
public class SpringCloudRegistry extends AbstractSpringCloudRegistry {
private final DubboServiceMetadataRepository dubboServiceMetadataRepository;
public SpringCloudRegistry(URL url, DiscoveryClient discoveryClient,
DubboServiceMetadataRepository dubboServiceMetadataRepository,
DubboMetadataServiceProxy dubboMetadataConfigServiceProxy,
JSONUtils jsonUtils, ConfigurableApplicationContext applicationContext) {
super(url, discoveryClient, dubboServiceMetadataRepository,
dubboMetadataConfigServiceProxy, jsonUtils, applicationContext);
this.dubboServiceMetadataRepository = dubboServiceMetadataRepository;
}
@Override
protected void doRegister0(URL url) {
dubboServiceMetadataRepository.exportURL(url);
}
@Override
protected void doUnregister0(URL url) {
dubboServiceMetadataRepository.unexportURL(url);
}
}- SpringCloudRegistry继承了AbstractSpringCloudRegistry，其doRegister0执行dubboServiceMetadataRepository.exportURL，doUnregister0执行dubboServiceMetadataRepository.unexportURL
AbstractSpringCloudRegistry
spring-cloud-alibaba-2.1.0.RELEASE/spring-cloud-alibaba-dubbo/src/main/java/com/alibaba/cloud/dubbo/registry/AbstractSpringCloudRegistry.java
public abstract class AbstractSpringCloudRegistry extends FailbackRegistry {
/**
* The parameter name of {@link #servicesLookupInterval}
*/
public static final String SERVICES_LOOKUP_INTERVAL_PARAM_NAME = "dubbo.services.lookup.interval";
protected static final String DUBBO_METADATA_SERVICE_CLASS_NAME = DubboMetadataService.class
.getName();
/**
* Caches the IDs of {@link ApplicationListener}
*/
private static final Set<String> registerListeners = new HashSet<>();
protected final Logger logger = LoggerFactory.getLogger(getClass());
/**
* The interval in second of lookup service names(only for Dubbo-OPS)
*/
private final long servicesLookupInterval;
private final DiscoveryClient discoveryClient;
private final DubboServiceMetadataRepository repository;
private final DubboMetadataServiceProxy dubboMetadataConfigServiceProxy;
private final JSONUtils jsonUtils;
private final ConfigurableApplicationContext applicationContext;
public AbstractSpringCloudRegistry(URL url, DiscoveryClient discoveryClient,
DubboServiceMetadataRepository dubboServiceMetadataRepository,
DubboMetadataServiceProxy dubboMetadataConfigServiceProxy,
JSONUtils jsonUtils, ConfigurableApplicationContext applicationContext) {
super(url);
this.servicesLookupInterval = url
.getParameter(SERVICES_LOOKUP_INTERVAL_PARAM_NAME, 60L);
this.discoveryClient = discoveryClient;
this.repository = dubboServiceMetadataRepository;
this.dubboMetadataConfigServiceProxy = dubboMetadataConfigServiceProxy;
this.jsonUtils = jsonUtils;
this.applicationContext = applicationContext;
}
//......
@Override
public final void doSubscribe(URL url, NotifyListener listener) {
if (isAdminURL(url)) {
// TODO in future
}
else if (isDubboMetadataServiceURL(url)) { // for DubboMetadataService
subscribeDubboMetadataServiceURLs(url, listener);
}
else { // for general Dubbo Services
subscribeDubboServiceURLs(url, listener);
}
}
protected void subscribeDubboServiceURLs(URL url, NotifyListener listener) {
doSubscribeDubboServiceURLs(url, listener);
registerServiceInstancesChangedEventListener(url, listener);
}
private void doSubscribeDubboServiceURLs(URL url, NotifyListener listener) {
Set<String> subscribedServices = repository.getSubscribedServices();
// Sync
subscribedServices.forEach(service -> subscribeDubboServiceURL(url, listener,
service, this::getServiceInstances));
}
private List<ServiceInstance> getServiceInstances(String serviceName) {
return hasText(serviceName) ? doGetServiceInstances(serviceName) : emptyList();
}
private List<ServiceInstance> doGetServiceInstances(String serviceName) {
List<ServiceInstance> serviceInstances = emptyList();
try {
serviceInstances = discoveryClient.getInstances(serviceName);
}
catch (Exception e) {
if (logger.isErrorEnabled()) {
logger.error(e.getMessage(), e);
}
}
return serviceInstances;
}
protected void subscribeDubboServiceURL(URL url, NotifyListener listener,
String serviceName,
Function<String, Collection<ServiceInstance>> serviceInstancesFunction) {
if (logger.isInfoEnabled()) {
logger.info(
"The Dubbo Service URL[ID : {}] is being subscribed for service[name : {}]",
generateId(url), serviceName);
}
DubboMetadataService dubboMetadataService = dubboMetadataConfigServiceProxy
.getProxy(serviceName);
if (dubboMetadataService == null) { // If not found, try to initialize
if (logger.isInfoEnabled()) {
logger.info(
"The metadata of Dubbo service[key : {}] can't be found when the subscribed service[name : {}], "
+ "and then try to initialize it",
url.getServiceKey(), serviceName);
}
repository.initializeMetadata(serviceName);
dubboMetadataService = dubboMetadataConfigServiceProxy.getProxy(serviceName);
}
if (dubboMetadataService == null) { // It makes sure not-found, return immediately
if (logger.isWarnEnabled()) {
logger.warn(
"The metadata of Dubbo service[key : {}] still can't be found, it could effect the further "
+ "Dubbo service invocation",
url.getServiceKey());
}
return;
}
Collection<ServiceInstance> serviceInstances = serviceInstancesFunction
.apply(serviceName);
List<URL> allSubscribedURLs = new LinkedList<>();
if (CollectionUtils.isEmpty(serviceInstances)) {
if (logger.isWarnEnabled()) {
logger.warn(
"There is no instance from service[name : {}], and then Dubbo Service[key : {}] will not be "
+ "available , please make sure the further impact",
serviceName, url.getServiceKey());
}
/**
* URLs with {@link RegistryConstants#EMPTY_PROTOCOL}
*/
allSubscribedURLs.addAll(emptyURLs(url));
}
else {
List<URL> exportedURLs = getExportedURLs(dubboMetadataService, url);
for (URL exportedURL : exportedURLs) {
String protocol = exportedURL.getProtocol();
List<URL> subscribedURLs = new LinkedList<>();
serviceInstances.forEach(serviceInstance -> {
Integer port = repository.getDubboProtocolPort(serviceInstance,
protocol);
String host = serviceInstance.getHost();
if (port == null) {
if (logger.isWarnEnabled()) {
logger.warn(
"The protocol[{}] port of Dubbo service instance[host : {}] "
+ "can't be resolved",
protocol, host);
}
}
else {
URL subscribedURL = new URL(protocol, host, port,
exportedURL.getParameters());
subscribedURLs.add(subscribedURL);
}
});
allSubscribedURLs.addAll(subscribedURLs);
}
}
if (logger.isDebugEnabled()) {
logger.debug("The subscribed URL[{}] will notify all URLs : {}", url,
allSubscribedURLs);
}
listener.notify(allSubscribedURLs);
}
//......
}- AbstractSpringCloudRegistry的doGetServiceInstances方法会使用discoveryClient.getInstances来获取ServiceInstance列表；subscribeDubboServiceURL方法会从ServiceInstance列表读取并组装subscribedURLs，然后使用listener.notify将这些subscribedURLs回传回去
小结
- SpringCloudRegistryFactory实现了RegistryFactory接口，其getRegistry方法首先调用init方法，然后创建并返回SpringCloudRegistry；init方法会从spring容器中获取DiscoveryClient、DubboServiceMetadataRepository、DubboMetadataServiceProxy、JSONUtils
- SpringCloudRegistry继承了AbstractSpringCloudRegistry，其doRegister0执行dubboServiceMetadataRepository.exportURL，doUnregister0执行dubboServiceMetadataRepository.unexportURL
- AbstractSpringCloudRegistry的doGetServiceInstances方法会使用discoveryClient.getInstances来获取ServiceInstance列表；subscribeDubboServiceURL方法会从ServiceInstance列表读取并组装subscribedURLs，然后使用listener.notify将这些subscribedURLs回传回去