dubbo源码之服务暴露

Love The Way You Lie 2022-12-06 12:56 264阅读 0赞

Dubbo 作为rpc 封装的典型框架，我们其实要了解一个rpc调用大致过程，dubbo可以作为一个比较好学习资料。

在这里插入图片描述

这个是dubbo 调用的流程图，这篇文件主要要介绍第一步中的服务暴露过程，这次使用的源码为2.7.1

服务暴露过程

这里先将具体暴露过程贴出来，配合源码进行分析

在这里插入图片描述

我们在看源码的时候需要一个入口，dubbo的入口可以从ServiceBean 开始

  1. public class ServiceBean<T> extends ServiceConfig<T> implements InitializingBean,
  2.  DisposableBean, ApplicationContextAware, ApplicationListener<ContextRefreshedEvent>, 
  3.  BeanNameAware, ApplicationEventPublisherAware {

这里涉及到Spring 相关内容了，主要是实现ApplicationContextAware、InitializingBean等接口。这两个是在spring生命周期中会先后调用，主要进行是一些初始化的操作，我们可以不关心。同时它实现了 ApplicationListener，这个是关于spring的监听器内容。这会在 Spring IOC 容器刷新完成后调用 onApplicationEvent 方法，而这个方法里面做的就是服务暴露，这就是服务暴露的启动点。

ServiceBean 中onApplicationEvent方法

  1. public void onApplicationEvent(ContextRefreshedEvent event) {
  2.  //是否没暴露过
  3.         if (!this.isExported() && !this.isUnexported()) {
  4.             if (logger.isInfoEnabled()) {
  5.                 logger.info("The service ready on spring started. service: " + this.getInterface());
  6.             }
  7. //如果不是延迟暴露，并且没有暴露过，直接调用暴露方法
  8.             this.export();
  9.         }
  11.     }

直接调用，父类暴露方法
在这里插入图片描述
父类的serviceConfig的export方法

  1. public synchronized void export() {
  2.     //检查更新配置
  3.         this.checkAndUpdateSubConfigs();
  4.         //判断是否需要暴露，并且是延迟暴露，如果延迟暴露通过延迟线程池进行暴露
  5.         if (this.shouldExport()) {
  6.             if (this.shouldDelay()) {
  7.                 delayExportExecutor.schedule(this::doExport, (long)this.delay, TimeUnit.MILLISECONDS);
  8.             } else {
  9.             //调用方法直接暴露
  10.                 this.doExport();
  11.             }
  13.         }
  14.     }

serviceConfig的doExport方法在这里插入图片描述

父类的serviceConfig的doExportUrls方法

  1. private void doExportUrls() {
  2.     //1、加载注册信息，构造url
  3.         List<URL> registryURLs = this.loadRegistries(true);
  4.         Iterator var2 = this.protocols.iterator();
  6.         while(var2.hasNext()) {
  7.             ProtocolConfig protocolConfig = (ProtocolConfig)var2.next();
  8.             String pathKey = URL.buildKey((String)this.getContextPath(protocolConfig).map((p) -> {
  9.                 return p + "/" + this.path;
  10.             }).orElse(this.path), this.group, this.version);
  11.             ProviderModel providerModel = new ProviderModel(pathKey, this.ref, this.interfaceClass);
  12.             ApplicationModel.initProviderModel(pathKey, providerModel);
  13.             //根据 URL 来进行服务暴露了
  14.             this.doExportUrlsFor1Protocol(protocolConfig, registryURLs);
  15.         }
  17.     }
  19. private void doExportUrlsFor1Protocol(ProtocolConfig protocolConfig, List<URL> registryURLs) {
  20.         String name = protocolConfig.getName();
  21.         if (StringUtils.isEmpty(name)) {
  22.             name = "dubbo";
  23.         }
  24. //将参数塞进map，构建url
  25.         Map<String, String> map = new HashMap();
  26.         map.put("side", "provider");
  27.         appendRuntimeParameters(map);
  28.         appendParameters(map, this.application);
  29.         appendParameters(map, this.module);
  30.         appendParameters(map, this.provider, "default");
  31.         appendParameters(map, protocolConfig);
  32.         appendParameters(map, this);
  33.         String scope;
  34.         Iterator metadataReportService;
  35.         if (CollectionUtils.isNotEmpty(this.methods)) {
  36.             Iterator var5 = this.methods.iterator();
  38.             label161:
  39.             while(true) {
  40.                 MethodConfig method;
  41.                 List arguments;
  42.                 do {
  43.                     if (!var5.hasNext()) {
  44.                         break label161;
  45.                     }
  47.                     method = (MethodConfig)var5.next();
  48.                     appendParameters(map, method, method.getName());
  49.                     String retryKey = method.getName() + ".retry";
  50.                     if (map.containsKey(retryKey)) {
  51.                         scope = (String)map.remove(retryKey);
  52.                         if ("false".equals(scope)) {
  53.                             map.put(method.getName() + ".retries", "0");
  54.                         }
  55.                     }
  57.                     arguments = method.getArguments();
  58.                 } while(!CollectionUtils.isNotEmpty(arguments));
  60.                 metadataReportService = arguments.iterator();
  62.               、//... 省略部分代码（关于一些参数的判断）
  63.             }
  64.         }
  66.     //..省略部分代码
  67.         if (ExtensionLoader.getExtensionLoader(ConfiguratorFactory.class).hasExtension(url.getProtocol())) {
  68.             url = ((ConfiguratorFactory)ExtensionLoader.getExtensionLoader(ConfiguratorFactory.class).getExtension(url.getProtocol())).getConfigurator(url).configure(url);
  69.         }
  71. //获取scope为null,会进入判断进行本地暴露
  72.         scope = url.getParameter("scope");
  73.         if (!"none".equalsIgnoreCase(scope)) {
  74.             if (!"remote".equalsIgnoreCase(scope)) {
  75.             //进行本地暴露，默认javassist 代理对象，由于本地暴露和远程暴露流程大致一样，不再展开
  76.                 this.exportLocal(url);
  77.             }
  79.             if (!"local".equalsIgnoreCase(scope)) {
  80.                 if (logger.isInfoEnabled()) {
  81.                     logger.info("Export dubbo service " + this.interfaceClass.getName() + " to url " + url);
  82.                 }
  84.                 if (CollectionUtils.isNotEmpty(registryURLs)) {
  85.                     metadataReportService = registryURLs.iterator();
  87.                     while(metadataReportService.hasNext()) {
  88.                         URL registryURL = (URL)metadataReportService.next();
  89.                         url = url.addParameterIfAbsent("dynamic", registryURL.getParameter("dynamic"));
  90.                         URL monitorUrl = this.loadMonitor(registryURL);
  91.                         if (monitorUrl != null) {
  92.                             url = url.addParameterAndEncoded("monitor", monitorUrl.toFullString());
  93.                         }
  95.                         if (logger.isInfoEnabled()) {
  96.                             logger.info("Register dubbo service " + this.interfaceClass.getName() + " url " + url + " to registry " + registryURL);
  97.                         }
  101.                         String proxy = url.getParameter("proxy");
  102.                         if (StringUtils.isNotEmpty(proxy)) {
  103.                             registryURL = registryURL.addParameter("proxy", proxy);
  104.                         }
  105.                         //通过proxyFactory 将接口封装为invoker 的代理
  106.                         Invoker<?> invoker = proxyFactory.getInvoker(this.ref, this.interfaceClass, registryURL.addParameterAndEncoded("export", url.toFullString()));
  107.                         DelegateProviderMetaDataInvoker wrapperInvoker = new DelegateProviderMetaDataInvoker(invoker, this);
  108.                         //根据协议对象进行远程暴露
  109.                         Exporter<?> exporter = protocol.export(wrapperInvoker);
  110.                         this.exporters.add(exporter);
  111.                     }
  112.                 } else {
  113.                     Invoker<?> invoker = proxyFactory.getInvoker(this.ref, this.interfaceClass, url);
  114.                     DelegateProviderMetaDataInvoker wrapperInvoker = new DelegateProviderMetaDataInvoker(invoker, this);
  115.                     Exporter<?> exporter = protocol.export(wrapperInvoker);
  116.                     this.exporters.add(exporter);
  117.                 }
  119.                 metadataReportService = null;
  120.                 MetadataReportService metadataReportService;
  121.                 if ((metadataReportService = this.getMetadataReportService()) != null) {
  122.                     metadataReportService.publishProvider(url);
  123.                 }
  124.             }
  125.         }
  127.         this.urls.add(url);
  128.     }

在这里插入图片描述

远程暴露

这个是远程暴露的大致流程
在这里插入图片描述

由于目前协议是registery，调用registeryProtocol#export 进行暴露

  1. public <T> Exporter<T> export(Invoker<T> originInvoker) throws RpcException {
  2.         URL registryUrl = this.getRegistryUrl(originInvoker);
  3.         URL providerUrl = this.getProviderUrl(originInvoker);
  4.         URL overrideSubscribeUrl = this.getSubscribedOverrideUrl(providerUrl);
  5.         RegistryProtocol.OverrideListener overrideSubscribeListener = new RegistryProtocol.OverrideListener(overrideSubscribeUrl, originInvoker);
  6.         this.overrideListeners.put(overrideSubscribeUrl, overrideSubscribeListener);
  7.         providerUrl = this.overrideUrlWithConfig(providerUrl, overrideSubscribeListener);
  9.         RegistryProtocol.ExporterChangeableWrapper<T> exporter = this.doLocalExport(originInvoker, providerUrl);
  10.         //获取注册中心的URL 
  11.         Registry registry = this.getRegistry(originInvoker);
  12.         // 获取注册服务提供者的URL
  13.         URL registeredProviderUrl = this.getRegisteredProviderUrl(providerUrl, registryUrl);
  14.         //将提供者的信息注册到服务提供和消费者注册表中
  15.         ProviderInvokerWrapper<T> providerInvokerWrapper = ProviderConsumerRegTable.registerProvider(originInvoker, registryUrl, registeredProviderUrl);
  16.         boolean register = registeredProviderUrl.getParameter("register", true);
  17.         //如果需要注册
  18.         if (register) {
  19.         //想注册中心注册服务，这里是向zookeeper注册
  20.             this.register(registryUrl, registeredProviderUrl);
  21.             providerInvokerWrapper.setReg(true);
  22.         }
  23.     //获取订阅url
  24.         registry.subscribe(overrideSubscribeUrl, overrideSubscribeListener);
  25.         exporter.setRegisterUrl(registeredProviderUrl);
  26.         exporter.setSubscribeUrl(overrideSubscribeUrl);
  27.         return new RegistryProtocol.DestroyableExporter(exporter);
  28.     }

调用registeryProtocol#export 之后会再调用DubboProtocol#export进行暴露

  1. public <T> Exporter<T> export(Invoker<T> invoker) throws RpcException {
  2. //获取url
  3.         URL url = invoker.getUrl();
  4.         //这里构建的时候serverMap的key
  5.         String key = serviceKey(url);
  6.         DubboExporter<T> exporter = new DubboExporter(invoker, key, this.exporterMap);
  7.         this.exporterMap.put(key, exporter);
  8.         Boolean isStubSupportEvent = url.getParameter("dubbo.stub.event", false);
  9.         Boolean isCallbackservice = url.getParameter("is_callback_service", false);
  10.         if (isStubSupportEvent && !isCallbackservice) {
  11.             String stubServiceMethods = url.getParameter("dubbo.stub.event.methods");
  12.             if (stubServiceMethods != null && stubServiceMethods.length() != 0) {
  13.                 this.stubServiceMethodsMap.put(url.getServiceKey(), stubServiceMethods);
  14.             } else if (this.logger.isWarnEnabled()) {
  15.                 this.logger.warn(new IllegalStateException("consumer [" + url.getParameter("interface") + "], has set stubproxy support event ,but no stub methods founded."));
  16.             }
  17.         }
  18.     //如果没有server创建server方法
  19.         this.openServer(url);
  20.         this.optimizeSerialization(url);
  21.         return exporter;
  22.     }
  24.  private void openServer(URL url) {
  25.         String key = url.getAddress();
  26.         boolean isServer = url.getParameter("isserver", true);
  27.         if (isServer) {
  28.             ExchangeServer server = (ExchangeServer)this.serverMap.get(key);
  29.             if (server == null) {
  30.                 synchronized(this) {
  31.                     server = (ExchangeServer)this.serverMap.get(key);
  32.                     if (server == null) {
  33.                     //如果构建server为空，则创建server(这个方法是创建Netty监听器，这里不再跟了)
  34.                         this.serverMap.put(key, this.createServer(url));
  35.                     }
  36.                 }
  37.             } else {
  38.                 server.reset(url);
  39.             }
  40.         }
  42.     }

可以看到将provider信息已经注册到zookeeper节点上了
在这里插入图片描述

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