dubbo 源码分析-2

1.入口

@EnableDubbo 会引入@EnableDubboConfig->DubboConfigConfigurationRegistrar.class
引入 DubboBeanUtils.class ->registerCommonBeans（）

1.1 ReferenceAnnotationBeanPostProcessor.class

public class ReferenceAnnotationBeanPostProcessor extends AbstractAnnotationBeanPostProcessor{
  //ReferenceAnnotationBeanPostProcessor  集成了AbstractAnnotationBeanPostProcessor
  //spring 容器在实例化以后会依次注入依赖的实例
  // 这里采用的是迭代设计模式，依次遍历集成AbstractAnnotationBeanPostProcessor的实例，
  //执行 doGetInjectedBean 方法
  // 这里是为了将@Reference 煮给该实例信息
    protected Object doGetInjectedBean(AnnotationAttributes attributes, Object bean, String beanName, Class<?> injectedType,
                                       InjectionMetadata.InjectedElement injectedElement) throws Exception {
        /**
         * The name of bean that annotated Dubbo's {@link Service @Service} in local Spring {@link ApplicationContext}
         */
        String referencedBeanName = buildReferencedBeanName(attributes, injectedType);

        /**
         * The name of bean that is declared by {@link Reference @Reference} annotation injection
         */
        String referenceBeanName = getReferenceBeanName(attributes, injectedType);

        ReferenceBean referenceBean = buildReferenceBeanIfAbsent(referenceBeanName, attributes, injectedType);
		// 判断是否是本地暴露的方法
        boolean localServiceBean = isLocalServiceBean(referencedBeanName, referenceBean, attributes);
		
        registerReferenceBean(referencedBeanName, referenceBean, attributes, localServiceBean, injectedType);

        cacheInjectedReferenceBean(referenceBean, injectedElement);
		// 重点是这个会创建一个动态代理类，注入到容器中
        return getOrCreateProxy(referencedBeanName, referenceBean, localServiceBean, injectedType);
    }
}

1.2 ReferenceAnnotationBeanPostProcessor.class->getOrCreateProxy()

1.3 ReferenceConfig.class ->get（）

1.4 ReferenceConfig.class ->init（）

    public synchronized void init() {
        if (initialized) {
            return;
        }

        if (bootstrap == null) {
            bootstrap = DubboBootstrap.getInstance();
            bootstrap.init();
        }

        checkAndUpdateSubConfigs();

        checkStubAndLocal(interfaceClass);
        ConfigValidationUtils.checkMock(interfaceClass, this);

        Map<String, String> map = new HashMap<String, String>();
        map.put(SIDE_KEY, CONSUMER_SIDE);

        ReferenceConfigBase.appendRuntimeParameters(map);
        if (!ProtocolUtils.isGeneric(generic)) {
            String revision = Version.getVersion(interfaceClass, version);
            if (revision != null && revision.length() > 0) {
                map.put(REVISION_KEY, revision);
            }

            String[] methods = Wrapper.getWrapper(interfaceClass).getMethodNames();
            if (methods.length == 0) {
                logger.warn("No method found in service interface " + interfaceClass.getName());
                map.put(METHODS_KEY, ANY_VALUE);
            } else {
                map.put(METHODS_KEY, StringUtils.join(new HashSet<String>(Arrays.asList(methods)), COMMA_SEPARATOR));
            }
        }
        map.put(INTERFACE_KEY, interfaceName);
        AbstractConfig.appendParameters(map, getMetrics());
        AbstractConfig.appendParameters(map, getApplication());
        AbstractConfig.appendParameters(map, getModule());
        // remove 'default.' prefix for configs from ConsumerConfig
        // appendParameters(map, consumer, Constants.DEFAULT_KEY);
        AbstractConfig.appendParameters(map, consumer);
        AbstractConfig.appendParameters(map, this);
        MetadataReportConfig metadataReportConfig = getMetadataReportConfig();
        if (metadataReportConfig != null && metadataReportConfig.isValid()) {
            map.putIfAbsent(METADATA_KEY, REMOTE_METADATA_STORAGE_TYPE);
        }
        Map<String, AsyncMethodInfo> attributes = null;
        if (CollectionUtils.isNotEmpty(getMethods())) {
            attributes = new HashMap<>();
            for (MethodConfig methodConfig : getMethods()) {
                AbstractConfig.appendParameters(map, methodConfig, methodConfig.getName());
                String retryKey = methodConfig.getName() + ".retry";
                if (map.containsKey(retryKey)) {
                    String retryValue = map.remove(retryKey);
                    if ("false".equals(retryValue)) {
                        map.put(methodConfig.getName() + ".retries", "0");
                    }
                }
                AsyncMethodInfo asyncMethodInfo = AbstractConfig.convertMethodConfig2AsyncInfo(methodConfig);
                if (asyncMethodInfo != null) {
//                    consumerModel.getMethodModel(methodConfig.getName()).addAttribute(ASYNC_KEY, asyncMethodInfo);
                    attributes.put(methodConfig.getName(), asyncMethodInfo);
                }
            }
        }

        String hostToRegistry = ConfigUtils.getSystemProperty(DUBBO_IP_TO_REGISTRY);
        if (StringUtils.isEmpty(hostToRegistry)) {
            hostToRegistry = NetUtils.getLocalHost();
        } else if (isInvalidLocalHost(hostToRegistry)) {
            throw new IllegalArgumentException("Specified invalid registry ip from property:" + DUBBO_IP_TO_REGISTRY + ", value:" + hostToRegistry);
        }
        map.put(REGISTER_IP_KEY, hostToRegistry);

        serviceMetadata.getAttachments().putAll(map);
		
		// 创建代理对象同时 注册及其watct 生产者节点
        ref = createProxy(map);

        serviceMetadata.setTarget(ref);
        serviceMetadata.addAttribute(PROXY_CLASS_REF, ref);
        ConsumerModel consumerModel = repository.lookupReferredService(serviceMetadata.getServiceKey());
        consumerModel.setProxyObject(ref);
        consumerModel.init(attributes);

        initialized = true;

        // dispatch a ReferenceConfigInitializedEvent since 2.7.4
        dispatch(new ReferenceConfigInitializedEvent(this, invoker));
    }

1.5 ReferenceConfig.class ->createProxy（）

 private T createProxy(Map<String, String> map) {
        if (shouldJvmRefer(map)) {
            URL url = new URL(LOCAL_PROTOCOL, LOCALHOST_VALUE, 0, interfaceClass.getName()).addParameters(map);
            invoker = REF_PROTOCOL.refer(interfaceClass, url);
            if (logger.isInfoEnabled()) {
                logger.info("Using injvm service " + interfaceClass.getName());
            }
        } else {
            urls.clear();
            if (url != null && url.length() > 0) { // user specified URL, could be peer-to-peer address, or register center's address.
                String[] us = SEMICOLON_SPLIT_PATTERN.split(url);
                if (us != null && us.length > 0) {
                    for (String u : us) {
                        URL url = URL.valueOf(u);
                        if (StringUtils.isEmpty(url.getPath())) {
                            url = url.setPath(interfaceName);
                        }
                        if (UrlUtils.isRegistry(url)) {
                            urls.add(url.addParameterAndEncoded(REFER_KEY, StringUtils.toQueryString(map)));
                        } else {
                            urls.add(ClusterUtils.mergeUrl(url, map));
                        }
                    }
                }
            } else { // assemble URL from register center's configuration
                // if protocols not injvm checkRegistry
                if (!LOCAL_PROTOCOL.equalsIgnoreCase(getProtocol())) {
                    checkRegistry();
                    List<URL> us = ConfigValidationUtils.loadRegistries(this, false);
                    if (CollectionUtils.isNotEmpty(us)) {
                        for (URL u : us) {
                            URL monitorUrl = ConfigValidationUtils.loadMonitor(this, u);
                            if (monitorUrl != null) {
                                map.put(MONITOR_KEY, URL.encode(monitorUrl.toFullString()));
                            }
                            urls.add(u.addParameterAndEncoded(REFER_KEY, StringUtils.toQueryString(map)));
                        }
                    }
                    if (urls.isEmpty()) {
                        throw new IllegalStateException("No such any registry to reference " + interfaceName + " on the consumer " + NetUtils.getLocalHost() + " use dubbo version " + Version.getVersion() + ", please config <dubbo:registry address=\"...\" /> to your spring config.");
                    }
                }
            }

            if (urls.size() == 1) {
                // 注册zookeeper
                invoker = REF_PROTOCOL.refer(interfaceClass, urls.get(0));
            } else {
                List<Invoker<?>> invokers = new ArrayList<Invoker<?>>();
                URL registryURL = null;
                for (URL url : urls) {
                    invokers.add(REF_PROTOCOL.refer(interfaceClass, url));
                    if (UrlUtils.isRegistry(url)) {
                        registryURL = url; // use last registry url
                    }
                }
                if (registryURL != null) { // registry url is available
                    // for multi-subscription scenario, use 'zone-aware' policy by default
                    URL u = registryURL.addParameterIfAbsent(CLUSTER_KEY, ZoneAwareCluster.NAME);
                    // The invoker wrap relation would be like: ZoneAwareClusterInvoker(StaticDirectory) -> FailoverClusterInvoker(RegistryDirectory, routing happens here) -> Invoker
                    invoker = CLUSTER.join(new StaticDirectory(u, invokers));
                } else { // not a registry url, must be direct invoke.
                    invoker = CLUSTER.join(new StaticDirectory(invokers));
                }
            }
        }

        if (shouldCheck() && !invoker.isAvailable()) {
            invoker.destroy();
            throw new IllegalStateException("Failed to check the status of the service "
                    + interfaceName
                    + ". No provider available for the service "
                    + (group == null ? "" : group + "/")
                    + interfaceName +
                    (version == null ? "" : ":" + version)
                    + " from the url "
                    + invoker.getUrl()
                    + " to the consumer "
                    + NetUtils.getLocalHost() + " use dubbo version " + Version.getVersion());
        }
        if (logger.isInfoEnabled()) {
            logger.info("Refer dubbo service " + interfaceClass.getName() + " from url " + invoker.getUrl());
        }
        /**
         * @since 2.7.0
         * ServiceData Store
         */
        String metadata = map.get(METADATA_KEY);
        WritableMetadataService metadataService = WritableMetadataService.getExtension(metadata == null ? DEFAULT_METADATA_STORAGE_TYPE : metadata);
        if (metadataService != null) {
            URL consumerURL = new URL(CONSUMER_PROTOCOL, map.remove(REGISTER_IP_KEY), 0, map.get(INTERFACE_KEY), map);
            metadataService.publishServiceDefinition(consumerURL);
        }
        // 创建一个代理对象
        return (T) PROXY_FACTORY.getProxy(invoker, ProtocolUtils.isGeneric(generic));
    }

invoker = REF_PROTOCOL.refer(interfaceClass, urls.get(0)); 这里也是dubbo的spi

这是dubbo 的调用栈信息直接来到RegistryProtocol.class的doRefer()

1.6 RegistryProtocol.class->doRefer()

 private <T> Invoker<T> doRefer(Cluster cluster, Registry registry, Class<T> type, URL url) {
        RegistryDirectory<T> directory = new RegistryDirectory<T>(type, url);
        directory.setRegistry(registry);
        directory.setProtocol(protocol);
        // all attributes of REFER_KEY
        Map<String, String> parameters = new HashMap<String, String>(directory.getConsumerUrl().getParameters());
        URL subscribeUrl = new URL(CONSUMER_PROTOCOL, parameters.remove(REGISTER_IP_KEY), 0, type.getName(), parameters);
        if (directory.isShouldRegister()) {
            directory.setRegisteredConsumerUrl(subscribeUrl);
            // 注册消费者信息
            registry.register(directory.getRegisteredConsumerUrl());
        }
        directory.buildRouterChain(subscribeUrl);
        // 订阅watch 事件
        directory.subscribe(toSubscribeUrl(subscribeUrl));

        Invoker<T> invoker = cluster.join(directory);
        List<RegistryProtocolListener> listeners = findRegistryProtocolListeners(url);
        if (CollectionUtils.isEmpty(listeners)) {
            return invoker;
        }

        RegistryInvokerWrapper<T> registryInvokerWrapper = new RegistryInvokerWrapper<>(directory, cluster, invoker, subscribeUrl);
        for (RegistryProtocolListener listener : listeners) {
            listener.onRefer(this, registryInvokerWrapper);
        }
        return registryInvokerWrapper;
    }