dubbo源码阅读-注册中心(十三)之Zookeeper
类图
服务注册
RegistryProtocol
<1>register
参见《dubbo源码阅读-服务暴露(七)之远程暴露(dubbo)》
public void register(URL registryUrl, URL registedProviderUrl) { //<2>SPI扩展点 此时url已经变成了配置的协议而不是registry 如:zookeeper:/ Registry registry = registryFactory.getRegistry(registryUrl); //<3>注册到注册中心 registry.register(registedProviderUrl); }
服务订阅
RegistryDirectory
<6>subscribe
参见《dubbo源码阅读-服务订阅(八)之远程订阅(dubbo)》
public void subscribe(URL url) { //此时的url为:consumer://192.168.2.1/com.alibaba.dubbo.demo.DemoService?* setConsumerUrl(url); //<7>对应的注册中心实现类 调用订阅方法 通知添加监听器 就是当前对象 实现了 NotifyListener registry.subscribe(url, this); }
ZookeeperRegistry
<3>register
com.alibaba.dubbo.registry.support.FailbackRegistry#register
@Override public void register(URL url) { //<4>在成员列表增加registered 已注册url super.register(url); //成员变变量失败集合url failedRegistered.remove(url); failedUnregistered.remove(url); try { //<5>模板方法模式 具体的注册逻辑由子类实现 doRegister(url); } catch (Exception e) { Throwable t = e; // 是否配置了跳过检查 默认不跳过 check=true 如果注册失败会抛出异常 否则只打印错误日志 boolean check = getUrl().getParameter(Constants.CHECK_KEY, true) && url.getParameter(Constants.CHECK_KEY, true) && !Constants.CONSUMER_PROTOCOL.equals(url.getProtocol()); boolean skipFailback = t instanceof SkipFailbackWrapperException; if (check || skipFailback) { if (skipFailback) { t = t.getCause(); } throw new IllegalStateException("Failed to register " + url + " to registry " + getUrl().getAddress() + ", cause: " + t.getMessage(), t); } else { logger.error("Failed to register " + url + ", waiting for retry, cause: " + t.getMessage(), t); } // 注册失败 放入失败集合 failedRegistered.add(url); } }
<4>supper.register
com.alibaba.dubbo.registry.support.FailbackRegistry#register
->
com.alibaba.dubbo.registry.support.AbstractRegistry#register
@Override public void register(URL url) { if (url == null) { throw new IllegalArgumentException("register url == null"); } if (logger.isInfoEnabled()) { logger.info("Register: " + url); } registered.add(url); }
<5>doRegister
com.alibaba.dubbo.registry.zookeeper.ZookeeperRegistry#doRegister
@Override protected void doRegister(URL url) { try { //添加节点/dubbo/com.alibaba.dubbo.demo.DemoService/providers 同时添加服务信息 zkClient.create(toUrlPath(url), url.getParameter(Constants.DYNAMIC_KEY, true)); } catch (Throwable e) { throw new RpcException("Failed to register " + url + " to zookeeper " + getUrl() + ", cause: " + e.getMessage(), e); } }
注:zkClikent也是SPI注解 可选有CuratorZookeeperClient，ZkclientZookeeperClient
<7>subscribe
com.alibaba.dubbo.registry.support.FailbackRegistry#subscribe
@Override public void subscribe(URL url, NotifyListener listener) { //将监听器添加到 成员变量 key为url value为lists super.subscribe(url, listener); //从异常监听里面移除 removeFailedSubscribed(url, listener); try { // <8>具体的订阅逻辑 子类实现 模板方法模式 doSubscribe(url, listener); } catch (Exception e) { Throwable t = e; List<URL> urls = getCacheUrls(url); if (urls != null && !urls.isEmpty()) { notify(url, listener, urls); logger.error("Failed to subscribe " + url + ", Using cached list: " + urls + " from cache file: " + getUrl().getParameter(Constants.FILE_KEY, System.getProperty("user.home") + "/dubbo-registry-" + url.getHost() + ".cache") + ", cause: " + t.getMessage(), t); } else { // If the startup detection is opened, the Exception is thrown directly. boolean check = getUrl().getParameter(Constants.CHECK_KEY, true) && url.getParameter(Constants.CHECK_KEY, true); boolean skipFailback = t instanceof SkipFailbackWrapperException; //是否配了check如果配了如果订阅失败就报错 if (check || skipFailback) { if (skipFailback) { t = t.getCause(); } throw new IllegalStateException("Failed to subscribe " + url + ", cause: " + t.getMessage(), t); } else { logger.error("Failed to subscribe " + url + ", waiting for retry, cause: " + t.getMessage(), t); } } // Record a failed registration request to a failed list, retry regularly addFailedSubscribed(url, listener); } }
<8>doSubscribe
@Override protected void doSubscribe(final URL url, final NotifyListener listener) { try { // 处理所有 Service 层的发起订阅，例如监控中心的订阅 if (Constants.ANY_VALUE.equals(url.getServiceInterface())) { ..... } else { List<URL> urls = new ArrayList<URL>(); for (String path : toCategoriesPath(url)) { ConcurrentMap<NotifyListener, ChildListener> listeners = zkListeners.get(url); //根据Url获取zk的监听器 没获取到则初始化 if (listeners == null) { zkListeners.putIfAbsent(url, new ConcurrentHashMap<NotifyListener, ChildListener>()); listeners = zkListeners.get(url); } // 获得 ChildListener 对象 zk使用 ChildListener zkListener = listeners.get(listener); if (zkListener == null) { //获取不到则添加一个 这里可以理解成 将dubbo的监听器 适配 当zk节点变动触发 listeners.putIfAbsent(listener, new ChildListener() { @Override public void childChanged(String parentPath, List<String> currentChilds) { //发起通知 ZookeeperRegistry.this.notify(url, listener, toUrlsWithEmpty(url, parentPath, currentChilds)); } }); zkListener = listeners.get(listener); } //ZK创建一个节点 如:/dubbo/com.alibaba.dubbo.demo.DemoService/providers zkClient.create(path, false); //像path节点发起订阅 List<String> children = zkClient.addChildListener(path, zkListener); if (children != null) { urls.addAll(toUrlsWithEmpty(url, path, children)); } } //<9>订阅成功调用notify 通知监听器 如:RegistryDirectory notify(url, listener, urls); } } catch (Throwable e) { throw new RpcException("Failed to subscribe " + url + " to zookeeper " + getUrl() + ", cause: " + e.getMessage(), e); } }
<9>notify
前面还有多个方法处理忽略了 只放出了 最终的notify
com.alibaba.dubbo.registry.support.AbstractRegistry#notify(com.alibaba.dubbo.common.URL, com.alibaba.dubbo.registry.NotifyListener, java.util.List<com.alibaba.dubbo.common.URL>)
protected void notify(URL url, NotifyListener listener, List<URL> urls) { if (url == null) { throw new IllegalArgumentException("notify url == null"); } if (listener == null) { throw new IllegalArgumentException("notify listener == null"); } if ((urls == null || urls.isEmpty()) && !Constants.ANY_VALUE.equals(url.getServiceInterface())) { logger.warn("Ignore empty notify urls for subscribe url " + url); return; } if (logger.isInfoEnabled()) { logger.info("Notify urls for subscribe url " + url + ", urls: " + urls); } Map<String, List<URL>> result = new HashMap<String, List<URL>>(); for (URL u : urls) { if (UrlUtils.isMatch(url, u)) { //将订阅url根据category进行分组 默认为providers String category = u.getParameter(Constants.CATEGORY_KEY, Constants.DEFAULT_CATEGORY); List<URL> categoryList = result.get(category); if (categoryList == null) { categoryList = new ArrayList<URL>(); result.put(category, categoryList); } categoryList.add(u); } } if (result.size() == 0) { return; } Map<String, List<URL>> categoryNotified = notified.get(url); if (categoryNotified == null) { notified.putIfAbsent(url, new ConcurrentHashMap<String, List<URL>>()); categoryNotified = notified.get(url); } for (Map.Entry<String, List<URL>> entry : result.entrySet()) { String category = entry.getKey(); List<URL> categoryList = entry.getValue(); categoryNotified.put(category, categoryList); saveProperties(url); //<10>将分组后的通知lintener listener.notify(categoryList); } }
RegistryDirectory
<10>notify
com.alibaba.dubbo.registry.integration.RegistryDirectory#notify
@Override public synchronized void notify(List<URL> urls) { //提供者url List<URL> invokerUrls = new ArrayList<URL>(); //路由规则https://cloud.tencent.com/developer/article/1443518 List<URL> routerUrls = new ArrayList<URL>(); //处理配置规则 URL 集合 http://dubbo.apache.org/zh-cn/docs/user/demos/config-rule-deprecated.html List<URL> configuratorUrls = new ArrayList<URL>(); /** *通过订阅到数据进行数据分组 * */ for (URL url : urls) { String protocol = url.getProtocol(); String category = url.getParameter(Constants.CATEGORY_KEY, Constants.DEFAULT_CATEGORY); //当url是route或者是routes表示是路由规则 if (Constants.ROUTERS_CATEGORY.equals(category) || Constants.ROUTE_PROTOCOL.equals(protocol)) { routerUrls.add(url); //当url是configurators 或者 override 表示是路由规则 } else if (Constants.CONFIGURATORS_CATEGORY.equals(category) || Constants.OVERRIDE_PROTOCOL.equals(protocol)) { configuratorUrls.add(url); //当url是providers 表示是提供者url } else if (Constants.PROVIDERS_CATEGORY.equals(category)) { invokerUrls.add(url); } else { logger.warn("Unsupported category " + category + " in notified url: " + url + " from registry " + getUrl().getAddress() + " to consumer " + NetUtils.getLocalHost()); } } // configurators if (configuratorUrls != null && !configuratorUrls.isEmpty()) { //<11> this.configurators = toConfigurators(configuratorUrls); } // routers if (routerUrls != null && !routerUrls.isEmpty()) { //获得routers List<Router> routers = toRouters(routerUrls); if (routers != null) { // null - do nothing //<12> setRouters(routers); } } List<Configurator> localConfigurators = this.configurators; // local reference // merge override parameters this.overrideDirectoryUrl = directoryUrl; if (localConfigurators != null && !localConfigurators.isEmpty()) { for (Configurator configurator : localConfigurators) { this.overrideDirectoryUrl = configurator.configure(overrideDirectoryUrl); } } // <13>处理服务提供者 URL 集合 refreshInvoker(invokerUrls); }
<11>toConfigurators
com.alibaba.dubbo.registry.integration.RegistryDirectory#toConfigurators
public static List<Configurator> toConfigurators(List<URL> urls) { if (urls == null || urls.isEmpty()) { return Collections.emptyList(); } List<Configurator> configurators = new ArrayList<Configurator>(urls.size()); for (URL url : urls) { //如果协议为空 则忽略 表示未配置 配置规则 /** * empty://10.3.17.72/com.alibaba.dubbo.demo.DemoService?accesslog=true&application=soa-promotion-consumer&category=configurators&dubbo=2.0.2&interface=com.alibaba.dubbo.demo.DemoService&methods=sayHello,save&pid=23772&side=consumer×tamp=1584603775927&validation=jvalidation */ if (Constants.EMPTY_PROTOCOL.equals(url.getProtocol())) { configurators.clear(); break; } Map<String, String> override = new HashMap<String, String>(url.getParameters()); //The anyhost parameter of override may be added automatically, it can't change the judgement of changing url override.remove(Constants.ANYHOST_KEY); if (override.size() == 0) { configurators.clear(); continue; } //SPI扩展点 获得对应的configurator configurators.add(configuratorFactory.getConfigurator(url)); } Collections.sort(configurators); return configurators; }
<12>setRouters
com.alibaba.dubbo.rpc.cluster.directory.AbstractDirectory#setRouters
protected void setRouters(List<Router> routers) { // copy list routers = routers == null ? new ArrayList<Router>() : new ArrayList<Router>(routers); // 根据url配置的route通过SPI获取并添加到routers String routerkey = url.getParameter(Constants.ROUTER_KEY); if (routerkey != null && routerkey.length() > 0) { RouterFactory routerFactory = ExtensionLoader.getExtensionLoader(RouterFactory.class).getExtension(routerkey); routers.add(routerFactory.getRouter(url)); } // append mock invoker selector //添加默认router routers.add(new MockInvokersSelector()); routers.add(new TagRouter()); Collections.sort(routers); this.routers = routers; }
<13>refreshInvoker
private void refreshInvoker(List<URL> invokerUrls) { //如果是empty if (invokerUrls != null && invokerUrls.size() == 1 && invokerUrls.get(0) != null && Constants.EMPTY_PROTOCOL.equals(invokerUrls.get(0).getProtocol())) { // 设置禁止访问 this.forbidden = true; // 销毁所有 Invoker 集合 this.methodInvokerMap = null; // Set the method invoker map to null destroyAllInvokers(); // Close all invokers } else { // // 设置允许访问 this.forbidden = false; // Allow to access // 引用老的 urlInvokerMap Map<String, Invoker<T>> oldUrlInvokerMap = this.urlInvokerMap; // local reference //// 传入的 invokerUrls 为空，说明是路由规则或配置规则发生改变，此时 invokerUrls 是空的，直接使用 cachedInvokerUrls 。 if (invokerUrls.isEmpty() && this.cachedInvokerUrls != null) { invokerUrls.addAll(this.cachedInvokerUrls); } else { this.cachedInvokerUrls = new HashSet<URL>(); this.cachedInvokerUrls.addAll(invokerUrls);//Cached invoker urls, convenient for comparison } if (invokerUrls.isEmpty()) { return; } //<14>将传入的 invokerUrls ，转成新的 urlInvokerMap Map<String, Invoker<T>> newUrlInvokerMap = toInvokers(invokerUrls);// Translate url list to Invoker map // // 转换出新的 methodInvokerMap Map<String, List<Invoker<T>>> newMethodInvokerMap = toMethodInvokers(newUrlInvokerMap); // Change method name to map Invoker Map // state change // If the calculation is wrong, it is not processed. if (newUrlInvokerMap == null || newUrlInvokerMap.size() == 0) { logger.error(new IllegalStateException("urls to invokers error .invokerUrls.size :" + invokerUrls.size() + ", invoker.size :0. urls :" + invokerUrls.toString())); return; } // // 若服务引用多 group ，则按照 method + group 聚合 Invoker 集合 this.methodInvokerMap = multiGroup ? toMergeMethodInvokerMap(newMethodInvokerMap) : newMethodInvokerMap; // // 销毁不再使用的 Invoker 集合 this.urlInvokerMap = newUrlInvokerMap; try { destroyUnusedInvokers(oldUrlInvokerMap, newUrlInvokerMap); // Close the unused Invoker } catch (Exception e) { logger.warn("destroyUnusedInvokers error. ", e); } } }
<14>toInvokers
/** * Turn urls into invokers, and if url has been refer, will not re-reference. * * @param urls * @return invokers */ private Map<String, Invoker<T>> toInvokers(List<URL> urls) { Map<String, Invoker<T>> newUrlInvokerMap = new HashMap<String, Invoker<T>>(); // 若为空，直接返回 if (urls == null || urls.isEmpty()) { return newUrlInvokerMap; } // 已初始化的服务器提供 URL 集合 避免重复初始化 Set<String> keys = new HashSet<String>(); // 获得引用服务的协议 String queryProtocols = this.queryMap.get(Constants.PROTOCOL_KEY); // 循环服务提供者 URL 集合，转成 Invoker 集合 for (URL providerUrl : urls) { // If protocol is configured at the reference side, only the matching protocol is selected // 如果 reference 端配置了 protocol ，则只选择匹配的 protocol if (queryProtocols != null && queryProtocols.length() > 0) { boolean accept = false; String[] acceptProtocols = queryProtocols.split(","); for (String acceptProtocol : acceptProtocols) { if (providerUrl.getProtocol().equals(acceptProtocol)) { accept = true; break; } } if (!accept) { continue; } } // 忽略，若为 `empty://` 协议 if (Constants.EMPTY_PROTOCOL.equals(providerUrl.getProtocol())) { continue; } // 忽略，若应用程序不支持该协议 if (!ExtensionLoader.getExtensionLoader(Protocol.class).hasExtension(providerUrl.getProtocol())) { logger.error(new IllegalStateException("Unsupported protocol " + providerUrl.getProtocol() + " in notified url: " + providerUrl + " from registry " + getUrl().getAddress() + " to consumer " + NetUtils.getLocalHost() + ", supported protocol: " + ExtensionLoader.getExtensionLoader(Protocol.class).getSupportedExtensions())); continue; } // 合并 URL 参数 URL url = mergeUrl(providerUrl); // 添加到 `keys` 中 String key = url.toFullString(); // The parameter urls are sorted //如果初始化过 则忽略 if (keys.contains(key)) { // Repeated url continue; } keys.add(key); // Cache key is url that does not merge with consumer side parameters, regardless of how the consumer combines parameters, if the server url changes, then refer again // 如果服务端 URL 发生变化，则重新 refer 引用 Map<String, Invoker<T>> localUrlInvokerMap = this.urlInvokerMap; // local reference Invoker<T> invoker = localUrlInvokerMap == null ? null : localUrlInvokerMap.get(key); //未在缓存中，重新引用 防止重复生成 if (invoker == null) { // Not in the cache, refer again try { //判断是否开始 disabled=true boolean enabled = true; if (url.hasParameter(Constants.DISABLED_KEY)) { enabled = !url.getParameter(Constants.DISABLED_KEY, false); } else { enabled = url.getParameter(Constants.ENABLED_KEY, true); } if (enabled) { //<15>引用服务protocol.refer(serviceType, url) invoker = new InvokerDelegate<T>(protocol.refer(serviceType, url), url, providerUrl); } } catch (Throwable t) { logger.error("Failed to refer invoker for interface:" + serviceType + ",url:(" + url + ")" + t.getMessage(), t); } if (invoker != null) { // Put new invoker in cache //将新生成的传入 newUrlInvokerMap.put(key, invoker); } } else { newUrlInvokerMap.put(key, invoker); } } keys.clear(); return newUrlInvokerMap; }
DubboProtocol
<15>refer
@Override public <T> Invoker<T> refer(Class<T> serviceType, URL url) throws RpcException { optimizeSerialization(url); //创建DubboInvoker <16>getClients DubboInvoker<T> invoker = new DubboInvoker<T>(serviceType, url, getClients(url), invokers); //添加到已订阅列表 invokers.add(invoker); return invoker; }
<16>getClients
private ExchangeClient[] getClients(URL url) { // whether to share connection //是否共享连接 同一个远程服务公用同一个连接 文档:http://dubbo.apache.org/zh-cn/docs/user/demos/config-connections.html //http://dubbo.apache.org/zh-cn/docs/user/references/xml/dubbo-reference.html boolean service_share_connect = false; //从url获取是否共享连接 默认为0 共享 int connections = url.getParameter(Constants.CONNECTIONS_KEY, 0); // if not configured, connection is shared, otherwise, one connection for one service if (connections == 0) { service_share_connect = true; connections = 1; } ExchangeClient[] clients = new ExchangeClient[connections]; for (int i = 0; i < clients.length; i++) { if (service_share_connect) { // // <17>共享 clients[i] = getSharedClient(url); } else { //<18>不共享 clients[i] = initClient(url); } } return clients; }
<17>getSharedClient
/** * Get shared connection */ private ExchangeClient getSharedClient(URL url) { //获得url地址 ip:port String key = url.getAddress(); //在缓存中获取 ReferenceCountExchangeClient client = referenceClientMap.get(key); //不等于null表示初始化过了 if (client != null) { //是否关闭 if (!client.isClosed()) { //记录获取次数 client.incrementAndGetCount(); return client; } else { //如果关闭移除 重新建立连接 referenceClientMap.remove(key); } } //存入锁对象 如果不存在 如果存在直接返回 locks.putIfAbsent(key, new Object()); //加锁防止重复初始化 synchronized (locks.get(key)) { //防止锁穿透 if (referenceClientMap.containsKey(key)) { return referenceClientMap.get(key); } //<18>初始化clieeent ExchangeClient exchangeClient = initClient(url); // 将 `exchangeClient` 包装，创建 ReferenceCountExchangeClient 对象 client = new ReferenceCountExchangeClient(exchangeClient, ghostClientMap); //添加到集合 referenceClientMap.put(key, client); ghostClientMap.remove(key); locks.remove(key); return client; } }
<18>initClient
/** * Create new connection */ private ExchangeClient initClient(URL url) { // client type setting. String str = url.getParameter(Constants.CLIENT_KEY, url.getParameter(Constants.SERVER_KEY, Constants.DEFAULT_REMOTING_CLIENT)); url = url.addParameter(Constants.CODEC_KEY, DubboCodec.NAME); // enable heartbeat by default url = url.addParameterIfAbsent(Constants.HEARTBEAT_KEY, String.valueOf(Constants.DEFAULT_HEARTBEAT)); // BIO is not allowed since it has severe performance issue. if (str != null && str.length() > 0 && !ExtensionLoader.getExtensionLoader(Transporter.class).hasExtension(str)) { throw new RpcException("Unsupported client type: " + str + "," + " supported client type is " + StringUtils.join(ExtensionLoader.getExtensionLoader(Transporter.class).getSupportedExtensions(), " ")); } ExchangeClient client; try { // 懒连接，创建 LazyConnectExchangeClient 对象 // connection should be lazy if (url.getParameter(Constants.LAZY_CONNECT_KEY, false)) { client = new LazyConnectExchangeClient(url, requestHandler); } else { // 直接连接，创建 HeaderExchangeClient 对象 client = Exchangers.connect(url, requestHandler); } } catch (RemotingException e) { throw new RpcException("Fail to create remoting client for service(" + url + "): " + e.getMessage(), e); } return client; }
<2>RegistryFactory
接口定义
@SPI("dubbo")//缺省值dubbo
public interface RegistryFactory {
/**
* Connect to the registry
* <p>
* Connecting the registry needs to support the contract: <br>
* 1. When the check=false is set, the connection is not checked, otherwise the exception is thrown when disconnection <br>
* 2. Support username:password authority authentication on URL.<br>
* 3. Support the backup=10.20.153.10 candidate registry cluster address.<br>
* 4. Support file=registry.cache local disk file cache.<br>
* 5. Support the timeout=1000 request timeout setting.<br>
* 6. Support session=60000 session timeout or expiration settings.<br>
*
* @param url Registry address, is not allowed to be empty
* @return Registry reference, never return empty value
*/
@Adaptive({"protocol"}) //url带有protocol参数
Registry getRegistry(URL url);
}
类图
