dubbo 多版本部分源码分析

不想你离开。 提交于 2019-12-02 05:27:10

提供端分析

服务提供者在起动时,会执行到DubboProtocol.export,生成DubboExporter对象,并放入exportMap中。

public <T> Exporter<T> export(Invoker<T> invoker) throws RpcException {
        URL url = invoker.getUrl();
        
        // export service.
        String key = serviceKey(url);
        DubboExporter<T> exporter = new DubboExporter<T>(invoker, key, exporterMap);
        exporterMap.put(key, exporter);
        
        //export an stub service for dispaching event
        Boolean isStubSupportEvent = url.getParameter(Constants.STUB_EVENT_KEY,Constants.DEFAULT_STUB_EVENT);
        Boolean isCallbackservice = url.getParameter(Constants.IS_CALLBACK_SERVICE, false);
        if (isStubSupportEvent && !isCallbackservice){
            String stubServiceMethods = url.getParameter(Constants.STUB_EVENT_METHODS_KEY);
            if (stubServiceMethods == null || stubServiceMethods.length() == 0 ){
                if (logger.isWarnEnabled()){
                    logger.warn(new IllegalStateException("consumer [" +url.getParameter(Constants.INTERFACE_KEY) +
                            "], has set stubproxy support event ,but no stub methods founded."));
                }
            } else {
                stubServiceMethodsMap.put(url.getServiceKey(), stubServiceMethods);
            }
        }

 

在调用的时候,可以通过exportMap获取到dubboExporter,再从dubboExporter中取到invoker,从而调用真正的服务,而exportMap中对应的key值

/** serviceGroup/serviceName:serviceVersion:port*/
    public static String serviceKey(int port, String serviceName, String serviceVersion, String serviceGroup) {
        StringBuilder buf = new StringBuilder();
        if (serviceGroup != null && serviceGroup.length() > 0) {
            buf.append(serviceGroup);
            buf.append("/");
        }
        buf.append(serviceName);
        if (serviceVersion != null && serviceVersion.length() > 0 && !"0.0.0".equals(serviceVersion)) {
            buf.append(":");
            buf.append(serviceVersion);
        }
        buf.append(":");
        buf.append(port);
        return buf.toString();
    }


当调用到达服务端时,会被DubboProtocol的requestHandler处理,其中的requestHandler.reply只处理远程消息调用(Invocation),

public Object reply(ExchangeChannel channel, Object message) throws RemotingException {
            if (message instanceof Invocation) {//只处理远程调用消息Invocation
                Invocation inv = (Invocation) message;
                Invoker<?> invoker = getInvoker(channel, inv);
                //如果是callback 需要处理高版本调用低版本的问题
                if (Boolean.TRUE.toString().equals(inv.getAttachments().get(IS_CALLBACK_SERVICE_INVOKE))){
                    String methodsStr = invoker.getUrl().getParameters().get("methods");
                    boolean hasMethod = false;
                    if (methodsStr == null || methodsStr.indexOf(",") == -1){
                        hasMethod = inv.getMethodName().equals(methodsStr);
                    } else {
                        String[] methods = methodsStr.split(",");
                        for (String method : methods){
                            if (inv.getMethodName().equals(method)){
                                hasMethod = true;
                                break;
                            }
                        }
                    }
                    if (!hasMethod){
                        logger.warn(new IllegalStateException("The methodName "+inv.getMethodName()+" not found in callback service interface ,invoke will be ignored. please update the api interface. url is:" + invoker.getUrl()) +" ,invocation is :"+inv );
                        return null;
                    }
                }
                RpcContext.getContext().setRemoteAddress(channel.getRemoteAddress());
                return invoker.invoke(inv);
            }
            throw new RemotingException(channel, "Unsupported request: " + message == null ? null : (message.getClass().getName() + ": " + message) + ", channel: consumer: " + channel.getRemoteAddress() + " --> provider: " + channel.getLocalAddress());
        }


其后利用getInvoker方法,根据servicekey取到invoker

Invoker<?> getInvoker(Channel channel, Invocation inv) throws RemotingException{
        boolean isCallBackServiceInvoke = false;
        boolean isStubServiceInvoke = false;
        int port = channel.getLocalAddress().getPort();
        String path = inv.getAttachments().get(Constants.PATH_KEY);
        //如果是客户端的回调服务.
        isStubServiceInvoke = Boolean.TRUE.toString().equals(inv.getAttachments().get(Constants.STUB_EVENT_KEY));
        if (isStubServiceInvoke){
            port = channel.getRemoteAddress().getPort();
        }
        //callback
        isCallBackServiceInvoke = isClientSide(channel) && !isStubServiceInvoke;
        if(isCallBackServiceInvoke){
            path = inv.getAttachments().get(Constants.PATH_KEY)+"."+inv.getAttachments().get(Constants.CALLBACK_SERVICE_KEY);
            inv.getAttachments().put(IS_CALLBACK_SERVICE_INVOKE, Boolean.TRUE.toString());
        }
        String serviceKey = serviceKey(port, path, inv.getAttachments().get(Constants.VERSION_KEY), inv.getAttachments().get(Constants.GROUP_KEY));
        /** 从exporterMap中获取暴露服务的DubboExporter*/
        DubboExporter<?> exporter = (DubboExporter<?>) exporterMap.get(serviceKey);
        
        if (exporter == null)
            throw new RemotingException(channel, "Not found exported service: " + serviceKey + " in " + exporterMap.keySet() + ", may be version or group mismatch " + ", channel: consumer: " + channel.getRemoteAddress() + " --> provider: " + channel.getLocalAddress() + ", message:" + inv);

        return exporter.getInvoker();//从dubboExporter获取invoker返回
    }

 

调用端分析

消费者在初始化时,会调用到RegistryProtocol.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);
        //生成消费者URL
//        String ipAddr = NetUtils.getLocalHost();
//        if(!ConfUtil.getParamInEnv("HOST").isEmpty()){
//        	ipAddr = ConfUtil.getParamInEnv("HOST");
//        }
        URL subscribeUrl = new URL(Constants.CONSUMER_PROTOCOL, NetUtils.getLocalHost(), 0, type.getName(), directory.getUrl().getParameters());
//        URL subscribeUrl = new URL(Constants.CONSUMER_PROTOCOL, ipAddr, 0, type.getName(), directory.getUrl().getParameters());
        if (! Constants.ANY_VALUE.equals(url.getServiceInterface())
                && url.getParameter(Constants.REGISTER_KEY, true)) {
            registry.register(subscribeUrl.addParameters(Constants.CATEGORY_KEY, Constants.CONSUMERS_CATEGORY,
                    Constants.CHECK_KEY, String.valueOf(false)));
        }
        /** 订阅此url*/
        directory.subscribe(subscribeUrl.addParameter(Constants.CATEGORY_KEY, 
                Constants.PROVIDERS_CATEGORY 
                + "," + Constants.CONFIGURATORS_CATEGORY 
                + "," + Constants.ROUTERS_CATEGORY));//category (providers,configurators,routers)
        return cluster.join(directory);
    }

 

每个消费者创建一个RegistryDirectory(用于缓存Invoker等),所以分析directory.subscribe

 

 @Override
    public void subscribe(URL url, NotifyListener listener) {
        super.subscribe(url, listener);
        removeFailedSubscribed(url, listener);
        try {
            // 向服务器端发送订阅请求
            doSubscribe(url, listener);
        } catch (Exception e) {
            Throwable t = e;

            List<URL> urls = getCacheUrls(url);
            if (urls != null && urls.size() > 0) {
                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.dir") + "/.hsf/hsf-registry-" + url.getHost() + ".cache") + ", cause: " + t.getMessage(), t);
            } else {
                // 如果开启了启动时检测,则直接抛出异常,约定
                boolean check = getUrl().getParameter(Constants.CHECK_KEY, true)
                        && url.getParameter(Constants.CHECK_KEY, true);
                boolean skipFailback = t instanceof SkipFailbackWrapperException;
                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);
                }
            }

            // 将失败的订阅请求记录到失败列表,定时重试
            addFailedSubscribed(url, listener);
        }
    }


然后转到ZookeeperRegistry.doSubscribe方法

 else {
                List<URL> urls = new ArrayList<URL>();
                for (String path : toCategoriesPath(url)) {
                    ConcurrentMap<NotifyListener, ChildListener> listeners = zkListeners.get(url);
                    if (listeners == null) {
                        zkListeners.putIfAbsent(url, new ConcurrentHashMap<NotifyListener, ChildListener>());
                        listeners = zkListeners.get(url);
                    }
                    ChildListener zkListener = listeners.get(listener);
                    if (zkListener == null) {
                        listeners.putIfAbsent(listener, new ChildListener() {
                            public void childChanged(String parentPath, List<String> currentChilds) {
                            	List<URL> changeList = toUrlsWithEmpty(url, parentPath, currentChilds);
//                            	if(currentChilds.size()>0) updateData(changeList);   //cuihs
                            	ZookeeperRegistry.this.notify(url, listener, changeList);
                            }
                        });
                        zkListener = listeners.get(listener);
                    }
                    zkClient.create(path, false);
                    List<String> children = zkClient.addChildListener(path, zkListener);
                    if (children != null) {
                    	urls.addAll(toUrlsWithEmpty(url, path, children));
                    }
                }
                notify(url, listener, urls);
            }


注意toUrlsWithEmpty这个方法

 /** 如果提供者与消费者不匹配,则生成一个empty协议的标识性URL*/
    private List<URL> toUrlsWithEmpty(URL consumer, String path, List<String> providers) {
        List<URL> urls = toUrlsWithoutEmpty(consumer, providers);
        if (urls == null || urls.isEmpty()) {//通知的数据类型为空时,需要通知一个empty协议并带categroy参数的标识性URL
        	int i = path.lastIndexOf('/');
        	String category = i < 0 ? path : path.substring(i + 1);
        	URL empty = consumer.setProtocol(Constants.EMPTY_PROTOCOL).addParameter(Constants.CATEGORY_KEY, category);
            urls.add(empty);
        }
        return urls;
    }


找到toUrlsWithoutEmpty这个方法,里面调用了UrlsUtils.isMath

/** 获取与消费者匹配的提供者URL列表*/
    private List<URL> toUrlsWithoutEmpty(URL consumer, List<String> providers) {
    	List<URL> urls = new ArrayList<URL>();
        if (providers != null && providers.size() > 0) {
            for (String provider : providers) {
                provider = URL.decode(provider);
                if (provider.contains("://")) {
                    URL url = URL.valueOf(provider);
                    if (UrlUtils.isMatch(consumer, url)) {
                        urls.add(url);
                    }
                }
            }
        }
        return urls;
    }

 

/** 检查两个URL的接口名、group version classifier匹配,二者是否可用*/
    public static boolean isMatch(URL consumerUrl, URL providerUrl) {
        String consumerInterface = consumerUrl.getServiceInterface();
        String providerInterface = providerUrl.getServiceInterface();
        //检查接口名是否匹配
        if( ! (Constants.ANY_VALUE.equals(consumerInterface) || StringUtils.isEquals(consumerInterface, providerInterface)) ) return false;
        //检查分类是否匹配
        if (! isMatchCategory(providerUrl.getParameter(Constants.CATEGORY_KEY, Constants.DEFAULT_CATEGORY), 
                consumerUrl.getParameter(Constants.CATEGORY_KEY, Constants.DEFAULT_CATEGORY))) {
            return false;
        }
        //检查消费者和提供者是否都可用
        if (! providerUrl.getParameter(Constants.ENABLED_KEY, true) 
                && ! Constants.ANY_VALUE.equals(consumerUrl.getParameter(Constants.ENABLED_KEY))) {
            return false;
        }
       //检查group、version、classifier是否匹配
        String consumerGroup = consumerUrl.getParameter(Constants.GROUP_KEY);
        String consumerVersion = consumerUrl.getParameter(Constants.VERSION_KEY);
        String consumerClassifier = consumerUrl.getParameter(Constants.CLASSIFIER_KEY, Constants.ANY_VALUE);
        
        String providerGroup = providerUrl.getParameter(Constants.GROUP_KEY);
        String providerVersion = providerUrl.getParameter(Constants.VERSION_KEY);
        String providerClassifier = providerUrl.getParameter(Constants.CLASSIFIER_KEY, Constants.ANY_VALUE);
        return (Constants.ANY_VALUE.equals(consumerGroup) || StringUtils.isEquals(consumerGroup, providerGroup) || StringUtils.isContains(consumerGroup, providerGroup))
               && (Constants.ANY_VALUE.equals(consumerVersion) || StringUtils.isEquals(consumerVersion, providerVersion))
               && (consumerClassifier == null || Constants.ANY_VALUE.equals(consumerClassifier) || StringUtils.isEquals(consumerClassifier, providerClassifier));
    }

 

到这里为止就已经实现了版本的路由功能,

 

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