服务消费者端代码
@DubboReference(version = "1.0.0")
private DemoService demoService;
public static void main(String[] args) {
SpringApplication.run(DubboAutoConfigurationConsumerBootstrap.class).close();
}
@Bean
public ApplicationRunner runner() {
return new ApplicationRunner() {
public void run(ApplicationArguments args) throws Exception {
System.out.println(demoService.sayHello("mercyblitz"));
}
};
}
我们再次来到 DubboComponentScanRegistrar 中、
@Override
public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry) {
Set<String> packagesToScan = getPackagesToScan(importingClassMetadata);
registerServiceAnnotationBeanPostProcessor(packagesToScan, registry);
// @since 2.7.6 Register the common beans
registerCommonBeans(registry);
}
static void registerCommonBeans(BeanDefinitionRegistry registry) {
// Since 2.5.7 Register @Reference Annotation Bean Processor as an infrastructure Bean
registerInfrastructureBean(registry, ReferenceAnnotationBeanPostProcessor.BEAN_NAME,
ReferenceAnnotationBeanPostProcessor.class);
// Since 2.7.4 [Feature] https://github.com/apache/dubbo/issues/5093
registerInfrastructureBean(registry, DubboConfigAliasPostProcessor.BEAN_NAME,
DubboConfigAliasPostProcessor.class);
// Since 2.7.5 Register DubboLifecycleComponentApplicationListener as an infrastructure Bean
registerInfrastructureBean(registry, DubboLifecycleComponentApplicationListener.BEAN_NAME,
DubboLifecycleComponentApplicationListener.class);
// Since 2.7.4 Register DubboBootstrapApplicationListener as an infrastructure Bean
registerInfrastructureBean(registry, DubboBootstrapApplicationListener.BEAN_NAME,
DubboBootstrapApplicationListener.class);
// Since 2.7.6 Register DubboConfigDefaultPropertyValueBeanPostProcessor as an infrastructure Bean
registerInfrastructureBean(registry, DubboConfigDefaultPropertyValueBeanPostProcessor.BEAN_NAME,
DubboConfigDefaultPropertyValueBeanPostProcessor.class);
}
我们看到了 ReferenceAnnotationBeanPostProcessor、该类同时也实现了 InstantiationAwareBeanPostProcessor 接口。
该方法会在 Spring 填充属性的时候被调用、通过该方法返回注入的对象
@Override
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);
boolean localServiceBean = isLocalServiceBean(referencedBeanName, referenceBean, attributes);
prepareReferenceBean(referencedBeanName, referenceBean, localServiceBean);
registerReferenceBean(referencedBeanName, referenceBean, attributes, localServiceBean, injectedType);
cacheInjectedReferenceBean(referenceBean, injectedElement);
return referenceBean.get();
}
我们可以看到 最终调用 ReferenceBean 的 get 方法
public synchronized T get() {
if (destroyed) {
throw new IllegalStateException("The invoker of ReferenceConfig(" + url + ") has already destroyed!");
}
if (ref == null) {
init();
}
return ref;
}
ref 此时为 null 进入到 init 方法中
public synchronized void init() {
.......
// 构造参数 map
ref = createProxy(map);
.......
}
private T createProxy(Map<String, String> map) {
if (shouldJvmRefer(map)) {
........
} else {
urls.clear();
if (url != null && url.length() > 0) { // user specified URL, could be peer-to-peer address, or register center's address.
......//点对点通信
} 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.");
}
}
}
// 单个注册中心
if (urls.size() == 1) {
invoker = REF_PROTOCOL.refer(interfaceClass, urls.get(0));
} else {
// 多个注册中心
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));
}
}
}
.........
// create service proxy
return (T) PROXY_FACTORY.getProxy(invoker, ProtocolUtils.isGeneric(generic));
}
无论配置了单个注册中心、还是多个、都需要从注册中心中获取服务提供者的地址
REF_PROTOCOL.refer(interfaceClass, url)
RegistryProtocol
@Override
@SuppressWarnings("unchecked")
public <T> Invoker<T> refer(Class<T> type, URL url) throws RpcException {
url = getRegistryUrl(url);
Registry registry = registryFactory.getRegistry(url);
if (RegistryService.class.equals(type)) {
return proxyFactory.getInvoker((T) registry, type, url);
}
// group="a,b" or group="*"
Map<String, String> qs = StringUtils.parseQueryString(url.getParameterAndDecoded(REFER_KEY));
String group = qs.get(GROUP_KEY);
if (group != null && group.length() > 0) {
if ((COMMA_SPLIT_PATTERN.split(group)).length > 1 || "*".equals(group)) {
return doRefer(getMergeableCluster(), registry, type, url);
}
}
return doRefer(cluster, registry, type, url);
}
直接进入到 doRefer 中干实事
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);
registry.register(directory.getRegisteredConsumerUrl());
}
directory.buildRouterChain(subscribeUrl);
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;
}
进入到订阅服务注册中心的路径、会在此处获取到服务提供者的真实地址
public void subscribe(URL url) {
setConsumerUrl(url);
CONSUMER_CONFIGURATION_LISTENER.addNotifyListener(this);
serviceConfigurationListener = new ReferenceConfigurationListener(this, url);
registry.subscribe(url, this);
}
url 的地址如下。
consumer://192.168.1.103/com.demo.api.DemoService?application=dubbo-auto-configure-consumer-sample&category=providers,configurators,routers&dubbo=2.0.2&init=false&interface=com.demo.api.DemoService&metadata-type=remote&methods=sayHello&pid=85321&qos.enable=false&release=2.7.8&revision=1.0.0&side=consumer&sticky=false×tamp=1645947096408&version=1.0.0
订阅了 providers,configurators,routers 这三个目录
进入到 ZookeeperRegistry
@Override
public void doSubscribe(final URL url, final NotifyListener listener) {
try {
if (ANY_VALUE.equals(url.getServiceInterface())) {
......
} else {
List<URL> urls = new ArrayList<>();
for (String path : toCategoriesPath(url)) {
ConcurrentMap<NotifyListener, ChildListener> listeners = zkListeners.computeIfAbsent(url, k -> new ConcurrentHashMap<>());
ChildListener zkListener = listeners.computeIfAbsent(listener, k -> (parentPath, currentChilds) -> ZookeeperRegistry.this.notify(url, k, toUrlsWithEmpty(url, parentPath, currentChilds)));
zkClient.create(path, false);
List<String> children = zkClient.addChildListener(path, zkListener);
if (children != null) {
urls.addAll(toUrlsWithEmpty(url, path, children));
}
}
notify(url, listener, urls);
}
} catch (Throwable e) {
throw new RpcException("Failed to subscribe " + url + " to zookeeper " + getUrl() + ", cause: " + e.getMessage(), e);
}
}
path 分别为
/dubbo/com.demo.api.DemoService/providers
/dubbo/com.demo.api.DemoService/configurators
/dubbo/com.demo.api.DemoService/routers
providers 获取到到值
dubbo%3A%2F%2F127.0.0.1%3A12345%2Fcom.demo.api.DemoService%3Fanyhost%3Dtrue%26application%3Ddubbo-auto-configuration-provider-demo%26deprecated%3Dfalse%26dubbo%3D2.0.2%26dynamic%3Dtrue%26generic%3Dfalse%26interface%3Dcom.demo.api.DemoService%26methods%3DsayHello%26pid%3D85689%26release%3D2.7.7%26revision%3D1.0.0%26side%3Dprovider%26timestamp%3D1645947588375%26version%3D1.0.0
@Override
protected void notify(URL url, NotifyListener listener, List<URL> urls) {
.......
doNotify(url, listener, urls);
}
protected void doNotify(URL url, NotifyListener listener, List<URL> urls) {
super.notify(url, listener, urls);
}
protected void notify(URL url, NotifyListener listener, List<URL> urls) {
.......
Map<String, List<URL>> result = new HashMap<>();
for (URL u : urls) {
if (UrlUtils.isMatch(url, u)) {
String category = u.getParameter(CATEGORY_KEY, DEFAULT_CATEGORY);
List<URL> categoryList = result.computeIfAbsent(category, k -> new ArrayList<>());
categoryList.add(u);
}
}
Map<String, List<URL>> categoryNotified = notified.computeIfAbsent(url, u -> new ConcurrentHashMap<>());
for (Map.Entry<String, List<URL>> entry : result.entrySet()) {
String category = entry.getKey();
List<URL> categoryList = entry.getValue();
categoryNotified.put(category, categoryList);
listener.notify(categoryList);
saveProperties(url);
}
}
listener.notify(categoryList);
这里的 listener 就是我们一开始的 DiretoryRegistry
@Override
public synchronized void notify(List<URL> urls) {
Map<String, List<URL>> categoryUrls = urls.stream()
.filter(Objects::nonNull)
.filter(this::isValidCategory)
.filter(this::isNotCompatibleFor26x)
.collect(Collectors.groupingBy(this::judgeCategory));
List<URL> configuratorURLs = categoryUrls.getOrDefault(CONFIGURATORS_CATEGORY, Collections.emptyList());
this.configurators = Configurator.toConfigurators(configuratorURLs).orElse(this.configurators);
List<URL> routerURLs = categoryUrls.getOrDefault(ROUTERS_CATEGORY, Collections.emptyList());
toRouters(routerURLs).ifPresent(this::addRouters);
// providers
List<URL> providerURLs = categoryUrls.getOrDefault(PROVIDERS_CATEGORY, Collections.emptyList());
/**
* 3.x added for extend URL address
*/
ExtensionLoader<AddressListener> addressListenerExtensionLoader = ExtensionLoader.getExtensionLoader(AddressListener.class);
List<AddressListener> supportedListeners = addressListenerExtensionLoader.getActivateExtension(getUrl(), (String[]) null);
if (supportedListeners != null && !supportedListeners.isEmpty()) {
for (AddressListener addressListener : supportedListeners) {
providerURLs = addressListener.notify(providerURLs, getConsumerUrl(),this);
}
}
refreshOverrideAndInvoker(providerURLs);
}
进入到 refreshOverrideAndInvoker 中
private void refreshOverrideAndInvoker(List<URL> urls) {
// mock zookeeper://xxx?mock=return null
overrideDirectoryUrl();
refreshInvoker(urls);
}
private void refreshInvoker(List<URL> invokerUrls) {
Assert.notNull(invokerUrls, "invokerUrls should not be null");
if (invokerUrls.size() == 1
&& invokerUrls.get(0) != null
&& EMPTY_PROTOCOL.equals(invokerUrls.get(0).getProtocol())) {
.......
} else {
......
Map<String, Invoker<T>> newUrlInvokerMap = toInvokers(invokerUrls);// Translate url list to Invoker map
if (CollectionUtils.isEmptyMap(newUrlInvokerMap)) {
logger.error(new IllegalStateException("urls to invokers error .invokerUrls.size :" + invokerUrls.size() + ", invoker.size :0. urls :" + invokerUrls
.toString()));
return;
}
List<Invoker<T>> newInvokers = Collections.unmodifiableList(new ArrayList<>(newUrlInvokerMap.values()));
routerChain.setInvokers(newInvokers);
this.invokers = multiGroup ? toMergeInvokerList(newInvokers) : newInvokers;
this.urlInvokerMap = newUrlInvokerMap;
try {
destroyUnusedInvokers(oldUrlInvokerMap, newUrlInvokerMap); // Close the unused Invoker
} catch (Exception e) {
logger.warn("destroyUnusedInvokers error. ", e);
}
}
}
toInvokers(invokerUrls)
将 url 转化成 Invoker
private Map<String, Invoker<T>> toInvokers(List<URL> urls) {
Map<String, Invoker<T>> newUrlInvokerMap = new HashMap<>();
if (urls == null || urls.isEmpty()) {
return newUrlInvokerMap;
}
Set<String> keys = new HashSet<>();
String queryProtocols = this.queryMap.get(PROTOCOL_KEY);
for (URL providerUrl : urls) {
// If protocol is configured at the reference side, only the matching protocol is selected
............
if (EMPTY_PROTOCOL.equals(providerUrl.getProtocol())) {
continue;
}
if (!ExtensionLoader.getExtensionLoader(Protocol.class).hasExtension(providerUrl.getProtocol())) {
........
continue;
}
URL url = mergeUrl(providerUrl);
String key = url.toFullString(); // The parameter urls are sorted
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
Map<String, Invoker<T>> localUrlInvokerMap = this.urlInvokerMap; // local reference
Invoker<T> invoker = localUrlInvokerMap == null ? null : localUrlInvokerMap.get(key);
if (invoker == null) { // Not in the cache, refer again
try {
boolean enabled = true;
if (url.hasParameter(DISABLED_KEY)) {
enabled = !url.getParameter(DISABLED_KEY, false);
} else {
enabled = url.getParameter(ENABLED_KEY, true);
}
if (enabled) {
invoker = new InvokerDelegate<>(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
newUrlInvokerMap.put(key, invoker);
}
} else {
newUrlInvokerMap.put(key, invoker);
}
}
keys.clear();
return newUrlInvokerMap;
}
根据协议调用 refer 方法
invoker = new InvokerDelegate<>(protocol.refer(serviceType, url), url, providerUrl);
ProtocolFilterWrapper 这里也会创建一系列的 Filter、在调用真正的 Invoker 之前执行
@Override
public <T> Invoker<T> refer(Class<T> type, URL url) throws RpcException {
if (UrlUtils.isRegistry(url)) {
return protocol.refer(type, url);
}
return buildInvokerChain(protocol.refer(type, url), REFERENCE_FILTER_KEY, CommonConstants.CONSUMER);
}
AbstractProtocol 异步转同步
@Override
public <T> Invoker<T> refer(Class<T> type, URL url) throws RpcException {
return new AsyncToSyncInvoker<>(protocolBindingRefer(type, url));
}
DubboProtocol 这里直接返回一个 DubboInvoker
@Override
public <T> Invoker<T> protocolBindingRefer(Class<T> serviceType, URL url) throws RpcException {
optimizeSerialization(url);
// create rpc invoker.
DubboInvoker<T> invoker = new DubboInvoker<T>(serviceType, url, getClients(url), invokers);
invokers.add(invoker);
return invoker;
}
getClients 则会去与服务提供者建立连接
private ExchangeClient[] getClients(URL url) {
boolean useShareConnect = false;
int connections = url.getParameter(CONNECTIONS_KEY, 0);
List<ReferenceCountExchangeClient> shareClients = null;
if (connections == 0) {
useShareConnect = true;
String shareConnectionsStr = url.getParameter(SHARE_CONNECTIONS_KEY, (String) null);
connections = Integer.parseInt(StringUtils.isBlank(shareConnectionsStr) ? ConfigUtils.getProperty(SHARE_CONNECTIONS_KEY,
DEFAULT_SHARE_CONNECTIONS) : shareConnectionsStr);
shareClients = getSharedClient(url, connections);
}
ExchangeClient[] clients = new ExchangeClient[connections];
for (int i = 0; i < clients.length; i++) {
if (useShareConnect) {
clients[i] = shareClients.get(i);
} else {
clients[i] = initClient(url);
}
}
return clients;
}
我们现在回到 RegistryProtocol 中 directory.subscribe(toSubscribeUrl(subscribeUrl)); 的流程上面我们已经讲了
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);
registry.register(directory.getRegisteredConsumerUrl());
}
directory.buildRouterChain(subscribeUrl);
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;
Invoker<T> invoker = cluster.join(directory); 下面进入到这个方法中
MockClusterWrapper 就是我们常用的 mock 功能
@Override
public <T> Invoker<T> join(Directory<T> directory) throws RpcException {
return new MockClusterInvoker<T>(directory,
this.cluster.join(directory));
}
AbstractCluster 则会创建一系列的 Interceptor 、在真正调用 Invoker 之前执行
@Override
public <T> Invoker<T> join(Directory<T> directory) throws RpcException {
return buildClusterInterceptors(doJoin(directory), directory.getUrl().getParameter(REFERENCE_INTERCEPTOR_KEY));
}
FailoverCluster 我们默认是 Failover 策略
@Override
public <T> AbstractClusterInvoker<T> doJoin(Directory<T> directory) throws RpcException {
return new FailoverClusterInvoker<>(directory);
}
再回到我们的 org.apache.dubbo.config.ReferenceConfig#createProxy 中、如果是多个注册中心、则会再 join 一次、因为也要对不同的注册中心进行选择对应的服务提供者。多一层负载均衡
在 org.apache.dubbo.config.ReferenceConfig#createProxy 最后
return (T) PROXY_FACTORY.getProxy(invoker, ProtocolUtils.isGeneric(generic));
通过代理工厂创建一个代理 JavassistProxyFactory
@SuppressWarnings("unchecked")
public <T> T getProxy(Invoker<T> invoker, Class<?>[] interfaces) {
return (T) Proxy.getProxy(interfaces).newInstance(new InvokerInvocationHandler(invoker));
}
至于真正发起调用的逻辑、我们放到下一个文章去写
