dubbo源码阅读-服务调用之远程调用(十二)
ReferenceConfig
createProxy
rivate T createProxy(Map<String, String> map) { URL tmpUrl = new URL("temp", "localhost", 0, map); final boolean isJvmRefer; //是否是本地调用 if (isInjvm() == null) { if (url != null && url.length() > 0) { // if a url is specified, don't do local reference isJvmRefer = false; //根据url配置判断是否是本地调用 } else if (InjvmProtocol.getInjvmProtocol().isInjvmRefer(tmpUrl)) { // by default, reference local service if there is isJvmRefer = true; } else { isJvmRefer = false; } } else { isJvmRefer = isInjvm().booleanValue(); } //如果是本地引用 if (isJvmRefer) { //组织url为injvm://127.0.0.1 URL url = new URL(Constants.LOCAL_PROTOCOL, NetUtils.LOCALHOST, 0, interfaceClass.getName()).addParameters(map); /** * SPI扩展点 * private static final Protocol refprotocol = ExtensionLoader.getExtensionLoader(Protocol.class).getAdaptiveExtension(); */ invoker = refprotocol.refer(interfaceClass, url); if (logger.isInfoEnabled()) { logger.info("Using injvm service " + interfaceClass.getName()); } } else { //如果我们手动配置了url;隔开 追加到urls列表 if (url != null && url.length() > 0) { // user specified URL, could be peer-to-peer address, or register center's address. // 拆分地址成数组，使用 ";" 分隔。 String[] us = Constants.SEMICOLON_SPLIT_PATTERN.split(url); // 循环数组，添加到 `url` 中。 if (us != null && us.length > 0) { for (String u : us) { // 创建 URL 对象 URL url = URL.valueOf(u); // 设置默认路径 if (url.getPath() == null || url.getPath().length() == 0) { url = url.setPath(interfaceName); } // 注册中心的地址，带上服务引用的配置参数 if (Constants.REGISTRY_PROTOCOL.equals(url.getProtocol())) { urls.add(url.addParameterAndEncoded(Constants.REFER_KEY, StringUtils.toQueryString(map))); } else { // 服务提供者的地址 urls.add(ClusterUtils.mergeUrl(url, map)); } } } } else { // assemble URL from register center's configuration //获取注册中心地址 具体可以看你https://www.cnblogs.com/LQBlog/p/12469007.html#autoid-6-10-0 List<URL> us = loadRegistries(false); if (us != null && !us.isEmpty()) { for (URL u : us) { //加载Monitor 使用例子https://blog.csdn.net/sunhuaqiang1/article/details/80141651 URL monitorUrl = loadMonitor(u); if (monitorUrl != null) { map.put(Constants.MONITOR_KEY, URL.encode(monitorUrl.toFullString())); } //添加refer标识 标识是从注册中心地尼公约 urls.add(u.addParameterAndEncoded(Constants.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 `urls` 时，引用服务，返回 Invoker 对象 if (urls.size() == 1) { /** * <1>Protocol 取得registryProtocol 不过会被代理 具体可以看 https://www.cnblogs.com/LQBlog/p/12470179.html#autoid-2-0-0 * 默认是registry SPI扩展 private static final Protocol refprotocol = ExtensionLoader.getExtensionLoader(Protocol.class).getAdaptiveExtension(); */ invoker = refprotocol.refer(interfaceClass, urls.get(0)); } else { //集群订阅 List<Invoker<?>> invokers = new ArrayList<Invoker<?>>(); URL registryURL = null; // 循环 `urls` ，引用服务，返回 Invoker 对象 for (URL url : urls) { //<1>引用服务 invokers.add(refprotocol.refer(interfaceClass, url)); // 使用最后一个注册中心的 URL if (Constants.REGISTRY_PROTOCOL.equals(url.getProtocol())) { registryURL = url; // use last registry url } } // // 有注册中心 if (registryURL != null) { // registry url is available // 对有注册中心的 Cluster 只用 AvailableCluster // use AvailableCluster only when register's cluster is available URL u = registryURL.addParameterIfAbsent(Constants.CLUSTER_KEY, AvailableCluster.NAME); invoker = cluster.join(new StaticDirectory(u, invokers)); // 无注册中心，全部都是服务直连 } else { // not a registry url invoker = cluster.join(new StaticDirectory(invokers)); } } } //是否配置了启动检查 Boolean c = check; if (c == null && consumer != null) { c = consumer.isCheck(); } if (c == null) { c = true; // default true } if (c && !invoker.isAvailable()) { // make it possible for consumer to retry later if provider is temporarily unavailable initialized = false; 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()); } // <5>创建代理类 return (T) proxyFactory.getProxy(invoker); }
RegistryProtocol
<2>refer
参见《dubbo源码阅读-服务订阅(八)之远程订阅(dubbo)》
com.alibaba.dubbo.registry.integration.RegistryProtocol#refer
复制代码 private <T> Invoker<T> doRefer(Cluster cluster, Registry registry, Class<T> type, URL url) { //type为订阅接口类型 url为订阅url //zookeeper://IP:2181/com.alibaba.dubbo.registry.RegistryService?** RegistryDirectory<T> directory = new RegistryDirectory<T>(type, url); directory.setRegistry(registry); directory.setProtocol(protocol); // all attributes of REFER_KEY //获取参数 Map<String, String> parameters = new HashMap<String, String>(directory.getUrl().getParameters()); //订阅url URL subscribeUrl = new URL(Constants.CONSUMER_PROTOCOL, parameters.remove(Constants.REGISTER_IP_KEY), 0, type.getName(), parameters); if (!Constants.ANY_VALUE.equals(url.getServiceInterface()) && url.getParameter(Constants.REGISTER_KEY, true)) { URL registeredConsumerUrl = getRegisteredConsumerUrl(subscribeUrl, url); //将订阅url 添加到已注册列表 registryList registry.register(registeredConsumerUrl); //设置到directory directory.setRegisteredConsumerUrl(registeredConsumerUrl); } //<3>订阅服务 内部调用registry.subscribe directory.subscribe(subscribeUrl.addParameter(Constants.CATEGORY_KEY, Constants.PROVIDERS_CATEGORY + "," + Constants.CONFIGURATORS_CATEGORY + "," + Constants.ROUTERS_CATEGORY)); //<4>通过集群策略包装成一个Invoker返回 Invoker invoker = cluster.join(directory); //注册到订阅列表 ProviderConsumerRegTable.registerConsumer(invoker, url, subscribeUrl, directory); return invoker; }
RegistryDirectory
<3>subscribe
参见《dubbo源码阅读-注册中心(十三)之Zookeeper》
public void subscribe(URL url) { //此时的url为:consumer://192.168.2.1/com.alibaba.dubbo.demo.DemoService?* setConsumerUrl(url); //<4>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); }
可以发现订阅并回调自己 将订阅url存入到directory本地
FailbackCluster
<4>join
com.alibaba.dubbo.rpc.cluster.support.FailbackCluster#join
@Override public <T> Invoker<T> join(Directory<T> directory) throws RpcException { //通过FailbackClusterInvoker进行装饰 return new FailbackClusterInvoker<T>(directory); }
JdkProxyFactory
<5>getProxy
参见《dubbo源码阅读-ProxyFactory(十一)之JdkProxyFactory》
@Override @SuppressWarnings("unchecked") public <T> T getProxy(Invoker<T> invoker, Class<?>[] interfaces) { //<6>jdk代理 通过InvokerInvocationHandler代理 return (T) Proxy.newProxyInstance(Thread.currentThread().getContextClassLoader(), interfaces, new InvokerInvocationHandler(invoker)); }
可以发现服务订阅最终返回的代理的一个代理对象 执行入口是invokerInvocationHandler
InvokerInvocationHandler
<6>invoker
@Override public Object invoke(Object proxy, Method method, Object[] args) throws Throwable { String methodName = method.getName(); Class<?>[] parameterTypes = method.getParameterTypes(); //如果当前method是Object直接调用 if (method.getDeclaringClass() == Object.class) { return method.invoke(invoker, args); } //toString hashCode equals 直接调用object的 // 基础方法，不使用 RPC 调用 if ("toString".equals(methodName) && parameterTypes.length == 0) { return invoker.toString(); } if ("hashCode".equals(methodName) && parameterTypes.length == 0) { return invoker.hashCode(); } if ("equals".equals(methodName) && parameterTypes.length == 1) { return invoker.equals(args[0]); } //<7>走RPC 走得FailbackClusterInvoker <4>初始化 将参数封装成RpcInvocation return invoker.invoke(new RpcInvocation(method, args)).recreate(); }
FailbackClusterInvoker
<7>invoke
com.alibaba.dubbo.rpc.cluster.support.AbstractClusterInvoker#invoke
@Override public Result invoke(final Invocation invocation) throws RpcException { //服务是否销毁 如果销毁抛出异常 当调用destroy方法 checkWhetherDestroyed(); LoadBalance loadbalance = null; // binding attachments into invocation. //获取RPCContext的Attachments Map<String, String> contextAttachments = RpcContext.getContext().getAttachments(); if (contextAttachments != null && contextAttachments.size() != 0) { //添加到PRCInvocation ((RpcInvocation) invocation).addAttachments(contextAttachments); } //<8>获取所有服务提供者的invoker集合 List<Invoker<T>> invokers = list(invocation); if (invokers != null && !invokers.isEmpty()) { //spi扩展获取负载均衡策略 loadbalance = ExtensionLoader.getExtensionLoader(LoadBalance.class).getExtension(invokers.get(0).getUrl() .getMethodParameter(RpcUtils.getMethodName(invocation), Constants.LOADBALANCE_KEY, Constants.DEFAULT_LOADBALANCE)); } // 设置调用编号，若是异步调用 RpcUtils.attachInvocationIdIfAsync(getUrl(), invocation); //<10>模板方法调用子类的doInvoke 这个时候有负载均衡策略和服务提供者列表以及参数信息 return doInvoke(invocation, invokers, loadbalance); }
<8>list
com.alibaba.dubbo.rpc.cluster.support.AbstractClusterInvoker#list
protected List<Invoker<T>> list(Invocation invocation) throws RpcException { //<9>调用director的获取invoker的方法 List<Invoker<T>> invokers = directory.list(invocation); return invokers; }
<10>doInvoke
com.alibaba.dubbo.rpc.cluster.support.FailoverClusterInvoker#doInvoke
@SuppressWarnings({"unchecked", "rawtypes"})
public Result doInvoke(Invocation invocation, final List<Invoker<T>> invokers, LoadBalance loadbalance) throws RpcException {
List<Invoker<T>> copyinvokers = invokers;
checkInvokers(copyinvokers, invocation);
//url是否含有retries参数 默认重试3次
int len = getUrl().getMethodParameter(invocation.getMethodName(), Constants.RETRIES_KEY, Constants.DEFAULT_RETRIES) + 1;
if (len <= 0) {
len = 1;
}
// retry loop.
RpcException le = null; // last exception.
List<Invoker<T>> invoked = new ArrayList<Invoker<T>>(copyinvokers.size()); // invoked invokers.
Set<String> providers = new HashSet<String>(len);
for (int i = 0; i < len; i++) {
//Reselect before retry to avoid a change of candidate `invokers`.
//NOTE: if `invokers` changed, then `invoked` also lose accuracy.
//如果是重试没检查invoker是否为空 并从directory获取最新的invokers
if (i > 0) {
checkWhetherDestroyed();
//<9> 重新获取 防止 订阅发生改变
copyinvokers = list(invocation);
// check again
checkInvokers(copyinvokers, invocation);
}
//使用负载均衡策略 选取invoker
Invoker<T> invoker = select(loadbalance, invocation, copyinvokers, invoked);
invoked.add(invoker);
//将已经重试过得invoker添加到RPContext
RpcContext.getContext().setInvokers((List) invoked);
try {
//这里的invoker是dubboInvoker初始化: https://www.cnblogs.com/LQBlog/p/12522417.html#autoid-6-0-0
Result result = invoker.invoke(invocation);
if (le != null && logger.isWarnEnabled()) {
logger.warn("Although retry the method " + invocation.getMethodName()
+ " in the service " + getInterface().getName()
+ " was successful by the provider " + invoker.getUrl().getAddress()
+ ", but there have been failed providers " + providers
+ " (" + providers.size() + "/" + copyinvokers.size()
+ ") from the registry " + directory.getUrl().getAddress()
+ " on the consumer " + NetUtils.getLocalHost()
+ " using the dubbo version " + Version.getVersion() + ". Last error is: "
+ le.getMessage(), le);
}
return result;
} catch (RpcException e) {
if (e.isBiz()) { // biz exception.
throw e;
}
le = e;
} catch (Throwable e) {
le = new RpcException(e.getMessage(), e); //通过RPCException
} finally {
providers.add(invoker.getUrl().getAddress());
}
}
throw new RpcException(le != null ? le.getCode() : 0, "Failed to invoke the method "
+ invocation.getMethodName() + " in the service " + getInterface().getName()
+ ". Tried " + len + " times of the providers " + providers
+ " (" + providers.size() + "/" + copyinvokers.size()
+ ") from the registry " + directory.getUrl().getAddress()
+ " on the consumer " + NetUtils.getLocalHost() + " using the dubbo version "
+ Version.getVersion() + ". Last error is: "
+ (le != null ? le.getMessage() : ""), le != null && le.getCause() != null ? le.getCause() : le);
}
RegistryDirectory
<9>list
com.alibaba.dubbo.rpc.cluster.directory.AbstractDirectory#list
@Override public List<Invoker<T>> list(Invocation invocation) throws RpcException { if (destroyed) { throw new RpcException("Directory already destroyed .url: " + getUrl()); } List<Invoker<T>> invokers = doList(invocation); List<Router> localRouters = this.routers; // local reference //通过路由规则进行过滤 https://blog.csdn.net/prestigeding/article/details/80848594 //初始化时机参见https://www.cnblogs.com/LQBlog/p/12522417.html#autoid-5-0-0 if (localRouters != null && !localRouters.isEmpty()) { for (Router router : localRouters) { try { if (router.getUrl() == null || router.getUrl().getParameter(Constants.RUNTIME_KEY, false)) { invokers = router.route(invokers, getConsumerUrl(), invocation); } } catch (Throwable t) { logger.error("Failed to execute router: " + getUrl() + ", cause: " + t.getMessage(), t); } } } //返回符合条件的invoker return invokers; }
dubboInvoker
@Override public Result invoke(Invocation inv) throws RpcException { // if invoker is destroyed due to address refresh from registry, let's allow the current invoke to proceed if (destroyed.get()) { logger.warn("Invoker for service " + this + " on consumer " + NetUtils.getLocalHost() + " is destroyed, " + ", dubbo version is " + Version.getVersion() + ", this invoker should not be used any longer"); } RpcInvocation invocation = (RpcInvocation) inv; invocation.setInvoker(this); if (attachment != null && attachment.size() > 0) { invocation.addAttachmentsIfAbsent(attachment); } Map<String, String> contextAttachments = RpcContext.getContext().getAttachments(); if (contextAttachments != null && contextAttachments.size() != 0) { /** * invocation.addAttachmentsIfAbsent(context){@link RpcInvocation#addAttachmentsIfAbsent(Map)}should not be used here, * because the {@link RpcContext#setAttachment(String, String)} is passed in the Filter when the call is triggered * by the built-in retry mechanism of the Dubbo. The attachment to update RpcContext will no longer work, which is * a mistake in most cases (for example, through Filter to RpcContext output traceId and spanId and other information). */ invocation.addAttachments(contextAttachments); } if (getUrl().getMethodParameter(invocation.getMethodName(), Constants.ASYNC_KEY, false)) { invocation.setAttachment(Constants.ASYNC_KEY, Boolean.TRUE.toString()); } RpcUtils.attachInvocationIdIfAsync(getUrl(), invocation); try { //11 return doInvoke(invocation); } catch (InvocationTargetException e) { // biz exception Throwable te = e.getTargetException(); if (te == null) { return new RpcResult(e); } else { if (te instanceof RpcException) { ((RpcException) te).setCode(RpcException.BIZ_EXCEPTION); } return new RpcResult(te); } } catch (RpcException e) { if (e.isBiz()) { return new RpcResult(e); } else { throw e; } } catch (Throwable e) { return new RpcResult(e); } }
<11>doInvoke
@Override protected Result doInvoke(final Invocation invocation) throws Throwable { RpcInvocation inv = (RpcInvocation) invocation; final String methodName = RpcUtils.getMethodName(invocation); inv.setAttachment(Constants.PATH_KEY, getUrl().getPath()); inv.setAttachment(Constants.VERSION_KEY, version); ExchangeClient currentClient; if (clients.length == 1) { currentClient = clients[0]; } else { currentClient = clients[index.getAndIncrement() % clients.length]; } try { boolean isAsync = RpcUtils.isAsync(getUrl(), invocation); boolean isOneway = RpcUtils.isOneway(getUrl(), invocation); int timeout = getUrl().getMethodParameter(methodName, Constants.TIMEOUT_KEY, Constants.DEFAULT_TIMEOUT); if (isOneway) { boolean isSent = getUrl().getMethodParameter(methodName, Constants.SENT_KEY, false); currentClient.send(inv, isSent); RpcContext.getContext().setFuture(null); return new RpcResult(); } else if (isAsync) { ResponseFuture future = currentClient.request(inv, timeout); RpcContext.getContext().setFuture(new FutureAdapter<Object>(future)); return new RpcResult(); } else { RpcContext.getContext().setFuture(null); return (Result) currentClient.request(inv, timeout).get(); } } catch (TimeoutException e) { throw new RpcException(RpcException.TIMEOUT_EXCEPTION, "Invoke remote method timeout. method: " + invocation.getMethodName() + ", provider: " + getUrl() + ", cause: " + e.getMessage(), e); } catch (RemotingException e) { throw new RpcException(RpcException.NETWORK_EXCEPTION, "Failed to invoke remote method: " + invocation.getMethodName() + ", provider: " + getUrl() + ", cause: " + e.getMessage(), e); } }
