Dubbo服务调用动态选择版本.docx

Dubbo服务调用动态选择版本问题说明Dubbo是阿里巴巴SOA服务化治理方案的核心框架，致力于高性能和透明化的远程服务调用方案和服务治理方案。官方文档见：http:/alibaba.github.io/dubbo-doc-static/Home-zh.htm。Dubbo可以和Spring无缝集成，示例如下：1. 服务提供端Provider.xmlHelloServiceImpl.javapackage vider;import org.springframework.stereotype.Service;import f.IHelloService;Service(helloService)public class HelloServiceImpl implements IHelloServiceOverridepublic String sayHello(String name) return Hello +name;2. 客户端调用Consumer.xml服务端 dubbo:service 和 客户端 dubbo:reference 分别有1个version属性。说明：服务端发布provider时可以为服务分配1个版本号，客户端调用服务端的provider时，需要指定调用哪1个版本的服务。项目实施过程碰到一些问题：1. version属性在xml文件中配置，意味着服务端升级版本号，客户端也要相应修改配置文件并重启应用。2. 项目中存在灰度发布的要求，服务端的provider可能同时存在多个版本，客户端根据用户工号来选择调用哪个版本，比如指定一批测试工号，来测试新版本的provider。整个发布过程需要不重启web应用实现无缝切换，客户端在xml文件中指定版本号就显得不够，dubbo需要支持客户端自行实现版本选择规则，根据规则决定调用相应版本的provider。本文描述了如何重载dubbo的部分代码实现客户端版本规则。实现思路通过分析dubbo 2.5.3 的源码， 标签对应的类是 com.alibaba.dubbo.config.spring.ReferenceBean的version属性被写到ReferenceBean的version属性中，可以通过ReferenceBean.getVersion() 来获取配置文件中指定的远程服务的版本号。该类是工厂类，实现 org.springframework.beans.factory.FactoryBean，第64行代码public Object getObject() throws Exception return get(); 返回IHelloService的代理对象，调用该对象的sayHello方法即可调用远程dubbo服务，远程服务的版本号由ReferenceBean的version属性决定。本文的实现方法是重载 ReferenceBean 的get() 方法，使用javassist技术构造一个新的代理，根据用户自定义的规则来调用相应版本的dubbo服务。实现方法重写ReferenceBeanpackage com.telecom.dubbo.extend;import java.lang.reflect.Method;import java.util.concurrent.ConcurrentHashMap;import org.springframework.context.ApplicationContext;import com.alibaba.dubbo.config.ReferenceConfig;import com.alibaba.dubbo.config.annotation.Reference;import xy.MethodHandler;import xy.ProxyFactory;import xy.ProxyObject;/* * 自定义的referencebean，该类会创建动态代理，运行时根据上下文的版本号选择远程服务 * author wuchangzheng * * param */public class ReferenceBean extends com.alibaba.dubbo.config.spring.ReferenceBean implements Cloneableprivate static final long serialVersionUID = 8383612147446385736L;private transient T proxy;/代理private transient IVersionDesider versionDesider;/版本决定器private transient ApplicationContext applicationContext;private transient ReferenceBean self_=this;private transient ConcurrentHashMap versionMap = new ConcurrentHashMap();private transient final String DEFAULT_VERSION=DEFAULT_VERSION;SuppressWarnings( all)public void setApplicationContext(ApplicationContext applicationContext)super.setApplicationContext(applicationContext);this.applicationContext=applicationContext;SuppressWarnings( all) public void afterPropertiesSet() throws Exceptionsuper.afterPropertiesSet();tryversionDesider=applicationContext.getBean(IVersionDesider.class);/从上下文中查找IVersionDesider实现，该实现代表用户自定义版本规则catch(Exception ex)versionDesider = null;proxy=getVersionDecideProxy();/创建代理对象/* * * return * throws ClassNotFoundException * throws InstantiationException * throws IllegalAccessException */SuppressWarnings( all)private T getVersionDecideProxy() throws ClassNotFoundException, InstantiationException, IllegalAccessException/ 创建代理工厂 ProxyFactory proxyFactory = new ProxyFactory(); Class interfaces=Class.forName(this.getInterface(); proxyFactory.setInterfaces(interfaces); / 创建代理类型的Class Class proxyClass = proxyFactory.createClass(); T proxy = (T) proxyClass.newInstance(); (ProxyObject) proxy).setHandler(new MethodHandler() Override public T invoke(Object self, Method thisMethod, Method proceed, Object args) throws Throwable T target = null; String version=DEFAULT_VERSION; if (versionDesider!=null) version=versionDesider.desideVersion(self_); if (version=null) version=DEFAULT_VERSION; ReferenceConfig config =null; synchronized(self_) config=versionMap.get(version); if (config=null) config=(ReferenceConfig)self_.clone(); config.setVersion(version); config.setCheck(false);/ versionMap.put(version, config); target = (T)config.get(); T retObj = (T)thisMethod.invoke(target, args); return retObj; ); return proxy;public Object getObject() throws Exception return proxy; 重载dubbo命名空间解析器/* * Copyright 1999-2011 Alibaba Group. * * Licensed under the Apache License, Version 2.0 (the License); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * /licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an AS IS BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */package com.telecom.dubbo.extend;import org.springframework.beans.factory.xml.NamespaceHandlerSupport;import mon.Version;import com.alibaba.dubbo.config.ApplicationConfig;import com.alibaba.dubbo.config.ConsumerConfig;import com.alibaba.dubbo.config.ModuleConfig;import com.alibaba.dubbo.config.MonitorConfig;import com.alibaba.dubbo.config.ProtocolConfig;import com.alibaba.dubbo.config.ProviderConfig;import com.alibaba.dubbo.config.RegistryConfig;import com.alibaba.dubbo.config.spring.AnnotationBean;import com.telecom.dubbo.extend.ReferenceBean;import com.alibaba.dubbo.config.spring.ServiceBean;/* * DubboNamespaceHandler * * author william.liangf * export */public class DubboNamespaceHandler extends NamespaceHandlerSupport static Version.checkDuplicate(DubboNamespaceHandler.class);public void init() registerBeanDefinitionParser(application, new DubboBeanDefinitionParser(ApplicationConfig.class, true); registerBeanDefinitionParser(module, new DubboBeanDefinitionParser(ModuleConfig.class, true); registerBeanDefinitionParser(registry, new DubboBeanDefinitionParser(RegistryConfig.class, true); registerBeanDefinitionParser(monitor, new DubboBeanDefinitionParser(MonitorConfig.class, true); registerBeanDefinitionParser(provider, new DubboBeanDefinitionParser(ProviderConfig.class, true); registerBeanDefinitionParser(consumer, new DubboBeanDefinitionParser(ConsumerConfig.class, true); registerBeanDefinitionParser(protocol, new DubboBeanDefinitionParser(ProtocolConfig.class, true); registerBeanDefinitionParser(service, new DubboBeanDefinitionParser(ServiceBean.class, true); registerBeanDefinitionParser(reference, new DubboBeanDefinitionParser(ReferenceBean.class, false); registerBeanDefinitionParser(annotation, new DubboBeanDefinitionParser(AnnotationBean.class, true); /* * Copyright 1999-2011 Alibaba Group. * * Licensed under the Apache License, Version 2.0 (the License); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * /licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an AS IS BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */package com.telecom.dubbo.extend;import java.lang.reflect.Method;import java.lang.reflect.Modifier;import java.util.Date;import java.util.HashSet;import java.util.Set;import java.util.regex.Pattern;import org.springframework.beans.PropertyValue;import org.springframework.beans.factory.config.BeanDefinition;import org.springframework.beans.factory.config.BeanDefinitionHolder;import org.springframework.beans.factory.config.RuntimeBeanReference;import org.springframework.beans.factory.config.TypedStringValue;import org.springframework.beans.factory.support.ManagedList;import org.springframework.beans.factory.support.ManagedMap;import org.springframework.beans.factory.support.RootBeanDefinition;import org.springframework.beans.factory.xml.BeanDefinitionParser;import org.springframework.beans.factory.xml.ParserContext;import org.w3c.dom.Element;import org.w3c.dom.NamedNodeMap;import org.w3c.dom.Node;import org.w3c.dom.NodeList;import mon.Constants;import mon.extension.ExtensionLoader;import mon.logger.Logger;import mon.logger.LoggerFactory;import mon.utils.ReflectUtils;import mon.utils.StringUtils;import com.alibaba.dubbo.config.ArgumentConfig;import com.alibaba.dubbo.config.ConsumerConfig;import com.alibaba.dubbo.config.MethodConfig;import com.alibaba.dubbo.config.MonitorConfig;import com.alibaba.dubbo.config.ProtocolConfig;import com.alibaba.dubbo.config.ProviderConfig;import com.alibaba.dubbo.config.RegistryConfig;import com.telecom.dubbo.extend.ReferenceBean;import com.alibaba.dubbo.config.spring.ServiceBean;import com.alibaba.dubbo.rpc.Protocol;/* * AbstractBeanDefinitionParser * * author william.liangf * export */public class DubboBeanDefinitionParser implements BeanDefinitionParser private static final Logger logger = LoggerFactory.getLogger(DubboBeanDefinitionParser.class); private final Class beanClass; private final boolean required; public DubboBeanDefinitionParser(Class beanClass, boolean required) this.beanClass = beanClass; this.required = required; public BeanDefinition parse(Element element, ParserContext parserContext) return parse(element, parserContext, beanClass, required); SuppressWarnings(unchecked) private static BeanDefinition parse(Element element, ParserContext parserContext, Class beanClass, boolean required) RootBeanDefinition beanDefinition = new RootBeanDefinition(); beanDefinition.setBeanClass(beanClass); beanDefinition.setLazyInit(false); String id = element.getAttribute(id); if (id = null | id.length() = 0) & required) String generatedBeanName = element.getAttribute(name); if (generatedBeanName = null | generatedBeanName.length() = 0) if (ProtocolConfig.class.equals(beanClass) generatedBeanName = dubbo; else generatedBeanName = element.getAttribute(interface); if (generatedBeanName = null | generatedBeanName.length() = 0) generatedBeanName = beanClass.getName(); id = generatedBeanName; int counter = 2; while(parserContext.getRegistry().containsBeanDefinition(id) id = generatedBeanName + (counter +); if (id != null & id.length() 0) if (parserContext.getRegistry().containsBeanDefinition(id) throw new IllegalStateException(Duplicate spring bean id + id); parserContext.getRegistry().registerBeanDefinition(id, beanDefinition); beanDefinition.getPropertyValues().addPropertyValue(id, id); if (ProtocolConfig.class.equals(beanClass) for (String name : parserContext.getRegistry().getBeanDefinitionNames() BeanDefinition definition = parserContext.getRegistry().getBeanDefinition(name); PropertyValue property = definition.getPropertyValues().getPropertyValue(protocol); if (property != null) Object value = property.getValue(); if (value instanceof ProtocolConfig & id.equals(ProtocolConfig) value).getName() definition.getPropertyValues().addPropertyValue(protocol, new RuntimeBeanReference(id); else if (ServiceBean.class.equals(beanClass) String className = element.getAttribute(class); if(className != null & className.length() 0) RootBeanDefinition classDefinition = new RootBeanDefinition(); classDefinition.setBeanClass(ReflectUtils.forName(className); classDefinition.setLazyInit(false); parseProperties(element.getChildNodes(), classDefinition); beanDefinition.getPropertyValues().addPropertyValue(ref, new BeanDefinitionHolder(classDefinition, id + Impl); else if (ProviderConfig.class.equals(beanClass) parseNested(element, parserContext, ServiceBean.class, true, service, provider, id, beanDefinition); else if (ConsumerConfig.class.equals(beanClass) parseNested(element, parserContext, ReferenceBean.class, false, reference, consumer, id, beanDefinition); Set props = new HashSet(); ManagedMap parameters = null; for (Method setter : beanClass.getMethods() String name = setter.getName(); if (name.length() 3 & name.startsWith(set) & Modifier.isPublic(setter.getModifiers() & setter.getParameterTypes().length = 1) Class type = setter.getParameterTypes()0; String property = StringUtils.camelToSplitName(name.substring(3, 4).toLowerCase() + name.substring(4), -); props.add(property); Method getter = null; try getter = beanClass.getMethod(get + name.substring(3), new Class0); catch (NoSuchMethodException e) try getter = beanClass.getMethod(is + name.substring(3), new Class0); catch (NoSuchMethodException e2) if (getter = null | ! Modifier.isPublic(getter.getModifiers() | ! type.equals(getter.getReturnType() continue; if (parameters.equals(property) parameters = parseParameters(element.getChildNodes(), beanDefinition); else if (methods.equals(property) parseMethods(id, element.getChildNodes(), beanDefinition, parserContext); else if (arguments.equals(property) parseArguments(id, element.getChildNodes(), beanDefinition, parserContext); else String value = element.getAttribute(property); if (value != null) value = value.trim(); if (value.length() 0) if (registry.equals(property) & RegistryConfig.NO_AVAILABLE.equalsIgnoreCase(value) RegistryConfig registryConfig = new RegistryConfig(); registryConfig.setAddress(RegistryConfig.NO_AVAILABLE); beanDefinition.getPropertyValues().addPropertyValue(property, registryConfig); else if (registry.equals(property) & value.indexOf(,) !=