Dubbo服务的引用及其调用过程源码分析

获取invoker

 loadProperties();        

Registry

recover()

FailoverClusterInvoker

解析并注册

AbstractClusterInvoker

invoke(Invocation)

MockClusterInvoker

getRegistry(URL url)

ZookeeperRegistry

LoadBalance

子节点变化后调用

init()

订阅服务

InvokerInvocationHandler

createProxy(map)

Protocol$Adaptive

Cluster

doRegister(url)

缓存invoker到consumerInvokers

registryFactory.getRegistry(url)

consumer.xml

createPersistent(path)

返回ZookeeperReigstry

创建ChildListener，监听子节点变化

会在com.alibaba.dubbo.demo.DemoService/comsumers 节点下创建子节点toUrlPath(url) ：/dubbo/com.alibaba.dubbo.demo.DemoService/consumers/consumer%3A%2F%2F192.168.3.1%2Fcom.alibaba.dubbo.demo.DemoService%3Fapplication%3Ddemo-consumer%26category%3Dconsumers%26check%3Dfalse%26dubbo%3D2.0.0%26interface%3Dcom.alibaba.dubbo.demo.DemoService%26methods%3DsayHello%26pid%3D29568%26qos.port%3D33333%26side%3Dconsumer%26timestamp%3D1567756038069创建持久节点： /dubbo创建持久节点： /dubbo/com.alibaba.dubbo.demo.DemoService创建持久节点：/dubbo/com.alibaba.dubbo.demo.DemoService/comsumers创建临时节点： toUrlPath(url)

引用服务：通过implements FactoryBean在getObject()中获取代理对象

overrideDirectoryUrl ：zookeeper://127.0.0.1:2181/com.alibaba.dubbo.registry.RegistryService?anyhost=true&application=demo-consumer&check=false&dubbo=2.0.0&generic=false&interface=com.alibaba.dubbo.demo.DemoService&loadbalance=roundrobin&methods=sayHello&mock=com.alibaba.dubbo.demo.consumer.DemoServiceMock&pid=26800&qos.port=33333®ister.ip=192.168.3.1&remote.timestamp=1567776260905&side=consumer×tamp=1567776471070

ZookeeperRegistryFactory

Protocol

注册subscribeUrl到注册中心consumers节点下

retry() 

JavassistProxyFactory

获取registry

ProtocolListenerWrapper

notify(url.getBackupUrls());

调父类构造器

notify(categoryList)

listener.notify(categoryList)

retryPeriod ： 重试周期 5秒retry();  重试 ， 重新注册和订阅failedRegistered： 缓存了注册失败的url

toMethodInvokers(newUrlInvokerMap)

恢复，父类实现

ConditionRouter

调用失败，执行mock逻辑

saveProperties(url)

InjvmProtocol

更新invoker列表

DubboProtocol

doRegister(URL url)

获取调用结果

injvm本地引用

RegistryFactory

directory.subscribe(subscribeUrl)

LeastActiveLoadBalance

ZookeeperRegistry

createEphemeral(path)

返回调用结果，exception或result

ZookeeperClient

AbstractZookeeperClient

client.create().withMode(CreateMode.EPHEMERAL).forPath(path)

连接zk，创建节点

DubboInvoker#doInvoke(Invocation)

返回invoker

根据负载均衡策略获取invoker

注册中心协议

proxyFactory.getProxy(invoker)

getObject()

dubbo远程引用

ProtocolFilterWrapper

如果invoker在selected中，或者invoker不可用&& availablecheck为真，则重新选择

client.create().forPath(path)

buildInvokerChain 调用3个默认过滤器ConsumerContextFilterFutureFilterMonitorFilter

zkClient.addStateListener

AbstractRegistryFactory

get()

缓存invoker到consumerInvokersProviderConsumerRegTable:    服务提供者消费者注册表缓存了providerInvokers和consumerInvokers

返回代理对象

返回结果result

refreshInvoker(invokerUrls)

先从缓存中取，没有创建

invokers.size()==1 ，直接返回invokers.size()>1 ，调用对应的负载均衡算法dubbo负载均衡算法1.RandomLoadBalance: 权重随机算法2.RoundRobinLoadBalance: 加权轮询算法3.LeastActiveLoadBalance: 最少活跃调用数算法3.ConsistentHashLoadBalance: 一致性hash 

recreate()

javassist生成代理对象

register(URL url)

AbstractRegistry

ReferenceBean

注册中心异步（默认）保存文件C:\\Users\\chaos/.dubbo/dubbo-registry-demo-provider-127.0.0.1:2181.cache

调用

引用服务，返回代理对象

通过代理对象调用业务逻辑

new FailoverClusterInvoker<T>(directory)

ReferenceConfig

创建节点

FailbackRegistry

RegistryDirectory 

根据loadBalance调用

subscribeUrl: consumer://192.168.3.1/com.alibaba.dubbo.demo.DemoService?application=demo-consumer&check=false&dubbo=2.0.0&interface=com.alibaba.dubbo.demo.DemoService&methods=sayHello&pid=29568&qos.port=33333&side=consumer×tamp=15677560380691. 注册subscribeUrl到 zookeeper的 consumers节点2. 订阅服务

proxy0.sayHello(\"fox\")

result = this.invoker.invoke(invocation)

FailbackRegistry

registry.register(subscribeUrl）

创建invoker对象

CuratorZookeeperClient

createRegistry(url)

定时器重试机制

RandomLoadBalance

Invoker invoker = cluster.join(directory)

监听zk的节点变化，通过notify更新url列表此处不做处理： getSubscribed().entrySet() 为空

join(Directory<T> directory)

invoker类型为 MockClusterInvoker 内部封装了服务降级逻辑

AbstractLoadBalance

RegistryFactory$Adaptive

条件路由

DubboNamespaceHandler

AbstractRegistry

url: zookeeper://127.0.0.1:2181/com.alibaba.dubbo.registry.RegistryService?application=demo-consumer&dubbo=2.0.0&pid=24988&qos.port=33333&refer=application%3Ddemo-consumer%26check%3Dfalse%26dubbo%3D2.0.0%26interface%3Dcom.alibaba.dubbo.demo.DemoService%26methods%3DsayHello%26pid%3D24988%26qos.port%3D33333%26register.ip%3D192.168.3.1%26side%3Dconsumer%26timestamp%3D1567754599462×tamp=1567754599603

获取invoker，返回代理对象

Spring IOC

ConsistentHashLoadBalance

RoundRobinLoadBalance

路由过滤invoker列表

解析配置，创建代理对象

Result result = invoker.invoke(invocation)