dubbo3.0引用源码简版

org.apache.dubbo.rpc.cluster.support.wrapper.AbstractCluster#buildClusterInterceptors

org.apache.dubbo.config.ReferenceConfig#createInvokerForRemote

org.apache.dubbo.registry.client.migration.MigrationInvoker#refreshServiceDiscoveryInvoker

org.apache.dubbo.rpc.cluster.support.FailoverCluster#doJoin

2

2创建MockClusterInvoker对象，它里面包含了ClusterFilterInvoker对象和ServiceDiscoveryRegistryDirectory对象

生成一个MetadataService代理对象，是个消费者，它去服务端的MetadataService服务通信那是怎么知道服务端的这个MetadataService的端口是多少呢？生成MetadataService代理对象

1

在这里面遍历dubbo-springboot-demo-provider节点的元数据

1.1、构造一个MetadataService客户端

org.apache.dubbo.registry.client.ServiceDiscoveryRegistryDirectory#toInvokers

org.apache.dubbo.registry.client.event.listener.ServiceInstancesChangedListener#onEvent

从/services/dubbo-springboot-demo-provider/192.168.124.10:20880和/services/dubbo-springboot-demo-provider/192.168.124.10:20881节点下，获取应用的元数据因为dubbo-springboot-demo-provider有可能是集群部署也就是多个实例，也就是获取所有dubbo-springboot-demo-provider应用的元数据

org.apache.dubbo.registry.integration.RegistryProtocol#doCreateInvoker

1、生成所有符合当前消费者的，已经和客户端建立好连接的invoker

[    {        \"name\": \"dubbo-springboot-demo-provider\

org.apache.dubbo.registry.client.metadata.MetadataUtils#getRemoteMetadata

org.apache.dubbo.registry.client.ServiceDiscoveryRegistry#subscribeURLs

currentAvailableInvoker = serviceDiscoveryInvoker;

返回

设置到org.apache.dubbo.rpc.cluster.directory.AbstractDirectory#invokers属性中

org.apache.dubbo.rpc.cluster.directory.AbstractDirectory#setInvokers

调用代理对象的org.apache.dubbo.metadata.MetadataService#getMetadataInfo方法

org.apache.dubbo.registry.client.migration.MigrationInvoker#calcPreferredInvoker

org.apache.dubbo.registry.client.event.listener.ServiceInstancesChangedListener#doOnEvent

1 接口级别的引用

将MetadataService对象转化成ProtocolServiceKeyWithUrls对象放到org.apache.dubbo.registry.client.event.listener.ServiceInstancesChangedListener#serviceUrls里面

org.apache.dubbo.registry.client.migration.MigrationInvoker#migrateToApplicationFirstInvoker

返回FailoverClusterInvoker对象

org.apache.dubbo.rpc.cluster.support.wrapper.AbstractCluster.ClusterFilterInvoker#ClusterFilterInvoker

org.apache.dubbo.registry.client.metadata.MetadataUtils#referProxy

org.apache.dubbo.registry.integration.RegistryProtocol#doRefer

org.apache.dubbo.registry.client.ServiceDiscoveryRegistryDirectory#refreshInvoker

3、决定用接口级别的引用还是应用级别的引用

2应用级别的引用

将应用级的invoker赋值给currentAvailableInvoker

返回ClusterFilterInvoker对象

返回FailoverClusterInvoker，它里面有负载均衡的逻辑且包含了ServiceDiscoveryRegistryDirectory，ServiceDiscoveryRegistryDirectory里面包含了获取的invoker对象

org.apache.dubbo.registry.client.event.listener.ServiceInstancesChangedListener#addListenerAndNotify

org.apache.dubbo.registry.client.ServiceDiscoveryRegistryDirectory#subscribe

在这里根据SPI生成消费端过滤器链放到org.apache.dubbo.rpc.cluster.support.wrapper.AbstractCluster.ClusterFilterInvoker#filterInvoker属性中，对象是ClusterCallbackRegistrationInvoker，这个对象里面有FailoverClusterInvoker对象和所有的拦截器对象

3

org.apache.dubbo.rpc.cluster.support.wrapper.AbstractCluster#join

org.apache.dubbo.registry.integration.InterfaceCompatibleRegistryProtocol#getServiceDiscoveryInvoker

返回DubboInvoker

作为入参传入

org.apache.dubbo.rpc.cluster.support.wrapper.MockClusterInvoker

获取79af34d6be7b9bb1234eed8330d10124上面的，所有接口级服务的所有元数据

List<ServiceInstance>

那必须是这里的port

赋值给serviceDiscoveryInvoker属性

org.apache.dubbo.registry.client.ServiceDiscoveryRegistryDirectory#notify

{    \"app\": \"dubbo-springboot-demo-provider\

org.apache.dubbo.registry.client.migration.MigrationInvoker#refreshInterfaceInvoker

org.apache.dubbo.rpc.Protocol#refer

ListenerInvokerWrapper

org.apache.dubbo.metadata.MetadataService#getMetadataInfo

org.apache.dubbo.rpc.protocol.dubbo.DubboProtocol#refer

进行过滤，匹配出符合当前消费者的服务提供者

org.apache.dubbo.rpc.cluster.support.wrapper.MockClusterWrapper#join

将返回结果包装

org.apache.dubbo.rpc.cluster.support.wrapper.AbstractCluster#buildInterceptorInvoker