[Nacos] what does nacosclient do during service registration

Project integration

With springboot and nacos As an example .
sb Add to the project nacos-discovery rely on ：

<dependency>
  <groupId>com.alibaba.boot</groupId>
  <artifactId>nacos-discovery-spring-boot-starter</artifactId>
  <version>0.2.10</version>
</dependency>

nacos:
discovery:
server-addr: http://localhost:8848
namespace: public
username: nacos
password: nacos
auto-register: true
register:
   service-name: sb-provider
   healthy: true

Properties to pay attention to ：

• auto-register： The default configuration is false, That is, by default, this instance will not be registered to nacos server
• register.service-name ： Of the current instance service name, Can't be empty , Otherwise, after the project is started , Sign up to nacos server When an error . This is a nacos-client An internal verification of .

analysis

starter

Find our integration nacos client The use of jar package ：nacos-discovery-spring-boot-starter

Look again nacos-discovery-spring-boot-autoconfigure , According to the name, we can see , This is a nacos The configuration of the assembly is here

Look directly at spring.factories file

org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
  com.alibaba.boot.nacos.discovery.autoconfigure.NacosDiscoveryAutoConfiguration

notice org.springframework.boot.autoconfigure.EnableAutoConfiguration In fact, I know where the key assembly code is , Then look directly NacosDiscoveryAutoConfiguration

The code is simple , from @Bean You can see that the automatic registration is through new NacosDiscoveryAutoRegister() Realized .

It's the same thing , adopt SpringEvent monitor WebServerInitializedEvent Events to achieve .

The previous verification logic is very simple , The key is namingService.registerInstance Here is the instance registration .

NamingService

@Override
public void registerInstance(String serviceName, String groupName, Instance instance) throws NacosException {
    
    NamingUtils.checkInstanceIsLegal(instance);
    clientProxy.registerService(serviceName, groupName, instance);
}

NamingUtils.checkInstanceIsLegal(instance); Here is business verification , Verify whether the following two settings are correct ：

• heart beat timeout must > heart beat interval
• ip delete timeout must > heart beat interval
  ps： In fact, it is to verify whether the set timeout meets the requirements , The requirement is to be greater than the default heartbeat cycle . Very reasonable.

Then the highlight is clientProxy.registerService(serviceName, groupName, instance) This method .
clientProxy It's an interface , It's packaged a lot of service Related operations . Um. , reasonable

So specifically registerService How did it happen

@Override
public void registerService(String serviceName, String groupName, Instance instance) throws NacosException {
    
    getExecuteClientProxy(instance).registerService(serviceName, groupName, instance);
}

private NamingClientProxy getExecuteClientProxy(Instance instance) {
    
    return instance.isEphemeral() ? grpcClientProxy : httpClientProxy;
}

Why choose a different one according to whether it is a temporary instance clientProxy？
it’s a question .
Regardless of the , Then look at

@Override
public void registerService(String serviceName, String groupName, Instance instance) throws NacosException {
    
    NAMING_LOGGER.info("[REGISTER-SERVICE] {} registering service {} with instance {}", namespaceId, serviceName,
                       instance);
    redoService.cacheInstanceForRedo(serviceName, groupName, instance);
    doRegisterService(serviceName, groupName, instance);
}

redoService.cacheInstanceForRedo All you need to do is cache this instance .

private final ConcurrentMap<String, InstanceRedoData> registeredInstances = new ConcurrentHashMap<>();

public void cacheInstanceForRedo(String serviceName, String groupName, Instance instance) {
    
    String key = NamingUtils.getGroupedName(serviceName, groupName);
    InstanceRedoData redoData = InstanceRedoData.build(serviceName, groupName, instance);
    //registeredInstances It's a map
    synchronized (registeredInstances) {
    
        registeredInstances.put(key, redoData);
    }
}

InstanceRedoData There is a property called registered, Semantic is : Register or not .
You can see that the first time you put it into the cache, this attribute is false

Then look at doRegisterService

public void doRegisterService(String serviceName, String groupName, Instance instance) throws NacosException {
    
    InstanceRequest request = new InstanceRequest(namespaceId, serviceName, groupName,
                                                  NamingRemoteConstants.REGISTER_INSTANCE, instance);
    requestToServer(request, Response.class);
    redoService.instanceRegistered(serviceName, groupName);
}

requestToServer Internally, it calls methods to server Registration instance , No more research .

public void instanceRegistered(String serviceName, String groupName) {
    
    String key = NamingUtils.getGroupedName(serviceName, groupName);
    synchronized (registeredInstances) {
    
        InstanceRedoData redoData = registeredInstances.get(key);
        if (null != redoData) {
    
            redoData.setRegistered(true);
        }
    }
}

instanceRegistered Just cache the instance registered Change the field to true, Represents that this instance has been in server End registration succeeded .

The next study server How to deal with client Of service Registration request