This Article introduces NACOS

NACOS allows user to manage the configuration of all applications and services in a centralized , externalized and dynamic manner across all environments

Nacos In Spring

There are 2 ways integrating NACOS to spring

1. nacos-spring-boot-starter
2. spring-cloud-starter-alibaba-nacos

SpringBoot integration

Spring cloud integration

NacosPropertySource represents nacos config with unique dataId in group

NacosContextRefresher add nacos listeners to all application level dataIds, when there is a change in the data, listeners will refresh configurations.

class  NacosContextRefresher implements ApplicationListener, ApplicationContextAware {
    NacosConfigProperties nacosConfigProperties
    ConfigService configService
    NacosConfigManager configManager
    ApplicationContext applicationContext
    Map<String, Listener> listenerMap
}

abstract class AbstractSharedListener implements Listener {
    String dataId
    String group
    abstract void innerReceive(String dataId, String group, String configInfo)
}


class NacosConfigService implements ConfigService {
    ClientWorker worker
    String namespace
    ConfigFilterChainManager configFilterChainManager
}

class ClientWorker implements Closeable {
    AtomicReference<Map<String, CacheData>> cacheMap
    ConfigRpcTransportClient agent
}

class CacheData {
    String envName
    String dataId
    String group
    String tenant
    String content
    List<ManagerListenerWrap> listeners
}
abstract class ConfigTransportClient {
    ScheduledExecutorService executor
    ServerListManager serverListManager
    abstract void startInternal()
}


class ConfigRpcTransportClient extends ConfigTransportClient {
    Map<String, ExecutorService> multiTaskExecutor
    BlockingQueue<Object> listenExecutebell
    RpcClient ensureRpcClient(String taskId)
}

class RpcClientFactory {
    static void destroyClient(String clientName)
    static RpcClient getClient(String clientName)
    static RpcClient createClient(clientName,connectionType,labels)
}

NacosContextRefresher o-- AbstractSharedListener
NacosConfigService *-- ClientWorker
ClientWorker o---- CacheData
CacheData *-- AbstractSharedListener
ClientWorker o-- ConfigRpcTransportClient 
ConfigRpcTransportClient -->  RpcClientFactory: get

Bootstrap

interface BootstrapConfiguration 

class NacosConfigBootstrapConfiguration {
    Bean NacosConfigManager
    Bean NacosPropertySourceLocator
}

interface  PropertySourceLocator {
    PropertySource<?> locate(Environment environment)
}

class NacosPropertySourceLocator implements PropertySourceLocator



BootstrapConfiguration <|-- NacosConfigBootstrapConfiguration 
NacosConfigBootstrapConfiguration --> NacosPropertySourceLocator: create

API

Naming and Configuration Service

Service registration

curl -X POST 'http://127.0.0.1:8848/nacos/v1/ns/instance?serviceName=nacos.naming.serviceName&ip=20.18.7.10&port=8080'

Service discovery

curl -X GET 'http://127.0.0.1:8848/nacos/v1/ns/instance/list?serviceName=nacos.naming.serviceName'

Publish Config

curl -X POST "http://127.0.0.1:8848/nacos/v1/cs/configs?dataId=nacos.cfg.dataId&group=test&content=helloWorld"

Get config

curl -X GET "http://127.0.0.1:8848/nacos/v1/cs/configs?dataId=nacos.cfg.dataId&group=test"