SpringCloud Nacos 【服务端】服务注册源码解析

迈不过友情╰ 2022-10-05 06:59 237阅读 0赞

# 1 环境介绍 #

nacos版本1.4.1

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# 2 注册入口 #

**描述：** 查看nacos官网, 请求url为：

/nacos/v1/ns/instance

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**描述：** 找到 InstanceController类，register方法。

@CanDistro
        @PostMapping
        @Secured(parser = NamingResourceParser.class, action = ActionTypes.WRITE)
        public String register(HttpServletRequest request) throws Exception { 
            
            final String namespaceId = WebUtils
                    .optional(request, CommonParams.NAMESPACE_ID, Constants.DEFAULT_NAMESPACE_ID);
            final String serviceName = WebUtils.required(request, CommonParams.SERVICE_NAME);
            NamingUtils.checkServiceNameFormat(serviceName);
            
            final Instance instance = parseInstance(request);
            
            /** * 服务端注册核心逻辑 */
            serviceManager.registerInstance(namespaceId, serviceName, instance);
            return "ok";
        }

# 3 核心逻辑分析 #

## 3.1 ServiceManager ##

**描述：** service注册nacos核心类。

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## 3.2 Nacos 注册表 ##

**描述：** nacos注册表采用双map结构，一套nacos 可以配置多套项目，其结构可以理解为：

(1) namespace: 用于区分项目。
    (2) group: 用于区分环境(dev、release)。
    (3) servcieName：微服务名称.
    (4) Service：真正的服务。
    
    用group::servcieName 确定Service。

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## 3.3 Service ##

**描述：** Nacos中服务端的服务，存储服务采用Map结构，其Key 代表集群名称（可以用于区分地区），Cluster用于存储服务端的服务。Cluster存储服务实例又分为持久服务集，临时服务集。  
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## 3.4 registerInstance 方法 ##

**描述：** ServiceManager类registerInstance方法。

public void registerInstance(String namespaceId, String serviceName, Instance instance) throws NacosException { 
            
            
            //创建一个空的service
            createEmptyService(namespaceId, serviceName, instance.isEphemeral());
    
            //获取service
            Service service = getService(namespaceId, serviceName);
    
            if (service == null) { 
                throw new NacosException(NacosException.INVALID_PARAM,
                    "service not found, namespace: " + namespaceId + ", service: " + serviceName);
            }
            //添加
            addInstance(namespaceId, serviceName, instance.isEphemeral(), instance);
        }

## 3.5 createEmptyService方法 ##

**描述：** ServiceManager类createEmptyService方法。  
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public void createServiceIfAbsent(String namespaceId, String serviceName, boolean local, Cluster cluster)
            throws NacosException { 
            //从注册表中获取服务
            Service service = getService(namespaceId, serviceName);
            
            //服务为空
            if (service == null) { 
                Loggers.SRV_LOG.info("creating empty service {}:{}", namespaceId, serviceName);
                //创建服务，初始化相关属性
                service = new Service();
                service.setName(serviceName);
                service.setNamespaceId(namespaceId);
                service.setGroupName(NamingUtils.getGroupName(serviceName));
                // now validate the service. if failed, exception will be thrown
                service.setLastModifiedMillis(System.currentTimeMillis());
                service.recalculateChecksum();
                if (cluster != null) { 
                    cluster.setService(service);
                    service.getClusterMap().put(cluster.getName(), cluster);
                }
                service.validate();
                //添加服务到注册表中，并且初始化心跳检测
                putServiceAndInit(service);
                if (!local) { 
                    addOrReplaceService(service);
                }
            }
        }

private void putServiceAndInit(Service service) throws NacosException { 
            //双重检测加入nacos注册表中
            putService(service);
    		//采用scheduleWithFixedDelay定期检测心跳
            service.init();
            consistencyService
                .listen(KeyBuilder.buildInstanceListKey(service.getNamespaceId(), service.getName(), true), service);
            consistencyService
                .listen(KeyBuilder.buildInstanceListKey(service.getNamespaceId(), service.getName(), false), service);
            Loggers.SRV_LOG.info("[NEW-SERVICE] {}", service.toJson());
        }

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## 3.6 addInstance 方法 ##

**描述：** ServiceManager类addInstance方法。

public void addInstance(String namespaceId, String serviceName, boolean ephemeral, Instance... ips)
            throws NacosException { 
                
            //生成一个key
            String key = KeyBuilder.buildInstanceListKey(namespaceId, serviceName, ephemeral);
            //获取当前服务
            Service service = getService(namespaceId, serviceName);
    
            synchronized (service) { 
                //ips转instances
                List<Instance> instanceList = addIpAddresses(service, ephemeral, ips);
                Instances instances = new Instances();
                instances.setInstanceList(instanceList);
                //一致性service存放instances
                consistencyService.put(key, instances);
            }
        }

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## 3.7 DistroConsistencyServiceImpl ##

**描述：** put方法。  
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**描述：** 客户端向nacos发送注册请求，最终在Notifier阻塞队列中添加了注册任务。  
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# 4 Notifier 分析 #

**描述：** 任务启动，DistroConsistencyServiceImpl类初始化时，会初始化线程池开启Notifier 方法，并且当前线程corePoolSize为1。

![在这里插入图片描述][20210608002847669.png]  
![在这里插入图片描述][20210608003014144.png]

**描述：** 当前类实现了Runnable接口，直接查看run方法。  
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@Override
            public void run() { 
                Loggers.DISTRO.info("distro notifier started");
    
                //自旋
                for (; ; ) { 
                    try { 
                        //从阻塞队列中获取任务
                        Pair<String, DataOperation> pair = tasks.take();
                        //处理
                        handle(pair);
                    } catch (Throwable e) { 
                        Loggers.DISTRO.error("[NACOS-DISTRO] Error while handling notifying task", e);
                    }
                }
            }

## 4.1 handle方法。 ##

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## 4.2 onChange ##

**描述：** Service类onChange方法会调用，updateIPs方法进行服务端ip列表的更新。  
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## 4.3 updateIPs ##

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