API

描述

删除服务下的一个实例。

请求类型

DELETE

请求路径

/nacos/v1/ns/instance

请求参数

错误编码

示例请求

curl -X DELETE '127.0.0.1:8848/nacos/v1/ns/instance?serviceName=nacos.test.1&ip=1.1.1.1&port=8888&clusterName=TEST1'

示例返回

ok

关键流程源码解析

InstanceController

/** * Deregister instances. * 实例下线 * @param request http request * @return 'ok' if success * @throws Exception any error during deregister */
    @CanDistro
    @DeleteMapping
    @Secured(parser = NamingResourceParser.class, action = ActionTypes.WRITE)
    public String deregister(HttpServletRequest request) throws Exception {
        //根据请求的参数构建出一个实例
        Instance instance = getIpAddress(request);
        String namespaceId = WebUtils.optional(request, CommonParams.NAMESPACE_ID, Constants.DEFAULT_NAMESPACE_ID);
        String serviceName = WebUtils.required(request, CommonParams.SERVICE_NAME);
        NamingUtils.checkServiceNameFormat(serviceName);
        //根据命名空间服务名获取服务管理中心map中的服务
        Service service = serviceManager.getService(namespaceId, serviceName);
        if (service == null) {
            Loggers.SRV_LOG.warn("remove instance from non-exist service: {}", serviceName);
            return "ok";
        }
        //删除实例节点
        serviceManager.removeInstance(namespaceId, serviceName, instance.isEphemeral(), instance);
        return "ok";
    }

ServiceManager

/** * Remove instance from service. * 删除服务中的某个实例节点 * @param namespaceId namespace * @param serviceName service name * @param ephemeral whether instance is ephemeral * @param ips instances * @throws NacosException nacos exception */
    public void removeInstance(String namespaceId, String serviceName, boolean ephemeral, Instance... ips)
            throws NacosException {
        Service service = getService(namespaceId, serviceName);

        synchronized (service) {
            removeInstance(namespaceId, serviceName, ephemeral, service, ips);
        }
    }

    private void removeInstance(String namespaceId, String serviceName, boolean ephemeral, Service service,
            Instance... ips) throws NacosException {
        //根据命名空间，服务名称，节点类型构建key值
        String key = KeyBuilder.buildInstanceListKey(namespaceId, serviceName, ephemeral);
        //获取剩余部分的实例节点列表
        List<Instance> instanceList = substractIpAddresses(service, ephemeral, ips);

        Instances instances = new Instances();
        instances.setInstanceList(instanceList);
        //一致性服务更新服务的最新实例节点列表
        consistencyService.put(key, instances);
    }
    private List<Instance> substractIpAddresses(Service service, boolean ephemeral, Instance... ips)
            throws NacosException {
        return updateIpAddresses(service, UtilsAndCommons.UPDATE_INSTANCE_ACTION_REMOVE, ephemeral, ips);
    }
    /** * Compare and get new instance list. * 比较有效实例并返回操作后的最新实例列表 * @param service service * @param action {@link UtilsAndCommons#UPDATE_INSTANCE_ACTION_REMOVE} or {@link UtilsAndCommons#UPDATE_INSTANCE_ACTION_ADD} * @param ephemeral whether instance is ephemeral * @param ips instances * @return instance list after operation * @throws NacosException nacos exception */
    public List<Instance> updateIpAddresses(Service service, String action, boolean ephemeral, Instance... ips)
            throws NacosException {
        //通过一致性服务获取最新的服务实例信息
        Datum datum = consistencyService
                .get(KeyBuilder.buildInstanceListKey(service.getNamespaceId(), service.getName(), ephemeral));
        //获取当前服务中存在的实例列表
        List<Instance> currentIPs = service.allIPs(ephemeral);
        Map<String, Instance> currentInstances = new HashMap<>(currentIPs.size());
        Set<String> currentInstanceIds = Sets.newHashSet();

        for (Instance instance : currentIPs) {
            currentInstances.put(instance.toIpAddr(), instance);
            currentInstanceIds.add(instance.getInstanceId());
        }
        //过滤出当前持有的服务中存在的实例列表
        Map<String, Instance> instanceMap;
        if (datum != null && null != datum.value) {
            instanceMap = setValid(((Instances) datum.value).getInstanceList(), currentInstances);
        } else {
            instanceMap = new HashMap<>(ips.length);
        }
        //处理需要操作的实例列表
        for (Instance instance : ips) {
            if (!service.getClusterMap().containsKey(instance.getClusterName())) {
                Cluster cluster = new Cluster(instance.getClusterName(), service);
                cluster.init();
                service.getClusterMap().put(instance.getClusterName(), cluster);
                Loggers.SRV_LOG
                        .warn("cluster: {} not found, ip: {}, will create new cluster with default configuration.",
                                instance.getClusterName(), instance.toJson());
            }
            //如果接收到的动作是remove将从当前实例列表删除请求的实例节点，否则更新节点信息
            if (UtilsAndCommons.UPDATE_INSTANCE_ACTION_REMOVE.equals(action)) {
                instanceMap.remove(instance.getDatumKey());
            } else {
                Instance oldInstance = instanceMap.get(instance.getDatumKey());
                if (oldInstance != null) {
                    instance.setInstanceId(oldInstance.getInstanceId());
                } else {
                    instance.setInstanceId(instance.generateInstanceId(currentInstanceIds));
                }
                instanceMap.put(instance.getDatumKey(), instance);
            }

        }

        if (instanceMap.size() <= 0 && UtilsAndCommons.UPDATE_INSTANCE_ACTION_ADD.equals(action)) {
            throw new IllegalArgumentException(
                    "ip list can not be empty, service: " + service.getName() + ", ip list: " + JacksonUtils
                            .toJson(instanceMap.values()));
        }

        return new ArrayList<>(instanceMap.values());
    }

总结

注销实例没什么特别的处理，我们可以简单理解成Nacos是将请求下线的节点从持有的服务列表中删除该节点。