feat : support mcp server auto discovery for nacos registry (#2122)

Co-authored-by: 澄潭 <zty98751@alibaba-inc.com>

registry/nacos/mcpserver/util.go

@@ -0,0 +1,180 @@
+// Copyright (c) 2022 Alibaba Group Holding Ltd.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package mcpserver
+
+import (
+	"fmt"
+
+	"github.com/nacos-group/nacos-sdk-go/v2/clients/config_client"
+	"github.com/nacos-group/nacos-sdk-go/v2/clients/naming_client"
+	"github.com/nacos-group/nacos-sdk-go/v2/model"
+	"github.com/nacos-group/nacos-sdk-go/v2/vo"
+)
+
+type MultiConfigListener struct {
+	configClient  config_client.IConfigClient
+	onChange      func(map[string]string)
+	configCache   map[string]string
+	innerCallback func(string, string, string, string)
+}
+
+func NewMultiConfigListener(configClient config_client.IConfigClient, onChange func(map[string]string)) *MultiConfigListener {
+	result := &MultiConfigListener{
+		configClient: configClient,
+		configCache:  make(map[string]string),
+		onChange:     onChange,
+	}
+
+	result.innerCallback = func(namespace string, group string, dataId string, content string) {
+		result.configCache[group+DefaultJoiner+dataId] = content
+		result.onChange(result.configCache)
+	}
+
+	return result
+}
+
+func (l *MultiConfigListener) StartListen(configs []vo.ConfigParam) error {
+	for _, config := range configs {
+		content, err := l.configClient.GetConfig(vo.ConfigParam{
+			DataId: config.DataId,
+			Group:  config.Group,
+		})
+
+		if err != nil {
+			return fmt.Errorf("get config %s/%s err: %v", config.Group, config.DataId, err)
+		}
+		l.configCache[config.Group+DefaultJoiner+config.DataId] = content
+		err = l.configClient.ListenConfig(vo.ConfigParam{
+			DataId:   config.DataId,
+			Group:    config.Group,
+			OnChange: l.innerCallback,
+		})
+
+		if err != nil {
+			return fmt.Errorf("listener to config %s/%s error: %w", config.Group, config.DataId, err)
+		}
+	}
+
+	l.onChange(l.configCache)
+	return nil
+}
+
+func (l *MultiConfigListener) Stop() {
+	l.configClient.CloseClient()
+}
+
+func (l *MultiConfigListener) CancelListen(configs []vo.ConfigParam) error {
+	for _, config := range configs {
+		if _, ok := l.configCache[config.Group+DefaultJoiner+config.DataId]; ok {
+			err := l.configClient.CancelListenConfig(vo.ConfigParam{
+				DataId: config.DataId,
+				Group:  config.Group,
+			})
+
+			if err != nil {
+				return fmt.Errorf("cancel config %s/%s error: %w", config.Group, config.DataId, err)
+			}
+			delete(l.configCache, config.Group+config.DataId)
+		}
+	}
+	return nil
+}
+
+type ServiceCache struct {
+	services map[string]*NacosServiceRef
+	client   naming_client.INamingClient
+}
+
+type NacosServiceRef struct {
+	refs      map[string]func([]model.Instance)
+	callback  func(services []model.Instance, err error)
+	instances *[]model.Instance
+}
+
+func NewServiceCache(client naming_client.INamingClient) *ServiceCache {
+	return &ServiceCache{
+		client:   client,
+		services: make(map[string]*NacosServiceRef),
+	}
+}
+
+func (c *ServiceCache) AddListener(group string, serviceName string, key string, callback func([]model.Instance)) error {
+	uniqueServiceName := c.makeServiceUniqueName(group, serviceName)
+	if _, ok := c.services[uniqueServiceName]; !ok {
+		instances, err := c.client.SelectAllInstances(vo.SelectAllInstancesParam{
+			GroupName:   group,
+			ServiceName: serviceName,
+		})
+
+		if err != nil {
+			return err
+		}
+
+		ref := &NacosServiceRef{
+			refs:      map[string]func([]model.Instance){},
+			instances: &instances,
+		}
+
+		ref.callback = func(services []model.Instance, err error) {
+			ref.instances = &services
+			for _, refCallback := range ref.refs {
+				refCallback(*ref.instances)
+			}
+		}
+
+		c.services[uniqueServiceName] = ref
+
+		err = c.client.Subscribe(&vo.SubscribeParam{
+			GroupName:         group,
+			ServiceName:       serviceName,
+			SubscribeCallback: ref.callback,
+		})
+		if err != nil {
+			return err
+		}
+	}
+
+	ref := c.services[uniqueServiceName]
+	ref.refs[key] = callback
+	callback(*ref.instances)
+	return nil
+}
+
+func (c *ServiceCache) RemoveListener(group string, serviceName string, key string) error {
+	if ref, ok := c.services[c.makeServiceUniqueName(group, serviceName)]; ok {
+		delete(ref.refs, key)
+		if len(ref.refs) == 0 {
+			err := c.client.Unsubscribe(&vo.SubscribeParam{
+				GroupName:         group,
+				ServiceName:       serviceName,
+				SubscribeCallback: ref.callback,
+			})
+
+			delete(c.services, c.makeServiceUniqueName(group, serviceName))
+			if err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
+func (c *ServiceCache) makeServiceUniqueName(group string, serviceName string) string {
+	return fmt.Sprintf("%s-%s", group, serviceName)
+}
+
+func (c *ServiceCache) Stop() {
+	c.client.CloseClient()
+}