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企业级分布式 MCP 方案
!TIP
背景:现阶段 MCP Client 和 MCP Server 是一对一的连接方式,若当前 MCP Server 挂掉了,那么 MCP Client 便不能使用 MCP Server 提供的工具能力。工具稳定性的提供得不到保证
解决:做了一些分布式 Client 连接的探索,一个 MCP Client 端可以连接多个 MCP Server(分布式部署),目前采用的方案如下:
- 新建一个包含服务名和对应连接的类
- 另外实现监听机制,可以动态的应对 MCP Server 节点上下线,去动态调整 mcpAsyncClientList
- (读操作)获取 MCP Server 相关信息的,采用从 mcpAsyncClientList 列表中随机中获取一个去发起请求,比如获取工具列表信息
- (写操作)对应 MCP Server 需要更改的信息,由 MCP Client 端发起,需要修改所有的 MCP Server
public class LoadbalancedAsyncClient implements EventListener {
private String serviceName;
private List mcpAsyncClientList;
}
给社区贡献代码:https://github.com/alibaba/spring-ai-alibaba/pull/755
模块代码解析
yaml 文件
yaml
spring:
ai:
mcp:
client:
enabled: true
name: mcp-client-webflux
version: 1.0.0
type: SYNC
nacos-enabled: true # 开启nacos-client配置,启动分布式
alibaba:
mcp:
nacos: ## nacos的基础配置信息
enabled: true
server-addr: <nacos-sever-addr>
service-namespace: <nacos-namespace>
service-group: <nacos-group>
client:
sse:
connections: // 注册在nacos的MCP Server服务,这里mcp-server1代表多节点
nacos-server1: mcp-server1
nacos-server2: mcp-server2
自动注入部分
NacosMcpSseClientProperties(配置类)
java
@ConfigurationProperties("spring.ai.alibaba.mcp.client.sse")
public class NacosMcpSseClientProperties {
public static final String _CONFIG_PREFIX _= "spring.ai.alibaba.mcp.client.sse";
private final Map<String, String> connections = new HashMap<>();
public Map<String, String> getConnections() {
return connections;
}
}
NacosMcpSseClientAutoConfiguration
提供 Map<String, List> 的 bean
- 键代表服务名
- 值为对应的后续连接的 WebFluxSseClientTransport 列表
java
@AutoConfiguration
@EnableConfigurationProperties({ NacosMcpSseClientProperties.class, NacosMcpRegistryProperties.class })
public class NacosMcpSseClientAutoConfiguration {
private static final Logger _logger _= LoggerFactory._getLogger_(NacosMcpSseClientAutoConfiguration.class);
public NacosMcpSseClientAutoConfiguration() {
}
@Bean
public NamingService nacosNamingService(NacosMcpRegistryProperties nacosMcpRegistryProperties) {
Properties nacosProperties = nacosMcpRegistryProperties.getNacosProperties();
try {
return NamingFactory._createNamingService_(nacosProperties);
}
catch (NacosException e) {
throw new RuntimeException(e);
}
}
@Bean(name = "server2NamedTransport")
public Map<String, List<NamedClientMcpTransport>> server2NamedTransport(
NacosMcpSseClientProperties nacosMcpSseClientProperties, NamingService namingService,
ObjectProvider<WebClient.Builder> webClientBuilderProvider,
ObjectProvider<ObjectMapper> objectMapperProvider) {
Map<String, List<NamedClientMcpTransport>> server2NamedTransport = new HashMap<>();
WebClient.Builder webClientBuilderTemplate = (WebClient.Builder) webClientBuilderProvider
.getIfAvailable(WebClient::_builder_);
ObjectMapper objectMapper = (ObjectMapper) objectMapperProvider.getIfAvailable(ObjectMapper::new);
Map<String, String> connections = nacosMcpSseClientProperties.getConnections();
connections.forEach((serviceKey, serviceName) -> {
try {
List<Instance> instances = namingService.selectInstances(serviceName, true);
List<NamedClientMcpTransport> namedTransports = new ArrayList<>();
for (Instance instance : instances) {
String url = instance.getMetadata().getOrDefault("scheme", "http") + "://" + instance.getIp() + ":"
+ instance.getPort();
WebClient.Builder webClientBuilder = webClientBuilderTemplate.clone().baseUrl(url);
WebFluxSseClientTransport transport = new WebFluxSseClientTransport(webClientBuilder, objectMapper);
namedTransports
.add(new NamedClientMcpTransport(serviceName + "-" + instance.getInstanceId(), transport));
}
server2NamedTransport.put(serviceName, namedTransports);
}
catch (NacosException e) {
_logger_.error("nacos naming service: {} error", serviceName, e);
}
});
return server2NamedTransport;
}
}
NacosMcpClientAutoConfiguration
提供和 MCP Server 进行交互的客户端
- List
- List
java
@AutoConfiguration(after = { NacosMcpSseClientAutoConfiguration.class, McpClientAutoConfiguration.class })
@ConditionalOnClass({ McpSchema.class })
@EnableConfigurationProperties({ McpClientCommonProperties.class })
@ConditionalOnProperty(prefix = "spring.ai.mcp.client", name = { "nacos-enabled" }, havingValue = "true",
matchIfMissing = false)
public class NacosMcpClientAutoConfiguration {
public NacosMcpClientAutoConfiguration() {
}
private String connectedClientName(String clientName, String serverConnectionName) {
return clientName + " - " + serverConnectionName;
}
@Bean
@ConditionalOnProperty(prefix = "spring.ai.mcp.client", name = { "type" }, havingValue = "SYNC",
matchIfMissing = true)
public List<LoadbalancedMcpSyncClient> loadbalancedMcpSyncClientList(
ObjectProvider<McpSyncClientConfigurer> mcpSyncClientConfigurerProvider,
McpClientCommonProperties commonProperties,
@Qualifier("server2NamedTransport") ObjectProvider<Map<String, List<NamedClientMcpTransport>>> server2NamedTransportProvider,
ObjectProvider<NamingService> namingServiceProvider) {
NamingService namingService = namingServiceProvider.getObject();
McpSyncClientConfigurer mcpSyncClientConfigurer = mcpSyncClientConfigurerProvider.getObject();
List<LoadbalancedMcpSyncClient> loadbalancedMcpSyncClients = new ArrayList<>();
Map<String, List<NamedClientMcpTransport>> server2NamedTransport = server2NamedTransportProvider.getObject();
for (Map.Entry<String, List<NamedClientMcpTransport>> entry : server2NamedTransport.entrySet()) {
String serviceName = entry.getKey();
List<NamedClientMcpTransport> namedTransports = entry.getValue();
List<McpSyncClient> mcpSyncClients = new ArrayList<>();
McpSyncClient syncClient;
for (NamedClientMcpTransport namedTransport : namedTransports) {
McpSchema.Implementation clientInfo = new McpSchema.Implementation(
this.connectedClientName(commonProperties.getName(), namedTransport.name()),
commonProperties.getVersion());
McpClient.SyncSpec syncSpec = McpClient._sync_(namedTransport.transport())
.clientInfo(clientInfo)
.requestTimeout(commonProperties.getRequestTimeout());
syncSpec = mcpSyncClientConfigurer.configure(namedTransport.name(), syncSpec);
syncClient = syncSpec.build();
if (commonProperties.isInitialized()) {
syncClient.initialize();
}
mcpSyncClients.add(syncClient);
}
LoadbalancedMcpSyncClient loadbalancedMcpSyncClient = LoadbalancedMcpSyncClient._builder_()
.serviceName(serviceName)
.mcpSyncClientList(mcpSyncClients)
.namingService(namingService)
.build();
loadbalancedMcpSyncClient.subscribe();
loadbalancedMcpSyncClients.add(loadbalancedMcpSyncClient);
}
return loadbalancedMcpSyncClients;
}
@Bean
@ConditionalOnProperty(prefix = "spring.ai.mcp.client", name = { "type" }, havingValue = "ASYNC")
public List<LoadbalancedMcpAsyncClient> loadbalancedMcpAsyncClientList(
ObjectProvider<McpAsyncClientConfigurer> mcpAsyncClientConfigurerProvider,
McpClientCommonProperties commonProperties,
@Qualifier("server2NamedTransport") ObjectProvider<Map<String, List<NamedClientMcpTransport>>> server2NamedTransportProvider,
ObjectProvider<NamingService> namingServiceProvider) {
NamingService namingService = namingServiceProvider.getObject();
McpAsyncClientConfigurer mcpAsyncClientConfigurer = mcpAsyncClientConfigurerProvider.getObject();
List<LoadbalancedMcpAsyncClient> loadbalancedMcpAsyncClients = new ArrayList<>();
Map<String, List<NamedClientMcpTransport>> server2NamedTransport = server2NamedTransportProvider.getObject();
for (Map.Entry<String, List<NamedClientMcpTransport>> entry : server2NamedTransport.entrySet()) {
String serviceName = entry.getKey();
List<NamedClientMcpTransport> namedTransports = entry.getValue();
List<McpAsyncClient> mcpAsyncClients = new ArrayList<>();
McpAsyncClient asyncClient;
for (NamedClientMcpTransport namedTransport : namedTransports) {
McpSchema.Implementation clientInfo = new McpSchema.Implementation(
this.connectedClientName(commonProperties.getName(), namedTransport.name()),
commonProperties.getVersion());
McpClient.AsyncSpec asyncSpec = McpClient._async_(namedTransport.transport())
.clientInfo(clientInfo)
.requestTimeout(commonProperties.getRequestTimeout());
asyncSpec = mcpAsyncClientConfigurer.configure(namedTransport.name(), asyncSpec);
asyncClient = asyncSpec.build();
if (commonProperties.isInitialized()) {
asyncClient.initialize().block();
}
mcpAsyncClients.add(asyncClient);
}
LoadbalancedMcpAsyncClient loadbalancedMcpAsyncClient = LoadbalancedMcpAsyncClient._builder_()
.serviceName(serviceName)
.mcpAsyncClientList(mcpAsyncClients)
.namingService(namingService)
.build();
loadbalancedMcpAsyncClient.subscribe();
loadbalancedMcpAsyncClients.add(loadbalancedMcpAsyncClient);
}
return loadbalancedMcpAsyncClients;
}
}
Client 端部分
LoadbalancedMcpAsyncClient
各字段含义:
String serviceName
:MCP Server 注册的服务名称List<McpAsyncClient> mcpAsyncClientList
:对应的多节点客户端NamingService namingService
:Nacos 服务List<Instance> instances
:Nacos 中 MCP Server 的实例列表
其余方法的使用和 McpAsyncClient
保持一致,已经全面封装好了
- 读操作:通过 getMcpAsyncClient()方法轮询得到
McpAsyncClient
列表 - 写操作:对所有
List<McpAsyncClient>
进行操作
通过实现 EventListener 接口,动态增加 or 减少 McpAsyncClient
java
public class LoadbalancedMcpAsyncClient implements EventListener {
private static final Logger _logger _= LoggerFactory._getLogger_(LoadbalancedMcpAsyncClient.class);
private final String serviceName;
private final List<McpAsyncClient> mcpAsyncClientList;
private final AtomicInteger currentIndex = new AtomicInteger(0);
private final NamingService namingService;
private List<Instance> instances;
public LoadbalancedMcpAsyncClient(String serviceName, List<McpAsyncClient> mcpAsyncClientList,
NamingService namingService) {
Assert._notNull_(serviceName, "serviceName cannot be null");
Assert._notNull_(mcpAsyncClientList, "mcpAsyncClientList cannot be null");
Assert._notNull_(namingService, "namingService cannot be null");
this.serviceName = serviceName;
this.mcpAsyncClientList = mcpAsyncClientList;
try {
this.namingService = namingService;
this.instances = namingService.selectInstances(serviceName, true);
}
catch (NacosException e) {
throw new RuntimeException(String._format_("Failed to get instances for service: %s", serviceName));
}
}
public void subscribe() {
try {
this.namingService.subscribe(this.serviceName, this);
}
catch (NacosException e) {
throw new RuntimeException(String._format_("Failed to subscribe to service: %s", this.serviceName));
}
}
public String getServiceName() {
return serviceName;
}
public List<McpAsyncClient> getMcpAsyncClientList() {
return mcpAsyncClientList;
}
public NamingService getNamingService() {
return this.namingService;
}
public List<Instance> getInstances() {
return this.instances;
}
private McpAsyncClient getMcpAsyncClient() {
if (mcpAsyncClientList.isEmpty()) {
throw new IllegalStateException("No McpAsyncClient available");
}
int index = currentIndex.getAndIncrement() % mcpAsyncClientList.size();
return mcpAsyncClientList.get(index);
}
// ------------------------------------------------------------------------------------------------------------------------------------------------
public McpSchema.ServerCapabilities getServerCapabilities() {
return getMcpAsyncClient().getServerCapabilities();
}
public McpSchema.Implementation getServerInfo() {
return getMcpAsyncClient().getServerInfo();
}
public boolean isInitialized() {
return getMcpAsyncClient().isInitialized();
}
public McpSchema.ClientCapabilities getClientCapabilities() {
return getMcpAsyncClient().getClientCapabilities();
}
public McpSchema.Implementation getClientInfo() {
return getMcpAsyncClient().getClientInfo();
}
public void close() {
Iterator<McpAsyncClient> iterator = mcpAsyncClientList.iterator();
while (iterator.hasNext()) {
McpAsyncClient mcpAsyncClient = iterator.next();
mcpAsyncClient.close();
iterator.remove();
_logger_.info("Closed and removed McpSyncClient: {}", mcpAsyncClient.getClientInfo().name());
}
}
public Mono<Void> closeGracefully() {
Iterator<McpAsyncClient> iterator = mcpAsyncClientList.iterator();
List<Mono<Void>> closeMonos = new ArrayList<>();
while (iterator.hasNext()) {
McpAsyncClient mcpAsyncClient = iterator.next();
Mono<Void> voidMono = mcpAsyncClient.closeGracefully().doOnSuccess(v -> {
iterator.remove();
_logger_.info("Closed and removed McpAsyncClient: {}", mcpAsyncClient.getClientInfo().name());
});
closeMonos.add(voidMono);
}
return Mono._when_(closeMonos);
}
public Mono<Object> ping() {
return getMcpAsyncClient().ping();
}
public Mono<Void> addRoot(McpSchema.Root root) {
return Mono._when_(mcpAsyncClientList.stream()
.map(mcpAsyncClient -> mcpAsyncClient.addRoot(root))
.collect(Collectors._toList_()));
}
public Mono<Void> removeRoot(String rootUri) {
return Mono._when_(mcpAsyncClientList.stream()
.map(mcpAsyncClient -> mcpAsyncClient.removeRoot(rootUri))
.collect(Collectors._toList_()));
}
public Mono<Void> rootsListChangedNotification() {
return Mono._when_(mcpAsyncClientList.stream()
.map(McpAsyncClient::rootsListChangedNotification)
.collect(Collectors._toList_()));
}
public Mono<McpSchema.CallToolResult> callTool(McpSchema.CallToolRequest callToolRequest) {
return getMcpAsyncClient().callTool(callToolRequest);
}
public Mono<McpSchema.ListToolsResult> listTools() {
return getMcpAsyncClient().listTools();
}
public Mono<McpSchema.ListToolsResult> listTools(String cursor) {
return getMcpAsyncClient().listTools(cursor);
}
public Mono<McpSchema.ListResourcesResult> listResources() {
return getMcpAsyncClient().listResources();
}
public Mono<McpSchema.ListResourcesResult> listResources(String cursor) {
return getMcpAsyncClient().listResources(cursor);
}
public Mono<McpSchema.ReadResourceResult> readResource(McpSchema.Resource resource) {
return getMcpAsyncClient().readResource(resource);
}
public Mono<McpSchema.ReadResourceResult> readResource(McpSchema.ReadResourceRequest readResourceRequest) {
return getMcpAsyncClient().readResource(readResourceRequest);
}
public Mono<McpSchema.ListResourceTemplatesResult> listResourceTemplates() {
return getMcpAsyncClient().listResourceTemplates();
}
public Mono<McpSchema.ListResourceTemplatesResult> listResourceTemplates(String cursor) {
return getMcpAsyncClient().listResourceTemplates(cursor);
}
public Mono<Void> subscribeResource(McpSchema.SubscribeRequest subscribeRequest) {
return Mono._when_(mcpAsyncClientList.stream()
.map(mcpAsyncClient -> mcpAsyncClient.subscribeResource(subscribeRequest))
.collect(Collectors._toList_()));
}
public Mono<Void> unsubscribeResource(McpSchema.UnsubscribeRequest unsubscribeRequest) {
return Mono._when_(mcpAsyncClientList.stream()
.map(mcpAsyncClient -> mcpAsyncClient.unsubscribeResource(unsubscribeRequest))
.collect(Collectors._toList_()));
}
public Mono<McpSchema.ListPromptsResult> listPrompts() {
return getMcpAsyncClient().listPrompts();
}
public Mono<McpSchema.ListPromptsResult> listPrompts(String cursor) {
return getMcpAsyncClient().listPrompts(cursor);
}
public Mono<McpSchema.GetPromptResult> getPrompt(McpSchema.GetPromptRequest getPromptRequest) {
return getMcpAsyncClient().getPrompt(getPromptRequest);
}
public Mono<Void> setLoggingLevel(McpSchema.LoggingLevel loggingLevel) {
return Mono._when_(mcpAsyncClientList.stream()
.map(mcpAsyncClient -> mcpAsyncClient.setLoggingLevel(loggingLevel))
.collect(Collectors._toList_()));
}
// ------------------------------------------------------------------------------------------------------------------------------------------------
@Override
public void onEvent(Event event) {
if (event instanceof NamingEvent namingEvent) {
if (this.serviceName.equals(namingEvent.getServiceName())) {
_logger_.info("Received service instance change event for service: {}", namingEvent.getServiceName());
List<Instance> instances = namingEvent.getInstances();
_logger_.info("Updated instances count: {}", instances.size());
// 打印每个实例的详细信息
instances.forEach(instance -> {
_logger_.info("Instance: {}:{} (Healthy: {}, Enabled: {}, Metadata: {})", instance.getIp(),
instance.getPort(), instance.isHealthy(), instance.isEnabled(),
JacksonUtils._toJson_(instance.getMetadata()));
});
updateClientList(instances);
}
}
}
private void updateClientList(List<Instance> currentInstances) {
McpClientCommonProperties commonProperties = ApplicationContextHolder._getBean_(McpClientCommonProperties.class);
McpAsyncClientConfigurer mcpSyncClientConfigurer = ApplicationContextHolder
._getBean_(McpAsyncClientConfigurer.class);
ObjectMapper objectMapper = ApplicationContextHolder._getBean_(ObjectMapper.class);
WebClient.Builder webClientBuilderTemplate = ApplicationContextHolder._getBean_(WebClient.Builder.class);
// 移除的实例列表
List<Instance> removeInstances = instances.stream()
.filter(instance -> !currentInstances.contains(instance))
.collect(Collectors._toList_());
// 新增的实例列表
List<Instance> addInstances = currentInstances.stream()
.filter(instance -> !instances.contains(instance))
.collect(Collectors._toList_());
// 删除McpAsyncClient实例
List<String> clientInfoNames = removeInstances.stream()
.map(instance -> connectedClientName(commonProperties.getName(),
this.serviceName + "-" + instance.getInstanceId()))
.toList();
Iterator<McpAsyncClient> iterator = mcpAsyncClientList.iterator();
while (iterator.hasNext()) {
McpAsyncClient mcpAsyncClient = iterator.next();
McpSchema.Implementation clientInfo = mcpAsyncClient.getClientInfo();
if (clientInfoNames.contains(clientInfo.name())) {
_logger_.info("Removing McpAsyncClient: {}", clientInfo.name());
mcpAsyncClient.closeGracefully().subscribe(v -> {
iterator.remove();
}, e -> _logger_.error("Failed to remove McpAsyncClient: {}", clientInfo.name(), e));
}
}
// 新增McpAsyncClient实例
McpAsyncClient asyncClient;
for (Instance instance : addInstances) {
String baseUrl = instance.getMetadata().getOrDefault("scheme", "http") + "://" + instance.getIp() + ":"
+ instance.getPort();
WebClient.Builder webClientBuilder = webClientBuilderTemplate.clone().baseUrl(baseUrl);
WebFluxSseClientTransport transport = new WebFluxSseClientTransport(webClientBuilder, objectMapper);
NamedClientMcpTransport namedTransport = new NamedClientMcpTransport(
serviceName + "-" + instance.getInstanceId(), transport);
McpSchema.Implementation clientInfo = new McpSchema.Implementation(
this.connectedClientName(commonProperties.getName(), namedTransport.name()),
commonProperties.getVersion());
McpClient.AsyncSpec asyncSpec = McpClient._async_(namedTransport.transport())
.clientInfo(clientInfo)
.requestTimeout(commonProperties.getRequestTimeout());
asyncSpec = mcpSyncClientConfigurer.configure(namedTransport.name(), asyncSpec);
asyncClient = asyncSpec.build();
if (commonProperties.isInitialized()) {
asyncClient.initialize().block();
}
_logger_.info("Added McpAsyncClient: {}", clientInfo.name());
mcpAsyncClientList.add(asyncClient);
}
private String connectedClientName(String clientName, String serverConnectionName) {
return clientName + " - " + serverConnectionName;
}
public static Builder builder() {
return new Builder();
}
public static class Builder {
private String serviceName;
private List<McpAsyncClient> mcpAsyncClientList;
private NamingService namingService;
public Builder serviceName(String serviceName) {
this.serviceName = serviceName;
return this;
}
public Builder mcpAsyncClientList(List<McpAsyncClient> mcpAsyncClientList) {
this.mcpAsyncClientList = mcpAsyncClientList;
return this;
}
public Builder namingService(NamingService namingService) {
this.namingService = namingService;
return this;
}
public LoadbalancedMcpAsyncClient build() {
return new LoadbalancedMcpAsyncClient(this.serviceName, this.mcpAsyncClientList, this.namingService);
}
}
}
LoadbalancedMcpSyncClient
同上
java
public class LoadbalancedMcpSyncClient implements EventListener {
private static final Logger _logger _= LoggerFactory._getLogger_(LoadbalancedMcpAsyncClient.class);
private final String serviceName;
private final List<McpSyncClient> mcpSyncClientList;
private final AtomicInteger currentIndex = new AtomicInteger(0);
private final NamingService namingService;
private List<Instance> instances;
public LoadbalancedMcpSyncClient(String serviceName, List<McpSyncClient> mcpSyncClientList,
NamingService namingService) {
Assert._notNull_(serviceName, "Service name must not be null");
Assert._notNull_(mcpSyncClientList, "McpSyncClient list must not be null");
Assert._notNull_(namingService, "NamingService must not be null");
this.serviceName = serviceName;
this.mcpSyncClientList = mcpSyncClientList;
try {
this.namingService = namingService;
this.instances = namingService.selectInstances(serviceName, true);
}
catch (NacosException e) {
throw new RuntimeException(String._format_("Failed to get instances for service: %s", serviceName));
}
}
public void subscribe() {
try {
this.namingService.subscribe(this.serviceName, this);
}
catch (NacosException e) {
throw new RuntimeException(String._format_("Failed to subscribe to service: %s", this.serviceName));
}
}
public String getServiceName() {
return this.serviceName;
}
public List<McpSyncClient> getMcpSyncClientList() {
return this.mcpSyncClientList;
}
public NamingService getNamingService() {
return this.namingService;
}
public List<Instance> getInstances() {
return this.instances;
}
private McpSyncClient getMcpSyncClient() {
if (mcpSyncClientList.isEmpty()) {
throw new IllegalStateException("No McpAsyncClient available");
}
int index = currentIndex.getAndIncrement() % mcpSyncClientList.size();
return mcpSyncClientList.get(index);
}
// ------------------------------------------------------------------------------------------------------------------------------------------------
public McpSchema.ServerCapabilities getServerCapabilities() {
return getMcpSyncClient().getServerCapabilities();
}
public McpSchema.Implementation getServerInfo() {
return getMcpSyncClient().getServerInfo();
}
public McpSchema.ClientCapabilities getClientCapabilities() {
return getMcpSyncClient().getClientCapabilities();
}
public McpSchema.Implementation getClientInfo() {
return getMcpSyncClient().getClientInfo();
}
public void close() {
Iterator<McpSyncClient> iterator = mcpSyncClientList.iterator();
while (iterator.hasNext()) {
McpSyncClient mcpSyncClient = iterator.next();
mcpSyncClient.close();
iterator.remove();
_logger_.info("Closed and removed McpSyncClient: {}", mcpSyncClient.getClientInfo().name());
}
}
public boolean closeGracefully() {
List<Boolean> flagList = new ArrayList<>();
Iterator<McpSyncClient> iterator = mcpSyncClientList.iterator();
while (iterator.hasNext()) {
McpSyncClient mcpSyncClient = iterator.next();
boolean flag = mcpSyncClient.closeGracefully();
flagList.add(flag);
if (flag) {
iterator.remove();
_logger_.info("Closed and removed McpSyncClient: {}", mcpSyncClient.getClientInfo().name());
}
}
return !flagList.stream().allMatch(flag -> flag);
}
public Object ping() {
return getMcpSyncClient().ping();
}
public void addRoot(McpSchema.Root root) {
for (McpSyncClient mcpSyncClient : mcpSyncClientList) {
mcpSyncClient.addRoot(root);
}
}
public void removeRoot(String rootUri) {
for (McpSyncClient mcpSyncClient : mcpSyncClientList) {
mcpSyncClient.removeRoot(rootUri);
}
}
public McpSchema.CallToolResult callTool(McpSchema.CallToolRequest callToolRequest) {
return getMcpSyncClient().callTool(callToolRequest);
}
public McpSchema.ListToolsResult listTools() {
return getMcpSyncClient().listTools();
}
public McpSchema.ListToolsResult listTools(String cursor) {
return getMcpSyncClient().listTools(cursor);
}
public McpSchema.ListResourcesResult listResources(String cursor) {
return getMcpSyncClient().listResources(cursor);
}
public McpSchema.ListResourcesResult listResources() {
return getMcpSyncClient().listResources();
}
public McpSchema.ReadResourceResult readResource(McpSchema.Resource resource) {
return getMcpSyncClient().readResource(resource);
}
public McpSchema.ReadResourceResult readResource(McpSchema.ReadResourceRequest readResourceRequest) {
return getMcpSyncClient().readResource(readResourceRequest);
}
public McpSchema.ListResourceTemplatesResult listResourceTemplates(String cursor) {
return getMcpSyncClient().listResourceTemplates(cursor);
}
public McpSchema.ListResourceTemplatesResult listResourceTemplates() {
return getMcpSyncClient().listResourceTemplates();
}
public void subscribeResource(McpSchema.SubscribeRequest subscribeRequest) {
for (McpSyncClient mcpSyncClient : mcpSyncClientList) {
mcpSyncClient.subscribeResource(subscribeRequest);
}
}
public void unsubscribeResource(McpSchema.UnsubscribeRequest unsubscribeRequest) {
for (McpSyncClient mcpSyncClient : mcpSyncClientList) {
mcpSyncClient.unsubscribeResource(unsubscribeRequest);
}
}
public McpSchema.ListPromptsResult listPrompts(String cursor) {
return getMcpSyncClient().listPrompts(cursor);
}
public McpSchema.ListPromptsResult listPrompts() {
return getMcpSyncClient().listPrompts();
}
public McpSchema.GetPromptResult getPrompt(McpSchema.GetPromptRequest getPromptRequest) {
return getMcpSyncClient().getPrompt(getPromptRequest);
}
public void setLoggingLevel(McpSchema.LoggingLevel loggingLevel) {
for (McpSyncClient mcpSyncClient : mcpSyncClientList) {
mcpSyncClient.setLoggingLevel(loggingLevel);
}
}
// ------------------------------------------------------------------------------------------------------------------------------------------------
@Override
public void onEvent(Event event) {
if (event instanceof NamingEvent namingEvent) {
if (this.serviceName.equals(namingEvent.getServiceName())) {
_logger_.info("Received service instance change event for service: {}", namingEvent.getServiceName());
List<Instance> instances = namingEvent.getInstances();
_logger_.info("Updated instances count: {}", instances.size());
// 打印每个实例的详细信息
instances.forEach(instance -> {
_logger_.info("Instance: {}:{} (Healthy: {}, Enabled: {}, Metadata: {})", instance.getIp(),
instance.getPort(), instance.isHealthy(), instance.isEnabled(),
JacksonUtils._toJson_(instance.getMetadata()));
});
updateClientList(instances);
}
}
}
private void updateClientList(List<Instance> currentInstances) {
McpClientCommonProperties commonProperties = ApplicationContextHolder._getBean_(McpClientCommonProperties.class);
McpSyncClientConfigurer mcpSyncClientConfigurer = ApplicationContextHolder
._getBean_(McpSyncClientConfigurer.class);
ObjectMapper objectMapper = ApplicationContextHolder._getBean_(ObjectMapper.class);
WebClient.Builder webClientBuilderTemplate = ApplicationContextHolder._getBean_(WebClient.Builder.class);
// 移除的实例列表
List<Instance> removeInstances = instances.stream()
.filter(instance -> !currentInstances.contains(instance))
.collect(Collectors._toList_());
// 新增的实例列表
List<Instance> addInstances = currentInstances.stream()
.filter(instance -> !instances.contains(instance))
.collect(Collectors._toList_());
// 删除McpSyncClient实例
List<String> clientInfoNames = removeInstances.stream()
.map(instance -> connectedClientName(commonProperties.getName(),
this.serviceName + "-" + instance.getInstanceId()))
.toList();
Iterator<McpSyncClient> iterator = mcpSyncClientList.iterator();
while (iterator.hasNext()) {
McpSyncClient mcpSyncClient = iterator.next();
McpSchema.Implementation clientInfo = mcpSyncClient.getClientInfo();
if (clientInfoNames.contains(clientInfo.name())) {
_logger_.info("Removing McpsyncClient: {}", clientInfo.name());
if (mcpSyncClient.closeGracefully()) {
iterator.remove();
}
else {
_logger_.warn("Failed to remove mcpSyncClient: {}", clientInfo.name());
}
}
}
// 新增McpSyncClient实例
McpSyncClient syncClient;
for (Instance instance : addInstances) {
String baseUrl = instance.getMetadata().getOrDefault("scheme", "http") + "://" + instance.getIp() + ":"
+ instance.getPort();
WebClient.Builder webClientBuilder = webClientBuilderTemplate.clone().baseUrl(baseUrl);
WebFluxSseClientTransport transport = new WebFluxSseClientTransport(webClientBuilder, objectMapper);
NamedClientMcpTransport namedTransport = new NamedClientMcpTransport(
serviceName + "-" + instance.getInstanceId(), transport);
McpSchema.Implementation clientInfo = new McpSchema.Implementation(
this.connectedClientName(commonProperties.getName(), namedTransport.name()),
commonProperties.getVersion());
McpClient.SyncSpec syncSpec = McpClient._sync_(namedTransport.transport())
.clientInfo(clientInfo)
.requestTimeout(commonProperties.getRequestTimeout());
syncSpec = mcpSyncClientConfigurer.configure(namedTransport.name(), syncSpec);
syncClient = syncSpec.build();
if (commonProperties.isInitialized()) {
syncClient.initialize();
}
_logger_.info("Added McpAsyncClient: {}", clientInfo.name());
mcpSyncClientList.add(syncClient);
}
this.instances = currentInstances;
}
private String connectedClientName(String clientName, String serverConnectionName) {
return clientName + " - " + serverConnectionName;
}
public static Builder builder() {
return new Builder();
}
public static class Builder {
private String serviceName;
private List<McpSyncClient> mcpSyncClientList;
private NamingService namingService;
public Builder serviceName(String serviceName) {
this.serviceName = serviceName;
return this;
}
public Builder mcpSyncClientList(List<McpSyncClient> mcpSyncClientList) {
this.mcpSyncClientList = mcpSyncClientList;
return this;
}
public Builder namingService(NamingService namingService) {
this.namingService = namingService;
return this;
}
public LoadbalancedMcpSyncClient build() {
return new LoadbalancedMcpSyncClient(this.serviceName, this.mcpSyncClientList, this.namingService);
}
}
}
工具类
ApplicationContextHolder
java
@Component
public class ApplicationContextHolder implements ApplicationContextAware {
private static ApplicationContext _applicationContext_;
@Override
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
ApplicationContextHolder._applicationContext _= applicationContext;
}
public static <T> T getBean(Class<T> clazz) {
return _applicationContext_.getBean(clazz);
}
}
效果演示
我在 nacos 中,注册了 MCP Server 服务,部署两个节点
- 同一台机器以不同端口号启动的 MCP Server 服务,分别是 19000、19001,注册在 Nacos 中以 mcp-server-provider 为服务名

yml 配置如下
yaml
server:
port: 8080
spring:
application:
name: mcp-client-webflux
_ _ai:
alibaba:
mcp:
nacos:
enabled: true
server-addr: 127.0.0.1:8848
username: nacos
password: nacos
client:
sse:
connections:
nacos-server1: mcp-server-provider
mcp:
client:
enabled: true
name: mcp-client-webflux
version: 0.0.1
initialized: true
request-timeout: 600s
nacos-enabled: true
我们能发现已经成功注入 LoadbalancedMcpSyncClient 类,其中 mcp-server-provider 有两个实例,对应的两个 McpSyncClient

我们停掉其中的 MCP Server19001 端口的服务,通过 removeInstances 获取移除的实例列表,同步在 mcpSyncClientList 移除对应的 McpSyncClient

我们再新启动 MCP Server19001 端口的服务,通过 addInstances 获取新增的实例列表,同步在 mcpSyncClientList 新增对应的 McpSyncClient
