Similarityoung commented on code in PR #702: URL: https://github.com/apache/dubbo-go-pixiu/pull/702#discussion_r2257120382
########## pkg/filter/mcp/mcpserver/handlers.go: ########## @@ -0,0 +1,560 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You 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 ( + "encoding/json" + "fmt" + "io" + "net/http" + "strings" +) + +import ( + "github.com/mark3labs/mcp-go/mcp" +) + +import ( + "github.com/apache/dubbo-go-pixiu/pkg/client" + "github.com/apache/dubbo-go-pixiu/pkg/common/constant" + "github.com/apache/dubbo-go-pixiu/pkg/common/extension/filter" + "github.com/apache/dubbo-go-pixiu/pkg/logger" + "github.com/apache/dubbo-go-pixiu/pkg/model" +) + +// handleInitialize handles the initialize method +func (f *MCPServerFilter) handleInitialize(ctx *MCPContext, req mcp.JSONRPCRequest) filter.FilterStatus { + // Build server capabilities using mcp-go structures + capabilities := mcp.ServerCapabilities{ + Tools: &struct { + ListChanged bool `json:"listChanged,omitempty"` + }{ + // TODO: Dynamic update capabilities - enable after Nacos integration + // Currently set to false, future Nacos integration will support: + // 1. Dynamic discovery and registration of new backend services + // 2. Automatic generation of corresponding MCP tools + // 3. Send notifications/tools/list_changed notifications + ListChanged: false, + }, + Resources: &struct { + Subscribe bool `json:"subscribe,omitempty"` + ListChanged bool `json:"listChanged,omitempty"` + }{ + Subscribe: false, + ListChanged: false, + }, + Prompts: &struct { + ListChanged bool `json:"listChanged,omitempty"` + }{ + ListChanged: false, + }, + } + + // Build server info using mcp-go structures + serverInfo := mcp.Implementation{ + Name: f.cfg.ServerInfo.Name, + Version: f.cfg.ServerInfo.Version, + } + + // Create initialization result using mcp-go API + instructions := f.cfg.ServerInfo.Instructions + if instructions == "" { + instructions = "This MCP server provides API access through tools, documentation through resources, and AI assistance through prompts." + } + result := mcp.NewInitializeResult(mcp.LATEST_PROTOCOL_VERSION, capabilities, serverInfo, instructions) + + // Create JSON-RPC response + response := f.responseBuilder.Success(req.ID, result) + return f.sendJSONResponse(ctx, response) +} + +// handleToolsList handles the tools/list method using mcp-go APIs +func (f *MCPServerFilter) handleToolsList(ctx *MCPContext, req mcp.JSONRPCRequest) filter.FilterStatus { + tools := make([]mcp.Tool, 0, len(f.cfg.Tools)) + + // Build tools using mcp-go API for standard compliance + for _, toolCfg := range f.cfg.Tools { + // Start with basic tool options + toolOptions := []mcp.ToolOption{ + mcp.WithDescription(toolCfg.Description), + } + + // Add parameter definitions using mcp-go APIs + for _, arg := range toolCfg.Args { + switch arg.Type { + case "string": + opts := []mcp.PropertyOption{mcp.Description(arg.Description)} + if arg.Required { + opts = append(opts, mcp.Required()) + } + if arg.Default != nil { + if defaultStr, ok := arg.Default.(string); ok { + opts = append(opts, mcp.DefaultString(defaultStr)) + } + } + if len(arg.Enum) > 0 { + opts = append(opts, mcp.Enum(arg.Enum...)) + } + toolOptions = append(toolOptions, mcp.WithString(arg.Name, opts...)) + + case "integer", "number": + opts := []mcp.PropertyOption{mcp.Description(arg.Description)} + if arg.Required { + opts = append(opts, mcp.Required()) + } + if arg.Default != nil { + // Handle both int and float64 types from YAML parsing + switch defaultVal := arg.Default.(type) { + case float64: + opts = append(opts, mcp.DefaultNumber(defaultVal)) + case int: + opts = append(opts, mcp.DefaultNumber(float64(defaultVal))) + case int64: + opts = append(opts, mcp.DefaultNumber(float64(defaultVal))) + } + } + toolOptions = append(toolOptions, mcp.WithNumber(arg.Name, opts...)) + + case "boolean": + opts := []mcp.PropertyOption{mcp.Description(arg.Description)} + if arg.Required { + opts = append(opts, mcp.Required()) + } + if arg.Default != nil { + if defaultBool, ok := arg.Default.(bool); ok { + opts = append(opts, mcp.DefaultBool(defaultBool)) + } + } + toolOptions = append(toolOptions, mcp.WithBoolean(arg.Name, opts...)) + } + } + + // Create tool using mcp-go API + tool := mcp.NewTool(toolCfg.Name, toolOptions...) + tools = append(tools, tool) + } + + // Build standard MCP tools list response using mcp-go structures + result := mcp.NewListToolsResult(tools, "") // empty cursor for no pagination + + response := f.responseBuilder.Success(req.ID, result) + return f.sendJSONResponse(ctx, response) +} + +// handleResourcesList handles the resources/list method +func (f *MCPServerFilter) handleResourcesList(ctx *MCPContext, req mcp.JSONRPCRequest) filter.FilterStatus { + // Get all resources + mcpResources, err := f.registry.ToMCPResources() + if err != nil { + logger.Errorf("[dubbo-go-pixiu] mcp server failed to get MCP resources: %v", err) + return f.errorHandler.SendInternalError(ctx, req.ID, "failed to get resources") + } + + // Build resources list response using mcp-go structures + result := mcp.NewListResourcesResult(mcpResources, "") // empty cursor for no pagination + + response := f.responseBuilder.Success(req.ID, result) + return f.sendJSONResponse(ctx, response) +} + +// handlePing handles the ping method +func (f *MCPServerFilter) handlePing(ctx *MCPContext, req mcp.JSONRPCRequest) filter.FilterStatus { + logger.Debugf("[dubbo-go-pixiu] mcp server handling ping request") + + // Simple ping response + result := map[string]any{} + + response := f.responseBuilder.Success(req.ID, result) + return f.sendJSONResponse(ctx, response) +} + +// handleNotificationsInitialized handles notifications/initialized notification +func (f *MCPServerFilter) handleNotificationsInitialized(ctx *MCPContext, req mcp.JSONRPCRequest) filter.FilterStatus { + logger.Debugf("[dubbo-go-pixiu] mcp server received initialized notification from client") + + // Store client initialization state + // This notification indicates that the client has completed initialization + // and is ready to receive requests + + // For notifications, we don't send a response, just return Stop + return filter.Stop +} + +// handleResourceRead handles the resources/read method +func (f *MCPServerFilter) handleResourceRead(ctx *MCPContext, req mcp.JSONRPCRequest) filter.FilterStatus { + logger.Debugf("[dubbo-go-pixiu] mcp server handling resources/read") + + // Parse request parameters + paramsBytes, err := json.Marshal(req.Params) + if err != nil { + logger.Errorf("[dubbo-go-pixiu] mcp server failed to marshal params: %v", err) + return f.errorHandler.SendInvalidParams(ctx, req.ID, "invalid parameters") + } + + var params struct { + URI string `json:"uri"` + } + if err := json.Unmarshal(paramsBytes, ¶ms); err != nil { + logger.Errorf("[dubbo-go-pixiu] mcp server failed to parse resource read params: %v", err) + return f.errorHandler.SendInvalidParams(ctx, req.ID, "invalid parameters") + } + + // Find resource (by URI) + resource, exists := f.registry.GetResourceByURI(params.URI) + if !exists { + logger.Warnf("[dubbo-go-pixiu] mcp server resource not found: %s", params.URI) + return f.errorHandler.SendInternalError(ctx, req.ID, fmt.Sprintf("resource not found: %s", params.URI)) + } + + // Build resource content response + // TODO: Implement actual resource content loading from source + content := fmt.Sprintf("Resource content for %s (source: %s)", resource.URI, resource.Source.Type) + + result := map[string]any{ + "contents": []map[string]any{ + { + "uri": resource.URI, + "mimeType": resource.MIMEType, + "text": content, + }, + }, + } + + response := f.responseBuilder.Success(req.ID, result) + return f.sendJSONResponse(ctx, response) +} + +// handleResourceTemplatesList handles the resources/templates/list method +func (f *MCPServerFilter) handleResourceTemplatesList(ctx *MCPContext, req mcp.JSONRPCRequest) filter.FilterStatus { + // Get all resource templates (parameterized resource patterns) + mcpResourceTemplates, err := f.registry.ToMCPResourceTemplates() + if err != nil { + logger.Errorf("[dubbo-go-pixiu] mcp server failed to get MCP resource templates: %v", err) + return f.errorHandler.SendInternalError(ctx, req.ID, "failed to get resource templates") + } + + // Build resource templates list response + result := map[string]any{ + "resourceTemplates": mcpResourceTemplates, + } + + response := f.responseBuilder.Success(req.ID, result) + return f.sendJSONResponse(ctx, response) +} + +// handlePromptsList handles the prompts/list method +func (f *MCPServerFilter) handlePromptsList(ctx *MCPContext, req mcp.JSONRPCRequest) filter.FilterStatus { + logger.Debugf("[dubbo-go-pixiu] mcp server handling prompts/list request") + + // Get all prompts + mcpPrompts, err := f.registry.ToMCPPrompts() + if err != nil { + logger.Errorf("[dubbo-go-pixiu] mcp server failed to get prompts: %v", err) + return f.errorHandler.SendInternalError(ctx, req.ID, "failed to get prompts") + } + + // Build prompts list response + result := map[string]any{ + "prompts": mcpPrompts, + } + + response := f.responseBuilder.Success(req.ID, result) + return f.sendJSONResponse(ctx, response) +} + +// handlePromptsGet handles the prompts/get method +func (f *MCPServerFilter) handlePromptsGet(ctx *MCPContext, req mcp.JSONRPCRequest) filter.FilterStatus { + logger.Debugf("[dubbo-go-pixiu] mcp server handling prompts/get request") + + // Parse request parameters + paramsBytes, err := json.Marshal(req.Params) + if err != nil { + logger.Errorf("[dubbo-go-pixiu] mcp server failed to marshal params: %v", err) + return f.errorHandler.SendInvalidParams(ctx, req.ID, "invalid parameters") + } + + var params struct { + Name string `json:"name"` + Arguments map[string]any `json:"arguments,omitempty"` + } + if err := json.Unmarshal(paramsBytes, ¶ms); err != nil { + logger.Errorf("[dubbo-go-pixiu] mcp server failed to parse prompts/get params: %v", err) + return f.errorHandler.SendInvalidParams(ctx, req.ID, "invalid parameters") + } + + // Find prompt configuration + promptConfig, exists := f.registry.GetPrompt(params.Name) + if !exists { + logger.Warnf("[dubbo-go-pixiu] mcp server prompt not found: %s", params.Name) + return f.errorHandler.SendInternalError(ctx, req.ID, fmt.Sprintf("prompt not found: %s", params.Name)) + } + + // Build prompt messages with parameter replacement + messages, err := f.buildPromptMessages(promptConfig, params.Arguments) + if err != nil { + logger.Errorf("[dubbo-go-pixiu] mcp server failed to build prompt messages: %v", err) + return f.errorHandler.SendInternalError(ctx, req.ID, "failed to build prompt messages") + } + + // Build prompts/get response + result := map[string]any{ + "description": promptConfig.Description, + "messages": messages, + } + + response := f.responseBuilder.Success(req.ID, result) + return f.sendJSONResponse(ctx, response) +} + +// buildPromptMessages builds prompt messages with parameter replacement support +func (f *MCPServerFilter) buildPromptMessages(promptConfig PromptConfig, arguments map[string]any) ([]map[string]any, error) { + messages := make([]map[string]any, 0, len(promptConfig.Messages)) + + for _, msg := range promptConfig.Messages { + // Replace parameter placeholders in content + content := f.replacePromptArguments(msg.Content, arguments) + + message := map[string]any{ + "role": msg.Role, + "content": content, + } + messages = append(messages, message) + } + + return messages, nil +} + +// replacePromptArguments replaces parameter placeholders in prompt content +func (f *MCPServerFilter) replacePromptArguments(content string, arguments map[string]any) string { + if arguments == nil { + return content + } + + result := content + for key, value := range arguments { + placeholder := fmt.Sprintf("{{%s}}", key) + replacement := fmt.Sprintf("%v", value) + result = strings.ReplaceAll(result, placeholder, replacement) + } + + return result +} + +// handleToolCall handles tool call requests by forwarding to backend +func (f *MCPServerFilter) handleToolCall(ctx *MCPContext, req mcp.JSONRPCRequest) filter.FilterStatus { + // Parse tool call parameters + paramsBytes, err := json.Marshal(req.Params) + if err != nil { + logger.Errorf("[dubbo-go-pixiu] mcp server failed to marshal tool call params: %v", err) + return f.errorHandler.SendInternalError(ctx, req.ID, "invalid tool call parameters") + } + + var params struct { + Name string `json:"name"` + Arguments map[string]any `json:"arguments,omitempty"` + } + if err := json.Unmarshal(paramsBytes, ¶ms); err != nil { + logger.Errorf("[dubbo-go-pixiu] mcp server failed to parse tool call params: %v", err) + return f.errorHandler.SendInvalidParams(ctx, req.ID, "invalid tool call parameters") + } + + // Find tool configuration + toolConfig, exists := f.registry.GetTool(params.Name) + if !exists { + logger.Warnf("[dubbo-go-pixiu] mcp server tool not found: %s", params.Name) + return f.errorHandler.SendToolCallError(ctx, req.ID, fmt.Sprintf("tool not found: %s", params.Name)) + } + + // Build backend request + err = f.buildBackendRequest(ctx, toolConfig, params.Arguments) + if err != nil { + logger.Errorf("[dubbo-go-pixiu] mcp server failed to build backend request: %v", err) + return f.errorHandler.SendToolCallError(ctx, req.ID, "failed to build backend request") + } + + // Set cluster information for routing + if ctx.Params == nil { + ctx.Params = make(map[string]any) + } + + logger.Infof("[dubbo-go-pixiu] mcp server forwarding tool call: %s -> %s %s (cluster: %s)", + params.Name, toolConfig.Request.Method, ctx.Request.URL.Path, toolConfig.Cluster) + + // Store MCP data for Encode stage processing + ctx.StoreMCPDataInParams() + + ctx.Route = &model.RouteAction{ + Cluster: toolConfig.Cluster, + } + + // Continue to next filter for backend forwarding + return filter.Continue +} + +// buildBackendRequest builds the complete backend request including path, body, and headers +func (f *MCPServerFilter) buildBackendRequest(ctx *MCPContext, toolConfig ToolConfig, arguments map[string]any) error { + // Set HTTP method + ctx.Request.Method = toolConfig.Request.Method + + // Build request path and body based on argument locations + path := toolConfig.Request.Path + bodyParams := make(map[string]any) + queryParams := make(map[string]string) + + // Process arguments based on their location (path, query, body) + if arguments != nil { + for argName, argValue := range arguments { + // Find argument configuration + var argConfig *ArgConfig + for _, arg := range toolConfig.Args { + if arg.Name == argName { + argConfig = &arg + break + } + } + + if argConfig == nil { + continue // Skip unknown arguments + } + + switch argConfig.In { + case "path": Review Comment: done ########## pkg/filter/mcp/mcpserver/handlers.go: ########## @@ -0,0 +1,560 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You 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 ( + "encoding/json" + "fmt" + "io" + "net/http" + "strings" +) + +import ( + "github.com/mark3labs/mcp-go/mcp" +) + +import ( + "github.com/apache/dubbo-go-pixiu/pkg/client" + "github.com/apache/dubbo-go-pixiu/pkg/common/constant" + "github.com/apache/dubbo-go-pixiu/pkg/common/extension/filter" + "github.com/apache/dubbo-go-pixiu/pkg/logger" + "github.com/apache/dubbo-go-pixiu/pkg/model" +) + +// handleInitialize handles the initialize method +func (f *MCPServerFilter) handleInitialize(ctx *MCPContext, req mcp.JSONRPCRequest) filter.FilterStatus { + // Build server capabilities using mcp-go structures + capabilities := mcp.ServerCapabilities{ + Tools: &struct { + ListChanged bool `json:"listChanged,omitempty"` + }{ + // TODO: Dynamic update capabilities - enable after Nacos integration + // Currently set to false, future Nacos integration will support: + // 1. Dynamic discovery and registration of new backend services + // 2. Automatic generation of corresponding MCP tools + // 3. Send notifications/tools/list_changed notifications + ListChanged: false, + }, + Resources: &struct { + Subscribe bool `json:"subscribe,omitempty"` + ListChanged bool `json:"listChanged,omitempty"` + }{ + Subscribe: false, + ListChanged: false, + }, + Prompts: &struct { + ListChanged bool `json:"listChanged,omitempty"` + }{ + ListChanged: false, + }, + } + + // Build server info using mcp-go structures + serverInfo := mcp.Implementation{ + Name: f.cfg.ServerInfo.Name, + Version: f.cfg.ServerInfo.Version, + } + + // Create initialization result using mcp-go API + instructions := f.cfg.ServerInfo.Instructions + if instructions == "" { + instructions = "This MCP server provides API access through tools, documentation through resources, and AI assistance through prompts." + } + result := mcp.NewInitializeResult(mcp.LATEST_PROTOCOL_VERSION, capabilities, serverInfo, instructions) + + // Create JSON-RPC response + response := f.responseBuilder.Success(req.ID, result) + return f.sendJSONResponse(ctx, response) +} + +// handleToolsList handles the tools/list method using mcp-go APIs +func (f *MCPServerFilter) handleToolsList(ctx *MCPContext, req mcp.JSONRPCRequest) filter.FilterStatus { + tools := make([]mcp.Tool, 0, len(f.cfg.Tools)) + + // Build tools using mcp-go API for standard compliance + for _, toolCfg := range f.cfg.Tools { + // Start with basic tool options + toolOptions := []mcp.ToolOption{ + mcp.WithDescription(toolCfg.Description), + } + + // Add parameter definitions using mcp-go APIs + for _, arg := range toolCfg.Args { + switch arg.Type { + case "string": Review Comment: done -- This is an automated message from the Apache Git Service. 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