refactor: migrate MCP SDK to main repo (#3516)

plugins/wasm-go/pkg/mcp/server/composed_server.go

@@ -0,0 +1,127 @@
+package server
+
+import (
+	"fmt"
+
+	"github.com/higress-group/wasm-go/pkg/log"
+	"github.com/alibaba/higress/plugins/wasm-go/pkg/mcp/consts"
+)
+
+// ComposedMCPServer represents a server composed of tools from other servers.
+type ComposedMCPServer struct {
+	name        string              // Name of the composed server (from toolSet.name)
+	serverTools []ServerToolConfig  // Configuration of which tools to include
+	registry    *GlobalToolRegistry // Reference to the global tool registry
+	config      []byte              // Configuration for the composed server itself (if any)
+}
+
+// NewComposedMCPServer creates a new ComposedMCPServer.
+func NewComposedMCPServer(name string, serverToolsConfig []ServerToolConfig, registry *GlobalToolRegistry) *ComposedMCPServer {
+	return &ComposedMCPServer{
+		name:        name,
+		serverTools: serverToolsConfig,
+		registry:    registry,
+	}
+}
+
+// GetName returns the name of the composed server.
+func (cs *ComposedMCPServer) GetName() string {
+	return cs.name
+}
+
+// AddMCPTool for ComposedMCPServer is a no-op as tools are defined by toolSet.
+func (cs *ComposedMCPServer) AddMCPTool(name string, tool Tool) Server {
+	log.Warnf("AddMCPTool called on ComposedMCPServer '%s'; this is a no-op.", cs.name)
+	return cs
+}
+
+// GetMCPTools constructs and returns the map of tools exposed by this composed server.
+// The tool names are prefixed with their original server name, e.g., "${originalServer}___${toolName}".
+// The Tool instances are DescriptiveTool, only providing Description and InputSchema.
+func (cs *ComposedMCPServer) GetMCPTools() map[string]Tool {
+	composedTools := make(map[string]Tool)
+	for _, stc := range cs.serverTools {
+		originalServerName := stc.ServerName
+		for _, originalToolName := range stc.Tools {
+			toolInfo, found := cs.registry.GetToolInfo(originalServerName, originalToolName)
+			if !found {
+				log.Warnf("Tool %s/%s not found in global registry for composed server %s", originalServerName, originalToolName, cs.name)
+				continue
+			}
+
+			composedToolName := fmt.Sprintf("%s%s%s", originalServerName, consts.ToolSetNameSplitter, originalToolName)
+			composedTools[composedToolName] = &DescriptiveTool{
+				description:  toolInfo.Description,
+				inputSchema:  toolInfo.InputSchema,
+				outputSchema: toolInfo.OutputSchema, // New field for MCP Protocol Version 2025-06-18
+			}
+		}
+	}
+	return composedTools
+}
+
+// SetConfig sets the configuration for the composed server itself.
+func (cs *ComposedMCPServer) SetConfig(config []byte) {
+	cs.config = config
+}
+
+// GetConfig retrieves the configuration of the composed server itself.
+func (cs *ComposedMCPServer) GetConfig(v any) {
+	if len(cs.config) == 0 {
+		return
+	}
+	if ptrBytes, ok := v.(*[]byte); ok {
+		*ptrBytes = cs.config
+	} else {
+		// If you need to unmarshal to a struct, you'd do it here.
+		// For now, keeping it simple as per previous discussions.
+		log.Warnf("ComposedMCPServer.GetConfig called with unhandled type for v. Config not set.")
+	}
+}
+
+// Clone creates a new instance of the ComposedMCPServer with the same configuration.
+func (cs *ComposedMCPServer) Clone() Server {
+	cloned := NewComposedMCPServer(cs.name, cs.serverTools, cs.registry)
+	cloned.SetConfig(cs.config)
+	return cloned
+}
+
+// DescriptiveTool is a placeholder Tool implementation for ComposedMCPServer.
+// Its Call and Create methods should never be invoked.
+type DescriptiveTool struct {
+	description  string
+	inputSchema  map[string]any
+	outputSchema map[string]any // New field for MCP Protocol Version 2025-06-18
+}
+
+// Create for DescriptiveTool should not be called.
+func (dt *DescriptiveTool) Create(params []byte) Tool {
+	log.Errorf("DescriptiveTool.Create called for tool used in ComposedMCPServer. This should not happen.")
+	// Return a new instance to fulfill the interface, though it's an error state.
+	return &DescriptiveTool{
+		description:  dt.description,
+		inputSchema:  dt.inputSchema,
+		outputSchema: dt.outputSchema,
+	}
+}
+
+// Call for DescriptiveTool should not be called.
+func (dt *DescriptiveTool) Call(httpCtx HttpContext, server Server) error {
+	log.Errorf("DescriptiveTool.Call called for tool used in ComposedMCPServer. This should not happen.")
+	return fmt.Errorf("DescriptiveTool.Call should not be invoked on a ComposedMCPServer's tool")
+}
+
+// Description returns the tool's description.
+func (dt *DescriptiveTool) Description() string {
+	return dt.description
+}
+
+// InputSchema returns the tool's input schema.
+func (dt *DescriptiveTool) InputSchema() map[string]any {
+	return dt.inputSchema
+}
+
+// OutputSchema returns the tool's output schema (MCP Protocol Version 2025-06-18).
+func (dt *DescriptiveTool) OutputSchema() map[string]any {
+	return dt.outputSchema
+}