middleware.go

package main

import (
	"context"
	"log"
	"time"

	"github.com/modelcontextprotocol/go-sdk/mcp"
)

// createLoggingMiddleware creates an MCP middleware that logs method calls.
func createLoggingMiddleware() mcp.Middleware {
	return func(next mcp.MethodHandler) mcp.MethodHandler {
		return func(
			ctx context.Context,
			method string,
			req mcp.Request,
		) (mcp.Result, error) {
			start := time.Now()
			sessionID := req.GetSession().ID()

			// Log request details.
			log.Printf("[REQUEST] Session: %s | Method: %s",
				sessionID,
				method)

			// Call the actual handler.
			result, err := next(ctx, method, req)

			// Log response details.
			duration := time.Since(start)

			if err != nil {
				log.Printf("[RESPONSE] Session: %s | Method: %s | Status: ERROR | Duration: %v | Error: %v",
					sessionID,
					method,
					duration,
					err)
			} else {
				log.Printf("[RESPONSE] Session: %s | Method: %s | Status: OK | Duration: %v",
					sessionID,
					method,
					duration)
			}

			return result, err
		}
	}
}