Echo Authorization Debugging

When implementing authorization in your Echo framework applications, you'll inevitably encounter situations where permissions don't behave as expected. In this guide, we'll explore comprehensive debugging techniques to help you identify and resolve authorization issues in your Echo applications.

Introduction to Authorization Debugging

Authorization debugging involves investigating why users can or cannot access certain resources in your application. It requires understanding the flow of authentication, authorization middleware, and how permission checks are executed in your Echo routes.

Common authorization issues include:

• Users unable to access resources they should have permission for
• Unauthorized users accessing protected resources
• Middleware not correctly validating tokens or credentials
• Role-based permissions not functioning as expected

Setting Up Debugging Tools

Before diving into debugging, let's set up some essential tools to help us identify issues:

1. Enable Echo Debug Logging

Echo has built-in logging capabilities that can be configured to output detailed information:

go

e := echo.New()
e.Debug = true
e.Logger.SetLevel(log.DEBUG)

This configuration enables verbose output of Echo's internal operations, including middleware execution.

2. Create a Custom Authorization Logger

We can implement a custom middleware to log authorization-related information:

go

func AuthDebugMiddleware(next echo.HandlerFunc) echo.HandlerFunc {
    return func(c echo.Context) error {
        // Log request info
        fmt.Printf("Auth Debug: Request to %s\n", c.Request().URL)
        
        // Extract authorization header if exists
        authHeader := c.Request().Header.Get("Authorization")
        if authHeader != "" {
            fmt.Printf("Auth Debug: Authorization header present: %s\n", 
                       authHeader[:10] + "...")
        } else {
            fmt.Printf("Auth Debug: No Authorization header\n")
        }
        
        // Log user from context if exists
        if user := c.Get("user"); user != nil {
            fmt.Printf("Auth Debug: User in context: %+v\n", user)
        }
        
        return next(c)
    }
}

Apply this middleware globally or to specific routes:

go

e.Use(AuthDebugMiddleware)
// Or for specific group
adminGroup := e.Group("/admin")
adminGroup.Use(AuthDebugMiddleware)

Common Authorization Issues and Debugging Techniques

Issue 1: JWT Token Validation Problems

One of the most common authorization issues involves JWT token validation.

Debugging Steps:

1. Inspect the token itself:

go

func inspectJWTToken(tokenString string) {
    // Remove "Bearer " prefix if present
    tokenString = strings.TrimPrefix(tokenString, "Bearer ")
    
    // Split the token into parts
    parts := strings.Split(tokenString, ".")
    if len(parts) != 3 {
        fmt.Println("Invalid JWT format")
        return
    }
    
    // Decode header
    headerJSON, _ := base64.RawURLEncoding.DecodeString(parts[0])
    fmt.Printf("Header: %s\n", headerJSON)
    
    // Decode payload
    payloadJSON, _ := base64.RawURLEncoding.DecodeString(parts[1])
    fmt.Printf("Payload: %s\n", payloadJSON)
    
    fmt.Println("Signature: [omitted]")
}

2. Create a middleware that checks token expiration explicitly:

go

func TokenExpirationDebugMiddleware(next echo.HandlerFunc) echo.HandlerFunc {
    return func(c echo.Context) error {
        tokenString := c.Request().Header.Get("Authorization")
        tokenString = strings.TrimPrefix(tokenString, "Bearer ")
        
        token, _ := jwt.Parse(tokenString, func(t *jwt.Token) (interface{}, error) {
            return []byte("your-secret-key"), nil
        })
        
        if claims, ok := token.Claims.(jwt.MapClaims); ok {
            if exp, exists := claims["exp"]; exists {
                expTime := time.Unix(int64(exp.(float64)), 0)
                fmt.Printf("Token expires at: %v (in %v)\n", 
                           expTime, time.Until(expTime))
                
                if time.Until(expTime) <= 0 {
                    fmt.Println("DEBUG: Token is expired!")
                }
            } else {
                fmt.Println("DEBUG: No expiration claim found in token")
            }
        }
        
        return next(c)
    }
}

Issue 2: Role-Based Access Control Debugging

If your permissions are role-based, you need to verify the correct roles are assigned and checked.

Debugging Steps:

1. Create a middleware to log user roles:

go

func RoleDebugMiddleware(next echo.HandlerFunc) echo.HandlerFunc {
    return func(c echo.Context) error {
        // Assume user and roles are stored in context after authentication
        user := c.Get("user")
        if user != nil {
            // This will vary based on how you structure your user data
            if userData, ok := user.(map[string]interface{}); ok {
                if roles, exists := userData["roles"]; exists {
                    fmt.Printf("User roles: %v\n", roles)
                } else {
                    fmt.Println("No roles found for authenticated user")
                }
            }
        } else {
            fmt.Println("No user found in context")
        }
        
        return next(c)
    }
}

2. Test endpoint with explicit role checks:

go

// Role-checking handler for debugging
e.GET("/debug/check-admin", func(c echo.Context) error {
    user := c.Get("user")
    if user == nil {
        return c.JSON(http.StatusUnauthorized, map[string]string{
            "error": "No user in context",
        })
    }
    
    userData := user.(map[string]interface{})
    roles, exists := userData["roles"].([]string)
    if !exists {
        return c.JSON(http.StatusInternalServerError, map[string]string{
            "error": "User has no roles attribute",
        })
    }
    
    hasAdminRole := false
    for _, role := range roles {
        if role == "admin" {
            hasAdminRole = true
            break
        }
    }
    
    return c.JSON(http.StatusOK, map[string]interface{}{
        "has_admin_role": hasAdminRole,
        "all_roles": roles,
    })
})

Issue 3: Middleware Execution Order

Authorization bugs can arise from incorrect middleware ordering. Echo middlewares execute in the order they're added.

Debugging Steps:

1. Implement a middleware to trace execution order:

go

func MiddlewareTracingMiddleware(name string) echo.MiddlewareFunc {
    return func(next echo.HandlerFunc) echo.HandlerFunc {
        return func(c echo.Context) error {
            fmt.Printf("⏱️ Entering middleware: %s\n", name)
            err := next(c)
            fmt.Printf("⏱️ Exiting middleware: %s\n", name)
            return err
        }
    }
}

Apply it to understand execution flow:

go

e := echo.New()
e.Use(MiddlewareTracingMiddleware("Global"))
e.Use(middleware.Logger())
e.Use(MiddlewareTracingMiddleware("Authentication"))
e.Use(AuthenticationMiddleware)
e.Use(MiddlewareTracingMiddleware("Authorization"))
e.Use(AuthorizationMiddleware)

Real-world Debugging Example

Let's walk through a complete example debugging an authorization issue in an Echo application.

Scenario: Admin User Unable to Access Admin Dashboard

Step 1: Create a debugging endpoint

go

// Add this temporary endpoint for debugging
e.GET("/debug/auth-check", func(c echo.Context) error {
    // 1. Check if authorization header is present
    authHeader := c.Request().Header.Get("Authorization")
    if authHeader == "" {
        return c.JSON(http.StatusBadRequest, map[string]string{
            "error": "No Authorization header provided",
        })
    }
    
    // 2. Extract and basic-validate token format
    tokenString := strings.TrimPrefix(authHeader, "Bearer ")
    parts := strings.Split(tokenString, ".")
    if len(parts) != 3 {
        return c.JSON(http.StatusBadRequest, map[string]string{
            "error": "Invalid JWT format",
        })
    }
    
    // 3. Parse JWT without verification (for debugging only!)
    token, _ := jwt.Parse(tokenString, func(t *jwt.Token) (interface{}, error) {
        return nil, nil // Skip verification for debugging
    })
    
    // 4. Extract and return claims
    var debugInfo = map[string]interface{}{
        "header": token.Header,
        "claims": token.Claims,
        "token_format_valid": len(parts) == 3,
    }
    
    return c.JSON(http.StatusOK, debugInfo)
})

Step 2: Add context dumping middleware to the admin routes

go

adminGroup := e.Group("/admin")
adminGroup.Use(func(next echo.HandlerFunc) echo.HandlerFunc {
    return func(c echo.Context) error {
        fmt.Println("--- Admin Route Context Dump ---")
        fmt.Printf("User in context: %+v\n", c.Get("user"))
        fmt.Printf("Roles in context: %+v\n", c.Get("roles"))
        fmt.Println("-------------------------------")
        return next(c)
    }
})

Step 3: Test your actual authorization middleware logic separately

go

// Temporary endpoint to test only the authorization logic
e.GET("/debug/test-admin-auth", AuthenticationMiddleware, func(c echo.Context) error {
    user := c.Get("user")
    if user == nil {
        return c.String(http.StatusInternalServerError, "Authentication middleware did not set user")
    }
    
    // Extract user data based on your application's structure
    userData := user.(*models.User) // Adjust based on your user type
    
    // Test the exact authorization logic used in your admin middleware
    if !userData.HasRole("admin") {
        return c.String(http.StatusForbidden, 
            fmt.Sprintf("User lacks admin role. Roles: %v", userData.Roles))
    }
    
    return c.String(http.StatusOK, "✅ User has admin rights")
})

Common Fixes for Authorization Issues

Based on debugging results, here are common fixes:

1. Expired tokens:

   go

   // Increase token expiration time in your issuing logic
   token := jwt.NewWithClaims(jwt.SigningMethodHS256, jwt.MapClaims{
       "sub": user.ID,
       "roles": user.Roles,
       "exp": time.Now().Add(24 * time.Hour).Unix(), // Increase from 1h to 24h
   })

2. Missing user roles:

   go

   // Ensure roles are included in the token
   token := jwt.NewWithClaims(jwt.SigningMethodHS256, jwt.MapClaims{
       "sub": user.ID,
       "name": user.Name,
       "roles": user.Roles, // Make sure this is included!
       "exp": time.Now().Add(time.Hour).Unix(),
   })

3. Incorrect middleware order:

   go

   // Correct order: first authenticate, then authorize
   e.Use(AuthenticationMiddleware) // First authenticate
   adminGroup := e.Group("/admin")
   adminGroup.Use(RequireAdminMiddleware) // Then check for admin role

Advanced Authorization Debugging Techniques

1. HTTP Request Tracing

For complex authorization flows, trace the HTTP requests:

go

func RequestTracingMiddleware(next echo.HandlerFunc) echo.HandlerFunc {
    return func(c echo.Context) error {
        req := c.Request()
        requestID := uuid.New().String()
        
        // Log start of request
        fmt.Printf("[%s] %s %s - started\n", requestID, req.Method, req.URL.Path)
        
        // Start timer
        start := time.Now()
        
        // Process request
        err := next(c)
        
        // Log end of request
        elapsed := time.Since(start)
        fmt.Printf("[%s] %s %s - completed in %v with status %d\n", 
            requestID, req.Method, req.URL.Path, elapsed, c.Response().Status)
        
        return err
    }
}

2. Create a Temporary Superuser Bypass

During debugging, you may need to temporarily bypass authorization:

go

// DEVELOPMENT USE ONLY - NEVER IN PRODUCTION
func DebugSuperuserMiddleware(next echo.HandlerFunc) echo.HandlerFunc {
    return func(c echo.Context) error {
        // Check for a special debug header
        if c.Request().Header.Get("X-Debug-Superuser") == "your-secret-key" {
            // Create superuser and inject into context
            debugUser := &models.User{
                ID: "debug-user",
                Name: "Debugging Superuser",
                Email: "[email protected]",
                Roles: []string{"admin", "superuser", "debug"},
            }
            c.Set("user", debugUser)
            fmt.Println("⚠️ Debug superuser activated")
        }
        
        return next(c)
    }
}

// Add early in middleware chain ONLY IN DEVELOPMENT
if os.Getenv("APP_ENV") == "development" {
    e.Use(DebugSuperuserMiddleware)
}

Summary

Authorization debugging in Echo applications requires systematic investigation into:

1. The authentication process and token validation
2. Role and permission assignment and checking
3. Middleware execution order
4. Context data propagation through handlers

By using the debugging techniques covered in this guide, you can quickly identify and resolve authorization issues in your Echo applications. Remember to remove or disable any debugging code before deploying to production.

Additional Resources and Exercises

Resources

• Echo Framework Documentation
• JWT Debugging Tools
• Go Authorization Patterns

Exercises

1. Debug token expiration issues: Create a scenario where a token is about to expire, and implement a system to detect and refresh tokens before they expire.

2. Implement role-based debugging: Create a debugging middleware that logs all role checks being performed on a route and why they pass or fail.

3. Build an authorization troubleshooting endpoint: Create a protected /debug/check-permissions endpoint that reports what permissions the current user has and what resources they can access.

4. Debug header-based authorization: Implement and debug a system that uses API keys in headers instead of JWTs, focusing on debugging techniques specific to key-based authentication.

With these techniques and exercises, you'll be well-equipped to handle any authorization debugging challenges in your Echo applications.