locker

Overview ¶

Package locker provides rate limiting and attempt counting with Redis storage.

It's useful for limiting login attempts, API rate limiting, or any scenario where you need to track and limit the number of operations within a time window.

Hertz Backend Setup ¶

// Initialize locker with Redis client
lock := locker.New(redisClient)

// Login endpoint with attempt limiting
h.POST("/auth/login", func(ctx context.Context, c *app.RequestContext) {
	username := c.Query("username")
	lockKey := "login:" + username

	// Check if already locked (max 5 attempts)
	if err := lock.Check(ctx, lockKey, 5); err != nil {
		if errors.Is(err, locker.ErrLocked) {
			c.JSON(429, utils.H{"error": "too many attempts, try again later"})
			return
		}
	}

	// Validate credentials...
	if !validCredentials {
		// Increment attempt counter (5 minute window)
		lock.Increment(ctx, lockKey, 5*time.Minute)
		c.JSON(401, utils.H{"error": "invalid credentials"})
		return
	}

	// Success - clear the counter
	lock.Delete(ctx, lockKey)
	c.JSON(200, utils.H{"token": token})
})

How It Works ¶

• Increment: Atomically increments counter, sets TTL on first call
• Check: Returns ErrLocked if counter >= max
• Delete: Clears the counter (e.g., after successful login)

Security Notes ¶

• Use appropriate TTL based on your security requirements
• Consider using IP + username combination for login limiting
• The counter auto-expires after TTL, no manual cleanup needed