Sliding Window Log

Parameters

• capacity, threshold

Description

• Maintains a log of timestamps for each request, providing an exact count within the sliding window.
• Enables accurate rate limiting by considering the exact timing of requests.
• Suitable for scenarios where maintaining an accurate request count is crucial.

Example: windowSize = 1 min, maxRequests = 5.

• T0 (01:00:00): Window starts, request log is empty.
• T1 (01:00:10): 2 requests arrive, timestamps [01:00:10, 01:00:10] logged.
• T2 (01:00:20): 3 requests arrive, timestamps [01:00:20, 01:00:20, 01:00:20] logged.
• T3 (01:00:30): 1 request arrives, timestamp [01:00:30] logged. But the window is full, so the request is dropped.
• T4 (01:01:20): Now the logs before 01:00:20 are cleared, and the new request is allowed. Because the window is sliding, and the window has room for more requests.

How to use

When creating your API, you can use the RateLimitFactory to create a leaking bucket rate limit.

Api.create(8080)
      .rateLimit(RateLimitFactory.customSlidingWindowLog(4, Duration.ofSeconds(1)))
      .addRoute(Route.builder("/"),
      .path(RouteMethod.GET, "/", controller::handler))
      .start();
          

Factory

The RateLimitFactory provides a default and a custom method for this rate limiter.

• For more details on the check the source code of the RateLimitFactory

See more in our blog post about Rate Limiters