Spring Boot Tutorial 0/110 lessons ~6 min read Lesson 61“Production-grade backends”

Rate Limiting

Rate limiting protects your service from abuse, runaway clients, and the occasional internal bug-loop.

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Focus

2 guided sections

Practice signal

Examples included

Career prep

Foundation builder

Introduction

Rate limiting protects your service from abuse, runaway clients, and the occasional internal bug-loop. The simplest viable algorithm: token bucket in Redis.

Informative example

Bucket4j + Redis (in-app fallback when no gateway):

@Component @RequiredArgsConstructor
public class RateLimitFilter extends OncePerRequestFilter {
  private final ProxyManager<String> buckets;

  protected void doFilterInternal(HttpServletRequest req, HttpServletResponse res, FilterChain chain)
      throws IOException, ServletException {
    String key = req.getHeader("X-Api-Key");
    Bucket bucket = buckets.builder().build(key,
        () -> BucketConfiguration.builder()
            .addLimit(Bandwidth.classic(100, Refill.intervally(100, Duration.ofMinutes(1))))
            .build());

    if (bucket.tryConsume(1)) {
      chain.doFilter(req, res);
    } else {
      res.setStatus(429);
      res.getWriter().write("{\"error\":\"rate_limited\"}");
    }
  }
}

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