In addition to techniques such as circuit breaking, rate limiting can be an effective way to prevent cascading failures in a distributed system. Rate limiting can be effective at preventing spam, protecting against Denial of Service (DoS) attacks, and protecting parts of a system from becoming overloaded by too many simultaneous requests. Typically implemented as either a global or per-client limit, rate limiting is usually part of a proxy or load balancer. In this recipe, we'll use NGINX, a popular open source load balancer, web server, and reverse proxy.
Most rate-limiting implementations use the leaky-bucket algorithm—an algorithm that originated in computer network switches and telecommunications networks. As the name suggests, the leaky-bucket algorithm is based on the metaphor of a bucket with a small leak in it that controls a constant rate. Water...
