circuit-breaker

Introduction In distributed systems, cascading failures are one of the most devastating failure modes. When a downstream service becomes slow or unresponsive, upstream services can exhaust their resources waiting for responses, causing a domino effect that brings down entire systems. The 2017 AWS S3 outage, which cascaded across multiple services and lasted nearly four hours, demonstrated how a single service failure can ripple through interconnected systems. Circuit breakers act as automatic safety switches that prevent cascading failures by detecting when a service is unhealthy and temporarily blocking requests to it.

In today’s distributed systems landscape, services are interconnected through complex networks of API calls, database queries, and external service dependencies. When one service experiences issues, it can create a cascading failure that brings down entire systems. This is where the Circuit Breaker pattern becomes invaluable—acting as a protective mechanism that prevents failing services from overwhelming the entire system. The Circuit Breaker pattern, inspired by electrical circuit breakers, monitors service calls and “trips” when failures exceed a certain threshold, temporarily blocking requests to give the failing service time to recover.