Failure Handling

Circuit Breakers as Admission Control for Failing Dependencies

Circuit Breakers as Admission Control for Failing Dependencies A remote call that has little chance of succeeding still consumes something: a connection slot, a worker, a deadline budget, memory for request state, or capacity in the dependency itself. When repeated failures indicate that a downstream service is currently unable to serve useful work, continuing to admit every call can preserve the very pressure that callers need to escape. A circuit breaker changes that admission decision. Instead of treating each call as independent, it retains a small amount of state about recent outcomes. That state can temporarily reject new calls before network I/O begins, then permit controlled probes after a recovery interval.