Half-open state.
also: half-open · HALF-OPEN · half openThe circuit breaker's testing state: after the open timeout a trial request goes through; success closes the circuit, failure reopens it.
the two-minute refresher
- Reached from OPEN once the recovery timeout passes.
- Lets one (or a few) trial requests through to the dependency.
- Success → CLOSED and normal traffic; failure → OPEN again, and the timer restarts.
- Admitting only a few probes avoids a thundering herd on a just-recovered service.