Struct CircuitBreaker 

pub struct CircuitBreaker { /* private fields */ }

Per-backend circuit breaker.

Concurrency

CircuitBreaker is not Sync on its own — wrap it in a Mutex for shared use across threads (see global()).

Implementations

impl CircuitBreaker

pub fn new(failure_threshold: u32, recovery_secs: u64) -> Self

Create a new circuit breaker.

• failure_threshold — how many consecutive failures open the circuit.
• recovery_secs — how long the circuit stays Open before testing again.

Defaults to letting exactly one probe through while HalfOpen — see CircuitBreaker::max_half_open_probes to change that.

pub fn max_half_open_probes(self, n: u32) -> Self

Override how many concurrent probe requests are let through while a backend is HalfOpen (default: 1). Chainable — call before the breaker is put behind a shared Mutex/Arc.

pub fn is_available(&mut self, backend: &str) -> bool

Returns true if a request should be forwarded to backend.

Transitions Open → HalfOpen when the recovery window has elapsed. While HalfOpen, at most max_half_open_probes concurrent calls return true — further calls are rejected like Open until the in-flight probe(s) resolve via record_success/record_failure.

pub fn record_success(&mut self, backend: &str)

Record a successful response for backend.

Transitions HalfOpen → Closed and resets the failure counter and the in-flight half-open probe count.

pub fn record_failure(&mut self, backend: &str)

Record a failed response for backend.

In Closed state, increments the counter and opens the circuit when failure_threshold is reached. In HalfOpen state, immediately re-opens the circuit and resets the recovery timer.

pub fn reset(&mut self, backend: &str)

Reset backend to Closed with zero failures.

pub fn state(&self, backend: &str) -> BreakerState

Return the current state for backend (defaults to Closed if unseen).

pub fn all_states(&self) -> Vec<(String, BreakerState)>

Snapshot of every backend this breaker has ever seen, with its current state. Powers the rws_circuit_breaker_state{backend} metric (crate::metrics::prometheus_text) — there is no RedisCircuitBreaker equivalent, since enumerating keys isn’t something the minimal hand-rolled RESP client supports (no SCAN/KEYS array-reply decoding).