Module circuit_breaker 

Circuit breaker state machine and retry middleware.

Circuit breaker

CircuitBreaker tracks per-backend failure counts and transitions through three states:

• Closed — the backend is healthy; failures are counted. When the count reaches failure_threshold the breaker moves to Open.
• Open — the backend is considered unhealthy; all requests are rejected immediately (no TCP connection is attempted). After recovery seconds the breaker moves to HalfOpen.
• HalfOpen — one probe request is let through. On success the breaker closes; on failure it re-opens and the recovery timer resets.

Retry middleware

RetryLayer wraps any Application and re-dispatches the request when the inner app returns one of the configured status codes (default: 502, 503, 504) up to max_retries additional times.

Persistence

CircuitBreaker keeps state in a plain in-process HashMap — a restart (or a deploy) resets every backend back to Closed, so a backend that tripped the breaker moments before a restart looks healthy again immediately, and may cascade failures again before anything notices. RedisCircuitBreaker has the same state machine and the same is_available/record_success/record_failure/reset/state shape, but persists each backend’s state in Redis (via the same hand-rolled RESP client crate::rate_limit::RedisRateLimiter and crate::session::RedisSessionStore use) — surviving a restart, and shared across every rws instance pointed at that Redis server.

Example

use rust_web_server::app::App;
use rust_web_server::core::New;
use rust_web_server::circuit_breaker::RetryLayer;
use rust_web_server::middleware::WithMiddleware;

let app = WithMiddleware::new(App::new())
    .wrap(RetryLayer::new().max_retries(2));

Structs

CircuitBreaker

Per-backend circuit breaker.

RedisCircuitBreaker

Per-backend circuit breaker, persisted in Redis.

RetryLayer

Retry middleware.

Enums

BreakerState

Current state of a single backend’s circuit breaker.

Functions

global

Return the process-wide default circuit breaker (threshold=5, recovery=30 s).