Shared Policy Backends

MLForm ships in-memory reference implementations and stable interfaces for external backends.

Shared interfaces:

• TransportCacheStore
• SharedRateLimiter
• CircuitBreakerSharedState
• TransportHealthState

All of them are scope-aware. That means your backend should isolate policy state by scope.

Example cache signature:

interface TransportCacheStore {
  get(scope: string, key: string): Promise<TransportCacheEntry | undefined>;
  set(scope: string, key: string, entry: TransportCacheEntry): Promise<void>;
  delete(scope: string, key: string): Promise<void>;
}

Use memory implementations for single-process apps. Use a distributed backend when many workers must share quota, breaker state, or cached responses.