CacheStrategy

public enum CacheStrategy

Defines the caching strategy for storage operations.

The cache strategy determines how StorageDelegate manages its in-memory cache in relation to the underlying storage. Each strategy offers different trade-offs between performance, consistency, and resilience.

Available Strategies

CACHE

Priority: Performance

Items are cached in memory when saved. Reads are served from cache when available, providing the fastest possible access.

Use when: Performance is critical and you can tolerate cache-storage inconsistencies on save failures.

NO_CACHE

Priority: Consistency

No caching layer is used. All operations go directly to the underlying storage, ensuring you always have the most recent data from the source of truth.

Use when: You always need fresh data or memory usage is a concern.

CACHE_ON_FAILURE

Priority: Resilience

Cache serves as a fallback mechanism when storage operations fail. On successful operations, fresh data is fetched from storage and cached. Cache is used only when storage is unavailable.

Use when: You need resilience against intermittent failures and can tolerate stale data.

Choosing a Strategy

Use this decision tree:

1. Is storage reliable and always available?

   • Yes → Consider NO_CACHE or CACHE
   • No → Use CACHE_ON_FAILURE

2. Is read performance critical?

   • Yes → Use CACHE
   • No → Consider NO_CACHE or CACHE_ON_FAILURE

3. Must data always be fresh?

   • Yes → Use NO_CACHE
   • No → Use CACHE or CACHE_ON_FAILURE

Thread Safety

All cache strategies are thread-safe through Swift actor isolation.