AwsEncryptionSdk.Cache.CryptographicMaterialsCache behaviour (AWS Encryption SDK v0.7.0)

Behaviour for Cryptographic Materials Cache implementations.

The CMC provides a caching layer for cryptographic materials, allowing the Caching CMM to reuse data keys across multiple encryption operations.

Spec Reference

cache()

Cache implementation module or process reference

cache_id()

48-byte SHA-384 cache identifier

Removes a cache entry.

Retrieves a cache entry.

Stores a cache entry.

Updates usage statistics for a cache entry.

@type cache() :: module() | pid() | atom()

Cache implementation module or process reference

@type cache_id() :: binary()

48-byte SHA-384 cache identifier

@callback delete_cache_entry(cache(), cache_id()) :: :ok

Removes a cache entry.

This operation MUST succeed even if no entry exists for the cache ID.

@callback get_cache_entry(cache(), cache_id()) ::
  {:ok, AwsEncryptionSdk.Cache.CacheEntry.t()} | {:error, :cache_miss}

Retrieves a cache entry.

Returns {:ok, entry} if found and not expired, {:error, :cache_miss} otherwise. Expired entries MUST NOT be returned and SHOULD be removed.

@callback put_cache_entry(cache(), cache_id(), AwsEncryptionSdk.Cache.CacheEntry.t()) ::
  :ok

Stores a cache entry.

If an entry with the given cache ID already exists, it MUST be replaced. This operation MUST NOT return the inserted entry.

@callback update_usage(cache(), cache_id(), pos_integer(), non_neg_integer()) ::
  :ok | {:error, :cache_miss}

Updates usage statistics for a cache entry.

Increments messages_used and bytes_used counters atomically. Returns {:error, :cache_miss} if entry doesn't exist.