Struct TieredCache 

pub struct TieredCache { /* private fields */ }

Multi-level cache with automatic promotion.

Checks tiers in order: Memory → Local → (Remote, future). On a hit in a lower tier, promotes the entry to faster tiers.

Implementations

impl TieredCache

pub fn new(tiers: Vec<(CacheTier, Box<dyn CacheStore>)>) -> Self

Create a tiered cache from a list of (tier, store) pairs. Tiers should be ordered fastest-first.

pub fn memory_and_local( memory: Box<dyn CacheStore>, local: Box<dyn CacheStore>, ) -> Self

Create a two-level cache: Memory + Local.

Trait Implementations

impl CacheStore for TieredCache

fn tier(&self) -> CacheTier

The fastest tier — what a caller reaches first.

fn get_located(&self, key: &CacheKey) -> Result<Option<(Value, CacheTier)>>

Which tier answered is the number that says whether the slower tiers are earning their keep, so it is reported rather than flattened into “the cache was used”.

fn get(&self, key: &CacheKey) -> Result<Option<Value>>

Look up the value stored under key, None on a miss.

fn put(&self, key: &CacheKey, value: &Value) -> Result<()>

Store value under key, replacing any existing entry.

fn put_with_origin( &self, key: &CacheKey, value: &Value, origin: &Origin, ) -> Result<()>

Store a value together with its provenance. Stores that persist metadata should override this; the default discards the origin.

fn exists(&self, key: &CacheKey) -> Result<bool>

Whether key has an entry, without loading the value.

fn remove(&self, key: &CacheKey) -> Result<()>

Delete the entry under key; absent keys are not an error.

fn metadata(&self, key: &CacheKey) -> Result<Option<EntryMeta>>

The entry’s EntryMeta, without loading the value.

fn put_computed( &self, key: &CacheKey, value: &Value, origin: &Origin, compute: Duration, deterministic: bool, ) -> Result<(), SomaError>

Store a freshly-computed value with its full provenance record: origin, wall-clock compute cost, and the producer’s determinism declaration. Cost-aware eviction needs the compute time — a tiny value that took days must outlive a huge one that took seconds. The default discards the extra metadata.