Cache

The Cache component provides an async-safe in-memory LRU cache with per-key atomicity. It prevents cache stampedes in concurrent fiber environments - if two fibers request the same key simultaneously, only one computes the value while the other waits.

Basic Usage

compute() is the primary API - get a cached value or compute it if absent. update() always recomputes, receiving the old value.

@example('other/cache-basic.php')

Async Safety

Operations on the same key are serialized via KeyedSequence. Different keys run in parallel with no blocking.

@example('other/cache-async.php')

LRU Eviction

LocalStore maintains a bounded cache with configurable maximum size. When full, the least recently used entry is evicted. Accessed entries are promoted to most-recently-used.

TTL Expiration

Entries with a TTL are proactively cleaned up via an event loop timer, not lazily on access. The timer activates when TTL'd entries exist and disables itself when none remain, adding zero overhead when no entries have expiration.

NullStore

NullStore implements StoreInterface but never caches - every compute() invokes the computer, every get() throws. Useful for testing or disabling caching without changing calling code.

See src/Psl/Cache/ for the full API.