sqlite-cache

SQLite-based on-disk cache for Rust.

Usage

let cache = Cache::new(
    CacheConfig::default(),
    rusqlite::Connection::open_in_memory().unwrap(),
).unwrap();
let topic = cache.topic("test-topic").unwrap();
assert!(topic.get("hello").unwrap().is_none());
topic.set("hello", b"world", Duration::from_secs(60))
assert!(&topic.get("hello").unwrap().unwrap().data[..] == b"world");

Locked updates

This library supports locked updates to prevent the thundering herd problem on cache misses. The get_for_update API acquires a per-key lock and returns a KeyUpdater; subsequent get_for_update calls on the same key will block until the previous KeyUpdater is dropped.

let (updater, current_value) = topic.get_for_update("hello").await.unwrap();
let new_value = expensive_computation(current_value).await;
updater.write(new_value, Duration::from_secs(60)).unwrap();