Struct ExpiringCache

pub struct ExpiringCache<T, E> { /* private fields */ }

Expiry-aware cache

ExpiringCache implements two important features:

1. Respect expiry of contents
2. Deduplicate load requests to prevent thundering herds when no value is present.

Implementations

impl<T, E> ExpiringCache<T, E>

where T: Clone,

pub fn new(buffer_time: Duration) -> Self

Creates ExpiringCache with the given buffer_time.

pub async fn get_or_load<F, Fut>(&self, f: F) -> Result<T, E>

where F: FnOnce() -> Fut, Fut: Future<Output = Result<(T, SystemTime), E>>,

Attempts to refresh the cached value with the given future. If multiple threads attempt to refresh at the same time, one of them will win, and the others will await that thread’s result rather than multiple refreshes occurring. The function given to acquire a value future, f, will not be called if another thread is chosen to load the value.

pub async fn yield_or_clear_if_expired(&self, now: SystemTime) -> Option<T>

If the value is expired, clears the cache. Otherwise, yields the current value.

Trait Implementations

impl<T, E> Clone for ExpiringCache<T, E>

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T: Debug, E: Debug> Debug for ExpiringCache<T, E>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.