Struct FoyerBackend 

pub struct FoyerBackend { /* private fields */ }

Implementations

impl FoyerBackend

pub async fn new( dir: &str, ram_bytes: usize, disk_bytes: usize, ) -> Result<FoyerBackend, Error>

pub async fn new_with_shards( dir: &str, ram_bytes: usize, disk_bytes: usize, shards: usize, tuning: WriteTuning, prefix_labels: Arc<[&'static str]>, ) -> Result<FoyerBackend, Error>

pub fn mark_shutting_down(&self)

Marks this backend as shutting down, so RamEvictionListener::on_leave skips emitting object_cache_ram_tier_eviction_count/_age_ms for the entries close()’s full-tier flush is about to evict. Call immediately before close() – the only place this is needed, since a flush that never runs (the overall shutdown deadline elapses first) emits nothing to suppress.

pub async fn close(&self) -> Result<(), Error>

pub fn ram_usage(&self) -> usize

Current RAM-tier byte usage. Exposed so integration tests (which compile as a separate crate and cannot reach the private cache field) can assert prefetch fills do not grow RAM-tier residency.

pub fn ram_entry_count(&self) -> usize

Current RAM-tier entry count. Backs the trait’s ram_entries() method, which feeds the saturation gauge.

Trait Implementations

impl RangeCacheBackend for FoyerBackend

fn get<'life0, 'life1, 'async_trait>( &'life0 self, key: &'life1 str, expected_len: u64, ) -> Pin<Box<dyn Future<Output = Option<Bytes>> + Send + 'async_trait>>

where 'life0: 'async_trait, 'life1: 'async_trait, FoyerBackend: 'async_trait,

expected_len is the exact length the caller will accept for key. A backend MUST NOT copy a value whose length differs into any faster tier it maintains (the promotion gate) and MUST treat such a value as a miss. Single-tier backends accept and ignore the parameter.

fn put<'life0, 'async_trait>( &'life0 self, key: String, value: Bytes, hint: FillHint, ) -> Pin<Box<dyn Future<Output = ()> + Send + 'async_trait>>

where 'life0: 'async_trait, FoyerBackend: 'async_trait,

fn disk_stats(&self) -> Option<BackendDiskStats>

Disk write-path counters, for the saturation monitor’s per-second gauges. Defaulted to None so backends without a disk tier (e.g. MemoryBackend) need no override.

fn ram_usage_bytes(&self) -> Option<usize>

Accounted RAM-tier byte usage, for the saturation monitor’s residency gauge. None for backends with no RAM tier accounting (e.g. MemoryBackend). Divergence between this and process RSS is the signature of a cached value pinning more than its accounted weight.

fn ram_entries(&self) -> Option<usize>

Accounted RAM-tier entry count, the entry-count sibling to ram_usage_bytes. None for backends with no RAM tier accounting (e.g. MemoryBackend).