Documentation
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Overview ¶
Package cache provides reusable in-memory caching primitives.
Cache is a capacity-bounded TTL cache with Prometheus metrics and singleflight de-duplication; consumers compose their own value semantics (negative caching, optional wrapping, etc.) on top of it.
VersionedCache lazily fetches and caches lists of values keyed by a version tag, de-duplicating concurrent loads and respecting context cancellation.
Index ¶
Constants ¶
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Variables ¶
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Functions ¶
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Types ¶
type Cache ¶
type Cache[K comparable, V any] struct { TTL *ttlcache.Cache[K, V] SF singleflight.Group // contains filtered or unexported fields }
Cache is a capacity-bounded TTL cache with a Prometheus size gauge and a singleflight group for de-duplicating concurrent loads.
TTL and SF are exposed so consumers can use the underlying ttlcache and singleflight APIs directly without thin re-wrapping.
func New ¶
func New[K comparable, V any](options Options) *Cache[K, V]
New constructs a Cache with WithDisableTouchOnHit (pure TTL, no LRU touch).
func (*Cache[K, V]) Collect ¶
func (c *Cache[K, V]) Collect(ch chan<- prometheus.Metric)
Collect implements prom.Collector.
func (*Cache[K, V]) Describe ¶
func (c *Cache[K, V]) Describe(ch chan<- *prometheus.Desc)
Describe implements prom.Collector.
type Options ¶
type Options struct {
// MetricsNamespace is prepended to MetricsName in the exported gauge.
MetricsNamespace string
// MetricsName is the Prometheus gauge name for the cache size.
MetricsName string
// MetricsHelp is the Prometheus gauge help string.
MetricsHelp string
// Capacity caps the number of entries; LRU eviction kicks in at the limit.
Capacity uint64
}
Options configures a Cache.
type SingleFlightCache ¶ added in v1.4.0
type SingleFlightCache[T any] struct { // contains filtered or unexported fields }
SingleFlightCache lazily fetches and caches a list of values keyed by a version tag.
Fetches are de-duplicated across concurrent callers via an internal singleflight group, and respect the caller's context for cancellation. Failed fetches are not cached.
func NewSingleFlightCache ¶ added in v1.4.0
func NewSingleFlightCache[T any](fetch func(tag string) (T, error)) *SingleFlightCache[T]
NewSingleFlightCache creates a cache that uses fetch to populate missing entries.
Source Files