87 lines
3.1 KiB
Go
87 lines
3.1 KiB
Go
// Package lcw adds a thin layer on top of lru and expirable cache providing more limits and common interface.
|
|
// The primary method to get (and set) data to/from the cache is LoadingCache.Get returning stored data for a given key or
|
|
// call provided func to retrieve and store, similar to Guava loading cache.
|
|
// Limits allow max values for key size, number of keys, value size and total size of values in the cache.
|
|
// CacheStat gives general stats on cache performance.
|
|
// 3 flavors of cache provided - NoP (do-nothing cache), ExpirableCache (TTL based), and LruCache
|
|
package lcw
|
|
|
|
//go:generate sh -c "mockery -inpkg -name LoadingCache -print > /tmp/cache-mock.tmp && mv /tmp/cache-mock.tmp cache_mock.go"
|
|
|
|
import (
|
|
"fmt"
|
|
)
|
|
|
|
// Sizer allows to perform size-based restrictions, optional.
|
|
// If not defined both maxValueSize and maxCacheSize checks will be ignored
|
|
type Sizer interface {
|
|
Size() int
|
|
}
|
|
|
|
// LoadingCache defines guava-like cache with Get method returning cached value ao retrieving it if not in cache
|
|
type LoadingCache interface {
|
|
Get(key string, fn func() (interface{}, error)) (val interface{}, err error) // load or get from cache
|
|
Peek(key string) (interface{}, bool) // get from cache by key
|
|
Invalidate(fn func(key string) bool) // invalidate items for func(key) == true
|
|
Delete(key string) // delete by key
|
|
Purge() // clear cache
|
|
Stat() CacheStat // cache stats
|
|
Keys() []string // list of all keys
|
|
Close() error // close open connections
|
|
}
|
|
|
|
// CacheStat represent stats values
|
|
type CacheStat struct {
|
|
Hits int64
|
|
Misses int64
|
|
Keys int
|
|
Size int64
|
|
Errors int64
|
|
}
|
|
|
|
// String formats cache stats
|
|
func (s CacheStat) String() string {
|
|
ratio := 0.0
|
|
if s.Hits+s.Misses > 0 {
|
|
ratio = float64(s.Hits) / float64(s.Hits+s.Misses)
|
|
}
|
|
return fmt.Sprintf("{hits:%d, misses:%d, ratio:%.2f, keys:%d, size:%d, errors:%d}",
|
|
s.Hits, s.Misses, ratio, s.Keys, s.Size, s.Errors)
|
|
}
|
|
|
|
// Nop is do-nothing implementation of LoadingCache
|
|
type Nop struct{}
|
|
|
|
// NewNopCache makes new do-nothing cache
|
|
func NewNopCache() *Nop {
|
|
return &Nop{}
|
|
}
|
|
|
|
// Get calls fn without any caching
|
|
func (n *Nop) Get(key string, fn func() (interface{}, error)) (interface{}, error) { return fn() }
|
|
|
|
// Peek does nothing and always returns false
|
|
func (n *Nop) Peek(key string) (interface{}, bool) { return nil, false }
|
|
|
|
// Invalidate does nothing for nop cache
|
|
func (n *Nop) Invalidate(fn func(key string) bool) {}
|
|
|
|
// Purge does nothing for nop cache
|
|
func (n *Nop) Purge() {}
|
|
|
|
// Delete does nothing for nop cache
|
|
func (n *Nop) Delete(key string) {}
|
|
|
|
// Keys does nothing for nop cache
|
|
func (n *Nop) Keys() []string { return nil }
|
|
|
|
// Stat always 0s for nop cache
|
|
func (n *Nop) Stat() CacheStat {
|
|
return CacheStat{}
|
|
}
|
|
|
|
// Close does nothing for nop cache
|
|
func (n *Nop) Close() error {
|
|
return nil
|
|
}
|