Cache library for golang. It supports expirable Cache, LFU, LRU and ARC.
Supports expirable Cache, LFU, LRU and ARC.
Goroutine safe.
Supports event handlers which evict, purge, and add entry. (Optional)
Automatically load cache if it doesn't exists. (Optional)
$ go get github.com/bluele/gcache
package main
import (
"github.com/bluele/gcache""fmt"
)
funcmain() {
gc:=gcache.New(20).
LRU().
Build()
gc.Set("key", "ok")
value, err:=gc.Get("key")
iferr!=nil {
panic(err)
}
fmt.Println("Get:", value)
}Get: ok
package main
import (
"github.com/bluele/gcache""fmt""time"
)
funcmain() {
gc:=gcache.New(20).
LRU().
Build()
gc.SetWithExpire("key", "ok", time.Second*10)
value, _:=gc.Get("key")
fmt.Println("Get:", value)
// Wait for value to expiretime.Sleep(time.Second*10)
value, err=gc.Get("key")
iferr!=nil {
panic(err)
}
fmt.Println("Get:", value)
}Get: ok
// 10 seconds later, new attempt:
panic: ErrKeyNotFound
package main
import (
"github.com/bluele/gcache""fmt"
)
funcmain() {
gc:=gcache.New(20).
LRU().
LoaderFunc(func(keyinterface{}) (interface{}, error) {
return"ok", nil
}).
Build()
value, err:=gc.Get("key")
iferr!=nil {
panic(err)
}
fmt.Println("Get:", value)
}Get: ok
package main
import (
"fmt""time""github.com/bluele/gcache"
)
funcmain() {
varevictCounter, loaderCounter, purgeCounterintgc:=gcache.New(20).
LRU().
LoaderExpireFunc(func(keyinterface{}) (interface{}, *time.Duration, error) {
loaderCounter++expire:=1*time.Secondreturn"ok", &expire, nil
}).
EvictedFunc(func(key, valueinterface{}) {
evictCounter++fmt.Println("evicted key:", key)
}).
PurgeVisitorFunc(func(key, valueinterface{}) {
purgeCounter++fmt.Println("purged key:", key)
}).
Build()
value, err:=gc.Get("key")
iferr!=nil {
panic(err)
}
fmt.Println("Get:", value)
time.Sleep(1*time.Second)
value, err=gc.Get("key")
iferr!=nil {
panic(err)
}
fmt.Println("Get:", value)
gc.Purge()
ifloaderCounter!=evictCounter+purgeCounter {
panic("bad")
}
}Get: ok
evicted key: key
Get: ok
purged key: key
- Least-Frequently Used (LFU)
Discards the least frequently used items first.
funcmain() {
// size: 10gc:=gcache.New(10).
LFU().
Build()
gc.Set("key", "value")
}- Least Recently Used (LRU)
Discards the least recently used items first.
funcmain() {
// size: 10gc:=gcache.New(10).
LRU().
Build()
gc.Set("key", "value")
}- Adaptive Replacement Cache (ARC)
Constantly balances between LRU and LFU, to improve the combined result.
detail: http://en.wikipedia.org/wiki/Adaptive_replacement_cache
funcmain() {
// size: 10gc:=gcache.New(10).
ARC().
Build()
gc.Set("key", "value")
}- SimpleCache (Default)
SimpleCache has no clear priority for evict cache. It depends on key-value map order.
funcmain() {
// size: 10gc:=gcache.New(10).Build()
gc.Set("key", "value")
v, err:=gc.Get("key")
iferr!=nil {
panic(err)
}
}If specified LoaderFunc, values are automatically loaded by the cache, and are stored in the cache until either evicted or manually invalidated.
funcmain() {
gc:=gcache.New(10).
LRU().
LoaderFunc(func(keyinterface{}) (interface{}, error) {
return"value", nil
}).
Build()
v, _:=gc.Get("key")
// output: "value"fmt.Println(v)
}GCache coordinates cache fills such that only one load in one process of an entire replicated set of processes populates the cache, then multiplexes the loaded value to all callers.
funcmain() {
// LRU cache, size: 10, expiration: after a hourgc:=gcache.New(10).
LRU().
Expiration(time.Hour).
Build()
}Event handler for evict the entry.
funcmain() {
gc:=gcache.New(2).
EvictedFunc(func(key, valueinterface{}) {
fmt.Println("evicted key:", key)
}).
Build()
fori:=0; i<3; i++ {
gc.Set(i, i*i)
}
}evicted key: 0
Event handler for add the entry.
funcmain() {
gc:=gcache.New(2).
AddedFunc(func(key, valueinterface{}) {
fmt.Println("added key:", key)
}).
Build()
fori:=0; i<3; i++ {
gc.Set(i, i*i)
}
}added key: 0
added key: 1
added key: 2
Jun Kimura