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Libcache
A Lightweight in-memory key:value cache library for Go.
Introduction
Caches are tremendously useful in a wide variety of use cases.
you should consider using caches when a value is expensive to compute or retrieve,
and you will need its value on a certain input more than once.
libcache is here to help with that.
Libcache are local to a single run of your application.
They do not store data in files, or on outside servers.
Libcache previously an go-guardian package and designed to be a companion with it.
While both can operate completely independently.
Features
- Rich caching API
- Maximum cache size enforcement
- Default cache TTL (time-to-live) as well as custom TTLs per cache entry
- Thread safe as well as non-thread safe
- Event-Driven callbacks (OnExpired,OnEvicted)
- Dynamic cache creation
- Multiple cache replacement policies:
- FIFO (First In, First Out)
- LIFO (Last In, First Out)
- LRU (Least Recently Used)
- MRU (Most Recently Used)
- LFU (Least Frequently Used)
- ARC (Adaptive Replacement Cache)
Quickstart
Installing
Using libcache is easy. First, use go get to install the latest version of the library.
go get github.com/shaj13/libcache
Next, include libcache in your application:
import (
_ "github.com/shaj13/libcache/<desired-replacement-policy>"
"github.com/shaj13/libcache"
)
Examples
Note: All examples use the LRU cache replacement policy for simplicity, any other cache replacement policy can be applied to them.
Basic
package main
import (
"fmt"
"github.com/shaj13/libcache"
_ "github.com/shaj13/libcache/lru"
)
func main() {
size := 10
cache := libcache.LRU.NewUnsafe(size)
for i:= 0 ; i < 10 ; i++ {
cache.Store(i, i)
}
fmt.Println(cache.Load(0)) // nil, false
fmt.Println(cache.Load(1)) // 1, true
}
Thread Safe
package main
import (
"fmt"
"github.com/shaj13/libcache"
_ "github.com/shaj13/libcache/lru"
)
func main() {
done := make(chan struct{})
f := func(c libcache.Cache) {
for !c.Contains(5) {
}
fmt.Println(c.Load(5)) // 5, true
done <- struct{}{}
}
size := 10
cache := libcache.LRU.New(size)
go f(cache)
for i := 0; i < 10; i++ {
cache.Store(i, i)
}
<-done
}
Unlimited Size
zero capacity means cache has no limit and replacement policy turned off.
package main
import (
"fmt"
"github.com/shaj13/libcache"
_ "github.com/shaj13/libcache/lru"
)
func main() {
cache := libcache.LRU.New(0)
for i:= 0 ; i < 100000 ; i++ {
cache.Store(i, i)
}
fmt.Println(cache.Load(55555))
}
TTL
package main
import (
"fmt"
"time"
"github.com/shaj13/libcache"
_ "github.com/shaj13/libcache/lru"
)
func main() {
cache := libcache.LRU.New(10)
cache.SetTTL(time.Second) // default TTL
for i:= 0 ; i < 10 ; i++ {
cache.Store(i, i)
}
fmt.Println(cache.Expiry(1))
cache.StoreWithTTL("mykey", "value", time.Hour) // TTL per cache entry
fmt.Println(cache.Expiry("mykey"))
}
Events
Timed expiration by default is performed with lazy maintenance during reads operations,
Evict an expired entry immediately can be done using on expired callback.
You may also specify a eviction listener for your cache to perform some operation when an entry is evicted.
Note: Expiration events relying on golang runtime timers heap to call on expired callback when an entry TTL elapsed.
package main
import (
"fmt"
"time"
"github.com/shaj13/libcache"
_ "github.com/shaj13/libcache/lru"
)
func main() {
cache := libcache.LRU.New(10)
cache.RegisterOnEvicted(func(key, value interface{}) {
fmt.Printf("Cache Key %v Evicted\n", key)
})
cache.RegisterOnExpired(func(key, value interface{}) {
fmt.Printf("Cache Key %v Expired, Removing it from cache\n", key)
// use delete directly when your application
// guarantee no other goroutine can store items with the same key.
// Peek also invoke lazy expiry.
//
// Note this should done only with safe cache.
cache.Peek(key)
})
for i:= 0 ; i < 10 ; i++ {
cache.StoreWithTTL(i, i, time.Microsecond)
}
time.Sleep(time.Second)
fmt.Println(cache.Len())
}
Contributing
- Fork it
- Download your fork to your PC (
git clone https://github.com/your_username/libcache && cd libcache) - Create your feature branch (
git checkout -b my-new-feature) - Make changes and add them (
git add .) - Commit your changes (
git commit -m 'Add some feature') - Push to the branch (
git push origin my-new-feature) - Create new pull request
License
Libcache is released under the MIT license. See LICENSE