# README
golang-lru
This provides the lru
package which implements a fixed-size
thread safe LRU cache. It is based on the cache in Groupcache.
Documentation
Full docs are available on Go Packages
LRU cache example
package main
import (
"fmt"
"github.com/hashicorp/golang-lru/v2"
)
func main() {
l, _ := lru.New[int, any](128)
for i := 0; i < 256; i++ {
l.Add(i, nil)
}
if l.Len() != 128 {
panic(fmt.Sprintf("bad len: %v", l.Len()))
}
}
Expirable LRU cache example
package main
import (
"fmt"
"time"
"github.com/hashicorp/golang-lru/v2/expirable"
)
func main() {
// make cache with 10ms TTL and 5 max keys
cache := expirable.NewLRU[string, string](5, nil, time.Millisecond*10)
// set value under key1.
cache.Add("key1", "val1")
// get value under key1
r, ok := cache.Get("key1")
// check for OK value
if ok {
fmt.Printf("value before expiration is found: %v, value: %q\n", ok, r)
}
// wait for cache to expire
time.Sleep(time.Millisecond * 12)
// get value under key1 after key expiration
r, ok = cache.Get("key1")
fmt.Printf("value after expiration is found: %v, value: %q\n", ok, r)
// set value under key2, would evict old entry because it is already expired.
cache.Add("key2", "val2")
fmt.Printf("Cache len: %d\n", cache.Len())
// Output:
// value before expiration is found: true, value: "val1"
// value after expiration is found: false, value: ""
// Cache len: 1
}
# Functions
New creates an LRU of the given size.
New2Q creates a new TwoQueueCache using the default values for the parameters.
New2QParams creates a new TwoQueueCache using the provided parameter values.
NewWithEvict constructs a fixed size cache with the given eviction callback.
# Constants
Default2QGhostEntries is the default ratio of ghost entries kept to track entries recently evicted.
Default2QRecentRatio is the ratio of the 2Q cache dedicated to recently added entries that have only been accessed once.
DefaultEvictedBufferSize defines the default buffer size to store evicted key/val.
# Structs
Cache is a thread-safe fixed size LRU cache.
TwoQueueCache is a thread-safe fixed size 2Q cache.