LRU Cache with TTL support for Golang

LRUCache is an LRU cache written in Go. The cache supports TTL background cleaning.

The LRUCache is thread-safe

Installation

Use a go-get tool (or any go-compatible package manager) to download the cache:

go get github.com/alexions/go-lru-ttl-cache

Import the cache in your go file:

import (
    lrucache "github.com/alexions/go-lru-ttl-cache"
)

It is highly recommended to use tags to lock the cache version for your project.

Configuration

Import and create a Cache instance:

var cache = lrucache.NewLRUCache(lrucache.Configuration())

Configure allows you to configure cache using chainable API:

var cache = lrucache.NewLRUCache(
    lrucache.Configuration().
    SetDefaultTTL(5 * time.Minute).
    SetMaxSize(100)
)

Possible configuration with default values:

• SetDefaultTTL(ttl time.Duration) - default expiration TTL. Item will be removed after the specified time (default: -1, no expiration)
• SetMaxSize(size int) - cache storage limitation. After exceeding the limit the LRU item will be removed (default: math.MaxInt32 - 1)
• SetCleanupInterval(interval time.Duration) - the cleaning interval. All the items with expired TTL will be removed from the cache. Works only with DefaultTTL greater than 0 (default: run every 1 min)
• SetDeleteCallback(callback func(count int64)) - callback function to get amount of removed items. Runs every Cleanup interval.

Usage

Set/Get

config := Configuration()
cache := NewLRUCache(config)
cache.Set("hello", "world")

value := cache.Get("hello")
fmt.Println(value) // "hello"

Any data can be stored

type User struct {
    login string
    pass  string
}

config := Configuration()
cache := NewLRUCache(config)

cache.Set(1, &User{login: "alexions", pass: "password"})

user := cache.Get(1)
fmt.Println(user.(*User).login)

Checks if item is set:

if _, found := cache.Get("my_item"); !found {
    // Item not found
}

TTL Usage

config := Configuration().
	SetCleanupInterval(10 * time.Millisecond).
	SetDefaultTTL(25)

cache := NewLRUCache(config)

cache.Set("remove_by_ttl", 1)
cache.Set("keep_by_ttl", 2)

<-time.After(15 * time.Millisecond)
_, ok := cache.Get("remove_by_ttl") // ok is false, not found
_, ok = cache.Get("keep_by_ttl") // ok is true, found
fmt.Println(ok)

<-time.After(15 * time.Millisecond)
fmt.Println(cache.Size()) // will be 0

Size

config := Configuration()
cache := NewLRUCache(config)
cache.Set(1, "hello")
cache.Set(2, "world")

fmt.Println(cache.Size()) // 2

Delete

config := Configuration()
cache := NewLRUCache(config)
cache.Set(1, "hello")

cache.Size() // 1
cache.Delete(1)
cache.Size() // 0

Clean

config := Configuration()
cache := NewLRUCache(config)
cache.Set(1, "hello")
cache.Set(2, "world")

cache.Size() // 2
cache.Clean()
cache.Size() // 0