An in-memory LRU string-interface{} map with expiration for golang
Pull request Compare This branch is 40 commits ahead of wunderlist:master.
Latest commit f56cbb9 Aug 18, 2016 @diegobernardes committed on GitHub Update


This project have some problems, don't use it in production. I'm really out of time to fix it now, so if you must use this project, please, fix it first and send a PR or join as a contributor.

If you really need something ready to use just take a look here

TTLCache - an in-memory cache with expiration

TTLCache is a simple key/value cache in golang with the following functions:

  1. Thread-safe
  2. Individual expiring time or global expiring time, you can choose
  3. Auto-Extending expiration on Get
  4. Fast and memory efficient
  5. Can trigger callback on key expiration

Build Status


import (


func main () {
  newItemCallback := func(key string, value interface{}) {
        fmt.Printf("New key(%s) added\n", key)
  checkExpirationCallback := func(key string, value interface{}) bool {
        if key == "key1" {
            // if the key equals "key1", the value
            // will not be allowed to expire
            return false
        // all other values are allowed to expire
        return true
  expirationCallback := func(key string, value interface{}) {
        fmt.Printf("This key(%s) has expired\n", key)

  cache := ttlcache.NewCache()
  cache.SetTTL(time.Duration(10 * time.Second))

  cache.Set("key", "value")
  cache.SetWithTTL("keyWithTTL", "value", 10 * time.Second)

  value, exists := cache.Get("key")
  count := cache.Count()
  result := cache.Remove("key")


  • Comment the code
  • Add a roadmap
  • Add benchmarks
  • Improve map performance

Original Project

TTLCache was forked from wunderlist/ttlcache to add extra functions not avaiable in the original scope. The main differences are:

  1. A item can store any kind of object, previously, only strings could be saved
  2. Optionally, you can add callbacks to: check if a value should expire, be notified if a value expires, and be notified when new values are added to the cache
  3. The expiration can be either global or per item
  4. Can exist items without expiration time
  5. Expirations and callbacks are realtime. Don't have a pooling time to check anymore, now it's done with a heap.