rcache

rcache is a simple cache that periodically erases stale items and which can help mitigate the thundering herd problem. rcache's growth is unbound. It is meant to cache a small number of items.

Usage:

// thread-safe
apps := rcache.New(fetcher, time.Minute * 2)

func fetcher(key string) interface{} {
  // HIT YOUR DB, GET THE APP
  // ...
  return theApp
}

// in code:
app := apps.Get("spice").(*Application)

There's a short 20 second grace window in which an expired item will be returned. In other words, the real TTL of items placed in the above cache is 120-140seconds. Even if multiple goroutines concurrently GET an item which is in this grace window, only 1 call to fetcher will be executed.

Methods

• Get(key string) - Returns the value or nil. Either gets it from the cache or fetches it via the fetcher
• Set(key string, value interface{}) - Sets the value
• Replace(key string, value interface{}) - Replaces an existing value, extending it's TTL. Noop if key isn't already in the cache
• Delete(key string) - Deletes an item
• Clear() - removes all items from the cache

Integer Keys

By default, the cache key is a string. You can create a cache that uses an integer key by using NewInt (instead of New). Everything works the same, except keys are int.

LRU Cache Alternative

For a more powerful LRU cache, checkout ccache