This modules implements a simple LRU cache, using 2 ets tables for it.

For using it, you need to start it:

iex> LruCache.start_link(:my_cache, 1000)

Or add it to your supervisor tree, like: worker(LruCache, [:my_cache, 1000])

Using

iex> LruCache.start_link(:my_cache, 1000)
{:ok, #PID<0.60.0>}

iex> LruCache.put(:my_cache, "id", "value")
:ok

iex> LruCache.get(:my_cache, "id", touch = false)
"value"

To take some action when old keys are evicted from the cache when it is full, you can pass an :evict_fn option to LruCache.start_link/3. This is helpful for cleaning up processes that depend on values in the cache, or logging, or instrumentation of cache evictions etc.

iex> evict = fn(key,value) -> IO.inspect("#{key}=#{value} evicted") end
iex> LruCache.start_link(:my_cache, 10, evict_fn: evict)
{:ok, #PID<0.60.0>}

Design

First ets table save the key values pairs, the second save order of inserted elements.