|\     /\                   ,, 
       _     \\   ||    _               || 
 _-_  < \,  / \\ =||=  < \,  _-_  ,._-_ || 
||    /-|| || ||  ||   /-|| || \\  ||   || 
||   (( || || ||  ||  (( || ||/    ||   || 
\\,/  \/\\  \\/   \\,  \/\\ \\,/   \\,  \\ 

CAching Datastructure For Applications in ERLang

Features

• In-memory non-persistent cache,
• Local gen_server backed,
• No support for functional partition: start one cache per partition,
• Values can optionally be expirable,
• Support for a read-through mechanism, using a self populating function,
• Optionally size-limited using a LRU strategy for removing supernumerous entries,
• Simple hit/miss statistics.

Limitations

• The cache doesn't regularly auto-prune expired entries.

Build

Compile, test and document with:

./rebar clean compile eunit doc

Usage

Start a cache with no size limit:

{ok, Pid} = cadfaerl:start_link(my_cache).

Start a LRU cache with a size limit of 1000:

{ok, Pid} = cadfaerl:start_link(my_cache, 1000).

Put and get a value (keys and values are any term):

ok = cadfaerl:put(my_cache, my_key, "my_val").
{ok, "my_val"} = cadfaerl:get(my_cache, my_key).

undefined = cadfaerl:get(my_cache, unknown_key).

{ok, "default_value"} = cadfaerl:get(my_cache, unknown_key, "default_value").

ok = cadfaerl:put(my_cache, my_key, "override_val").
{ok, "override_val"} = cadfaerl:get(my_cache, my_key).

Put a value with a TTL of 60 seconds:

ok = cadfaerl:put_ttl(my_cache, my_key, "my_val", 60).
{ok, "my_val"} = cadfaerl:get(my_cache, my_key).
% after 61 seconds
undefined = cadfaerl:get(my_cache, my_key).

Get a value, using a self-populating function in case the key is not known:

{ok, 123} = cadfaerl:get_or_fetch(my_cache, my_key, fun() -> 123 end).
% the fetched value is accessible like any other
{ok, 123} = cadfaerl:get(my_cache, my_key).

Same but use a TTL of 60 seconds when self-populating the cache:

{ok, 123} = cadfaerl:get_or_fetch(my_cache, my_key, fun() -> 123 end, 60).
% after 61 seconds
undefined = cadfaerl:get(my_cache, my_key).

Get all the keys of a cache, potentially including keys of expired entries:

Keys = cadfaerl:keys(my_cache).

Remove a value (or ignore if the key is unknown):

ok = cadfaerl:remove(my_cache, my_key).

Get a cache size:

Size = cadfaerl:size(my_cache).

Reset a cache, removing all its content:

ok = cadfaerl:reset(my_cache).

Stop a cache:

ok = cadfaerl:stop(my_cache).

Copyright 2011 - David Dossot - MIT License