marianoguerra/rscbag

Erlang library to store resources in a simple memory kv store with plugable kv implementations and init them on get if not found

Resource Bag

An Erlang library to hold a bag of resources, get them by key and initialize them and store them on get if not found.

The store and the resouce life cycle can be parameterized, we provide a default store using ets (default) and another one using gb_trees for your convenience.

Concepts

Store

a simple key value store that holds for each key a reference to a resource, it can put/get/remove and remove_by_value.

Resource Handler

a simple behaviour that provides logic to init and stop your resource, you have to provide this since we don't know what kind of resources you want to handle.

see test/test_resource_handler.erl for a simple example that initializes a resource that is simply the Opts passed to it during init.

Usage

You have to have a module that manages your resources, it must implement two functions:

init(opts()) -> {ok, state()} | {error, reason()}.
stop(state()) -> ok | {error, reason()}.

then create an instance of rscbag:

{ok, Bag} = rscbag_server:start_link(Opts),

where Opts is a proplist with one required key and one optional one:

• resource_handler (Required): an atom with the name of the module that implements init/1, stop/1
• kv_mod (Optional, defaults to rscbag_ets): an atom with the name of the module that will be used as kv store for the resources, there are two implemented in this library, rscbag_ets and rscbag_gb_trees, you can implement your own by implemented the rscbag_store behaviour.

then you can use the rscbag API to get, get_existing, remove, remove_by_val, clean, stop etc.

License

MPL 2.0, see LICENSE