reg

An Erlang process registry based on/inspired by the Elixir process registry.

This registry allows for the lookup of processes based on a given key. The registry comes in two flavors/kinds: unique and duplicate. When a registry is started as unique registry, only one process is allowed to register using the given key, that is a given key will point to 0 or 1 processes.

Setup

You need to add reg as a dependency to your project. If you are using rebar3, you can add the following to your rebar.config:

{deps, [
    {reg, "0.1.0"}
]}.

Also ensure that reg is added as a dependency to your application, by updating your .app.src file:

{application, my_app, [

    {applications, [
        kernel,
        stdlib,

        reg  % <- You need this in your applications list
    ]}
]}.

Usage

Starting a registry

You can start one or more registries in your application, it is recommended to start reg under your supervision tree:

init([]) ->
    Flags = #{strategy => rest_for_one},
    Children = [
        reg:child_spec(my_registry, #{
            kind => duplicate % <- This should be set to `unique` for unique registries
        }),
        % ...
    ],
    {ok, {Flags, Children}}.

Registering a process

To register a process with the key key1 and the value value, you just need to call register/3 from the registering process

> reg:register(my_registry, key1, value).
ok

Looking up processes

To find all processes registered under the key key1:

> reg:lookup(my_registry, key1).
[{<0.145.0>, value}]

Unregistering

A process can unregister by calling the reg:unregister/2 function. A process is also automatically unregistered when it terminates.

> reg:unregister(my_registry, key1).
ok