Simple Singleton Supervisor

It allows you to run a single globally unique process in a cluster. It uses only :global and doesn’t create any additional processes. Name of the supervisor is determining of the global uniqueness.

You can find supporting documentation and usage examples here.

Installation

Simple Singleton Supervisor is available on Hex, the package can be installed by adding simple_singleton_supervisor to your list of dependencies in mix.exs:

def deps do
  [
    {:simple_singleton_supervisor, "~> MAJ.MIN"}
  ]
end

You can determine the latest version by running mix hex.info simple_singleton_supervisor in your shell, or by going to the simple_singleton_supervisorpage on hex.pm.

Usage

To start a process you can add SimpleSingletonSupervisor to your application’s children list:

defmodule MyApp.Application do
  use Application

  def start(_type, _args) do
    singleton_children = [
      {MyApp.SingletonProcess, []}
    ]

    children = [
      {SimpleSingletonSupervisor, [
        name: MyApp.SingletonSupervisor,
        strategy: :one_for_one,
        children: singleton_children
      ]}
    ]

    opts = [strategy: :one_for_one, name: MyApp.Supervisor]
    Supervisor.start_link(children, opts)
  end
end

SingletonSupervisor can also be used as a module-based supervisor:

defmodule MySingletonSupervisor do
  @moduledoc false

  use Supervisor

  def start_link(init_arg) do
    SimpleSingletonSupervisor.start_link(__MODULE__, init_arg, name: __MODULE__)
  end

  @impl Supervisor
  def init(_init_arg) do
    children = [
      {MyApp.SingletonProcess, []}
    ]

    Supervisor.init(children, strategy: :one_for_one)
  end
end

Copyright and License

This library is MIT licensed. See the LICENSE.md for details.