elixir-todo-list/lib/todo/cache.ex

defmodule Todo.Cache do
  use DynamicSupervisor

  def start_link(init_arg) do
    IO.puts("Starting #{__MODULE__}")

    DynamicSupervisor.start_link(__MODULE__, init_arg, name: __MODULE__)
  end

  @impl DynamicSupervisor
  def init(_) do
    DynamicSupervisor.init(strategy: :one_for_one)
  end

  def server_process(todo_list_name) do
    case start_child(todo_list_name) do
      {:ok, pid} -> pid
      {:error, {:already_started, pid}} -> pid
    end
  end

  defp start_child(todo_list_name) do
    DynamicSupervisor.start_child(__MODULE__, {Todo.Server, todo_list_name})
  end
end