GenServer

Exemplo de GenServer

defmodule ServidorDeNumero do
  use GenServer

  def start_link(state \\ []) do
    GenServer.start_link(__MODULE__, state, name: __MODULE__)
  end

  @impl true
  def init(numero), do: {:ok, numero}

  @impl true
  def handle_call(:num, _from, state) do
    {:reply, "O número atual é #{state}.", state}
  end

  @impl true
  def handle_cast({:newstate, newstate}, _state) do
    {:noreply, newstate}
  end

  @impl true
  def handle_cast({:addtostate, increment}, state) do
    {:noreply, state + increment}
  end
end

{_, {_, pid}} = ServidorDeNumero.start_link(1)

Process.alive?(pid)

GenServer.call(pid, :num)

GenServer.cast(pid, {:newstate, 76876})

GenServer.cast(pid, {:newstate, 1})

GenServer.cast(pid, {:newstate, 123})

GenServer.cast(pid, {:addtostate, 100})