medium-consumer-rabbitmq-messages-using-elixir-connection-worker.ex

defmodule Rabbit.ConnectionWorker do
  use Connection
  
  def start_link(opts) do
    Connection.start_link(__MODULE__, opts)
  end
  
  def init(opts) do
    state = %{opts: opts, conn: nil}
    {:connect, nil, state}
  end
  
  def disconnect(_info, state) do
    {:connect, :reconnect, %{state | conn: nil}}
  end
  
  def connect(_info, state = %{conn: nil, opts: %{host: host, port: port}}) do
    case AMQP.Connection.open(
      host: host,
      port: port,
      connection_timeout: 5000,
      heartbeat: 60
    ) do
      {:ok, conn = %AMQP.Connection{pid: pid}} ->
        Process.link(pid)
        {:ok, %{state | conn: conn}}
      {:error, _reason} ->
        {:backoff, 1000, state}
    end
  end
  
  def handle_call(_, _, state = %{conn: nil}) do
    {:reply, {:error, :closed}, state}
  end
  
  def handle_call(:close, from, state) do
    {:disconnect, {:close, from}, state}
  end
end