lib_notifier_webhook_app.ex

defmodule Notifier.Webhook.App do
  use Application
  require Logger

  def start(_type, _args) do
    Logger.debug("App.start")
    import Supervisor.Spec

    children = [
      supervisor(Notifier.Webhook.Worker, []),
    ]
    opts = [
      strategy: :one_for_one,
      name: Notifier.Webhook.Supervisor,
    ]

    Supervisor.start_link(children, opts)
  end
end

lib_notifier_webhook_worker.ex

defmodule Notifier.Webhook.Worker do
    require Logger
    use GenServer
    use AMQP

    @exchange "amq.topic"
    @queue "notifier.webhook"

    ## Client API

    def start_link() do
        Logger.debug("Worker.start_link")
        GenServer.start_link(__MODULE__, :ok, [])
    end

    ## Server Callbacks

    def init(:ok) do
        Logger.debug("Worker.init")
        {:ok, conn} = Connection.open(Application.get_env(:notifier_webhook, :mqUrl))
        {:ok, chan} = Channel.open(conn)
        setup_queue(chan)

        :ok = Basic.qos(chan, prefetch_count: 10)
        {:ok, _consumer_tag} = Basic.consume(chan, @queue)
        {:ok, chan}
    end

    def handle_info({:basic_consume_ok, %{consumer_tag: consumer_tag}}, chan) do
        {:noreply, chan}
    end
    def handle_info({:basic_cancel, %{consumer_tag: consumer_tag}}, chan) do
        {:stop, :normal, chan}
    end
    def handle_info({:basic_cancel_ok, %{consumer_tag: consumer_tag}}, chan) do
        {:noreply, chan}
    end
    def handle_info({:basic_deliver, payload, %{delivery_tag: tag}}, chan) do
        spawn fn -> consume(chan, tag, payload) end
        {:noreply, chan}
    end

    defp setup_queue(chan) do
        {:ok, _} = Queue.declare(chan, @queue, durable: true)
        :ok = Exchange.topic(chan, @exchange, durable: true)
        :ok = Queue.bind(chan, @queue, @exchange)
    end

    defp consume(chan, tag, payload) do
        IO.puts("GOT #{payload}")
        :ok = Basic.ack(chan, tag)
    rescue
        exception ->
            :ok = Basic.reject(chan, tag)
    end
end

mix.exs

defmodule Notifier.Webhook.MixProject do
  use Mix.Project

  def project do
    [
      app: :notifier_webhook,
      version: "0.1.0",
      elixir: "~> 1.7",
      start_permanent: Mix.env() == :prod,
      deps: deps()
    ]
  end

  # Run "mix help compile.app" to learn about applications.
  def application do
    [
      extra_applications: [:logger],
      mod: {Notifier.Webhook.App, []}
    ]
  end

  # Run "mix help deps" to learn about dependencies.
  defp deps do
    [
      { :amqp, "~> 1.0" },

      { :distillery, "~> 2.0", runtime: false }
    ]
  end
end