Heroku Cloud for Oban Auto Scaling

heroku.ex

defmodule Oban.Pro.Clouds.Heroku do
  @moduledoc false

  @behaviour Oban.Pro.Cloud

  @enforce_keys [:app, :auth_token, :dyno]
  defstruct @enforce_keys

  @impl Oban.Pro.Cloud
  def init(opts) do
    struct!(__MODULE__, opts)
  end

  @impl Oban.Pro.Cloud
  def scale(quantity, %{app: app, auth_token: auth_token, dyno: dyno}) do
    url = "https://api.heroku.com/apps/#{app}/formation/#{dyno}"

    headers = [
      {"Content-Type", "application/json"},
      {"Accept", "application/vnd.heroku+json; version=3"},
      {"Authorization", "Bearer #{auth_token}"}
    ]

    Req.patch!(url, json: %{quantity: quantity}, headers: headers)
  end
end