GCP Instance Group Manager for Oban Auto Scaling

gcp_igm.ex

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

  @behaviour Oban.Pro.Cloud

  @enforce_keys [:api_key, :instance_group_manager, :project_id, :zone]
  defstruct @enforce_keys

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

  @impl Oban.Pro.Cloud
  def scale(quantity, %__MODULE__{} = conf) do
    %{
      project_id: project_id,
      zone: zone,
      instance_group_manager: instance_group_manager,
      api_key: api_key
    } = conf

    url =
      "https://compute.googleapis.com/compute/v1/projects/#{project_id}/" <>
        "zones/#{zone}/instanceGroupManagers/#{instance_group_manager}/resize?key=#{api_key}"

    headers = [
      {"Content-Type", "application/json"},
      {"Accept", "application/json"}
    ]

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