inets_blogpost_3.ex

defmodule Api do
  require Record

  # Wrap the Erlang Record to make the request_uri parameter easier to access
  Record.defrecord :httpd, Record.extract(:mod, from_lib: "inets/include/httpd.hrl")

  def child_spec(_) do
    opts = [
      server_name: 'Api', 
      server_root: '/tmp',
      document_root: '/tmp', 
      port: 3000, 
      modules: [__MODULE__]
    ]

    args = [:httpd, opts]

    %{
      id: make_ref(),
      start: {:inets, :start, args}
    }
  end

  def unquote(:do)(data) do
    response =
        case httpd(data, :request_uri) do
        '/' ->
          if is_healthy?() do
            {200, 'I am healthy'}
          else
            {503, 'I am unhealthy'}
          end
        _   -> {404, 'Not found'}
      end

    {:proceed, [response: response]}
  end

  defp is_healthy?() do
    # Checks some of the other processes
  end
end