error_codes.ex

defmodule ErrorCodes.Repo do
  use Ecto.Repo, otp_app: :error_codes
end

defmodule ErrorCodes.ErrorCode do
  use Ecto.Schema
  schema "errors" do
  end
end

defmodule ErrorCodes.Router do
  import Plug.Conn
  import Ecto.Query
  alias ErrorCodes.Repo, as: R
  alias ErrorCodes.ErrorCode, as: EC

  def init(opts), do: opts

  def call(%Plug.Conn{request_path: "/error-codes"} = conn, opts) do
    res = R.all(from ec in EC, select: ec.id)
    send_resp(conn, 200, inspect(res))
  end
end

defmodule ErrorCodes do
  use Application

  # See http://elixir-lang.org/docs/stable/elixir/Application.html
  # for more information on OTP Applications
  def start(_type, _args) do
    import Supervisor.Spec, warn: false

    children = [
      # Define workers and child supervisors to be supervised
      supervisor(ErrorCodes.Repo, []),
      Plug.Adapters.Cowboy.child_spec(:http, ErrorCodes.Router, [], [port: 4001])
    ]

    # See http://elixir-lang.org/docs/stable/elixir/Supervisor.html
    # for other strategies and supported options
    opts = [strategy: :one_for_one, name: ErrorCodes.Supervisor]
    Supervisor.start_link(children, opts)
  end
end