lib/env_error.ex
defmodule ConfigHelpers.EnvError do
@moduledoc """
Error raised when vairable does not exist in environment and no default could be found for current env.
"""
defexception [:var, :env]
@impl true
def message(%{var: var, env: env}) do
"could not fetch environment variable #{inspect(var)} because it is not set and no default for env \"#{inspect(env)}\" exists"
end
end