erlang_logger.ex

defmodule ErlangLogger do
  @moduledoc """
  Designed to mirror [`kernel/include/logger.hrl`](https://github.com/erlang/otp/blob/da166b76de977171243dd2ea7f86b98f451fabc5/lib/kernel/include/logger.hrl)
  
  *WARNING:* Currently blows up if `__CALLER__` does not have a valid `mfa`
  """

  defmacro log_emergency(a) do
    do_log(:emergency, [a], __CALLER__)
  end

  defmacro log_emergency(a, b) do
    do_log(:emergency, [a, b], __CALLER__)
  end

  defmacro log_emergency(a, b, c) do
    do_log(:emergency, [a, b, c], __CALLER__)
  end

  defmacro log_alert(a) do
    do_log(:alert, [a], __CALLER__)
  end

  defmacro log_alert(a, b) do
    do_log(:alert, [a, b], __CALLER__)
  end

  defmacro log_alert(a, b, c) do
    do_log(:alert, [a, b, c], __CALLER__)
  end

  defmacro log_critical(a) do
    do_log(:critical, [a], __CALLER__)
  end

  defmacro log_critical(a, b) do
    do_log(:critical, [a, b], __CALLER__)
  end

  defmacro log_critical(a, b, c) do
    do_log(:critical, [a, b, c], __CALLER__)
  end

  defmacro log_error(a) do
    do_log(:error, [a], __CALLER__)
  end

  defmacro log_error(a, b) do
    do_log(:error, [a, b], __CALLER__)
  end

  defmacro log_error(a, b, c) do
    do_log(:error, [a, b, c], __CALLER__)
  end

  defmacro log_warning(a) do
    do_log(:warning, [a], __CALLER__)
  end

  defmacro log_warning(a, b) do
    do_log(:warning, [a, b], __CALLER__)
  end

  defmacro log_warning(a, b, c) do
    do_log(:warning, [a, b, c], __CALLER__)
  end

  defmacro log_notice(a) do
    do_log(:notice, [a], __CALLER__)
  end

  defmacro log_notice(a, b) do
    do_log(:notice, [a, b], __CALLER__)
  end

  defmacro log_notice(a, b, c) do
    do_log(:notice, [a, b, c], __CALLER__)
  end

  defmacro log_info(a) do
    do_log(:info, [a], __CALLER__)
  end

  defmacro log_info(a, b) do
    do_log(:info, [a, b], __CALLER__)
  end

  defmacro log_info(a, b, c) do
    do_log(:info, [a, b, c], __CALLER__)
  end

  defmacro log_debug(a) do
    do_log(:debug, [a], __CALLER__)
  end

  defmacro log_debug(a, b) do
    do_log(:debug, [a, b], __CALLER__)
  end

  defmacro log_debug(a, b, c) do
    do_log(:debug, [a, b, c], __CALLER__)
  end

  @doc false
  defp do_log(level, args, caller) do
    %{module: module, function: {function, arity}, file: file, line: line} = caller
    location = Macro.escape(%{mfa: {module, function, arity}, line: line, file: file})
    quote do
      case :logger.allow(unquote(level), unquote(module)) do
        true ->
          apply(:logger, :macro_log, [unquote(location), unquote(level) | unquote(args)])
        false ->
          :ok
      end
    end
  end
end