gen_logger

%%%-----------------------------------------------------------------------------
%%% Copyright (c) 2014-2016 Feng Lee <feng@emqtt.io>. All Rights Reserved.
%%%
%%% Permission is hereby granted, free of charge, to any person obtaining a copy
%%% of this software and associated documentation files (the "Software"), to deal
%%% in the Software without restriction, including without limitation the rights
%%% to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
%%% copies of the Software, and to permit persons to whom the Software is
%%% furnished to do so, subject to the following conditions:
%%%
%%% The above copyright notice and this permission notice shall be included in all
%%% copies or substantial portions of the Software.
%%%
%%% THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
%%% IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
%%% FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
%%% AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
%%% LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
%%% OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
%%% SOFTWARE.
%%%-----------------------------------------------------------------------------

-module(gen_logger).

-author("Feng Lee <feng@emqtt.io>").

-include("gen_logger.hrl").

%%%=========================================================================
%%% API
%%%=========================================================================

-export([new/1, new/2,
         debug/2, debug/3,
         info/2, info/3,
         warning/2, warning/3,
         error/2, error/3,
         critical/2, critical/3]).

%%%=========================================================================
%%% Types
%%%=========================================================================

-type(level() :: all | debug | info | warning | error | critical | none).

-type(logcfg() :: level() | {module(), level()}).

-type(logmod() :: {gen_logger, module(), level()}).

-export_type([level/0, logcfg/0, logmod/0]).

%%%=========================================================================
%%% Behaviour Callbacks
%%%=========================================================================

-ifdef(use_specs).

-callback(debug(Msg :: string()) -> ok).
-callback(debug(Format :: io:format(), Args :: [term()]) -> ok).

-callback(info(Msg :: string()) -> ok).
-callback(info(Format :: io:format(), Args :: [term()]) -> ok).

-callback(warning(Msg :: string()) -> ok).
-callback(warning(Format :: io:format(), Args :: [term()]) -> ok).

-callback(error(Msg :: string()) -> ok).
-callback(error(Format :: io:format(), Args :: [term()]) -> ok).

-callback(critical(Msg :: string()) -> ok).
-callback(critical(Format:: io:format(), Args :: [term()]) -> ok).

-else.

-export([behaviour_info/1]).

behaviour_info(callbacks) ->
    [{debug, 1}, {debug, 2},
     {info, 1}, {info, 2},
     {warning, 1}, {warning, 2},
     {error, 1}, {error, 2},
     {critical, 1}, {critical, 2}];
behaviour_info(_Other) ->
    undefined.

-endif.

%%%=========================================================================
%%% gen_logger API
%%%=========================================================================

-spec(new(Level :: level()) -> logmod();
         ({Name :: atom(), Level :: level()})  -> logmod()).
new(Level) when is_atom(Level) -> new(console, Level);
new({Name, Level}) -> new(Name, Level).

-spec(new(Name :: atom(), Level :: level()) -> logmod()).
new(Name, Level) when is_atom(Name) and is_atom(Level) ->
    LogMod = logmod(Name),
    {module, LogMod} = code:ensure_loaded(LogMod),
    {?MODULE, LogMod, ?LOG_LEVEL_NUM(Level)}.

logmod(Name) -> list_to_atom(lists:concat([Name, "_logger"])).

%%%-------------------------------------------------------------------------
%%% DEBUG
%%%-------------------------------------------------------------------------
-spec(debug(Msg :: string(), Mod :: logmod()) -> ok).
debug(Msg, {?MODULE, Logger, Level}) when Level =< ?LOG_DEBUG ->
    Logger:debug(Msg);
debug(_Msg, {?MODULE, _Logger, _Level}) ->
    ok.

-spec(debug(Format :: io:format(), Args :: [term()], Mod :: logmod()) -> ok).
debug(Format, Args, {?MODULE, Logger, Level}) when Level =< ?LOG_DEBUG ->
    Logger:debug(Format, Args);
debug(_Format, _Args, {?MODULE, _Logger, _Level}) ->
    ok.

%%%-------------------------------------------------------------------------
%%% INFO
%%%-------------------------------------------------------------------------
-spec(info(Msg :: string(), Mod :: logmod()) -> ok).
info(Msg, {?MODULE, Logger, Level}) when Level =< ?LOG_INFO ->
    Logger:info(Msg);
info(_Msg, {?MODULE, _Logger, _Level}) ->
    ok.

-spec(info(Format :: io:format(), Args :: [term()], Mod :: logmod()) -> ok).
info(Format, Args, {?MODULE, Logger, Level}) when Level =< ?LOG_INFO ->
    Logger:info(Format, Args);
info(_Format, _Args, {?MODULE, _Logger, _Level}) ->
    ok.

%%%-------------------------------------------------------------------------
%%% WARNING
%%%-------------------------------------------------------------------------
-spec(warning(Msg :: string(), Mod :: logmod()) -> ok).
warning(Msg, {?MODULE, Logger, Level}) when Level =< ?LOG_WARNING ->
    Logger:warning(Msg);
warning(_Msg, {?MODULE, _Logger, _Level}) ->
    ok.

-spec(warning(Format :: io:format(), Args :: [term()], Mod :: logmod()) -> ok).
warning(Format, Args, {?MODULE, Logger, Level}) when Level =< ?LOG_WARNING ->
    Logger:warning(Format, Args);
warning(_Format, _Args, {?MODULE, _Logger, _Level}) ->
    ok.
    
%%%-------------------------------------------------------------------------
%%% ERROR
%%%-------------------------------------------------------------------------
-spec(error(Msg :: string(), Mod :: logmod()) -> ok).
error(Msg, {?MODULE, Logger, Level}) when Level =< ?LOG_ERROR ->
    Logger:error(Msg);
error(_Msg, {?MODULE, _Logger, _Level}) ->
    ok.

-spec(error(Format :: io:format(), Args :: [term()], Mod :: logmod()) -> ok).
error(Format, Args, {?MODULE, Logger, Level}) when Level =< ?LOG_ERROR ->
    Logger:error(Format, Args);
error(_Format, _Args, {?MODULE, _Logger, _Level}) ->
    ok.

%%%-------------------------------------------------------------------------
%%% CRITICAL
%%%-------------------------------------------------------------------------
-spec(critical(Msg :: string(), Mod :: logmod()) -> ok).
critical(Msg, {?MODULE, Logger, Level}) when Level =< ?LOG_CRITICAL ->
    Logger:critical(Msg);
critical(_Msg, {?MODULE, _Logger, _Level}) ->
    ok.

-spec(critical(Format :: io:format(), Args :: [term()], Mod :: logmod()) -> ok).
critical(Format, Args, {?MODULE, Logger, Level}) when Level =< ?LOG_CRITICAL ->
    Logger:critical(Format, Args);
critical(_Format, _Args, {?MODULE, _Logger, _Level}) ->
    ok.