%% Copyright (c) 2011-2012 Basho Technologies, Inc. All Rights Reserved. %% %% This file is provided to you under the Apache License, %% Version 2.0 (the "License"); you may not use this file %% except in compliance with the License. You may obtain %% a copy of the License at %% %% http://www.apache.org/licenses/LICENSE-2.0 %% %% Unless required by applicable law or agreed to in writing, %% software distributed under the License is distributed on an %% "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY %% KIND, either express or implied. See the License for the %% specific language governing permissions and limitations %% under the License. -module(lager_default_formatter). %% %% Include files %% -include("lager.hrl"). -ifdef(TEST). -include_lib("eunit/include/eunit.hrl"). -endif. %% %% Exported Functions %% -export([format/2, format/3]). %% %% API Functions %% %% @doc Provides a generic, default formatting for log messages using a semi-iolist as configuration. Any iolist allowed %% elements in the configuration are printed verbatim. Atoms in the configuration are treated as metadata properties %% and extracted from the log message. Optionally, a tuple of {atom(),semi-iolist()} can be used. The atom will look %% up the property, but if not found it will use the semi-iolist() instead. These fallbacks can be similarly nested %% or refer to other properties, if desired. You can also use a {atom, semi-iolist(), semi-iolist()} formatter, which %% acts like a ternary operator's true/false branches. %% %% The metadata properties date,time, message, and severity will always exist. %% The properties pid, file, line, module, and function will always exist if the parser transform is used. %% %% Example: %% %% `["Foo"]' -> "Foo", regardless of message content. %% %% `[message]' -> The content of the logged message, alone. %% %% `[{pid,"Unknown Pid"}]' -> "?.?.?" if pid is in the metadata, "Unknown Pid" if not. %% %% `[{pid, ["My pid is ", pid], ["Unknown Pid"]}]' -> if pid is in the metada print "My pid is ?.?.?", otherwise print "Unknown Pid" %% @end -spec format(lager_msg:lager_msg(),list(),list()) -> any(). format(Msg,[], Colors) -> format(Msg, [{eol, "\n"}], Colors); format(Msg,[{eol, EOL}], Colors) -> format(Msg, [date, " ", time, " ", color, "[", severity, "] ", {pid, ""}, {module, [ {pid, ["@"], ""}, module, {function, [":", function], ""}, {line, [":",line], ""}], ""}, " ", message, EOL], Colors); format(Message,Config,Colors) -> [ case V of color -> output_color(Message,Colors); _ -> output(V,Message) end || V <- Config ]. -spec format(lager_msg:lager_msg(),list()) -> any(). format(Msg, Config) -> format(Msg, Config, []). -spec output(term(),lager_msg:lager_msg()) -> iolist(). output(message,Msg) -> lager_msg:message(Msg); output(date,Msg) -> {D, _T} = lager_msg:datetime(Msg), D; output(time,Msg) -> {_D, T} = lager_msg:datetime(Msg), T; output(severity,Msg) -> atom_to_list(lager_msg:severity(Msg)); output(Prop,Msg) when is_atom(Prop) -> Metadata = lager_msg:metadata(Msg), make_printable(get_metadata(Prop,Metadata,<<"Undefined">>)); output({Prop,Default},Msg) when is_atom(Prop) -> Metadata = lager_msg:metadata(Msg), make_printable(get_metadata(Prop,Metadata,output(Default,Msg))); output({Prop, Present, Absent}, Msg) when is_atom(Prop) -> %% sort of like a poor man's ternary operator Metadata = lager_msg:metadata(Msg), case get_metadata(Prop, Metadata) of undefined -> [ output(V, Msg) || V <- Absent]; _ -> [ output(V, Msg) || V <- Present] end; output(Other,_) -> make_printable(Other). output_color(_Msg,[]) -> []; output_color(Msg,Colors) -> Level = lager_msg:severity(Msg), case lists:keyfind(Level, 1, Colors) of {_, Color} -> Color; _ -> [] end. -spec make_printable(any()) -> iolist(). make_printable(A) when is_atom(A) -> atom_to_list(A); make_printable(P) when is_pid(P) -> pid_to_list(P); make_printable(L) when is_list(L) orelse is_binary(L) -> L; make_printable(Other) -> io_lib:format("~p",[Other]). get_metadata(Key, Metadata) -> get_metadata(Key, Metadata, undefined). get_metadata(Key, Metadata, Default) -> case lists:keyfind(Key, 1, Metadata) of false -> Default; {Key, Value} -> Value end. -ifdef(TEST). date_time_now() -> Now = os:timestamp(), {Date, Time} = lager_util:format_time(lager_util:maybe_utc(lager_util:localtime_ms(Now))), {Date, Time, Now}. basic_test_() -> {Date, Time, Now} = date_time_now(), [{"Default formatting test", ?_assertEqual(iolist_to_binary([Date, " ", Time, " [error] ", pid_to_list(self()), " Message\n"]), iolist_to_binary(format(lager_msg:new("Message", Now, error, [{pid, self()}], []), []))) }, {"Basic Formatting", ?_assertEqual(<<"Simplist Format">>, iolist_to_binary(format(lager_msg:new("Message", Now, error, [{pid, self()}], []), ["Simplist Format"]))) }, {"Default equivalent formatting test", ?_assertEqual(iolist_to_binary([Date, " ", Time, " [error] ", pid_to_list(self()), " Message\n"]), iolist_to_binary(format(lager_msg:new("Message", Now, error, [{pid, self()}], []), [date, " ", time," [",severity,"] ",pid, " ", message, "\n"] ))) }, {"Non existant metadata can default to string", ?_assertEqual(iolist_to_binary([Date, " ", Time, " [error] Fallback Message\n"]), iolist_to_binary(format(lager_msg:new("Message", Now, error, [{pid, self()}], []), [date, " ", time," [",severity,"] ",{does_not_exist,"Fallback"}, " ", message, "\n"] ))) }, {"Non existant metadata can default to other metadata", ?_assertEqual(iolist_to_binary([Date, " ", Time, " [error] Fallback Message\n"]), iolist_to_binary(format(lager_msg:new("Message", Now, error, [{pid, "Fallback"}], []), [date, " ", time," [",severity,"] ",{does_not_exist,pid}, " ", message, "\n"] ))) }, {"Non existant metadata can default to a string2", ?_assertEqual(iolist_to_binary(["Unknown Pid"]), iolist_to_binary(format(lager_msg:new("Message", Now, error, [], []), [{pid, ["My pid is ", pid], ["Unknown Pid"]}] ))) }, {"Metadata can have extra formatting", ?_assertEqual(iolist_to_binary(["My pid is hello"]), iolist_to_binary(format(lager_msg:new("Message", Now, error, [{pid, hello}], []), [{pid, ["My pid is ", pid], ["Unknown Pid"]}] ))) }, {"Metadata can have extra formatting1", ?_assertEqual(iolist_to_binary(["servername"]), iolist_to_binary(format(lager_msg:new("Message", Now, error, [{pid, hello}, {server, servername}], []), [{server,{pid, ["(", pid, ")"], ["(Unknown Server)"]}}] ))) }, {"Metadata can have extra formatting2", ?_assertEqual(iolist_to_binary(["(hello)"]), iolist_to_binary(format(lager_msg:new("Message", Now, error, [{pid, hello}], []), [{server,{pid, ["(", pid, ")"], ["(Unknown Server)"]}}] ))) }, {"Metadata can have extra formatting3", ?_assertEqual(iolist_to_binary(["(Unknown Server)"]), iolist_to_binary(format(lager_msg:new("Message", Now, error, [], []), [{server,{pid, ["(", pid, ")"], ["(Unknown Server)"]}}] ))) } ]. -endif.