%% Copyright (c) 2011-2012 Basho Technologies, Inc. All Rights Reserved.
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%%
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%% This file is provided to you under the Apache License,
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%% Version 2.0 (the "License"); you may not use this file
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%% except in compliance with the License. You may obtain
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%% a copy of the License at
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%%
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%% http://www.apache.org/licenses/LICENSE-2.0
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%%
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%% Unless required by applicable law or agreed to in writing,
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%% software distributed under the License is distributed on an
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%% "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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%% KIND, either express or implied. See the License for the
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%% specific language governing permissions and limitations
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%% under the License.
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%% @doc The lager logging framework.
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-module(lager).
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-include("lager.hrl").
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-define(LAGER_MD_KEY, '__lager_metadata').
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-define(TRACE_SINK, '__trace_sink').
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%% API
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-export([start/0,
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log/3, log/4, log/5,
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md/0, md/1,
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trace/2, trace/3, trace_file/2, trace_file/3, trace_file/4, trace_console/1, trace_console/2,
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clear_all_traces/0, stop_trace/1, stop_trace/3, status/0,
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get_loglevel/1, set_loglevel/2, set_loglevel/3, set_loglevel/4, get_loglevels/1,
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update_loglevel_config/1, posix_error/1,
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safe_format/3, safe_format_chop/3, dispatch_log/5, dispatch_log/6, dispatch_log/9,
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do_log/10, pr/2]).
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-type log_level() :: debug | info | notice | warning | error | critical | alert | emergency.
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-type log_level_number() :: 0..7.
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-export_type([log_level/0, log_level_number/0]).
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%% API
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%% @doc Start the application. Mainly useful for using `-s lager' as a command
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%% line switch to the VM to make lager start on boot.
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start() -> start(lager).
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start(App) ->
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start_ok(App, application:start(App, permanent)).
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start_ok(_App, ok) -> ok;
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start_ok(_App, {error, {already_started, _App}}) -> ok;
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start_ok(App, {error, {not_started, Dep}}) ->
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ok = start(Dep),
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start(App);
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start_ok(App, {error, Reason}) ->
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erlang:error({app_start_failed, App, Reason}).
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%% @doc Get lager metadata for current process
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-spec md() -> [{atom(), any()}].
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md() ->
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case erlang:get(?LAGER_MD_KEY) of
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undefined -> [];
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MD -> MD
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end.
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%% @doc Set lager metadata for current process.
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%% Will badarg if you don't supply a list of {key, value} tuples keyed by atoms.
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-spec md([{atom(), any()},...]) -> ok.
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md(NewMD) when is_list(NewMD) ->
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%% make sure its actually a real proplist
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case lists:all(
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fun({Key, _Value}) when is_atom(Key) -> true;
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(_) -> false
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end, NewMD) of
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true ->
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erlang:put(?LAGER_MD_KEY, NewMD),
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ok;
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false ->
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erlang:error(badarg)
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end;
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md(_) ->
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erlang:error(badarg).
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dispatch_log(Severity, Metadata, Format, Args, Size) when is_atom(Severity)->
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dispatch_log(?DEFAULT_SINK, Severity, Metadata, Format, Args, Size).
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-spec dispatch_log(atom(), log_level(), list(), string(), list() | none, pos_integer()) -> ok | {error, lager_not_running}.
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%% this is the same check that the parse transform bakes into the module at compile time
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dispatch_log(Sink, Severity, Metadata, Format, Args, Size) when is_atom(Severity)->
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SeverityAsInt=lager_util:level_to_num(Severity),
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case {whereis(Sink), lager_config:get({Sink, loglevel}, {?LOG_NONE, []})} of
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{undefined, _} ->
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{error, lager_not_running};
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{SinkPid, {Level, Traces}} when (Level band SeverityAsInt) /= 0 orelse Traces /= [] ->
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do_log(Severity, Metadata, Format, Args, Size, SeverityAsInt, Level, Traces, Sink, SinkPid);
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_ ->
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ok
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end.
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%% @private Should only be called externally from code generated from the parse transform
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do_log(Severity, Metadata, Format, Args, Size, SeverityAsInt, LevelThreshold, TraceFilters, Sink, SinkPid) when is_atom(Severity) ->
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{Destinations, TraceSinkPid} = case TraceFilters of
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[] ->
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{[], undefined};
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_ ->
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{lager_util:check_traces(Metadata,SeverityAsInt,TraceFilters,[]), whereis(?TRACE_SINK)}
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end,
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case (LevelThreshold band SeverityAsInt) /= 0 orelse Destinations /= [] of
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true ->
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Msg = case Args of
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A when is_list(A) ->
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safe_format_chop(Format,Args,Size);
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_ ->
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Format
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end,
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LagerMsg = lager_msg:new(Msg,
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Severity, Metadata, Destinations),
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case lager_config:get({Sink, async}, false) of %% this needs to be able to get value from a non-default sink
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true ->
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gen_event:notify(SinkPid, {log, LagerMsg});
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false ->
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gen_event:sync_notify(SinkPid, {log, LagerMsg})
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end,
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case TraceSinkPid /= undefined of
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true ->
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gen_event:notify(TraceSinkPid, {log, LagerMsg});
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false ->
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ok
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end;
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false ->
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ok
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end.
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%% backwards compatible with beams compiled with lager 1.x
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dispatch_log(Severity, _Module, _Function, _Line, _Pid, Metadata, Format, Args, Size) ->
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dispatch_log(Severity, Metadata, Format, Args, Size).
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%% TODO:
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%% Consider making log2/4 that takes the Level, Pid and Message params of log/3
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%% along with a Sink param??
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%% @doc Manually log a message into lager without using the parse transform.
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-spec log(log_level(), pid() | atom() | [tuple(),...], list()) -> ok | {error, lager_not_running}.
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log(Level, Pid, Message) when is_pid(Pid); is_atom(Pid) ->
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dispatch_log(Level, [{pid,Pid}], Message, [], ?DEFAULT_TRUNCATION);
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log(Level, Metadata, Message) when is_list(Metadata) ->
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dispatch_log(Level, Metadata, Message, [], ?DEFAULT_TRUNCATION).
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%% @doc Manually log a message into lager without using the parse transform.
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-spec log(log_level(), pid() | atom() | [tuple(),...], string(), list()) -> ok | {error, lager_not_running}.
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log(Level, Pid, Format, Args) when is_pid(Pid); is_atom(Pid) ->
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dispatch_log(Level, [{pid,Pid}], Format, Args, ?DEFAULT_TRUNCATION);
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log(Level, Metadata, Format, Args) when is_list(Metadata) ->
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dispatch_log(Level, Metadata, Format, Args, ?DEFAULT_TRUNCATION).
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%% @doc Manually log a message into lager without using the parse transform.
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-spec log(atom(), log_level(), pid() | atom() | [tuple(),...], string(), list()) -> ok | {error, lager_not_running}.
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log(Sink, Level, Pid, Format, Args) when is_pid(Pid); is_atom(Pid) ->
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dispatch_log(Sink, Level, [{pid,Pid}], Format, Args, ?DEFAULT_TRUNCATION);
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log(Sink, Level, Metadata, Format, Args) when is_list(Metadata) ->
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dispatch_log(Sink, Level, Metadata, Format, Args, ?DEFAULT_TRUNCATION).
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validate_trace_filters(Filters, Level, Backend) ->
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Sink = proplists:get_value(sink, Filters, ?DEFAULT_SINK),
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{Sink,
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lager_util:validate_trace({
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proplists:delete(sink, Filters),
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Level,
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Backend
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})
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}.
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trace_file(File, Filter) ->
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trace_file(File, Filter, debug, []).
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trace_file(File, Filter, Level) when is_atom(Level) ->
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trace_file(File, Filter, Level, []);
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trace_file(File, Filter, Options) when is_list(Options) ->
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trace_file(File, Filter, debug, Options).
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trace_file(File, Filter, Level, Options) ->
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case validate_trace_filters(Filter, Level, {lager_file_backend, File}) of
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{Sink, {ok, Trace}} ->
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Handlers = lager_config:global_get(handlers, []),
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%% check if this file backend is already installed
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Res = case lists:keyfind({lager_file_backend, File}, 1, Handlers) of
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false ->
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%% install the handler
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LogFileConfig =
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lists:keystore(level, 1,
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lists:keystore(file, 1,
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Options,
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{file, File}),
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{level, none}),
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HandlerInfo =
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lager_app:start_handler(Sink, lager_file_backend,
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LogFileConfig),
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lager_config:global_set(handlers, [HandlerInfo|Handlers]),
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{ok, installed};
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{_Watcher, _Handler, Sink} ->
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{ok, exists};
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{_Watcher, _Handler, _OtherSink} ->
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{error, file_in_use}
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end,
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case Res of
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{ok, _} ->
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%% XXX Double-check this logic for {ok, exists}
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add_trace_to_loglevel_config(Trace, Sink),
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{ok, {{lager_file_backend, File}, Filter, Level}};
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{error, _} = E ->
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E
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end;
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{_Sink, Error} ->
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Error
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end.
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trace_console(Filter) ->
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trace_console(Filter, debug).
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trace_console(Filter, Level) ->
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trace(lager_console_backend, Filter, Level).
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trace(Backend, Filter) ->
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trace(Backend, Filter, debug).
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trace({lager_file_backend, File}, Filter, Level) ->
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trace_file(File, Filter, Level);
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trace(Backend, Filter, Level) ->
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case validate_trace_filters(Filter, Level, Backend) of
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{Sink, {ok, Trace}} ->
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add_trace_to_loglevel_config(Trace, Sink),
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{ok, {Backend, Filter, Level}};
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{_Sink, Error} ->
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Error
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end.
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stop_trace(Backend, Filter, Level) ->
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case validate_trace_filters(Filter, Level, Backend) of
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{Sink, {ok, Trace}} ->
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stop_trace_int(Trace, Sink);
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{_Sink, Error} ->
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Error
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end.
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stop_trace({Backend, Filter, Level}) ->
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stop_trace(Backend, Filter, Level).
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stop_trace_int({Backend, _Filter, _Level} = Trace, Sink) ->
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{Level, Traces} = lager_config:get({Sink, loglevel}),
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NewTraces = lists:delete(Trace, Traces),
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_ = lager_util:trace_filter([ element(1, T) || T <- NewTraces ]),
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%MinLevel = minimum_loglevel(get_loglevels() ++ get_trace_levels(NewTraces)),
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lager_config:set({Sink, loglevel}, {Level, NewTraces}),
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case get_loglevel(Sink, Backend) of
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none ->
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%% check no other traces point here
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case lists:keyfind(Backend, 3, NewTraces) of
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false ->
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gen_event:delete_handler(Sink, Backend, []);
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_ ->
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ok
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end;
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_ ->
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ok
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end,
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ok.
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clear_all_traces() ->
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Handlers = lager_config:global_get(handlers, []),
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_ = lager_util:trace_filter(none),
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lists:foreach(fun({_Watcher, Handler, Sink}) ->
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case get_loglevel(Sink, Handler) of
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none ->
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gen_event:delete_handler(Sink, Handler, []);
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_ ->
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ok
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end
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end, Handlers).
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%% XXX Needs heavy revision
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status() ->
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Handlers = lager_config:global_get(handlers, []),
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TraceCount = case length(element(2, lager_config:get(loglevel))) of
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0 -> 1;
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N -> N
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end,
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Status = ["Lager status:\n",
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[begin
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Level = get_loglevel(Handler),
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case Handler of
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{lager_file_backend, File} ->
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io_lib:format("File ~s at level ~p\n", [File, Level]);
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lager_console_backend ->
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io_lib:format("Console at level ~p\n", [Level]);
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_ ->
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[]
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end
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end || Handler <- Handlers],
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"Active Traces:\n",
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[begin
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LevelName = case Level of
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{mask, Mask} ->
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case lager_util:mask_to_levels(Mask) of
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[] -> none;
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Levels -> hd(Levels)
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end;
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Num ->
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lager_util:num_to_level(Num)
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end,
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io_lib:format("Tracing messages matching ~p at level ~p to ~p\n",
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[Filter, LevelName, Destination])
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end || {Filter, Level, Destination} <- element(2, lager_config:get(loglevel))],
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[
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"Tracing Reductions:\n",
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case ?DEFAULT_TRACER:info('query') of
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{null, false} -> "";
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Query -> io_lib:format("~p~n", [Query])
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end
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],
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[
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"Tracing Statistics:\n ",
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[ begin
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[" ", atom_to_list(Table), ": ",
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integer_to_list(?DEFAULT_TRACER:info(Table) div TraceCount),
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"\n"]
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end || Table <- [input, output, filter] ]
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]],
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io:put_chars(Status).
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%% @doc Set the loglevel for a particular backend.
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set_loglevel(Handler, Level) when is_atom(Level) ->
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set_loglevel(?DEFAULT_SINK, Handler, undefined, Level).
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%% @doc Set the loglevel for a particular backend that has multiple identifiers
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%% (eg. the file backend).
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set_loglevel(Handler, Ident, Level) when is_atom(Level) ->
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set_loglevel(?DEFAULT_SINK, Handler, Ident, Level).
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%% @doc Set the loglevel for a particular sink's backend that potentially has
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%% multiple identifiers. (Use `undefined' if it doesn't have any.)
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set_loglevel(Sink, Handler, Ident, Level) when is_atom(Level) ->
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HandlerArg = case Ident of
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undefined -> Handler;
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_ -> {Handler, Ident}
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end,
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Reply = gen_event:call(Sink, HandlerArg, {set_loglevel, Level}, infinity),
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update_loglevel_config(Sink),
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Reply.
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%% @doc Get the loglevel for a particular backend on the default sink. In the case that the backend
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%% has multiple identifiers, the lowest is returned.
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get_loglevel(Handler) ->
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get_loglevel(?DEFAULT_SINK, Handler).
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%% @doc Get the loglevel for a particular sink's backend. In the case that the backend
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%% has multiple identifiers, the lowest is returned.
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get_loglevel(Sink, Handler) ->
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case gen_event:call(Sink, Handler, get_loglevel, infinity) of
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{mask, Mask} ->
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case lager_util:mask_to_levels(Mask) of
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[] -> none;
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Levels -> hd(Levels)
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end;
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X when is_integer(X) ->
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lager_util:num_to_level(X);
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Y -> Y
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end.
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%% @doc Try to convert an atom to a posix error, but fall back on printing the
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%% term if its not a valid posix error code.
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posix_error(Error) when is_atom(Error) ->
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case erl_posix_msg:message(Error) of
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"unknown POSIX error" -> atom_to_list(Error);
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Message -> Message
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end;
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posix_error(Error) ->
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safe_format_chop("~p", [Error], ?DEFAULT_TRUNCATION).
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%% @private
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get_loglevels(Sink) ->
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[gen_event:call(Sink, Handler, get_loglevel, infinity) ||
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Handler <- gen_event:which_handlers(Sink)].
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%% @private
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add_trace_to_loglevel_config(Trace, Sink) ->
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{MinLevel, Traces} = lager_config:get({Sink, loglevel}),
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case lists:member(Trace, Traces) of
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false ->
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NewTraces = [Trace|Traces],
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_ = lager_util:trace_filter([ element(1, T) || T <- NewTraces]),
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lager_config:set({Sink, loglevel}, {MinLevel, [Trace|Traces]});
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_ ->
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ok
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end.
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%% @doc recalculate min log level
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update_loglevel_config(Sink) ->
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{_, Traces} = lager_config:get({Sink, loglevel}, {ignore_me, []}),
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MinLog = minimum_loglevel(get_loglevels(Sink)),
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lager_config:set({Sink, loglevel}, {MinLog, Traces}).
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%% @private
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minimum_loglevel(Levels) ->
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lists:foldl(fun({mask, Mask}, Acc) ->
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Mask bor Acc;
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(Level, Acc) when is_integer(Level) ->
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{mask, Mask} = lager_util:config_to_mask(lager_util:num_to_level(Level)),
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Mask bor Acc;
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(_, Acc) ->
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Acc
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end, 0, Levels).
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%% @doc Print the format string `Fmt' with `Args' safely with a size
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%% limit of `Limit'. If the format string is invalid, or not enough
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%% arguments are supplied 'FORMAT ERROR' is printed with the offending
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%% arguments. The caller is NOT crashed.
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safe_format(Fmt, Args, Limit) ->
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safe_format(Fmt, Args, Limit, []).
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safe_format(Fmt, Args, Limit, Options) ->
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try lager_trunc_io:format(Fmt, Args, Limit, Options)
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catch
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_:_ -> lager_trunc_io:format("FORMAT ERROR: ~p ~p", [Fmt, Args], Limit)
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end.
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%% @private
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safe_format_chop(Fmt, Args, Limit) ->
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safe_format(Fmt, Args, Limit, [{chomp, true}]).
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%% @doc Print a record lager found during parse transform
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pr(Record, Module) when is_tuple(Record), is_atom(element(1, Record)) ->
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try
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case is_record_known(Record, Module) of
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false ->
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Record;
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{RecordName, RecordFields} ->
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{'$lager_record', RecordName,
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zip(RecordFields, tl(tuple_to_list(Record)), Module, [])}
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end
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catch
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error:undef ->
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Record
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end;
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pr(Record, _) ->
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Record.
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zip([FieldName|RecordFields], [FieldValue|Record], Module, ToReturn) ->
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case is_tuple(FieldValue) andalso
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tuple_size(FieldValue) > 0 andalso
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is_atom(element(1, FieldValue)) andalso
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is_record_known(FieldValue, Module) of
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false ->
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zip(RecordFields, Record, Module, [{FieldName, FieldValue}|ToReturn]);
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_Else ->
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F = {FieldName, pr(FieldValue, Module)},
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zip(RecordFields, Record, Module, [F|ToReturn])
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end;
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zip([], [], _Module, ToReturn) ->
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lists:reverse(ToReturn).
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is_record_known(Record, Module) ->
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|
Name = element(1, Record),
|
|
Attrs = Module:module_info(attributes),
|
|
case lists:keyfind(lager_records, 1, Attrs) of
|
|
false -> false;
|
|
{lager_records, Records} ->
|
|
case lists:keyfind(Name, 1, Records) of
|
|
false -> false;
|
|
{Name, RecordFields} ->
|
|
case (tuple_size(Record) - 1) =:= length(RecordFields) of
|
|
false -> false;
|
|
true -> {Name, RecordFields}
|
|
end
|
|
end
|
|
end.
|