Add logger

1 files changed, 133 insertions, 0 deletions

diff --git a/lib/kernel/src/logger_backend.erl b/lib/kernel/src/logger_backend.erl
new file mode 100644
index 0000000000..d9f5aa6faf
--- /dev/null
+++ b/lib/kernel/src/logger_backend.erl
@@ -0,0 +1,133 @@
+%%
+%% %CopyrightBegin%
+%%
+%% Copyright Ericsson AB 2017. All Rights Reserved.
+%%
+%% Licensed 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.
+%%
+%% %CopyrightEnd%
+%%
+-module(logger_backend).
+
+-export([log_allowed/2]).
+
+-include("logger_internal.hrl").
+
+-define(OWN_KEYS,[level,filters,filter_default,handlers]).
+
+%%%-----------------------------------------------------------------
+%%% The default logger backend
+log_allowed(Log, Tid) ->
+    {ok,Config} = logger_config:get(Tid,logger),
+    Filters = maps:get(filters,Config,[]),
+    case apply_filters(logger,Log,Filters,Config) of
+        stop ->
+            ok;
+        Log1 ->
+            Handlers = maps:get(handlers,Config,[]),
+            call_handlers(Log1,Handlers,Tid)
+    end,
+    ok.
+
+call_handlers(#{level:=Level}=Log,[Id|Handlers],Tid) ->
+    case logger_config:get(Tid,Id,Level) of
+        {ok,{Module,Config}} ->
+            Filters = maps:get(filters,Config,[]),
+            case apply_filters(Id,Log,Filters,Config) of
+                stop ->
+                    ok;
+                Log1 ->
+                    Config1 = maps:without(?OWN_KEYS,Config),
+                    try Module:log(Log1,Config1)
+                    catch C:R:S ->
+                            case logger:remove_handler(Id) of
+                                ok ->
+                                    logger:internal_log(
+                                      error,{removed_failing_handler,Id}),
+                                    ?LOG_INTERNAL(
+                                       debug,
+                                       [{logger,removed_failing_handler},
+                                        {handler,{Id,Module}},
+                                        {log,Log1},
+                                        {config,Config1},
+                                        {reason,{C,R,filter_stacktrace(S)}}]);
+                                {error,{not_found,_}} ->
+                                    %% Probably already removed by other client
+                                    %% Don't report again
+                                    ok;
+                                {error,Reason} ->
+                                    ?LOG_INTERNAL(
+                                       debug,
+                                       [{logger,remove_handler_failed},
+                                        {reason,Reason}])
+                            end
+                    end
+            end;
+        _ ->
+            ok
+    end,
+    call_handlers(Log,Handlers,Tid);
+call_handlers(_Log,[],_Tid) ->
+    ok.
+
+apply_filters(Owner,Log,Filters,Config) ->
+    case do_apply_filters(Owner,Log,Filters,ignore) of
+        stop ->
+            stop;
+        ignore ->
+            case maps:get(filter_default,Config) of
+                log ->
+                    Log;
+                stop ->
+                    stop
+            end;
+        Log1 ->
+            Log1
+    end.
+
+do_apply_filters(Owner,Log,[{_Id,{FilterFun,FilterArgs}}=Filter|Filters],State) ->
+    try FilterFun(Log,FilterArgs) of
+        stop ->
+            stop;
+        ignore ->
+            do_apply_filters(Owner,Log,Filters,State);
+        Log1=#{level:=Level,msg:=Msg,meta:=Meta}
+          when is_atom(Level), ?IS_MSG(Msg), is_map(Meta) ->
+            do_apply_filters(Owner,Log1,Filters,log);
+        Bad ->
+            handle_filter_failed(Filter,Owner,Log,{bad_return_value,Bad})
+    catch C:R:S ->
+            handle_filter_failed(Filter,Owner,Log,{C,R,filter_stacktrace(S)})
+    end;
+do_apply_filters(_Owner,_Log,[],ignore) ->
+    ignore;
+do_apply_filters(_Owner,Log,[],log) ->
+    Log.
+
+handle_filter_failed({Id,_}=Filter,Owner,Log,Reason) ->
+    case logger_server:remove_filter(Owner,Id) of
+        ok ->
+            logger:internal_log(error,{removed_failing_filter,Id}),
+            ?LOG_INTERNAL(debug,
+                          [{logger,removed_failing_filter},
+                           {filter,Filter},
+                           {owner,Owner},
+                           {log,Log},
+                           {reason,Reason}]);
+        _ ->
+            ok
+    end,
+    ignore.
+
+filter_stacktrace(Stacktrace) ->
+    logger:filter_stacktrace(?MODULE,Stacktrace).