[logger] Refactor, and add error detection for configuration

4 files changed, 310 insertions, 70 deletions

diff --git a/lib/kernel/doc/src/logger.xml b/lib/kernel/doc/src/logger.xml
index a4d6efa2d8..464c65ba76 100644
--- a/lib/kernel/doc/src/logger.xml
+++ b/lib/kernel/doc/src/logger.xml
@@ -527,7 +527,7 @@ start(_, []) ->
         Error -> Error
      end.</code>
        <p>This reads the <c>logger</c> configuration parameter from
-         the <c>my_all</c> application and starts the configured
+         the <c>my_app</c> application and starts the configured
          handlers. The contents of the configuration use the same
          rules as the
          <seealso marker="logger_chapter#handler-configuration">logger handler configuration</seealso>.
diff --git a/lib/kernel/src/logger.erl b/lib/kernel/src/logger.erl
index df96367d82..0ada8b4924 100644
--- a/lib/kernel/src/logger.erl
+++ b/lib/kernel/src/logger.erl
@@ -115,6 +115,11 @@
 
 -type config_handler() :: {handler, handler_id(), module(), handler_config()}.
 
+-type config_logger() :: [{handler,default,undefined} |
+                          config_handler() |
+                          {filters,log | stop,[{filter_id(),filter()}]} |
+                          {module_level,level(),[module()]}].
+
 -export_type([log_event/0,
               level/0,
               report/0,
@@ -582,19 +587,21 @@ get_config() ->
 %% tree is started.
 internal_init_logger() ->
     try
+        Env = get_logger_env(kernel),
+        check_logger_config(kernel,Env),
         ok = logger:set_primary_config(level, get_logger_level()),
-        ok = logger:set_primary_config(filter_default, get_primary_filter_default()),
+        ok = logger:set_primary_config(filter_default,
+                                       get_primary_filter_default(Env)),
 
         [case logger:add_primary_filter(Id, Filter) of
              ok -> ok;
              {error, Reason} -> throw(Reason)
-         end || {Id, Filter} <- get_primary_filters()],
+         end || {Id, Filter} <- get_primary_filters(Env)],
 
-        _ = [[case logger:set_module_level(Module, Level) of
-                  ok -> ok;
-                  {error, Reason} -> throw(Reason)
-              end || Module <- Modules]
-             || {module_level, Level, Modules} <- get_logger_env()],
+        [case logger:set_module_level(Modules, Level) of
+             ok -> ok;
+             {error, Reason} -> throw(Reason)
+         end  || {module_level, Level, Modules} <- Env],
 
         case logger:set_handler_config(simple,filters,
                                        get_default_handler_filters()) of
@@ -602,24 +609,24 @@ internal_init_logger() ->
             {error,{not_found,simple}} -> ok
         end,
 
-        init_kernel_handlers()
+        init_kernel_handlers(Env)
     catch throw:Reason ->
             ?LOG_ERROR("Invalid logger config: ~p", [Reason]),
             {error, {bad_config, {kernel, Reason}}}
     end.
 
--spec init_kernel_handlers() -> ok | {error,term()}.
+-spec init_kernel_handlers(config_logger()) -> ok | {error,term()}.
 %% Setup the kernel environment variables to be correct
 %% The actual handlers are started by a call to add_handlers.
-init_kernel_handlers() ->
+init_kernel_handlers(Env) ->
     try
-        case get_logger_type() of
+        case get_logger_type(Env) of
             {ok,silent} ->
                 ok = logger:remove_handler(simple);
             {ok,false} ->
                 ok;
             {ok,Type} ->
-                init_default_config(Type)
+                init_default_config(Type,Env)
         end
     catch throw:Reason ->
             ?LOG_ERROR("Invalid default handler config: ~p", [Reason]),
@@ -634,10 +641,13 @@ init_kernel_handlers() ->
 %% and then starting the correct handlers. This is done after the
 %% kernel supervisor tree has been started as it needs the logger_sup.
 add_handlers(App) when is_atom(App) ->
-    add_handlers(application:get_env(App, logger, []));
+    add_handlers(App,get_logger_env(App));
 add_handlers(HandlerConfig) ->
+    add_handlers(application:get_application(),HandlerConfig).
+
+add_handlers(App,HandlerConfig) ->
     try
-        check_logger_config(HandlerConfig),
+        check_logger_config(App,HandlerConfig),
         DefaultAdded =
             lists:foldl(
               fun({handler, default = Id, Module, Config}, _)
@@ -651,17 +661,22 @@ add_handlers(HandlerConfig) ->
                  ({handler, Id, Module, Config}, Default) ->
                       setup_handler(Id, Module, Config),
                       Default orelse Id == default;
-                 (_, Default) -> Default
+                 (_,Default) -> Default
               end, false, HandlerConfig),
         %% If a default handler was added we try to remove the simple_logger
         %% If the simple logger exists it will replay its log events
         %% to the handler(s) added in the fold above.
-        _ = [case logger:remove_handler(simple) of
-                 ok -> ok;
-                 {error,{not_found,simple}} -> ok
-             end || DefaultAdded],
+        [case logger:remove_handler(simple) of
+             ok -> ok;
+             {error,{not_found,simple}} -> ok
+         end || DefaultAdded],
         ok
-    catch throw:Reason ->
+    catch throw:Reason0 ->
+            Reason =
+                case App of
+                    undefined -> Reason0;
+                    _ -> {App,Reason0}
+                end,
             ?LOG_ERROR("Invalid logger handler config: ~p", [Reason]),
             {error, {bad_config, {handler, Reason}}}
     end.
@@ -672,26 +687,35 @@ setup_handler(Id, Module, Config) ->
         {error, Reason} -> throw(Reason)
     end.
 
-check_logger_config(_) ->
-    ok.
-
--spec get_logger_type() -> {ok, standard_io | false | silent |
-                            {file, file:name_all()} |
-                            {file, file:name_all(), [file:mode()]}}.
-get_logger_type() ->
+check_logger_config(_,[]) ->
+    ok;
+check_logger_config(App,[{handler,_,_,_}|Env]) ->
+    check_logger_config(App,Env);
+check_logger_config(kernel,[{handler,default,undefined}|Env]) ->
+    check_logger_config(kernel,Env);
+check_logger_config(kernel,[{filters,_,_}|Env]) ->
+    check_logger_config(kernel,Env);
+check_logger_config(kernel,[{module_level,_,_}|Env]) ->
+    check_logger_config(kernel,Env);
+check_logger_config(_,Bad) ->
+    throw(Bad).
+
+-spec get_logger_type(config_logger()) ->
+                             {ok, standard_io | false | silent |
+                              {file, file:name_all()} |
+                              {file, file:name_all(), [file:mode()]}}.
+get_logger_type(Env) ->
     case application:get_env(kernel, error_logger) of
         {ok, tty} ->
             {ok, standard_io};
         {ok, {file, File}} when is_list(File) ->
             {ok, {file, File}};
-        {ok, {file, File, Modes}} when is_list(File), is_list(Modes) ->
-            {ok, {file, File, Modes}};
         {ok, false} ->
             {ok, false};
         {ok, silent} ->
             {ok, silent};
         undefined ->
-            case lists:member({handler,default,undefined}, get_logger_env()) of
+            case lists:member({handler,default,undefined}, Env) of
                 true ->
                     {ok, false};
                 false ->
@@ -709,56 +733,55 @@ get_logger_level() ->
             throw({logger_level, Level})
     end.
 
-get_primary_filter_default() ->
-    case lists:keyfind(filters,1,get_logger_env()) of
+get_primary_filter_default(Env) ->
+    case lists:keyfind(filters,1,Env) of
         {filters,Default,_} ->
             Default;
         false ->
             log
     end.
 
-get_primary_filters() ->
-    lists:foldl(
-      fun({filters, _, Filters}, _Acc) ->
-              Filters;
-         (_, Acc) ->
-              Acc
-      end, [], get_logger_env()).
+get_primary_filters(Env) ->
+    case [F || F={filters,_,_} <- Env] of
+        [{filters,_,Filters}] ->
+            case lists:all(fun({_,_}) -> true; (_) -> false end,Filters) of
+                true -> Filters;
+                false -> throw({invalid_filters,Filters})
+            end;
+        [] -> [];
+        _ -> throw({multiple_filters,Env})
+    end.
 
 %% This function looks at the kernel logger environment
 %% and updates it so that the correct logger is configured
-init_default_config(Type) when Type==standard_io;
-                                Type==standard_error;
-                                element(1,Type)==file ->
-    Env = get_logger_env(),
+init_default_config(Type,Env) when Type==standard_io;
+                                   Type==standard_error;
+                                   element(1,Type)==file ->
     DefaultFormatter = #{formatter=>{?DEFAULT_FORMATTER,?DEFAULT_FORMAT_CONFIG}},
     DefaultConfig = DefaultFormatter#{config=>#{type=>Type}},
     NewLoggerEnv =
         case lists:keyfind(default, 2, Env) of
-            {handler, default, Module, Config} ->
-                lists:map(
-                  fun({handler, default, logger_std_h, _}) ->
-                          %% Only want to add the logger_std_h config
-                          %% if not configured by user AND the default
-                          %% handler is still the logger_std_h.
-                          {handler, default, Module, maps:merge(DefaultConfig,Config)};
-                     ({handler, default, logger_disk_log_h, _}) ->
-                          %% Add default formatter. The point of this
-                          %% is to get the expected formatter config
-                          %% for the default handler, since this
-                          %% differs from the default values that
-                          %% logger_formatter itself adds.
-                          {handler, default, logger_disk_log_h, maps:merge(DefaultFormatter,Config)};
-                     (Other) ->
-                          Other
-                  end, Env);
+            {handler, default, logger_std_h, Config} ->
+                %% Only want to add the logger_std_h config
+                %% if not configured by user AND the default
+                %% handler is still the logger_std_h.
+                lists:keyreplace(default, 2, Env,
+                                 {handler, default, logger_std_h,
+                                  maps:merge(DefaultConfig,Config)});
+            {handler, default, Module,Config} ->
+                %% Add default formatter. The point of this
+                %% is to get the expected formatter config
+                %% for the default handler, since this
+                %% differs from the default values that
+                %% logger_formatter itself adds.
+                lists:keyreplace(default, 2, Env,
+                                 {handler, default, Module,
+                                  maps:merge(DefaultFormatter,Config)});
             _ ->
                 %% Nothing has been configured, use default
                 [{handler, default, logger_std_h, DefaultConfig} | Env]
         end,
-    application:set_env(kernel, logger, NewLoggerEnv, [{timeout,infinity}]);
-init_default_config(Type) ->
-    throw({illegal_logger_type,Type}).
+    application:set_env(kernel, logger, NewLoggerEnv, [{timeout,infinity}]).
 
 get_default_handler_filters() ->
     case application:get_env(kernel, logger_sasl_compatible, false) of
@@ -768,8 +791,8 @@ get_default_handler_filters() ->
             ?DEFAULT_HANDLER_FILTERS([otp,sasl])
     end.
 
-get_logger_env() ->
-    application:get_env(kernel, logger, []).
+get_logger_env(App) ->
+    application:get_env(App, logger, []).
 
 %%%-----------------------------------------------------------------
 %%% Internal
diff --git a/lib/kernel/test/logger_SUITE.erl b/lib/kernel/test/logger_SUITE.erl
index 824c95d6df..49b76f03b2 100644
--- a/lib/kernel/test/logger_SUITE.erl
+++ b/lib/kernel/test/logger_SUITE.erl
@@ -37,7 +37,8 @@
 
 
 suite() ->
-    [{timetrap,{seconds,30}}].
+    [{timetrap,{seconds,30}},
+     {ct_hooks,[logger_test_lib]}].
 
 init_per_suite(Config) ->
     case logger:get_handler_config(?STANDARD_HANDLER) of
@@ -98,7 +99,9 @@ all() ->
      via_logger_process,
      other_node,
      compare_levels,
-     process_metadata].
+     process_metadata,
+     app_config,
+     kernel_config].
 
 start_stop(_Config) ->
     S = whereis(logger),
@@ -895,12 +898,227 @@ process_metadata(_Config) ->
     ok = logger:unset_process_metadata(),
     undefined = logger:get_process_metadata(),
 
+    ok = logger:update_process_metadata(#{custom=>added_again}),
+    {error,badarg} = ?TRY(logger:update_process_metadata(bad)),
+    #{custom:=added_again} = logger:get_process_metadata(),
+
     ok.
 
 process_metadata(cleanup,_Config) ->
     logger:remove_handler(h1),
     ok.
 
+app_config(Config) ->
+    %% Start a node with default configuration
+    {ok,_,Node} = logger_test_lib:setup(Config,[]),
+
+    App1Name = app1,
+    App1 = {application, App1Name,
+            [{description, "Test of app with logger config"},
+             {applications, [kernel]}]},
+    ok = rpc:call(Node,application,load,[App1]),
+    ok = rpc:call(Node,application,set_env,
+                  [App1Name,logger,[{handler,default,logger_std_h,#{}}]]),
+
+    %% Try to add an own default handler
+    {error,{bad_config,{handler,{app1,{already_exist,default}}}}} =
+        rpc:call(Node,logger,add_handlers,[App1Name]),
+
+    %% Add a different handler
+    ok = rpc:call(Node,application,set_env,[App1Name,logger,
+                                            [{handler,myh,logger_std_h,#{}}]]),
+    ok = rpc:call(Node,logger,add_handlers,[App1Name]),
+
+    {ok,#{filters:=DF}} = rpc:call(Node,logger,get_handler_config,[default]),
+    {ok,#{filters:=[]}} = rpc:call(Node,logger,get_handler_config,[myh]),
+
+    true = test_server:stop_node(Node),
+
+    %% Start a node with no default handler, then add an own default handler
+    {ok,#{handlers:=[#{id:=simple}]},Node} =
+        logger_test_lib:setup(Config,[{logger,[{handler,default,undefined}]}]),
+
+    ok = rpc:call(Node,application,load,[App1]),
+    ok = rpc:call(Node,application,set_env,
+                  [App1Name,logger,[{handler,default,logger_std_h,#{}}]]),
+    ok = rpc:call(Node,logger,add_handlers,[App1Name]),
+
+    #{handlers:=[#{id:=default,filters:=DF}]} =
+        rpc:call(Node,logger,get_config,[]),
+
+    true = test_server:stop_node(Node),
+
+    %% Start a silent node, then add an own default handler
+    {ok,#{handlers:=[]},Node} =
+        logger_test_lib:setup(Config,[{error_logger,silent}]),
+
+    {error,{bad_config,{handler,[{some,bad,config}]}}} =
+        rpc:call(Node,logger,add_handlers,[[{some,bad,config}]]),
+    ok = rpc:call(Node,logger,add_handlers,
+                  [[{handler,default,logger_std_h,#{}}]]),
+
+    #{handlers:=[#{id:=default,filters:=DF}]} =
+        rpc:call(Node,logger,get_config,[]),
+
+    ok.
+
+%% This test case is maintly to see code coverage. Note that
+%% logger_env_var_SUITE tests a lot of the same, and checks the
+%% functionality more thoroughly, but since it all happens at node
+%% start, it is not possible to see code coverage in that test.
+kernel_config(Config) ->
+    %% Start a node with simple handler only, then simulate kernel
+    %% start by calling internally exported
+    %% internal_init_logger(). This is to test all variants of kernel
+    %% config, including bad config, and see the code coverage.
+    {ok,#{handlers:=[#{id:=simple,filters:=DF}]}=LC,Node} =
+        logger_test_lib:setup(Config,[{error_logger,false}]),
+
+    %% Same once more, to get coverage
+    ok = rpc:call(Node,logger,internal_init_logger,[]),
+    ok = rpc:call(Node,logger,add_handlers,[kernel]),
+    LC = rpc:call(Node,logger,get_config,[]),
+
+    %% This shall mean the same as above, but using 'logger' parameter
+    %% instead of 'error_logger'
+    ok = rpc:call(Node,application,unset_env,[kernel,error_logger]),
+    ok = rpc:call(Node,application,set_env,
+                  [kernel,logger,[{handler,default,undefined}]]),
+    ok = rpc:call(Node,logger,internal_init_logger,[]),
+    ok = rpc:call(Node,logger,add_handlers,[kernel]),
+    LC = rpc:call(Node,logger,get_config,[]),
+
+    %% Silent
+    ok = rpc:call(Node,application,unset_env,[kernel,logger]),
+    ok = rpc:call(Node,application,set_env,[kernel,error_logger,silent]),
+    ok = rpc:call(Node,logger,internal_init_logger,[]),
+    ok = rpc:call(Node,logger,add_handlers,[kernel]),
+    #{primary:=#{filter_default:=log,filters:=[]},
+      handlers:=[],
+      module_levels:=[]} = rpc:call(Node,logger,get_config,[]),
+
+    %% Default
+    ok = rpc:call(Node,application,unset_env,[kernel,error_logger]),
+    ok = rpc:call(Node,application,unset_env,[kernel,logger]),
+    ok = rpc:call(Node,logger,internal_init_logger,[]),
+    ok = rpc:call(Node,logger,add_handlers,[kernel]),
+    #{primary:=#{filter_default:=log,filters:=[]},
+      handlers:=[#{id:=default,filters:=DF,config:=#{type:=standard_io}}],
+      module_levels:=[]} = rpc:call(Node,logger,get_config,[]),
+
+    %% error_logger=tty (same as default)
+    ok = rpc:call(Node,logger,remove_handler,[default]),% so it can be added again
+    ok = rpc:call(Node,application,set_env,[kernel,error_logger,tty]),
+    ok = rpc:call(Node,application,unset_env,[kernel,logger]),
+    ok = rpc:call(Node,logger,internal_init_logger,[]),
+    ok = rpc:call(Node,logger,add_handlers,[kernel]),
+    #{primary:=#{filter_default:=log,filters:=[]},
+      handlers:=[#{id:=default,filters:=DF,config:=#{type:=standard_io}}],
+      module_levels:=[]} = rpc:call(Node,logger,get_config,[]),
+
+    %% error_logger={file,File}
+    ok = rpc:call(Node,logger,remove_handler,[default]),% so it can be added again
+    F = filename:join(?config(priv_dir,Config),
+                      atom_to_list(?FUNCTION_NAME)++".log"),
+    ok = rpc:call(Node,application,set_env,[kernel,error_logger,{file,F}]),
+    ok = rpc:call(Node,application,unset_env,[kernel,logger]),
+    ok = rpc:call(Node,logger,internal_init_logger,[]),
+    ok = rpc:call(Node,logger,add_handlers,[kernel]),
+    #{primary:=#{filter_default:=log,filters:=[]},
+      handlers:=[#{id:=default,filters:=DF,config:=#{type:={file,F}}}],
+      module_levels:=[]} = rpc:call(Node,logger,get_config,[]),
+
+    %% Same, but using 'logger' parameter instead of 'error_logger'
+    ok = rpc:call(Node,logger,remove_handler,[default]),% so it can be added again
+    ok = rpc:call(Node,application,unset_env,[kernel,error_logger]),
+    ok = rpc:call(Node,application,set_env,[kernel,logger,
+                                            [{handler,default,logger_std_h,
+                                              #{config=>#{type=>{file,F}}}}]]),
+    ok = rpc:call(Node,logger,internal_init_logger,[]),
+    ok = rpc:call(Node,logger,add_handlers,[kernel]),
+    #{primary:=#{filter_default:=log,filters:=[]},
+      handlers:=[#{id:=default,filters:=DF,config:=#{type:={file,F}}}],
+      module_levels:=[]} = rpc:call(Node,logger,get_config,[]),
+
+    %% Same, but with type={file,File,Modes}
+    ok = rpc:call(Node,logger,remove_handler,[default]),% so it can be added again
+    ok = rpc:call(Node,application,unset_env,[kernel,error_logger]),
+    M = [raw,write,delayed_write],
+    ok = rpc:call(Node,application,set_env,[kernel,logger,
+                                            [{handler,default,logger_std_h,
+                                              #{config=>#{type=>{file,F,M}}}}]]),
+    ok = rpc:call(Node,logger,internal_init_logger,[]),
+    ok = rpc:call(Node,logger,add_handlers,[kernel]),
+    #{primary:=#{filter_default:=log,filters:=[]},
+      handlers:=[#{id:=default,filters:=DF,config:=#{type:={file,F,M}}}],
+      module_levels:=[]} = rpc:call(Node,logger,get_config,[]),
+
+    %% Same, but with disk_log handler
+    ok = rpc:call(Node,logger,remove_handler,[default]),% so it can be added again
+    ok = rpc:call(Node,application,unset_env,[kernel,error_logger]),
+    M = [raw,write,delayed_write],
+    ok = rpc:call(Node,application,set_env,[kernel,logger,
+                                            [{handler,default,logger_disk_log_h,
+                                              #{config=>#{file=>F}}}]]),
+    ok = rpc:call(Node,logger,internal_init_logger,[]),
+    ok = rpc:call(Node,logger,add_handlers,[kernel]),
+    #{primary:=#{filter_default:=log,filters:=[]},
+      handlers:=[#{id:=default,filters:=DF,config:=#{file:=F}}],
+      module_levels:=[]} = rpc:call(Node,logger,get_config,[]),
+
+    %% Set primary filters and module level. No default handler.
+    ok = rpc:call(Node,logger,remove_handler,[default]),% so it can be added again
+    ok = rpc:call(Node,application,unset_env,[kernel,error_logger]),
+    ok = rpc:call(Node,application,set_env,
+                  [kernel,logger,[{handler,default,undefined},
+                                  {filters,stop,[{f1,{fun(_,_) -> log end,ok}}]},
+                                  {module_level,debug,[?MODULE]}]]),
+    ok = rpc:call(Node,logger,internal_init_logger,[]),
+    ok = rpc:call(Node,logger,add_handlers,[kernel]),
+    #{primary:=#{filter_default:=stop,filters:=[_]},
+      handlers:=[],
+      module_levels:=[{?MODULE,debug}]} = rpc:call(Node,logger,get_config,[]),
+
+    %% Bad config
+    ok = rpc:call(Node,application,unset_env,[kernel,logger]),
+
+    ok = rpc:call(Node,application,set_env,[kernel,error_logger,bad]),
+    {error,{bad_config,{kernel,{error_logger,bad}}}} =
+        rpc:call(Node,logger,internal_init_logger,[]),
+
+    ok = rpc:call(Node,application,unset_env,[kernel,error_logger]),
+    ok = rpc:call(Node,application,set_env,[kernel,logger_level,bad]),
+    {error,{bad_config,{kernel,{logger_level,bad}}}} =
+        rpc:call(Node,logger,internal_init_logger,[]),
+
+    ok = rpc:call(Node,application,unset_env,[kernel,logger_level]),
+    ok = rpc:call(Node,application,set_env,
+                  [kernel,logger,[{filters,stop,[bad]}]]),
+    {error,{bad_config,{kernel,{invalid_filters,[bad]}}}} =
+        rpc:call(Node,logger,internal_init_logger,[]),
+
+    ok = rpc:call(Node,application,set_env,
+                  [kernel,logger,[{filters,stop,[bad]}]]),
+    {error,{bad_config,{kernel,{invalid_filters,[bad]}}}} =
+        rpc:call(Node,logger,internal_init_logger,[]),
+
+    ok = rpc:call(Node,application,set_env,
+                  [kernel,logger,[{filters,stop,[{f1,bad}]}]]),
+    {error,{bad_config,{kernel,{invalid_filter,{f1,bad}}}}} =
+        rpc:call(Node,logger,internal_init_logger,[]),
+
+    ok = rpc:call(Node,application,set_env,
+                  [kernel,logger,MF=[{filters,stop,[]},{filters,log,[]}]]),
+    {error,{bad_config,{kernel,{multiple_filters,MF}}}} =
+        rpc:call(Node,logger,internal_init_logger,[]),
+
+    ok = rpc:call(Node,application,set_env,
+                  [kernel,logger,[{module_level,bad,[?MODULE]}]]),
+    {error,{bad_config,{kernel,{invalid_level,bad}}}} =
+        rpc:call(Node,logger,internal_init_logger,[]),
+
+    ok.
+
 %%%-----------------------------------------------------------------
 %%% Internal
 check_logged(Level,Format,Args,Meta) ->
diff --git a/lib/kernel/test/logger_simple_h_SUITE.erl b/lib/kernel/test/logger_simple_h_SUITE.erl
index 79e5c057ad..e0ad792bdb 100644
--- a/lib/kernel/test/logger_simple_h_SUITE.erl
+++ b/lib/kernel/test/logger_simple_h_SUITE.erl
@@ -117,8 +117,7 @@ replace_default(Config) ->
     log(Node, critical, [?str,[?keyval_rep]]),
     log(Node, notice, [["fake",string,"line:",?LINE]]),
 
-    Env = rpc:call(Node, application, get_env, [kernel, logger, []]),
-    ok = rpc:call(Node, logger, add_handlers, [Env]),
+    ok = rpc:call(Node, logger, add_handlers, [kernel]),
 
     ok.