Merge pull request #5186 from hauleth/feat/allow-reconfiguration-of-logger/OTP-17375

Allow reconfiguration of logger

3 files changed, 62 insertions, 39 deletions

diff --git a/lib/kernel/doc/src/logger.xml b/lib/kernel/doc/src/logger.xml
index 1c17004aa0..68d1984c7f 100644
--- a/lib/kernel/doc/src/logger.xml
+++ b/lib/kernel/doc/src/logger.xml
@@ -1189,6 +1189,18 @@ logger:set_proxy_config(maps:merge(Old, Config)).
       </desc>
     </func>
 
+    <func>
+      <name name="reconfigure" arity="0" since="OTP @OTP-17375@"/>
+      <fsummary>Reconfigure Logger.</fsummary>
+      <desc>
+        <p>Reconfigure Logger using updated <c>kernel</c> configuration
+	  that was set after <c>kernel</c> application was loaded.</p>
+        <p>Beware, that this is meant to be run only by the build tools,
+	  not manually during application lifetime, as this may cause
+	  missing log entries.</p>
+      </desc>
+    </func>
+
   </funcs>
 
  
diff --git a/lib/kernel/src/logger.erl b/lib/kernel/src/logger.erl
index ea75c8d720..9107bf0e61 100644
--- a/lib/kernel/src/logger.erl
+++ b/lib/kernel/src/logger.erl
@@ -51,9 +51,9 @@
          get_primary_config/0, get_handler_config/1,
          get_handler_config/0, get_handler_ids/0, get_config/0,
          get_proxy_config/0,
-         add_handlers/1]).
+         add_handlers/1,
+         reconfigure/0]).
 
-%% Private configuration
 -export([internal_init_logger/0]).
 
 %% Misc
@@ -794,6 +794,31 @@ print_module_levels(Modules,M) ->
     [print_module_levels(Module,M) || Module <- Modules],
     ok.
 
+-spec reconfigure() -> ok | {error,term()}.
+%% This function is meant to be used by the build tools like Rebar3 or Mix
+%% to ensure that the logger configuration is reset to the expected state
+%% before running main application.
+reconfigure() ->
+    try
+        [case logger:remove_handler(Id) of
+             ok -> ok;
+             {error, Reason} -> throw({remove, Id, Reason})
+         end || #{id := Id} <- logger:get_handler_config()],
+        ok=logger:add_handler(simple,logger_simple_h,
+                              #{filter_default=>stop,
+                                filters=>?DEFAULT_HANDLER_FILTERS}),
+        logger:unset_module_level(),
+        internal_init_logger()
+    of
+        ok ->
+            logger:add_handlers(kernel);
+        Error ->
+            Error
+    catch
+        throw:Reason ->
+            {error, Reason}
+    end.
+
 -spec internal_init_logger() -> ok | {error,term()}.
 %% This function is responsible for config of the logger
 %% This is done before add_handlers because we want the
@@ -807,6 +832,7 @@ internal_init_logger() ->
         ok = logger:set_primary_config(metadata, get_primary_metadata()),
         ok = logger:set_primary_config(filter_default,
                                        get_primary_filter_default(Env)),
+        ok = logger:set_primary_config(filters, []),
 
         [case logger:add_primary_filter(Id, Filter) of
              ok -> ok;
diff --git a/lib/kernel/test/logger_SUITE.erl b/lib/kernel/test/logger_SUITE.erl
index 82533ab572..5545759b5d 100644
--- a/lib/kernel/test/logger_SUITE.erl
+++ b/lib/kernel/test/logger_SUITE.erl
@@ -24,6 +24,7 @@
 -include_lib("common_test/include/ct.hrl").
 -include_lib("kernel/include/logger.hrl").
 -include_lib("kernel/src/logger_internal.hrl").
+-include_lib("stdlib/include/assert.hrl").
 
 -define(str,"Log from "++atom_to_list(?FUNCTION_NAME)++
             ":"++integer_to_list(?LINE)).
@@ -1009,15 +1010,14 @@ app_config(Config) ->
 %% 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.
+    %% start by calling logger:reconfigure(). 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
@@ -1025,15 +1025,13 @@ kernel_config(Config) ->
     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,[]),
+    ok = rpc:call(Node,logger,reconfigure,[]),
+    ?assertEqual(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]),
+    ok = rpc:call(Node,logger,reconfigure,[]),
     #{primary:=#{filter_default:=log,filters:=[]},
       handlers:=[],
       module_levels:=[]} = rpc:call(Node,logger,get_config,[]),
@@ -1041,30 +1039,25 @@ kernel_config(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]),
+    ok = rpc:call(Node,logger,reconfigure,[]),
     #{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]),
+    ok = rpc:call(Node,logger,reconfigure,[]),
     #{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]),
+    ok = rpc:call(Node,logger,reconfigure,[]),
     #{primary:=#{filter_default:=log,filters:=[]},
       handlers:=[#{id:=default,filters:=DF,
                    config:=#{type:=file,file:=F,modes:=Modes}}],
@@ -1073,55 +1066,47 @@ kernel_config(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]),
+    ok = rpc:call(Node,logger,reconfigure,[]),
     #{primary:=#{filter_default:=log,filters:=[]},
       handlers:=[#{id:=default,filters:=DF,
                    config:=#{type:=file,file:=F,modes:=Modes}}],
       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],
     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]),
+    ok = rpc:call(Node,logger,reconfigure,[]),
     #{primary:=#{filter_default:=log,filters:=[]},
       handlers:=[#{id:=default,filters:=DF,
                    config:=#{type:=file,file:=F,modes:=[delayed_write|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]),
     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]),
+    ok = rpc:call(Node,logger,reconfigure,[]),
     #{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]),
+    ok = rpc:call(Node,logger,reconfigure,[]),
     #{primary:=#{filter_default:=stop,filters:=[_]},
-      handlers:=[],
+      handlers:=[#{id:=simple}],
       module_levels:=[{?MODULE,debug}]} = rpc:call(Node,logger,get_config,[]),
 
     %% Bad config
@@ -1129,38 +1114,38 @@ kernel_config(Config) ->
 
     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,[]),
+        rpc:call(Node,logger,reconfigure,[]),
 
     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,[]),
+        rpc:call(Node,logger,reconfigure,[]),
 
     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,[]),
+        rpc:call(Node,logger,reconfigure,[]),
 
     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,[]),
+        rpc:call(Node,logger,reconfigure,[]),
 
     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,[]),
+        rpc:call(Node,logger,reconfigure,[]),
 
     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,[]),
+        rpc:call(Node,logger,reconfigure,[]),
 
     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,[]),
+        rpc:call(Node,logger,reconfigure,[]),
 
     ok.