[logger] Add SetOrUpdate parameter to handler callback changing_config

Since logger has now knowledge of the handler specific data ('config'
field in the handler configuration map), it can not merge this data
structure with default or old values upon configuration
change. Instead, the handler callback changing_config must do
this. Earlier, this callback did not reflect if the configuration
change was initiated by a call to set_handler_config or
update_handler_config, so the handler did not know if unspecified
fields should get default values or the values from the existing
configuration.

To overcome this problem, the new parameter SetOrUpdate is added to
this callback. If SetOrUpdate equals set, then default values should
be used. If SetOrUpdate equals update, then existing configuration
values should be used.

1 files changed, 44 insertions, 20 deletions

diff --git a/lib/kernel/src/logger_server.erl b/lib/kernel/src/logger_server.erl
index a1d40f1123..a14de2664e 100644
--- a/lib/kernel/src/logger_server.erl
+++ b/lib/kernel/src/logger_server.erl
@@ -105,12 +105,17 @@ cache_module_level(Module) ->
     gen_server:cast(?SERVER,{cache_module_level,Module}).
 
 set_config(Owner,Key,Value) ->
-    update_config(Owner,#{Key=>Value}).
+    case sanity_check(Owner,Key,Value) of
+        ok ->
+            call({change_config,set,Owner,Key,Value});
+        Error ->
+            Error
+    end.
 
 set_config(Owner,Config) ->
     case sanity_check(Owner,Config) of
         ok ->
-            call({set_config,Owner,Config});
+            call({change_config,set,Owner,Config});
         Error ->
             Error
     end.
@@ -118,7 +123,7 @@ set_config(Owner,Config) ->
 update_config(Owner, Config) ->
     case sanity_check(Owner,Config) of
         ok ->
-            call({update_config,Owner,Config});
+            call({change_config,update,Owner,Config});
         Error ->
             Error
     end.
@@ -204,17 +209,35 @@ handle_call({add_filter,Id,Filter}, _From,#state{tid=Tid}=State) ->
 handle_call({remove_filter,Id,FilterId}, _From, #state{tid=Tid}=State) ->
     Reply = do_remove_filter(Tid,Id,FilterId),
     {reply,Reply,State};
-handle_call({update_config,primary,NewConfig}, _From, #state{tid=Tid}=State) ->
+handle_call({change_config,SetOrUpd,primary,Config0}, _From,
+            #state{tid=Tid}=State) ->
+    {ok,#{handlers:=Handlers}=OldConfig} = logger_config:get(Tid,primary),
+    Default =
+        case SetOrUpd of
+            set -> default_config(primary);
+            update -> OldConfig
+        end,
+    Config = maps:merge(Default,Config0),
+    Reply = logger_config:set(Tid,primary,Config#{handlers=>Handlers}),
+    {reply,Reply,State};
+handle_call({change_config,_SetOrUpd,primary,Key,Value}, _From,
+            #state{tid=Tid}=State) ->
     {ok,OldConfig} = logger_config:get(Tid,primary),
-    Config = maps:merge(OldConfig,NewConfig),
-    {reply,logger_config:set(Tid,primary,Config),State};
-handle_call({update_config,HandlerId,NewConfig}, From, #state{tid=Tid}=State) ->
+    Reply = logger_config:set(Tid,primary,OldConfig#{Key=>Value}),
+    {reply,Reply,State};
+handle_call({change_config,SetOrUpd,HandlerId,Config0}, From,
+            #state{tid=Tid}=State) ->
     case logger_config:get(Tid,HandlerId) of
         {ok,#{module:=Module}=OldConfig} ->
-            Config = maps:merge(OldConfig,NewConfig),
+            Default =
+                case SetOrUpd of
+                    set -> default_config(HandlerId,Module);
+                    update -> OldConfig
+                end,
+            Config = maps:merge(Default,Config0),
             call_h_async(
               fun() ->
-                      call_h(Module,changing_config,[OldConfig,Config],
+                      call_h(Module,changing_config,[SetOrUpd,OldConfig,Config],
                              {ok,Config})
               end,
               fun({ok,Config1}) ->
@@ -222,21 +245,17 @@ handle_call({update_config,HandlerId,NewConfig}, From, #state{tid=Tid}=State) ->
                  (Error) ->
                       Error
               end,From,State);
-        Error ->
-            {reply,Error,State}
+        _ ->
+            {reply,{error,{not_found,HandlerId}},State}
     end;
-handle_call({set_config,primary,Config0}, _From, #state{tid=Tid}=State) ->
-    Config = maps:merge(default_config(primary),Config0),
-    {ok,#{handlers:=Handlers}} = logger_config:get(Tid,primary),
-    Reply = logger_config:set(Tid,primary,Config#{handlers=>Handlers}),
-    {reply,Reply,State};
-handle_call({set_config,HandlerId,Config0}, From, #state{tid=Tid}=State) ->
+handle_call({change_config,SetOrUpd,HandlerId,Key,Value}, From,
+            #state{tid=Tid}=State) ->
     case logger_config:get(Tid,HandlerId) of
         {ok,#{module:=Module}=OldConfig} ->
-            Config = maps:merge(default_config(HandlerId,Module),Config0),
+            Config = OldConfig#{Key=>Value},
             call_h_async(
               fun() ->
-                      call_h(Module,changing_config,[OldConfig,Config],
+                      call_h(Module,changing_config,[SetOrUpd,OldConfig,Config],
                              {ok,Config})
               end,
               fun({ok,Config1}) ->
@@ -320,7 +339,7 @@ call(Request) ->
         true when
               Action == add_handler; Action == remove_handler;
               Action == add_filter; Action == remove_filter;
-              Action == update_config; Action == set_config ->
+              Action == change_config ->
             {error,{attempting_syncronous_call_to_self,Request}};
         _ ->
             gen_server:call(?SERVER,Request,?DEFAULT_LOGGER_CALL_TIMEOUT)
@@ -466,6 +485,11 @@ call_h(Module, Function, Args, DefRet) ->
     catch
         C:R:S ->
             case {C,R,S} of
+                {error,undef,[{Module,Function=changing_config,Args,_}|_]}
+                  when length(Args)=:=3 ->
+                    %% Backwards compatible call, if changing_config/3
+                    %% did not exist.
+                    call_h(Module, Function, tl(Args), DefRet);
                 {error,undef,[{Module,Function,Args,_}|_]} ->
                     DefRet;
                 _ ->