feat: warning unknown config root key

apps/emqx/src/emqx_config.erl

@@ -18,6 +18,7 @@
 -compile({no_auto_import, [get/0, get/1, put/2, erase/1]}).
 -elvis([{elvis_style, god_modules, disable}]).
 -include("logger.hrl").
+-include_lib("snabbkaffe/include/snabbkaffe.hrl").
 
 -export([
     init_load/1,
@@ -323,6 +324,7 @@ init_load(SchemaMod, Conf) when is_list(Conf) orelse is_binary(Conf) ->
     ok = save_schema_mod_and_names(SchemaMod),
     HasDeprecatedFile = has_deprecated_file(),
     RawConf0 = load_config_files(HasDeprecatedFile, Conf),
+    warning_deprecated_root_key(RawConf0),
     RawConf1 =
         case HasDeprecatedFile of
             true ->
@@ -748,6 +750,22 @@ bin(Bin) when is_binary(Bin) -> Bin;
 bin(Str) when is_list(Str) -> list_to_binary(Str);
 bin(Atom) when is_atom(Atom) -> atom_to_binary(Atom, utf8).
 
+warning_deprecated_root_key(RawConf) ->
+    case maps:keys(RawConf) -- get_root_names() of
+        [] ->
+            ok;
+        Keys ->
+            Unknowns = string:join([binary_to_list(K) || K <- Keys], ","),
+            ?tp(unknown_config_keys, #{unknown_config_keys => Unknowns}),
+            ?SLOG(
+                warning,
+                #{
+                    msg => "config_key_not_recognized",
+                    unknown_config_keys => Unknowns
+                }
+            )
+    end.
+
 conf_key(?CONF, RootName) ->
     atom(RootName);
 conf_key(?RAW_CONF, RootName) ->

apps/emqx/test/emqx_config_SUITE.erl

@@ -19,6 +19,7 @@
 -compile(export_all).
 -compile(nowarn_export_all).
 -include_lib("eunit/include/eunit.hrl").
+-include_lib("snabbkaffe/include/snabbkaffe.hrl").
 
 all() -> emqx_common_test_helpers:all(?MODULE).
 
@@ -77,3 +78,21 @@ t_init_load(_Config) ->
     ?assertEqual(ExpectRootNames, lists:sort(emqx_config:get_root_names())),
     ?assertMatch({ok, #{raw_config := 128}}, emqx:update_config([mqtt, max_topic_levels], 128)),
     ok = file:delete(DeprecatedFile).
+
+t_unknown_rook_keys(_) ->
+    ?check_trace(
+        #{timetrap => 1000},
+        begin
+            ok = emqx_config:init_load(
+                emqx_schema, <<"test_1 {}\n test_2 {sub = 100}\n listeners {}">>
+            ),
+            ?block_until(#{?snk_kind := unknown_config_keys})
+        end,
+        fun(Trace) ->
+            ?assertMatch(
+                [#{unknown_config_keys := "test_1,test_2"}],
+                ?of_kind(unknown_config_keys, Trace)
+            )
+        end
+    ),
+    ok.