Add tracing support for metadata notfound

src/lager_util.erl

@@ -392,6 +392,7 @@ validate_trace_filter(Filter) when is_tuple(Filter), is_atom(element(1, Filter))
     false;
 validate_trace_filter(Filter) ->
         case lists:all(fun({Key, '*'}) when is_atom(Key) -> true; 
+                          ({Key, '!'}) when is_atom(Key) -> true;
                           ({Key, _Value})      when is_atom(Key) -> true;
                           ({Key, '=', _Value}) when is_atom(Key) -> true;
                           ({Key, '<', _Value}) when is_atom(Key) -> true;
@@ -416,6 +417,8 @@ trace_acc([], Acc) ->
 	lists:reverse(Acc);
 trace_acc([{Key, '*'}|T], Acc) ->
 	trace_acc(T, [glc:wc(Key)|Acc]);
+trace_acc([{Key, '!'}|T], Acc) ->
+	trace_acc(T, [glc:nf(Key)|Acc]);
 trace_acc([{Key, Val}|T], Acc) ->
 	trace_acc(T, [glc:eq(Key, Val)|Acc]);
 trace_acc([{Key, '=', Val}|T], Acc) ->

test/lager_test_backend.erl

@@ -388,10 +388,15 @@ lager_test_() ->
                         lager:info([{requestid, 8}], "hello world"),
                         lager:info([{requestid, 9}, {foo, bar}], "hello world"),
                         lager:info([{requestid, 10}], "hello world"),
-                        ?assertEqual(7, count()),
+                        lager:trace(?MODULE, [{fu, '!'}]),
+                        lager:info([{foo, bar}], "hello world"),
+                        lager:info([{ooh, car}], "hello world"),
+                        lager:trace(?MODULE, [{fu, '*'}]),
+                        lager:info([{fu, bar}], "hello world"),
+                        ?assertEqual(10, count()),
                         lager:clear_all_traces(),
                         lager:info([{requestid, 6}], "hello world"),
-                        ?assertEqual(7, count()),
+                        ?assertEqual(10, count()),
                         ok
                 end
             },