perf(emqx_placeholder): do not try to decode maps as json

fix

apps/emqx_utils/src/emqx_placeholder.erl

@@ -265,11 +265,16 @@ lookup_var(Var, Value) when Var == ?PH_VAR_THIS orelse Var == [] ->
     Value;
 lookup_var([Prop | Rest], Data0) ->
     Data =
+        case is_map(Data0) of
+            true ->
+                Data0;
+            false ->
                 case emqx_utils_json:safe_decode(Data0, [return_maps]) of
                     {ok, Data1} ->
                         Data1;
                     {error, _} ->
                         Data0
+                end
         end,
     case lookup(Prop, Data) of
         {ok, Value} ->
@@ -293,12 +298,10 @@ lookup(Prop, Data) when is_binary(Prop) ->
     end.
 
 do_one_lookup(Key, Data) ->
-    try
+    case Data of
-        {ok, maps:get(Key, Data)}
+        #{Key := Value} ->
-    catch
+            {ok, Value};
-        error:{badkey, _} ->
+        _ ->
-            {error, undefined};
-        error:{badmap, _} ->
             {error, undefined}
     end.
 

changes/ce/perf-13118.en.md

@@ -0,0 +1 @@
+Improve performance of template rendering in bridges.