fix: incorrect message order when batch is enabled

apps/emqx_resource/src/emqx_resource_worker.erl

@@ -303,11 +303,12 @@ flush(#{acc := []} = St) ->
 flush(
     #{
         id := Id,
-        acc := Batch,
+        acc := Batch0,
         batch_size := Size,
         queue := Q0
     } = St
 ) ->
+    Batch = lists:reverse(Batch0),
     QueryOpts = #{
         inflight_name => maps:get(name, St),
         inflight_window => maps:get(async_inflight_window, St)
@@ -393,12 +394,12 @@ handle_query_result(Id, ?RESOURCE_ERROR_M(Reason, _), BlockWorker) ->
     emqx_metrics_worker:inc(?RES_METRICS, Id, 'dropped'),
     emqx_metrics_worker:inc(?RES_METRICS, Id, 'dropped.other'),
     BlockWorker;
-handle_query_result(Id, {error, _}, BlockWorker) ->
-    emqx_metrics_worker:inc(?RES_METRICS, Id, 'sent.failed'),
-    BlockWorker;
 handle_query_result(Id, {error, {recoverable_error, _}}, _BlockWorker) ->
     emqx_metrics_worker:inc(?RES_METRICS, Id, 'sent', -1),
     true;
+handle_query_result(Id, {error, _}, BlockWorker) ->
+    emqx_metrics_worker:inc(?RES_METRICS, Id, 'sent.failed'),
+    BlockWorker;
 handle_query_result(_Id, {async_return, inflight_full}, _BlockWorker) ->
     true;
 handle_query_result(Id, {async_return, {error, _}}, BlockWorker) ->
@@ -449,7 +450,15 @@ call_query(QM0, Id, Query, QueryOpts) ->
 apply_query_fun(sync, Mod, Id, ?QUERY(_, Request) = _Query, ResSt, _QueryOpts) ->
     ?tp(call_query, #{id => Id, mod => Mod, query => _Query, res_st => ResSt}),
     ok = emqx_metrics_worker:inc(?RES_METRICS, Id, 'sent'),
-    ?APPLY_RESOURCE(Mod:on_query(Id, Request, ResSt), Request);
+    ?APPLY_RESOURCE(
+        begin
+            ok = emqx_metrics_worker:inc(?RES_METRICS, Id, 'sent.inflight'),
+            Result = Mod:on_query(Id, Request, ResSt),
+            ok = emqx_metrics_worker:inc(?RES_METRICS, Id, 'sent.inflight', -1),
+            Result
+        end,
+        Request
+    );
 apply_query_fun(async, Mod, Id, ?QUERY(_, Request) = Query, ResSt, QueryOpts) ->
     ?tp(call_query_async, #{id => Id, mod => Mod, query => Query, res_st => ResSt}),
     Name = maps:get(inflight_name, QueryOpts, undefined),
@@ -475,7 +484,15 @@ apply_query_fun(sync, Mod, Id, [?QUERY(_, _) | _] = Batch, ResSt, _QueryOpts) ->
     ?tp(call_batch_query, #{id => Id, mod => Mod, batch => Batch, res_st => ResSt}),
     Requests = [Request || ?QUERY(_From, Request) <- Batch],
     ok = emqx_metrics_worker:inc(?RES_METRICS, Id, 'sent', length(Batch)),
-    ?APPLY_RESOURCE(Mod:on_batch_query(Id, Requests, ResSt), Batch);
+    ?APPLY_RESOURCE(
+        begin
+            ok = emqx_metrics_worker:inc(?RES_METRICS, Id, 'sent.inflight'),
+            Result = Mod:on_batch_query(Id, Requests, ResSt),
+            ok = emqx_metrics_worker:inc(?RES_METRICS, Id, 'sent.inflight', -1),
+            Result
+        end,
+        Batch
+    );
 apply_query_fun(async, Mod, Id, [?QUERY(_, _) | _] = Batch, ResSt, QueryOpts) ->
     ?tp(call_batch_query_async, #{id => Id, mod => Mod, batch => Batch, res_st => ResSt}),
     Name = maps:get(inflight_name, QueryOpts, undefined),