refactor: do not cache in persistent_term for dryrun resources

apps/emqx_resource/src/emqx_resource_cache.erl

@@ -34,6 +34,7 @@
     manager_pid :: pid(),
     st_err :: st_err(),
     config :: term(),
+    stable :: term(),
     extra = []
 }).
 
@@ -69,6 +70,13 @@ write(ManagerPid, Group, Data) ->
         status := Status,
         added_channels := AddedChannels
     } = Data,
+    Stable = #{
+        mod => Mod,
+        callback_mode => CallbackMode,
+        query_mode => QueryMode,
+        state => State
+    },
+    IsDryrun = emqx_resource:is_dry_run(ID),
     Connector = #connector{
         id = ID,
         group = Group,
@@ -78,19 +86,27 @@ write(ManagerPid, Group, Data) ->
             error => external_error(Error)
         },
         config = Config,
+        stable =
+            case IsDryrun of
+                true ->
+                    %% save stable part in ets for dryrun
+                    Stable;
+                false ->
+                    undefined
+            end,
         extra = []
     },
     Channels = lists:map(fun to_channel_record/1, maps:to_list(AddedChannels)),
-    Stable = #{
-        mod => Mod,
-        callback_mode => CallbackMode,
-        query_mode => QueryMode,
-        state => State
-    },
     %% erase old channels (if any)
     ok = erase_old_channels(ID, maps:keys(AddedChannels)),
     %% put stable state in persistent_term
-    ok = put_state_pt(ID, Stable),
+    case IsDryrun of
+        true ->
+            %% do not write persistent_term for dryrun
+            ok;
+        false ->
+            ok = put_state_pt(ID, Stable)
+    end,
     %% insert connector and channel states
     true = ets:insert(?RESOURCE_STATE_CACHE, [Connector | Channels]),
     ok.
@@ -118,13 +134,22 @@ read_manager_pid(ID) ->
 
 -spec read_mod(resource_id()) -> not_found | {ok, module()}.
 read_mod(ID) ->
-    case get_state_pt(ID) of
+    case get_state(ID) of
         undefined ->
             not_found;
         #{mod := Mod} ->
             {ok, Mod}
     end.
 
+get_state(ID) ->
+    case get_state_pt(ID) of
+        undefined ->
+            %% maybe it's a dryrun connector
+            ets:lookup_element(?RESOURCE_STATE_CACHE, ConnectorId, #connector.stable, undefined);
+        InPt ->
+            InPt
+    end.
+
 -spec erase(resource_id()) -> ok.
 erase(ID) ->
     MS = ets:fun2ms(fun(#channel{id = {C, _}}) when C =:= ID -> true end),
@@ -172,7 +197,7 @@ all_ids() ->
 get_runtime(ID) ->
     ChanKey = {ConnectorId, _ChanID} = split_channel_id(ID),
     try
-        Stable = get_state_pt(ConnectorId),
+        Stable = get_state(ConnectorId),
         ChannelStatus = get_channel_status(ChanKey),
         StErr = ets:lookup_element(?RESOURCE_STATE_CACHE, ConnectorId, #connector.st_err),
         {ok, #rt{
@@ -253,15 +278,22 @@ make_resource_data(ID, Connector, Channels) ->
             error := Error,
             status := Status
         },
-        config = Config
+        config = Config,
+        stable = Stable0
     } = Connector,
+    Stable =
+        case Stable0 of
+            undefined ->
+                get_state_pt(ID);
+            X ->
+                X
+        end,
     #{
         mod := Mod,
         callback_mode := CallbackMode,
         query_mode := QueryMode,
         state := State
-    } = get_state_pt(ID),
-
+    } = Stable,
     #{
         id => ID,
         mod => Mod,