fix(rule_engine): reformat some code for dependent rules discovery

apps/emqx_rule_engine/src/emqx_rule_engine.erl

@@ -249,40 +249,30 @@ create_resource(#{type := Type, config := Config0} = Params) ->
 
 -spec(update_resource(resource_id(), map()) -> ok | {error, Reason :: term()}).
 update_resource(ResId, NewParams) ->
-    try
-        lists:foreach(fun(#rule{id = RuleId, enabled = Enabled, actions = Actions}) ->
-            lists:foreach(
-                fun (#action_instance{args = #{<<"$resource">> := ResId1}})
-                    when ResId =:= ResId1, Enabled =:= true ->
-                        throw({dependency_exists, RuleId});
-                    (_) -> ok
-                end, Actions)
-            end, ets:tab2list(?RULE_TAB)),
-        do_update_resource_check(ResId, NewParams)
-    catch _ : Reason ->
-        {error, Reason}
+    case emqx_rule_registry:find_enabled_rules_depends_on_resource(ResId) of
+        [] -> check_and_update_resource(ResId, NewParams);
+        Rules ->
+            {error, {dependent_rules_exists, [Id || #rule{id = Id} <- Rules]}}
     end.
 
-do_update_resource_check(Id, NewParams) ->
+check_and_update_resource(Id, NewParams) ->
     case emqx_rule_registry:find_resource(Id) of
-        {ok, #resource{id = Id,
-                       type = Type,
-                       config = OldConfig,
-                       description = OldDescription} = _OldResource} ->
+        {ok, #resource{id = Id, type = Type, config = OldConfig, description = OldDescr}} ->
             try
                 Conifg = maps:get(<<"config">>, NewParams, OldConfig),
-                Descr = maps:get(<<"description">>, NewParams, OldDescription),
-                do_update_resource(#{id => Id, config => Conifg, type => Type,
-                                     description => Descr}),
-                ok
-            catch _ : Reason ->
+                Descr = maps:get(<<"description">>, NewParams, OldDescr),
+                do_check_and_update_resource(#{id => Id, config => Conifg, type => Type,
+                    description => Descr})
+            catch Error:Reason:ST ->
+                ?LOG(error, "check_and_update_resource failed: ~0p", [{Error, Reason, ST}]),
                 {error, Reason}
             end;
         _Other ->
             {error, not_found}
     end.
 
-do_update_resource(#{id := Id, type := Type, description := NewDescription, config := NewConfig}) ->
+do_check_and_update_resource(#{id := Id, type := Type, description := NewDescription,
+                               config := NewConfig}) ->
     case emqx_rule_registry:find_resource_type(Type) of
         {ok, #resource_type{on_create = {Module, Create},
                             params_spec = ParamSpec}} ->
@@ -296,7 +286,8 @@ do_update_resource(#{id := Id, type := Type, description := NewDescription, conf
                         config = Config,
                         description = NewDescription,
                         created_at = erlang:system_time(millisecond)
-                    });
+                    }),
+                    ok;
                {error, Reason} ->
                     error({error, Reason})
             end

apps/emqx_rule_engine/src/emqx_rule_engine_api.erl

@@ -180,6 +180,7 @@
 -define(ERR_NO_ACTION(NAME), list_to_binary(io_lib:format("Action ~s Not Found", [(NAME)]))).
 -define(ERR_NO_RESOURCE(RESID), list_to_binary(io_lib:format("Resource ~s Not Found", [(RESID)]))).
 -define(ERR_NO_RESOURCE_TYPE(TYPE), list_to_binary(io_lib:format("Resource Type ~s Not Found", [(TYPE)]))).
+-define(ERR_DEP_RULES_EXISTS(RULEIDS), list_to_binary(io_lib:format("Found rules ~0p depends on this resource, disable them first", [(RULEIDS)]))).
 -define(ERR_BADARGS(REASON),
         begin
             R0 = list_to_binary(io_lib:format("~0p", [REASON])),
@@ -342,14 +343,11 @@ update_resource(#{id := Id}, NewParams) ->
         ok ->
             return(ok);
         {error, not_found} ->
-            ?LOG(error, "Resource not found: ~0p", [Id]),
             return({error, 400, <<"Resource not found:", Id/binary>>});
         {error, {init_resource, _}} ->
-            ?LOG(error, "Init resource failure: ~0p", [Id]),
             return({error, 500, <<"Init resource failure:", Id/binary>>});
-        {error, {dependency_exists, RuleId}} ->
-            ?LOG(error, "Dependency exists: ~0p", [RuleId]),
-            return({error, 500, <<"Dependency exists:", RuleId/binary>>});
+        {error, {dependent_rules_exists, RuleIds}} ->
+            return({error, 400, ?ERR_DEP_RULES_EXISTS(RuleIds)});
         {error, Reason} ->
             ?LOG(error, "Resource update failed: ~0p", [Reason]),
             return({error, 500, <<"Resource update failed!">>})
@@ -359,6 +357,8 @@ delete_resource(#{id := Id}, _Params) ->
     case emqx_rule_engine:delete_resource(Id) of
         ok -> return(ok);
         {error, not_found} -> return(ok);
+        {error, {dependent_rules_exists, RuleIds}} ->
+            return({error, 400, ?ERR_DEP_RULES_EXISTS(RuleIds)});
         {error, Reason} ->
             return({error, 400, ?ERR_BADARGS(Reason)})
     end.

apps/emqx_rule_engine/src/emqx_rule_registry.erl

@@ -63,6 +63,8 @@
 %% Resource Types
 -export([ get_resource_types/0
         , find_resource_type/1
+        , find_rules_depends_on_resource/1
+        , find_enabled_rules_depends_on_resource/1
         , register_resource_types/1
         , unregister_resource_types_of/1
         ]).
@@ -368,20 +370,33 @@ remove_resource_params(ResId) ->
 
 %% @private
 delete_resource(ResId) ->
-    lists:foreach(fun(#rule{id = Id, actions = Actions}) ->
-        lists:foreach(
-            fun (#action_instance{args = #{<<"$resource">> := ResId1}})
-                when ResId =:= ResId1 ->
-                    throw({dependency_exists, {rule, Id}});
-                (_) -> ok
-            end, Actions)
-    end, get_rules()),
+    case find_enabled_rules_depends_on_resource(ResId) of
+        [] -> ok;
+        Rules ->
+            throw({dependent_rules_exists, [Id || #rule{id = Id} <- Rules]})
+    end,
     mnesia:delete(?RES_TAB, ResId, write).
 
 %% @private
 insert_resource(Resource) ->
     mnesia:write(?RES_TAB, Resource, write).
 
+find_enabled_rules_depends_on_resource(ResId) ->
+    [R || #rule{enabled = true} = R <- find_rules_depends_on_resource(ResId)].
+
+find_rules_depends_on_resource(ResId) ->
+    lists:foldl(fun(#rule{actions = Actions} = R, Rules) ->
+        case search_action_despends_on_resource(ResId, Actions) of
+            false -> Rules;
+            {value, _} -> [R | Rules]
+        end
+    end, [], get_rules()).
+
+search_action_despends_on_resource(ResId, Actions) ->
+    lists:search(fun(#action_instance{args = #{<<"$resource">> := ResId0}}) ->
+        ResId0 =:= ResId
+    end, Actions).
+
 %%------------------------------------------------------------------------------
 %% Resource Type Management
 %%------------------------------------------------------------------------------