fix(bridge): prohibit deleting connectors that are in use

apps/emqx_bridge/src/emqx_bridge.erl

@@ -259,7 +259,7 @@ update(Type, Name, {OldConf, Conf}) ->
     end.
 
 recreate(Type, Name) ->
-    recreate(Type, Name, emqx:get_raw_config([bridges, Type, Name])).
+    recreate(Type, Name, emqx:get_config([bridges, Type, Name])).
 
 recreate(Type, Name, Conf) ->
     emqx_resource:recreate_local(resource_id(Type, Name),

apps/emqx_connector/src/emqx_connector.erl

@@ -37,31 +37,26 @@
 config_key_path() ->
     [connectors].
 
+-dialyzer([{nowarn_function, [post_config_update/5]}, error_handling]).
 post_config_update([connectors, Type, Name], '$remove', _, _OldConf, _AppEnvs) ->
     ConnId = connector_id(Type, Name),
-    LinkedBridgeIds = lists:foldl(fun
+    try foreach_linked_bridges(ConnId, fun(#{id := BId}) ->
-        (#{id := BId, raw_config := #{<<"connector">> := ConnId0}}, Acc)
+            throw({dependency_bridges_exist, BId})
-                when ConnId0 == ConnId ->
+        end)
-            [BId | Acc];
+    catch throw:Error -> {error, Error}
-        (_, Acc) -> Acc
-    end, [], emqx_bridge:list()),
-    case LinkedBridgeIds of
-        [] -> ok;
-        _ -> {error, {dependency_bridges_exist, LinkedBridgeIds}}
     end;
-post_config_update([connectors, Type, Name], _Req, NewConf, _OldConf, _AppEnvs) ->
+post_config_update([connectors, Type, Name], _Req, NewConf, OldConf, _AppEnvs) ->
     ConnId = connector_id(Type, Name),
-    lists:foreach(fun
+    foreach_linked_bridges(ConnId,
-        (#{id := BId, raw_config := #{<<"connector">> := ConnId0}}) when ConnId0 == ConnId ->
+        fun(#{id := BId}) ->
             {BType, BName} = emqx_bridge:parse_bridge_id(BId),
             BridgeConf = emqx:get_config([bridges, BType, BName]),
-            case emqx_bridge:recreate(BType, BName, BridgeConf#{connector => NewConf}) of
+            case emqx_bridge:update(BType, BName, {BridgeConf#{connector => OldConf},
-                {ok, _} -> ok;
+                    BridgeConf#{connector => NewConf}}) of
+                ok -> ok;
                 {error, Reason} -> error({update_bridge_error, Reason})
-            end;
+            end
-        (_) ->
+        end).
-            ok
-    end, emqx_bridge:list()).
 
 connector_id(Type0, Name0) ->
     Type = bin(Type0),
@@ -112,3 +107,10 @@ delete(Type, Name) ->
 bin(Bin) when is_binary(Bin) -> Bin;
 bin(Str) when is_list(Str) -> list_to_binary(Str);
 bin(Atom) when is_atom(Atom) -> atom_to_binary(Atom, utf8).
+
+foreach_linked_bridges(ConnId, Do) ->
+    lists:foreach(fun
+        (#{raw_config := #{<<"connector">> := ConnId0}} = Bridge) when ConnId0 == ConnId ->
+            Do(Bridge);
+        (_) -> ok
+    end, emqx_bridge:list()).

apps/emqx_connector/src/emqx_connector_api.erl

@@ -253,6 +253,10 @@ schema("/connectors/:id") ->
             {ok, _} ->
                 case emqx_connector:delete(ConnType, ConnName) of
                     {ok, _} -> {204};
+                    {error, {post_config_update, _, {dependency_bridges_exist, BridgeID}}} ->
+                        {403, error_msg('DEPENDENCY_EXISTS',
+                             <<"Cannot remove the connector as it's in use by a bridge: ",
+                                BridgeID/binary>>)};
                     {error, Error} -> {400, error_msg('BAD_ARG', Error)}
                 end;
             {error, not_found} ->

apps/emqx_connector/test/emqx_connector_api_SUITE.erl

@@ -108,6 +108,9 @@ end_per_suite(_Config) ->
 
 init_per_testcase(_, Config) ->
     {ok, _} = emqx_cluster_rpc:start_link(node(), emqx_cluster_rpc, 1000),
+    %% assert we there's no connectors and no bridges at first
+    {ok, 200, <<"[]">>} = request(get, uri(["connectors"]), []),
+    {ok, 200, <<"[]">>} = request(get, uri(["bridges"]), []),
     Config.
 end_per_testcase(_, _Config) ->
     clear_resources(),
@@ -200,10 +203,6 @@ t_mqtt_crud_apis(_) ->
     ok.
 
 t_mqtt_conn_bridge_ingress(_) ->
-    %% assert we there's no connectors and no bridges at first
-    {ok, 200, <<"[]">>} = request(get, uri(["connectors"]), []),
-    {ok, 200, <<"[]">>} = request(get, uri(["bridges"]), []),
-
     %% then we add a mqtt connector, using POST
     User1 = <<"user1">>,
     {ok, 201, Connector} = request(post, uri(["connectors"]),
@@ -272,10 +271,6 @@ t_mqtt_conn_bridge_ingress(_) ->
     ok.
 
 t_mqtt_conn_bridge_egress(_) ->
-    %% assert we there's no connectors and no bridges at first
-    {ok, 200, <<"[]">>} = request(get, uri(["connectors"]), []),
-    {ok, 200, <<"[]">>} = request(get, uri(["bridges"]), []),
-
     %% then we add a mqtt connector, using POST
     User1 = <<"user1">>,
     {ok, 201, Connector} = request(post, uri(["connectors"]),
@@ -350,10 +345,6 @@ t_mqtt_conn_bridge_egress(_) ->
 %% - update a connector should also update all of the the bridges
 %% - cannot delete a connector that is used by at least one bridge
 t_mqtt_conn_update(_) ->
-    %% assert we there's no connectors and no bridges at first
-    {ok, 200, <<"[]">>} = request(get, uri(["connectors"]), []),
-    {ok, 200, <<"[]">>} = request(get, uri(["bridges"]), []),
-
     %% then we add a mqtt connector, using POST
     {ok, 201, Connector} = request(post, uri(["connectors"]),
                             ?MQTT_CONNECOTR2(<<"127.0.0.1:1883">>)
@@ -396,10 +387,6 @@ t_mqtt_conn_update(_) ->
     {ok, 200, <<"[]">>} = request(get, uri(["connectors"]), []).
 
 t_mqtt_conn_update2(_) ->
-    %% assert we there's no connectors and no bridges at first
-    {ok, 200, <<"[]">>} = request(get, uri(["connectors"]), []),
-    {ok, 200, <<"[]">>} = request(get, uri(["bridges"]), []),
-
     %% then we add a mqtt connector, using POST
     %% but this connector is point to a unreachable server "2603"
     {ok, 201, Connector} = request(post, uri(["connectors"]),
@@ -440,6 +427,34 @@ t_mqtt_conn_update2(_) ->
     {ok, 204, <<>>} = request(delete, uri(["connectors", ConnctorID]), []),
     {ok, 200, <<"[]">>} = request(get, uri(["connectors"]), []).
 
+t_mqtt_conn_update3(_) ->
+    %% we add a mqtt connector, using POST
+    {ok, 201, Connector} = request(post, uri(["connectors"]),
+                            ?MQTT_CONNECOTR2(<<"127.0.0.1:1883">>)
+                                #{ <<"type">> => ?CONNECTR_TYPE
+                                 , <<"name">> => ?CONNECTR_NAME
+                                 }),
+    #{ <<"id">> := ConnctorID } = jsx:decode(Connector),
+
+    %% ... and a MQTT bridge, using POST
+    %% we bind this bridge to the connector created just now
+    {ok, 201, Bridge} = request(post, uri(["bridges"]),
+        ?MQTT_BRIDGE_EGRESS(ConnctorID)#{
+            <<"type">> => ?CONNECTR_TYPE,
+            <<"name">> => ?BRIDGE_NAME_EGRESS
+        }),
+    #{ <<"id">> := BridgeIDEgress
+     , <<"status">> := <<"connected">>
+     , <<"connector">> := ConnctorID
+     } = jsx:decode(Bridge),
+
+    %% delete the connector should fail because it is in use by a bridge
+    {ok, 403, _} = request(delete, uri(["connectors", ConnctorID]), []),
+    %% delete the bridge
+    {ok, 204, <<>>} = request(delete, uri(["bridges", BridgeIDEgress]), []),
+    %% the connector now can be deleted without problems
+    {ok, 204, <<>>} = request(delete, uri(["connectors", ConnctorID]), []).
+
 t_mqtt_conn_testing(_) ->
     %% APIs for testing the connectivity
     %% then we add a mqtt connector, using POST