fix: function_clause when sending messages to bridges

apps/emqx_bridge/src/emqx_bridge.erl

@@ -363,10 +363,13 @@ get_matched_egress_bridges(Topic) ->
 
 get_matched_bridge_id(_BType, #{enable := false}, _Topic, _BName, Acc) ->
     Acc;
-get_matched_bridge_id(BType, #{local_topic := Filter}, Topic, BName, Acc) when
-    ?EGRESS_DIR_BRIDGES(BType)
-->
-    do_get_matched_bridge_id(Topic, Filter, BType, BName, Acc);
+get_matched_bridge_id(BType, Conf, Topic, BName, Acc) when ?EGRESS_DIR_BRIDGES(BType) ->
+    case maps:get(local_topic, Conf, undefined) of
+        undefined ->
+            Acc;
+        Filter ->
+            do_get_matched_bridge_id(Topic, Filter, BType, BName, Acc)
+    end;
 get_matched_bridge_id(mqtt, #{egress := #{local := #{topic := Filter}}}, Topic, BName, Acc) ->
     do_get_matched_bridge_id(Topic, Filter, mqtt, BName, Acc);
 get_matched_bridge_id(kafka, #{producer := #{mqtt := #{topic := Filter}}}, Topic, BName, Acc) ->

apps/emqx_bridge/test/emqx_bridge_api_SUITE.erl

@@ -305,6 +305,55 @@ t_http_crud_apis(Config) ->
     ),
     ok.
 
+t_http_bridges_local_topic(Config) ->
+    Port = ?config(port, Config),
+    %% assert we there's no bridges at first
+    {ok, 200, <<"[]">>} = request(get, uri(["bridges"]), []),
+
+    %% then we add a webhook bridge, using POST
+    %% POST /bridges/ will create a bridge
+    URL1 = ?URL(Port, "path1"),
+    Name1 = <<"t_http_bridges_with_local_topic1">>,
+    Name2 = <<"t_http_bridges_without_local_topic1">>,
+    %% create one http bridge with local_topic
+    {ok, 201, _} = request(
+        post,
+        uri(["bridges"]),
+        ?HTTP_BRIDGE(URL1, ?BRIDGE_TYPE, Name1)
+    ),
+    %% and we create another one without local_topic
+    {ok, 201, _} = request(
+        post,
+        uri(["bridges"]),
+        maps:remove(<<"local_topic">>, ?HTTP_BRIDGE(URL1, ?BRIDGE_TYPE, Name2))
+    ),
+    BridgeID1 = emqx_bridge_resource:bridge_id(?BRIDGE_TYPE, Name1),
+    BridgeID2 = emqx_bridge_resource:bridge_id(?BRIDGE_TYPE, Name2),
+    %% Send an message to emqx and the message should be forwarded to the HTTP server.
+    %% This is to verify we can have 2 bridges with and without local_topic fields
+    %% at the same time.
+    Body = <<"my msg">>,
+    emqx:publish(emqx_message:make(<<"emqx_webhook/1">>, Body)),
+    ?assert(
+        receive
+            {http_server, received, #{
+                method := <<"POST">>,
+                path := <<"/path1">>,
+                body := Body
+            }} ->
+                true;
+            Msg ->
+                ct:pal("error: http got unexpected request: ~p", [Msg]),
+                false
+        after 100 ->
+            false
+        end
+    ),
+    %% delete the bridge
+    {ok, 204, <<>>} = request(delete, uri(["bridges", BridgeID1]), []),
+    {ok, 204, <<>>} = request(delete, uri(["bridges", BridgeID2]), []),
+    ok.
+
 t_check_dependent_actions_on_delete(Config) ->
     Port = ?config(port, Config),
     %% assert we there's no bridges at first

changes/v5.0.14/fix-9687.en.md

@@ -0,0 +1,2 @@
+Fix the problem that sending messages to data-bridges failed because of incorrect handling of some data-bridges without `local_topic` field configured.
+Before this change, if some bridges have configured the `local_topic` field but others have not, a `function_clause` error will occur when forwarding messages to the data-bridges.

changes/v5.0.14/fix-9687.zh.md

@@ -0,0 +1,2 @@
+修复由于某些数据桥接未配置 `local_topic` 字段，导致的所有数据桥接无法发送消息。
+在此改动之前，如果有些桥接设置了 `local_topic` 字段而有些没有设置，数据桥接转发消息时会出现 `function_clause` 的错误。