fix(mqtt_bridge): refine the message format from a mqtt bridge source

apps/emqx_connector/src/mqtt/emqx_connector_mqtt_mod.erl

@@ -213,16 +213,15 @@ maybe_publish_to_local_broker(#{topic := Topic} = Msg, #{remote_topic := SubTopi
 
 format_msg_received(#{dup := Dup, payload := Payload, properties := Props,
         qos := QoS, retain := Retain, topic := Topic}) ->
-    #{event => '$bridges/mqtt',
-      id => emqx_guid:to_hexstr(emqx_guid:gen()),
-      payload => Payload,
-      topic => Topic,
-      qos => QoS,
-      dup => Dup,
-      retain => Retain,
-      pub_props => printable_maps(Props),
-      timestamp => erlang:system_time(millisecond)
-    }.
+    #{ id => emqx_guid:to_hexstr(emqx_guid:gen())
+     , payload => Payload
+     , topic => Topic
+     , qos => QoS
+     , dup => Dup
+     , retain => Retain
+     , pub_props => printable_maps(Props)
+     , message_received_at => erlang:system_time(millisecond)
+     }.
 
 printable_maps(undefined) -> #{};
 printable_maps(Headers) ->

apps/emqx_rule_engine/src/emqx_rule_events.erl

@@ -74,10 +74,10 @@ reload() ->
 
 load(<<"$bridges/", _BridgeId/binary>> = BridgeTopic) ->
     emqx_hooks:put(BridgeTopic, {?MODULE, on_bridge_message_received,
-        [#{bridge_topic => BridgeTopic}]});
+        [#{bridge_event_name => BridgeTopic}]});
 load(Topic) ->
     HookPoint = event_name(Topic),
-    emqx_hooks:put(HookPoint, {?MODULE, hook_fun(HookPoint), [[]]}).
+    emqx_hooks:put(HookPoint, {?MODULE, hook_fun(HookPoint), [#{}]}).
 
 unload() ->
     lists:foreach(fun(HookPoint) ->
@@ -91,12 +91,6 @@ unload(Topic) ->
 %%--------------------------------------------------------------------
 %% Callbacks
 %%--------------------------------------------------------------------
-on_bridge_message_received(Message, #{bridge_topic := BridgeTopic}) ->
-    case emqx_rule_engine:get_rules_for_topic(BridgeTopic) of
-        [] -> ok;
-        Rules -> emqx_rule_runtime:apply_rules(Rules, Message)
-    end.
-
 on_message_publish(Message = #message{topic = Topic}, _Env) ->
     case ignore_sys_message(Message) of
         true -> ok;
@@ -108,6 +102,9 @@ on_message_publish(Message = #message{topic = Topic}, _Env) ->
     end,
     {ok, Message}.
 
+on_bridge_message_received(Message, Env = #{bridge_event_name := BridgeTopic}) ->
+    apply_event(BridgeTopic, fun() -> with_basic_columns(BridgeTopic, Message) end, Env).
+
 on_client_connected(ClientInfo, ConnInfo, Env) ->
     apply_event('client.connected',
         fun() -> eventmsg_connected(ClientInfo, ConnInfo) end, Env).
@@ -364,7 +361,9 @@ apply_event(EventName, GenEventMsg, _Env) ->
     EventTopic = event_topic(EventName),
     case emqx_rule_engine:get_rules_for_topic(EventTopic) of
         [] -> ok;
-        Rules -> emqx_rule_runtime:apply_rules(Rules, GenEventMsg())
+        Rules ->
+            %% delay the generating of eventmsg after we have found some rules to apply
+            emqx_rule_runtime:apply_rules(Rules, GenEventMsg())
     end.
 
 %%--------------------------------------------------------------------
@@ -383,6 +382,7 @@ event_info() ->
     , event_info_session_subscribed()
     , event_info_session_unsubscribed()
     , event_info_delivery_dropped()
+    , event_info_bridge_mqtt()
     ].
 
 event_info_message_publish() ->
@@ -449,6 +449,13 @@ event_info_session_unsubscribed() ->
         {<<"session unsubscribed">>, <<"会话取消订阅完成"/utf8>>},
         <<"SELECT * FROM \"$events/session_unsubscribed\" WHERE topic =~ 't/#'">>
     ).
+event_info_bridge_mqtt()->
+    event_info_common(
+        <<"$bridges/mqtt">>,
+        {<<"MQTT bridge message">>, <<"MQTT 桥接消息"/utf8>>},
+        {<<"received a message from MQTT bridge">>, <<"收到来自 MQTT 桥接的消息"/utf8>>},
+        <<"SELECT * FROM \"$bridges/mqtt:my_mqtt_bridge\" WHERE topic =~ 't/#'">>
+    ).
 
 event_info_common(Event, {TitleEN, TitleZH}, {DescrEN, DescrZH}, SqlExam) ->
     #{event => event_topic(Event),
@@ -500,6 +507,11 @@ test_columns('session.subscribed') ->
     , {<<"username">>, <<"u_emqx">>}
     , {<<"topic">>, <<"t/a">>}
     , {<<"qos">>, 1}
+    ];
+test_columns(<<"$bridges/mqtt">>) ->
+    [ {<<"topic">>, <<"t/a">>}
+    , {<<"qos">>, 1}
+    , {<<"payload">>, <<"{\"msg\": \"hello\"}">>}
     ].
 
 columns_with_exam('message.publish') ->
@@ -584,7 +596,22 @@ columns_with_exam('client.disconnected') ->
 columns_with_exam('session.subscribed') ->
     columns_message_sub_unsub('session.subscribed');
 columns_with_exam('session.unsubscribed') ->
-    columns_message_sub_unsub('session.unsubscribed').
+    columns_message_sub_unsub('session.unsubscribed');
+columns_with_exam(<<"$bridges/mqtt">>) ->
+    [ {<<"event">>, <<"$bridges/mqtt">>}
+    , {<<"id">>, emqx_guid:to_hexstr(emqx_guid:gen())}
+    , {<<"payload">>, <<"{\"msg\": \"hello\"}">>}
+    , {<<"peerhost">>, <<"192.168.0.10">>}
+    , {<<"topic">>, <<"t/a">>}
+    , {<<"qos">>, 1}
+    , {<<"dup">>, false}
+    , {<<"retain">>, false}
+    %% the time that we receiced the message from remote broker
+    , {<<"message_received_at">>, erlang:system_time(millisecond)}
+    %% the time that the rule is triggered
+    , {<<"timestamp">>, erlang:system_time(millisecond)}
+    , {<<"node">>, node()}
+    ].
 
 columns_message_sub_unsub(EventName) ->
     [ {<<"event">>, EventName}
@@ -646,6 +673,7 @@ event_name(<<"$events/message_delivered", _/binary>>) -> 'message.delivered';
 event_name(<<"$events/message_acked", _/binary>>) -> 'message.acked';
 event_name(<<"$events/message_dropped", _/binary>>) -> 'message.dropped';
 event_name(<<"$events/delivery_dropped", _/binary>>) -> 'delivery.dropped';
+event_name(<<"$bridges/", _/binary>> = Topic) -> Topic;
 event_name(_) -> 'message.publish'.
 
 event_topic('client.connected') -> <<"$events/client_connected">>;
@@ -656,7 +684,8 @@ event_topic('message.delivered') -> <<"$events/message_delivered">>;
 event_topic('message.acked') -> <<"$events/message_acked">>;
 event_topic('message.dropped') -> <<"$events/message_dropped">>;
 event_topic('delivery.dropped') -> <<"$events/delivery_dropped">>;
-event_topic('message.publish') -> <<"$events/message_publish">>.
+event_topic('message.publish') -> <<"$events/message_publish">>;
+event_topic(<<"$bridges/", _/binary>> = Topic) -> Topic.
 
 printable_maps(undefined) -> #{};
 printable_maps(Headers) ->