Merge pull request #7014 from gsychev/bridge_config_topic_node_template_43

Bridge config topic node template

CHANGES-4.3.md

@@ -24,6 +24,8 @@ File format:
 * Refactor the ExProto so that anonymous clients can also be displayed on the dashboard [#6983]
 * Force shutdown of processe that cannot answer takeover event [#7026]
 
+* `topic` parameter in bridge configuration can have `${node}` substitution (just like in `clientid` parameter)
+
 ### Bug fixes
 
 * Fix the `{error,eexist}` error when do release upgrade again if last run failed. [#7121]

apps/emqx_bridge_mqtt/src/emqx_bridge_mqtt.appup.src

@@ -31,4 +31,4 @@
     ]},
     {<<".*">>, []}
   ]
-}.
+}.

apps/emqx_bridge_mqtt/src/emqx_bridge_mqtt.erl

@@ -37,6 +37,11 @@
         , handle_disconnected/2
         ]).
 
+%% for testing
+-ifdef(TEST).
+-export([ replvar/1 ]).
+-endif.
+
 -include_lib("emqx/include/logger.hrl").
 -include_lib("emqx/include/emqx_mqtt.hrl").
 
@@ -176,13 +181,13 @@ subscribe_remote_topics(ClientPid, Subscriptions) ->
                           end
                   end, Subscriptions).
 
+replvar(Options) ->
+    replvar([topic, clientid, max_inflight], Options).
+
 %%--------------------------------------------------------------------
 %% Internal funcs
 %%--------------------------------------------------------------------
 
-replvar(Options) ->
-    replvar([clientid, max_inflight], Options).
-
 replvar([], Options) ->
     Options;
 replvar([Key|More], Options) ->
@@ -194,8 +199,8 @@ replvar([Key|More], Options) ->
     end.
 
 %% ${node} => node()
-feedvar(clientid, ClientId, _) ->
+feedvar(Key, Value, _) when Key =:= topic; Key =:= clientid ->
-    iolist_to_binary(re:replace(ClientId, "\\${node}", atom_to_list(node())));
+    iolist_to_binary(re:replace(Value, "\\${node}", atom_to_list(node())));
 
 feedvar(max_inflight, 0, _) ->
     infinity;

apps/emqx_bridge_mqtt/test/emqx_bridge_mqtt_tests.erl

@@ -44,4 +44,15 @@ send_and_ack_test() ->
         ok = emqx_bridge_mqtt:stop(Conn)
     after
         meck:unload(emqtt)
-    end.
+    end.
+
+replvar_test() ->
+    Node = atom_to_list(node()),
+    Config = #{clientid => <<"Hey ${node}">>, topic => <<"topic ${node}">>, other => <<"other">>},
+
+    ReplacedConfig = emqx_bridge_mqtt:replvar(Config),
+
+    ExpectedConfig = #{clientid => iolist_to_binary("Hey " ++ Node),
+                       topic    => iolist_to_binary("topic " ++ Node),
+                       other    => <<"other">>},
+    ?assertEqual(ExpectedConfig, ReplacedConfig).