fix(gateway): fix http-api 500 issue if setting max_connections to infinity

apps/emqx_gateway/src/emqx_gateway_api_listeners.erl

@@ -304,7 +304,6 @@ do_listeners_cluster_status(Listeners) ->
                     status => #{
                         running => Running,
                         current_connections => Curr,
-                        %% XXX: Since it is taken from raw-conf, it is possible a string
                         max_connections => int(Max)
                     }
                 }
@@ -314,10 +313,15 @@ do_listeners_cluster_status(Listeners) ->
         Listeners
     ).
 
+int(infinity) ->
+    infinity;
+int(<<"infinity">>) ->
+    infinity;
 int(B) when is_binary(B) ->
     binary_to_integer(B);
 int(I) when is_integer(I) ->
     I.
+
 aggregate_listener_status(NodeStatus) ->
     aggregate_listener_status(NodeStatus, 0, 0, undefined).
 
@@ -330,11 +334,19 @@ aggregate_listener_status(
     CurrAcc,
     RunningAcc
 ) ->
+    NMaxAcc = plus_max_connections(MaxAcc, Max),
     NRunning = aggregate_running(Running, RunningAcc),
-    aggregate_listener_status(T, MaxAcc + Max, Current + CurrAcc, NRunning);
+    aggregate_listener_status(T, NMaxAcc, Current + CurrAcc, NRunning);
 aggregate_listener_status([], MaxAcc, CurrAcc, RunningAcc) ->
     {MaxAcc, CurrAcc, RunningAcc}.
 
+plus_max_connections(_, infinity) ->
+    infinity;
+plus_max_connections(infinity, _) ->
+    infinity;
+plus_max_connections(A, B) when is_integer(A) andalso is_integer(B) ->
+    A + B.
+
 aggregate_running(R, R) -> R;
 aggregate_running(R, undefined) -> R;
 aggregate_running(_, _) -> inconsistent.

apps/emqx_gateway/src/emqx_gateway_schema.erl

@@ -266,7 +266,7 @@ common_listener_opts() ->
             )},
         {max_connections,
             sc(
-                integer(),
+                hoconsc:union([infinity, pos_integer()]),
                 #{
                     default => 1024,
                     desc => ?DESC(gateway_common_listener_max_connections)