Support enable_queue_totals when queue name is specified

For `/api/queues`, users can specify `disable_stats=true` and
`enable_queue_totals=true` parameters to return a concise set of
fields. However, the `enable_queue_totals` is not currently
supported for `/api/queues/<vhost>/<name>`, probably just a small
oversight that slipped through the cracks. This commit adds that
support and updates the respective unit test, focusing on not breaking
existing public functions and on simplicity, at the cost of a slight
bit of duplication.

deps/rabbitmq_management/src/rabbit_mgmt_wm_queue.erl

@@ -50,8 +50,13 @@ to_json(ReqData, Context) ->
                             rabbit_mgmt_format:strip_pids(Q)),
                 rabbit_mgmt_util:reply(ensure_defaults(Payload), ReqData, Context);
             true ->
-                rabbit_mgmt_util:reply(rabbit_mgmt_format:strip_pids(queue(ReqData)),
-                                       ReqData, Context)
+                Q = case rabbit_mgmt_util:enable_queue_totals(ReqData) of
+                    false -> queue(ReqData);
+                    true  -> queue_with_totals(ReqData)
+                end,
+                rabbit_mgmt_util:reply(
+                    rabbit_mgmt_format:strip_pids(Q),
+                    ReqData, Context)
         end
     catch
         {error, invalid_range_parameters, Reason} ->
@@ -110,10 +115,26 @@ queue(ReqData) ->
         VHost     -> queue(VHost, rabbit_mgmt_util:id(queue, ReqData))
     end.
 
-
 queue(VHost, QName) ->
     Name = rabbit_misc:r(VHost, queue, QName),
     case rabbit_amqqueue:lookup(Name) of
         {ok, Q}            -> rabbit_mgmt_format:queue(Q);
         {error, not_found} -> not_found
     end.
+
+queue_with_totals(ReqData) ->
+    case rabbit_mgmt_util:vhost(ReqData) of
+        not_found -> not_found;
+        VHost     -> queue_with_totals(VHost, rabbit_mgmt_util:id(queue, ReqData))
+    end. 
+
+queue_with_totals(VHost, QName) ->
+    Name = rabbit_misc:r(VHost, queue, QName),
+    case rabbit_amqqueue:lookup(Name) of
+        {ok, Q}            -> QueueInfo = rabbit_amqqueue:info(Q,
+                                    [name, durable, auto_delete, exclusive,
+                                    owner_pid, arguments, type, state,
+                                    policy, totals, online, type_specific]),
+                              rabbit_mgmt_format:queue_info(QueueInfo);
+        {error, not_found} -> not_found
+    end.

deps/rabbitmq_management/test/rabbit_mgmt_only_http_SUITE.erl

@@ -516,14 +516,14 @@ queues_enable_totals_test(Config) ->
                   vhost       => <<"/">>,
                   durable     => true,
                   auto_delete => false,
-                  exclusive   => false,
+                  exclusive   => null,
                   arguments   => #{'x-queue-type' => <<"quorum">>},
                   leader      => NodeBin,
+                  messages    => 2,
+                  messages_ready => 2,
+                  messages_unacknowledged => 0,
                   members     => [NodeBin]}, Queue),
 
-    ?assert(not maps:is_key(messages, Queue)),
-    ?assert(not maps:is_key(messages_ready, Queue)),
-    ?assert(not maps:is_key(messages_unacknowledged, Queue)),
     ?assert(not maps:is_key(message_stats, Queue)),
     ?assert(not maps:is_key(messages_details, Queue)),
     ?assert(not maps:is_key(reductions_details, Queue)),