fix quorum queue status calculation to ignore non-voters

Author: Alex Valiushko

deps/rabbit/src/rabbit_quorum_queue.erl

@@ -1672,18 +1672,17 @@ online(Q) when ?is_amqqueue(Q) ->
                   is_pid(Pid)].
 
 format(Q, Ctx) when ?is_amqqueue(Q) ->
-    %% TODO: this should really just be voters
-    Nodes = lists:sort(get_nodes(Q)),
+    Voters = get_voters(Q),
     Running = case Ctx of
                   #{running_nodes := Running0} ->
                       Running0;
                   _ ->
                       %% WARN: slow
                       rabbit_nodes:list_running()
               end,
-    Online = [N || N <- Nodes, lists:member(N, Running)],
+    Online = [N || N <- Voters, lists:member(N, Running)],
     {_, LeaderNode} = amqqueue:get_pid(Q),
-    State = case is_minority(Nodes, Online) of
+    State = case is_minority(Voters, Online) of
                 true when length(Online) == 0 ->
                     down;
                 true ->
@@ -1696,10 +1695,12 @@ format(Q, Ctx) when ?is_amqqueue(Q) ->
                             down
                     end
             end,
+    Nodes = lists:sort(get_nodes(Q)),
     [{type, quorum},
      {state, State},
      {node, LeaderNode},
      {members, Nodes},
+     {voters, Voters},
      {leader, LeaderNode},
      {online, Online}].
 
@@ -1783,6 +1784,15 @@ get_nodes(Q) when ?is_amqqueue(Q) ->
     #{nodes := Nodes} = amqqueue:get_type_state(Q),
     Nodes.
 
+get_voters(Q) when ?amqqueue_is_quorum(Q) ->
+    {_, Leader} = amqqueue:get_pid(Q),
+    %% FIXME replace with proper API pending rabbitmq/ra#411
+    case  ra_server_proc:state_query(Leader, voters, 1000) of
+       {ok, Members, _} -> Members;
+       _ -> []
+    end.
+
+
 get_connected_nodes(Q) when ?is_amqqueue(Q) ->
     ErlangNodes = [node() | nodes()],
     [N || N <- get_nodes(Q), lists:member(N, ErlangNodes)].
@@ -1907,6 +1917,9 @@ force_all_queues_shrink_member_to_current_member() ->
     rabbit_log:warning("Disaster recovery procedure: shrinking finished"),
     ok.
 
+is_minority([], _) ->
+    %% Leader couldn't list voters.
+    true;
 is_minority(All, Up) ->
     MinQuorum = length(All) div 2 + 1,
     length(Up) < MinQuorum.