Get a Preflist for a bucket key

preflist.erl

Preflist = fun(Bucket,Key) ->
  BKey = {Bucket,Key},
  {ok, Ring} = riak_core_ring_manager:get_my_ring(),
  DocIdx = riak_core_util:chash_key(BKey),
  BucketProps = riak_core_bucket:get_bucket(Bucket, Ring), 
  [NValue] = [Y || {X1, Y} <- BucketProps, n_val == X1],
  UpNodes = riak_core_node_watcher:nodes(riak_kv),
  Preflist2 = riak_core_apl:get_apl_ann(DocIdx, NValue, Ring, UpNodes),
  [IndexNode || {IndexNode, _Type} <- Preflist2]
end.