replicaset: validate name in locate_master

Currently, the name validation is not used, when locate_master()
is called. It makes an explicit call via the connection to obtain a
future object in order to figure out, whether the node is a master.

We should not make any calls to a replica until the time, we definitely
know, that its name and uuid was validated. Let's use replica_call
instead of conn.call.

Follow-up tarantool#426

NO_DOC=bugfix

test/replicaset-luatest/vconnect_test.lua

@@ -187,3 +187,30 @@ test_group.test_async_no_yield = function(g)
  ivshard.storage._call = _G._call
  end)
 end
+
+--
+-- Test, that during master search name is validated.
+--
+test_group.test_locate_master = function()
+ -- Replace name with the bad one.
+ local new_cfg = table.deepcopy(global_cfg)
+ local cfg_rs = new_cfg.sharding.replicaset
+ cfg_rs.replicas.bad = cfg_rs.replicas.replica
+ cfg_rs.replicas.replica = nil
+ local _, rs = next(vreplicaset.buildall(new_cfg))
+
+ -- Avoid noop in locate_master.
+ rs.master = nil
+ rs.is_master_auto = true
+ -- Retry, until the connection is established and
+ -- name mismach error is encountered.
+ local ok, is_nop, last_err
+ t.helpers.retrying(timeout_opts, function()
+ ok, is_nop, last_err = rs:locate_master()
+ t.assert_not_equals(last_err, nil)
+ end)
+
+ t.assert_equals(last_err.name, 'INSTANCE_NAME_MISMATCH')
+ t.assert_equals(is_nop, false)
+ t.assert_equals(ok, false)
+end

vshard/replicaset.lua

@@ -1060,7 +1060,7 @@ local function replicaset_locate_master(replicaset)
  local func = 'vshard.storage._call'
  local args = {'info'}
  local const_timeout = consts.MASTER_SEARCH_TIMEOUT
- local ok, res, err, f
+ local ok, res, err
  local master = replicaset.master
  if master then
  local sync_opts = {timeout = const_timeout}
@@ -1091,17 +1091,20 @@ local function replicaset_locate_master(replicaset)
  local futures = {}
  local timeout = const_timeout
  local deadline = fiber_clock() + timeout
- local async_opts = {is_async = true}
+ local async_opts = {is_async = true, timeout = timeout}
  local replicaset_id = replicaset.id
  for replica_id, replica in pairs(replicaset.replicas) do
- local conn = replicaset_connect_to_replica(replicaset, replica)
- if conn:is_connected() then
- ok, f = pcall(conn.call, conn, func, args, async_opts)
- if not ok then
- last_err = lerror.make(f)
+ replicaset_connect_to_replica(replicaset, replica)
+ ok, err = replica:check_is_connected()
+ if ok then
+ ok, res, err = replica_call(replica, func, args, async_opts)
+ if not ok and err ~= nil then
+ last_err = err
  else
- futures[replica_id] = f
+ futures[replica_id] = res
  end
+ elseif err ~= nil then
+ last_err = err
  end
  end
  local master_id
@@ -1201,6 +1204,16 @@ local replica_mt = {
  return replica.conn and replica.conn:is_connected() and
  conn_vconnect_check_or_close(replica.conn)
  end,
+ -- Does the same thing as is_connected(), but returns true or nil, err.
+ check_is_connected = function(replica)
+ if not replica.conn then
+ return nil, lerror.from_string("%s.conn is nil")
+ end
+ if not replica.conn:is_connected() then
+ return nil, lerror.from_string('%s.conn is not connected')
+ end
+ return conn_vconnect_check_or_close(replica.conn)
+ end,
  safe_uri = function(replica)
  local uri = luri.parse(replica.uri)
  uri.password = nil