replicaset: properly compare table URIs

URI comparison is used in order not to recreate netbox connections
on storage/router reconfig. For tables it wasn't working properly
when compared the tables by values. The patch introduces deep
comparison. For example, now {3313} and 3313 are considered the
same URI. If such a change happened in vshard config, it won't
lead to a reconnect.

Closes #325

test/router-luatest/router_test.lua

@@ -277,6 +277,39 @@ g.test_map_callrw_raw = function(g)
  end)
 end
 
+g.test_uri_compare_and_reuse = function(g)
+ -- Multilisten itself is not used, but URI-table is supported since the same
+ -- version.
+ t.run_only_if(vutil.feature.multilisten)
+
+ local rs1_uuid = g.replica_1_a:replicaset_uuid()
+ local rep_1_a_uuid = g.replica_1_a:instance_uuid()
+ local bid = vtest.storage_first_bucket(g.replica_1_a)
+ local res, err
+
+ local new_cfg = vtest.config_new(cfg_template)
+ local rs_1_cfg = new_cfg.sharding[rs1_uuid]
+ local rep_1_a_cfg = rs_1_cfg.replicas[rep_1_a_uuid]
+ t.assert_equals(type(rep_1_a_cfg.uri), 'string', 'URI is a string')
+
+ -- Set a key in the session to check later for a reconnect.
+ res, err = g.router:exec(callrw_session_set, {bid, 1, 10, wait_timeout})
+ t.assert_equals(err, nil, 'no error')
+ t.assert(res, 'set session key')
+
+ -- Make the URI a table but it is still the same.
+ rep_1_a_cfg.uri = {rep_1_a_cfg.uri}
+ vtest.router_cfg(g.router, new_cfg)
+
+ -- The connection is still the same - session key remains.
+ res, err = g.router:exec(callrw_session_get, {bid, 1, wait_timeout})
+ t.assert_equals(err, nil, 'no error')
+ t.assert_equals(res, 10, 'get session key')
+
+ -- Restore the globals back.
+ vtest.router_cfg(g.router, cluster_cfg)
+end
+
 g.test_multilisten = function(g)
  t.run_only_if(vutil.feature.multilisten)
 

test/unit-luatest/util_test.lua

@@ -0,0 +1,83 @@
+local t = require('luatest')
+local uuid = require('uuid')
+local util = require('vshard.util')
+
+local g = t.group('util')
+
+g.test_uri_eq = function()
+ local uri_eq = util.uri_eq
+ --
+ -- Equal.
+ --
+ t.assert(uri_eq(1, 1))
+ t.assert(uri_eq('1', '1'))
+ t.assert(uri_eq({1}, 1))
+ t.assert(uri_eq(1, {1}))
+ t.assert(uri_eq('1', {'1'}))
+ t.assert(uri_eq({'1'}, '1'))
+ t.assert(uri_eq({'1'}, {'1'}))
+ t.assert(uri_eq({1}, {1}))
+
+ t.assert(uri_eq(1, '1'))
+ t.assert(uri_eq('1', 1))
+ t.assert(uri_eq({'1'}, 1))
+ t.assert(uri_eq('1', {1}))
+ t.assert(uri_eq({1}, '1'))
+ t.assert(uri_eq(1, {'1'}))
+ t.assert(uri_eq({1}, {'1'}))
+ t.assert(uri_eq({'1'}, {1}))
+
+ t.assert(uri_eq({
+ 1, params = {key1 = 10, key2 = 20}
+ }, {
+ 1, params = {key1 = 10, key2 = 20}
+ }))
+
+ t.assert(uri_eq({
+ '1', params = {key1 = 10, key2 = '20'}
+ }, {
+ 1, params = {key1 = 10, key2 = 20}
+ }))
+
+ t.assert(uri_eq({
+ 1, params = {key1 = {'10', 20}, key2 = 30}
+ }, {
+ '1', params = {key1 = {10, 20}, key2 = 30}
+ }))
+
+ t.assert(uri_eq(
+ 'localhost:1?key1=10&key1=20&key2=30',
+ {'localhost:1', params = {key1 = {10, 20}, key2 = 30}}
+ ))
+ --
+ -- Not equal.
+ --
+ t.assert(not uri_eq(1, 2))
+ t.assert(not uri_eq('1', '2'))
+
+ t.assert(not uri_eq({
+ 1, params = {key1 = 10, key2 = 20}
+ }, {
+ 1, params = {key1 = 20, key2 = 10}
+ }))
+
+ t.assert(not uri_eq({
+ '1', params = {key1 = 10}
+ }, {
+ 1, params = {key1 = 10, key2 = 20}
+ }))
+
+ t.assert(not uri_eq({
+ 1, params = {key1 = {10}, key2 = 30}
+ }, {
+ 1, params = {key1 = {10, 20}, key2 = 30}
+ }))
+
+ t.assert(not uri_eq(
+ 'localhost:1?key1=10&key1=20&key2=30',
+ {'localhost:1', params = {key1 = {20, 10}, key2 = 30}}
+ ))
+
+ t.assert_error(uri_eq, 1, uuid.new())
+ t.assert_error(uri_eq, nil, 1)
+end

vshard/replicaset.lua

@@ -631,7 +631,7 @@ local function rebind_replicasets(replicasets, old_replicasets)
  for replica_uuid, replica in pairs(replicaset.replicas) do
  local old_replica = old_replicaset and
  old_replicaset.replicas[replica_uuid]
- if old_replica and old_replica.uri == replica.uri then
+ if old_replica and util.uri_eq(old_replica.uri, replica.uri) then
  local conn = old_replica.conn
  replica.conn = conn
  replica.down_ts = old_replica.down_ts

vshard/util.lua

@@ -21,6 +21,43 @@ end
 
 local tnt_version = lversion.parse(_TARANTOOL)
 
+--
+-- Deep comparison of tables. Stolen from built-in table.equals() which sadly is
+-- not available in 1.10.
+--
+local function table_equals(a, b)
+ if type(a) ~= 'table' or type(b) ~= 'table' then
+ return type(a) == type(b) and a == b
+ end
+ local mta = getmetatable(a)
+ local mtb = getmetatable(b)
+ if mta and mta.__eq or mtb and mtb.__eq then
+ return a == b
+ end
+ for k, v in pairs(a) do
+ if not table_equals(v, b[k]) then
+ return false
+ end
+ end
+ for k, _ in pairs(b) do
+ if type(a[k]) == 'nil' then
+ return false
+ end
+ end
+ return true
+end
+
+local function uri_eq(a, b)
+ a = luri.parse(a)
+ b = luri.parse(b)
+ -- Query is inconsistent: a string URI with query params and a table URI
+ -- with explicitly specified same params are parsed into tables whose
+ -- queries are different. Discard them.
+ a.query = nil
+ b.query = nil
+ return table_equals(a, b)
+end
+
 --
 -- Extract parts of a tuple.
 -- @param tuple Tuple to extract a key from.
@@ -243,6 +280,7 @@ local feature = {
 }
 
 return {
+ uri_eq = uri_eq,
  tuple_extract_key = tuple_extract_key,
  reloadable_fiber_create = reloadable_fiber_create,
  generate_self_checker = generate_self_checker,