[tarantool-patches] [PATCH 1/2] box: make replication_sync_lag option dynamic

[Olga Arkhangelskaia <krishtal.olja@gmail.com>]

In gh-3427 replication_sync_lag should be taken into account during
replication reconfiguration. In order to configure replication properly
this parameter is made dynamical and can be changed on demand.

@TarantoolBot document
Title: recation_sync_lag option can be set dynamically
recation_sync_lag now can be set at any time.
---
 src/box/box.cc            |  6 ++++++
 src/box/box.h             |  1 +
 src/box/lua/cfg.cc        | 12 ++++++++++++
 src/box/lua/load_cfg.lua  |  1 +
 test/box-tap/cfg.test.lua |  4 +++-
 5 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/src/box/box.cc b/src/box/box.cc
index 8d7454d1f..be5077da8 100644
--- a/src/box/box.cc
+++ b/src/box/box.cc
@@ -656,6 +656,12 @@ box_set_replication_connect_quorum(void)
 		replicaset_check_quorum();
 }
 
+void
+box_set_replication_sync_lag(void)
+{
+	replication_sync_lag = box_check_replication_sync_lag();
+}
+
 void
 box_bind(void)
 {
diff --git a/src/box/box.h b/src/box/box.h
index 9dfb3fd2a..3090fdcdb 100644
--- a/src/box/box.h
+++ b/src/box/box.h
@@ -176,6 +176,7 @@ void box_set_vinyl_timeout(void);
 void box_set_replication_timeout(void);
 void box_set_replication_connect_timeout(void);
 void box_set_replication_connect_quorum(void);
+void box_set_replication_sync_lag(void);
 
 extern "C" {
 #endif /* defined(__cplusplus) */
diff --git a/src/box/lua/cfg.cc b/src/box/lua/cfg.cc
index 0ca150877..5442723b5 100644
--- a/src/box/lua/cfg.cc
+++ b/src/box/lua/cfg.cc
@@ -262,6 +262,17 @@ lbox_cfg_set_replication_connect_quorum(struct lua_State *L)
 	return 0;
 }
 
+static int
+lbox_cfg_set_replication_sync_lag(struct lua_State *L)
+{
+	try {
+		box_set_replication_sync_lag();
+	} catch (Exception *) {
+		luaT_error(L);
+	}
+	return 0;
+}
+
 void
 box_lua_cfg_init(struct lua_State *L)
 {
@@ -286,6 +297,7 @@ box_lua_cfg_init(struct lua_State *L)
 		{"cfg_set_replication_timeout", lbox_cfg_set_replication_timeout},
 		{"cfg_set_replication_connect_timeout", lbox_cfg_set_replication_connect_timeout},
 		{"cfg_set_replication_connect_quorum", lbox_cfg_set_replication_connect_quorum},
+		{"cfg_set_replication_sync_lag", lbox_cfg_set_replication_sync_lag},
 		{NULL, NULL}
 	};
 
diff --git a/src/box/lua/load_cfg.lua b/src/box/lua/load_cfg.lua
index 2a7142de6..cdee475d5 100644
--- a/src/box/lua/load_cfg.lua
+++ b/src/box/lua/load_cfg.lua
@@ -211,6 +211,7 @@ local dynamic_cfg = {
                       'Can\'t change replicaset uuid')
         end
     end,
+    replication_sync_lag    = private.cfg_set_replication_sync_lag,
 }
 
 local dynamic_cfg_skip_at_load = {
diff --git a/test/box-tap/cfg.test.lua b/test/box-tap/cfg.test.lua
index 5e72004ca..7cb2ed9a3 100755
--- a/test/box-tap/cfg.test.lua
+++ b/test/box-tap/cfg.test.lua
@@ -6,7 +6,7 @@ local socket = require('socket')
 local fio = require('fio')
 local uuid = require('uuid')
 local msgpack = require('msgpack')
-test:plan(90)
+test:plan(92)
 
 --------------------------------------------------------------------------------
 -- Invalid values
@@ -32,6 +32,8 @@ invalid('replication_sync_lag', 0)
 invalid('replication_connect_timeout', -1)
 invalid('replication_connect_timeout', 0)
 invalid('replication_connect_quorum', -1)
+invalid('replication_sync_lag', -1)
+invalid('replication_sync_lag', -1)
 invalid('wal_mode', 'invalid')
 invalid('rows_per_wal', -1)
 invalid('listen', '//!')
-- 
2.14.3 (Apple Git-98)