[Tarantool-patches] [PATCH v3 2/3] cfg: support symbolic evaluation of replication_synchro_quorum

[Cyrill Gorcunov]

Here is a diff I force pushed
---
diff --git a/src/box/box.cc b/src/box/box.cc
index b9d078de4..2dfb5bc1c 100644
--- a/src/box/box.cc
+++ b/src/box/box.cc
@@ -578,17 +578,9 @@ eval_replication_synchro_quorum(int nr_replicas)
 			"fmod = math.fmod,"
 		"}})\n"
 		"return math.floor(f())\n";
-	char buf[1024];
 	int value = -1;
-
 	const char *expr = cfg_gets("replication_synchro_quorum");
-	size_t ret = snprintf(buf, sizeof(buf), fmt, expr, nr_replicas);
-	if (ret >= sizeof(buf)) {
-		diag_set(ClientError, ER_CFG,
-			 "replication_synchro_quorum",
-			 "the expression is too big");
-		return -1;
-	}
+	const char *buf = tt_sprintf(fmt, expr, nr_replicas);
 
 	luaL_loadstring(tarantool_L, buf);
 	if (lua_pcall(tarantool_L, 0, 1, 0) != 0) {
@@ -608,17 +600,11 @@ eval_replication_synchro_quorum(int nr_replicas)
 	 * value (say it was n-2) do not treat it as an
 	 * error but just yield a minimum valid magnitude.
 	 */
-	if (value < 0) {
-		const int value_min = 1;
-		say_warn_ratelimited("replication_synchro_quorum evaluated "
-				     "to the negative value %d, set to %d",
-				     value, value_min);
-		value = value_min;
-	} else if (value >= VCLOCK_MAX) {
+	if (value >= VCLOCK_MAX) {
 		const int value_max = VCLOCK_MAX - 1;
-		say_warn_ratelimited("replication_synchro_quorum evaluated "
-				     "to value %d, set to %d",
-				     value, value_max);
+		say_warn("replication_synchro_quorum evaluated "
+			 "to value %d, set to %d",
+			 value, value_max);
 		value = value_max;
 	}

We use tt_sprintf and drop value < 0 test (because we return MAX(1, value)

 
@@ -1001,30 +987,6 @@ box_set_replication_sync_lag(void)
 	replication_sync_lag = box_check_replication_sync_lag();
 }
 
-/**
- * Assign new replication_synchro_quorum value
- * and notify dependent subsystems.
- */
-static void
-set_replication_synchro_quorum(int quorum)
-{
-	assert(quorum > 0 && quorum < VCLOCK_MAX);
-
-	replication_synchro_quorum = quorum;
-	txn_limbo_on_parameters_change(&txn_limbo);
-	box_raft_update_election_quorum();
-}
-
-int
-box_set_replication_synchro_quorum(void)
-{
-	int value = box_check_replication_synchro_quorum();
-	if (value < 0)
-		return -1;
-	set_replication_synchro_quorum(value);
-	return 0;
-}
-
 /**
  * Renew replication_synchro_quorum value if defined
  * as a formula and we need to recalculate it.
@@ -1053,7 +1015,20 @@ box_update_replication_synchro_quorum(void)
 	if (quorum < 0 || quorum >= VCLOCK_MAX)
 		panic("failed to eval replication_synchro_quorum");
 	say_info("update replication_synchro_quorum = %d", quorum);
-	set_replication_synchro_quorum(quorum);
+
+	replication_synchro_quorum = quorum;
+	txn_limbo_on_parameters_change(&txn_limbo);
+	box_raft_update_election_quorum();
+}
+
+int
+box_set_replication_synchro_quorum(void)
+{
+	int value = box_check_replication_synchro_quorum();
+	if (value < 0)
+		return -1;
+	box_update_replication_synchro_quorum();
+	return 0;
 }

Use box_update_replication_synchro_quorum from inside of box_set_replication_synchro_quorum.

I'm working on test now but it is yet incomplete.