[Tarantool-patches] [PATCH 1/8] applier: store instance_id in struct applier

[Vladislav Shpilevoy <v.shpilevoy@tarantool.org>]

Applier is going to need its numeric ID in order to tell the
future Raft module who is a sender of a Raft message. An
alternative would be to add sender ID to each Raft message, but
this looks like a crutch. Moreover, applier still needs to know
its numeric ID in order to notify Raft about heartbeats from the
peer node.

Needed for #1146
---
 src/box/applier.cc | 19 +++++++++++++++++++
 src/box/applier.h  |  2 ++
 2 files changed, 21 insertions(+)

diff --git a/src/box/applier.cc b/src/box/applier.cc
index c1d07ca54..699b5a683 100644
--- a/src/box/applier.cc
+++ b/src/box/applier.cc
@@ -67,6 +67,23 @@ applier_set_state(struct applier *applier, enum applier_state state)
 	trigger_run_xc(&applier->on_state, applier);
 }
 
+static inline void
+applier_assign_instance_id(struct applier *applier)
+{
+	/*
+	 * After final join, the applier already received latest
+	 * records from _cluster, including the record about
+	 * source instance. It can be absent in case the source is
+	 * an anonymous replica.
+	 */
+	assert(applier->state == APPLIER_JOINED);
+	struct replica *replica = replica_by_uuid(&applier->uuid);
+	if (replica != NULL)
+		applier->instance_id = replica->id;
+	else
+		assert(applier->instance_id == 0);
+}
+
 /**
  * Write a nice error message to log file on SocketError or ClientError
  * in applier_f().
@@ -603,6 +620,7 @@ applier_join(struct applier *applier)
 	say_info("final data received");
 
 	applier_set_state(applier, APPLIER_JOINED);
+	applier_assign_instance_id(applier);
 	applier_set_state(applier, APPLIER_READY);
 }
 
@@ -1207,6 +1225,7 @@ applier_subscribe(struct applier *applier)
 		    instance_id != REPLICA_ID_NIL) {
 			say_info("final data received");
 			applier_set_state(applier, APPLIER_JOINED);
+			applier_assign_instance_id(applier);
 			applier_set_state(applier, APPLIER_READY);
 			applier_set_state(applier, APPLIER_FOLLOW);
 		}
diff --git a/src/box/applier.h b/src/box/applier.h
index 6e979a806..15ca1fcfd 100644
--- a/src/box/applier.h
+++ b/src/box/applier.h
@@ -95,6 +95,8 @@ struct applier {
 	ev_tstamp lag;
 	/** The last box_error_code() logged to avoid log flooding */
 	uint32_t last_logged_errcode;
+	/** Remote instance ID. */
+	uint32_t instance_id;
 	/** Remote instance UUID */
 	struct tt_uuid uuid;
 	/** Remote URI (string) */
-- 
2.21.1 (Apple Git-122.3)