[Tarantool-patches] [PATCH v2 09/11] raft: introduce state machine

[Vladislav Shpilevoy]

My new changes for this commit, on top of the branch:

====================
    [tosquash] raft: don't broadcast shit from WAL writer; add a log;
    
    raft_write_request() should not broadcast anything.
    
    1. It is a WAL write function, has nothing to do with talking to
    other nodes.
    
    2. Its caller, raft_worker_handle_io(), already does the
    broadcast.
    
    3. Broadcast was done wrong - it didn't send vclock when vote
    was == instance_id. Led to warnings about missing vclock.
    
    Also a new log was added for the skipped RAFT messages. Not to
    loose anything. Anyway the messages are rare. 99% of the RAFT
    interaction will be via empty heartbeats. So it makes sense to
    log everything happening in the rest of the time.

diff --git a/src/box/raft.c b/src/box/raft.c
index 237d71a2d..f712887a1 100644
--- a/src/box/raft.c
+++ b/src/box/raft.c
@@ -332,8 +332,11 @@ raft_process_msg(const struct raft_request *req, uint32_t source)
 	assert(source > 0);
 	assert(source != instance_id);
 	/* Outdated request. */
-	if (req->term < raft.volatile_term)
+	if (req->term < raft.volatile_term) {
+		say_info("RAFT: the message is ignored due to outdated term - "
+			 "current term is %u", raft.volatile_term);
 		return;
+	}
 
 	enum raft_state old_state = raft.state;
 
@@ -545,8 +548,6 @@ raft_write_request(const struct raft_request *req)
 		goto fail;
 	}
 
-	raft_broadcast(req);
-
 	region_truncate(region, svp);
 	return;
 fail: