raft: return leaderTransferee at raft status

raft/status.go

@@ -28,11 +28,17 @@ type Status struct {
 
 	Applied  uint64
 	Progress map[uint64]Progress
+
+	LeadTransferee uint64
 }
 
 // getStatus gets a copy of the current raft status.
 func getStatus(r *raft) Status {
-	s := Status{ID: r.id}
+	s := Status{
+		ID:             r.id,
+		LeadTransferee: r.leadTransferee,
+	}
+
 	s.HardState = r.hardState()
 	s.SoftState = *r.softState()
 
@@ -51,19 +57,21 @@ func getStatus(r *raft) Status {
 // MarshalJSON translates the raft status into JSON.
 // TODO: try to simplify this by introducing ID type into raft
 func (s Status) MarshalJSON() ([]byte, error) {
-	j := fmt.Sprintf(`{"id":"%x","term":%d,"vote":"%x","commit":%d,"lead":"%x","raftState":%q,"progress":{`,
-		s.ID, s.Term, s.Vote, s.Commit, s.Lead, s.RaftState)
+	j := fmt.Sprintf(`{"id":"%x","term":%d,"vote":"%x","commit":%d,"lead":"%x","raftState":%q,"applied":%d,"progress":{`,
+		s.ID, s.Term, s.Vote, s.Commit, s.Lead, s.RaftState, s.Applied)
 
 	if len(s.Progress) == 0 {
-		j += "}}"
+		j += "},"
 	} else {
 		for k, v := range s.Progress {
 			subj := fmt.Sprintf(`"%x":{"match":%d,"next":%d,"state":%q},`, k, v.Match, v.Next, v.State)
 			j += subj
 		}
 		// remove the trailing ","
-		j = j[:len(j)-1] + "}}"
+		j = j[:len(j)-1] + "},"
 	}
+
+	j += fmt.Sprintf(`"leadtransferee":"%x"}`, s.LeadTransferee)
 	return []byte(j), nil
 }