// sendAppend sends RRPC, with entries to the given peer. func (r *raft) sendAppend(to uint64) { pr := r.prs[to] if pr.isPaused() { return } m := pb.Message{} m.To = to term, errt := r.raftLog.term(pr.Next - 1) ents, erre := r.raftLog.entries(pr.Next, r.maxMsgSize) if errt != nil || erre != nil { // send snapshot if we failed to get term or entries m.Type = pb.MsgSnap snapshot, err := r.raftLog.snapshot() if err != nil { panic(err) // TODO(bdarnell) } if IsEmptySnap(snapshot) { panic("need non-empty snapshot") } m.Snapshot = snapshot sindex, sterm := snapshot.Metadata.Index, snapshot.Metadata.Term r.logger.Debugf("%x [firstindex: %d, commit: %d] sent snapshot[index: %d, term: %d] to %x [%s]", r.id, r.raftLog.firstIndex(), r.Commit, sindex, sterm, to, pr) pr.becomeSnapshot(sindex) r.logger.Debugf("%x paused sending replication messages to %x [%s]", r.id, to, pr) } else { m.Type = pb.MsgApp m.Index = pr.Next - 1 m.LogTerm = term m.Entries = ents m.Commit = r.raftLog.committed if n := len(m.Entries); n != 0 { switch pr.State { // optimistically increase the next when in ProgressStateReplicate case ProgressStateReplicate: last := m.Entries[n-1].Index pr.optimisticUpdate(last) pr.ins.add(last) case ProgressStateProbe: pr.pause() default: r.logger.Panicf("%x is sending append in unhandled state %s", r.id, pr.State) } } } r.send(m) }