etcdserver: improve error message when timeout due to leader fail

etcdserver/errors.go

@@ -29,7 +29,7 @@ var (
 	ErrPeerURLexists          = errors.New("etcdserver: peerURL exists")
 	ErrCanceled               = errors.New("etcdserver: request cancelled")
 	ErrTimeout                = errors.New("etcdserver: request timed out")
-	ErrTimeoutDueToLeaderLost = errors.New("etcdserver: request timed out, possibly due to leader lost")
+	ErrTimeoutDueToLeaderFail = errors.New("etcdserver: request timed out, possibly due to previous leader failure")
 )
 
 func isKeyNotFound(err error) bool {

etcdserver/etcdhttp/http.go

@@ -54,7 +54,7 @@ func writeError(w http.ResponseWriter, err error) {
 		herr := httptypes.NewHTTPError(e.HTTPStatus(), e.Error())
 		herr.WriteTo(w)
 	default:
-		if err == etcdserver.ErrTimeoutDueToLeaderLost {
+		if err == etcdserver.ErrTimeoutDueToLeaderFail {
 			plog.Error(err)
 		} else {
 			plog.Errorf("got unexpected response error (%v)", err)

etcdserver/server.go

@@ -1022,7 +1022,7 @@ func (s *EtcdServer) parseProposeCtxErr(err error, start time.Time) error {
 		curLeadElected := s.r.leadElectedTime()
 		prevLeadLost := curLeadElected.Add(-2 * time.Duration(s.cfg.ElectionTicks) * time.Duration(s.cfg.TickMs) * time.Millisecond)
 		if start.After(prevLeadLost) && start.Before(curLeadElected) {
-			return ErrTimeoutDueToLeaderLost
+			return ErrTimeoutDueToLeaderFail
 		}
 		return ErrTimeout
 	default: