// Send join requests to peer. func (s *PeerServer) joinByPeer(server raft.Server, peer string, scheme string) error { var b bytes.Buffer // t must be ok t, _ := server.Transporter().(*transporter) // Our version must match the leaders version versionURL := url.URL{Host: peer, Scheme: scheme, Path: "/version"} version, err := getVersion(t, versionURL) if err != nil { return fmt.Errorf("Error during join version check: %v", err) } if version < store.MinVersion() || version > store.MaxVersion() { return fmt.Errorf("Unable to join: cluster version is %d; version compatibility is %d - %d", version, store.MinVersion(), store.MaxVersion()) } json.NewEncoder(&b).Encode(NewJoinCommand(store.MinVersion(), store.MaxVersion(), server.Name(), s.url, s.server.URL())) joinURL := url.URL{Host: peer, Scheme: scheme, Path: "/join"} log.Debugf("Send Join Request to %s", joinURL.String()) resp, req, err := t.Post(joinURL.String(), &b) for { if err != nil { return fmt.Errorf("Unable to join: %v", err) } if resp != nil { defer resp.Body.Close() t.CancelWhenTimeout(req) if resp.StatusCode == http.StatusOK { b, _ := ioutil.ReadAll(resp.Body) s.joinIndex, _ = binary.Uvarint(b) return nil } if resp.StatusCode == http.StatusTemporaryRedirect { address := resp.Header.Get("Location") log.Debugf("Send Join Request to %s", address) json.NewEncoder(&b).Encode(NewJoinCommand(store.MinVersion(), store.MaxVersion(), server.Name(), s.url, s.server.URL())) resp, req, err = t.Post(address, &b) } else if resp.StatusCode == http.StatusBadRequest { log.Debug("Reach max number peers in the cluster") decoder := json.NewDecoder(resp.Body) err := &etcdErr.Error{} decoder.Decode(err) return *err } else { return fmt.Errorf("Unable to join") } } } }