/* Copyright 2014 CoreOS Inc. Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. */ package etcdserver import ( "fmt" "log" "net/http" "strconv" "sync" "time" "github.com/coreos/etcd/conf" ) var ( noneId int64 = -1 ) type standby struct { client *v2client peerHub *peerHub leader int64 leaderAddr string mu sync.RWMutex clusterConf *conf.ClusterConfig *http.ServeMux } func newStandby(client *v2client, peerHub *peerHub) *standby { s := &standby{ client: client, peerHub: peerHub, leader: noneId, leaderAddr: "", clusterConf: conf.NewClusterConfig(), ServeMux: http.NewServeMux(), } s.Handle("/", handlerErr(s.serveRedirect)) return s } func (s *standby) run(stop chan struct{}) { syncDuration := time.Millisecond * 100 nodes := s.peerHub.getSeeds() for { select { case <-time.After(syncDuration): case <-stop: log.Printf("standby.stop\n") return } if update, err := s.syncCluster(nodes); err != nil { log.Printf("standby.run syncErr=\"%v\"", err) continue } else { nodes = update } syncDuration = time.Duration(s.clusterConf.SyncInterval * float64(time.Second)) if s.clusterConf.ActiveSize <= len(nodes) { continue } log.Printf("standby.end\n") return } } func (s *standby) leaderInfo() (int64, string) { s.mu.RLock() defer s.mu.RUnlock() return s.leader, s.leaderAddr } func (s *standby) setLeaderInfo(leader int64, leaderAddr string) { s.mu.Lock() defer s.mu.Unlock() s.leader, s.leaderAddr = leader, leaderAddr } func (s *standby) serveRedirect(w http.ResponseWriter, r *http.Request) error { leader, leaderAddr := s.leaderInfo() if leader == noneId { return fmt.Errorf("no leader in the cluster") } redirectAddr, err := buildRedirectURL(leaderAddr, r.URL) if err != nil { return err } http.Redirect(w, r, redirectAddr, http.StatusTemporaryRedirect) return nil } func (s *standby) syncCluster(nodes map[string]bool) (map[string]bool, error) { for node := range nodes { machines, err := s.client.GetMachines(node) if err != nil { continue } cfg, err := s.client.GetClusterConfig(node) if err != nil { continue } nn := make(map[string]bool) for _, machine := range machines { nn[machine.PeerURL] = true if machine.State == stateLeader { id, err := strconv.ParseInt(machine.Name, 0, 64) if err != nil { return nil, err } s.setLeaderInfo(id, machine.PeerURL) } } s.clusterConf = cfg return nn, nil } return nil, fmt.Errorf("unreachable cluster") }