package weed_server import ( "bytes" "encoding/json" "errors" "fmt" "io/ioutil" "math/rand" "net/http" "net/url" "os" "path" "reflect" "sort" "strings" "time" "github.com/chrislusf/raft" "github.com/chrislusf/seaweedfs/weed/glog" "github.com/chrislusf/seaweedfs/weed/topology" "github.com/gorilla/mux" ) type RaftServer struct { peers []string // initial peers to join with raftServer raft.Server dataDir string httpAddr string router *mux.Router topo *topology.Topology } func NewRaftServer(r *mux.Router, peers []string, httpAddr string, dataDir string, topo *topology.Topology, pulseSeconds int) *RaftServer { s := &RaftServer{ peers: peers, httpAddr: httpAddr, dataDir: dataDir, router: r, topo: topo, } if glog.V(4) { raft.SetLogLevel(2) } raft.RegisterCommand(&topology.MaxVolumeIdCommand{}) var err error transporter := raft.NewHTTPTransporter("/cluster", 0) transporter.Transport.MaxIdleConnsPerHost = 1024 glog.V(1).Infof("Starting RaftServer with IP:%v:", httpAddr) // Clear old cluster configurations if peers are changed if oldPeers, changed := isPeersChanged(s.dataDir, httpAddr, s.peers); changed { glog.V(0).Infof("Peers Change: %v => %v", oldPeers, s.peers) os.RemoveAll(path.Join(s.dataDir, "conf")) os.RemoveAll(path.Join(s.dataDir, "log")) os.RemoveAll(path.Join(s.dataDir, "snapshot")) } s.raftServer, err = raft.NewServer(s.httpAddr, s.dataDir, transporter, nil, topo, "") if err != nil { glog.V(0).Infoln(err) return nil } transporter.Install(s.raftServer, s) s.raftServer.SetHeartbeatInterval(1 * time.Second) s.raftServer.SetElectionTimeout(time.Duration(pulseSeconds) * 3450 * time.Millisecond) s.raftServer.Start() s.router.HandleFunc("/cluster/join", s.joinHandler).Methods("POST") s.router.HandleFunc("/cluster/status", s.statusHandler).Methods("GET") if len(s.peers) > 0 { // Join to leader if specified. for { glog.V(0).Infoln("Joining cluster:", strings.Join(s.peers, ",")) time.Sleep(time.Duration(rand.Intn(1000)) * time.Millisecond) firstJoinError := s.Join(s.peers) if firstJoinError != nil { glog.V(0).Infoln("No existing server found. Starting as leader in the new cluster.") _, err := s.raftServer.Do(&raft.DefaultJoinCommand{ Name: s.raftServer.Name(), ConnectionString: "http://" + s.httpAddr, }) if err != nil { glog.V(0).Infoln(err) } else { break } } else { break } } } else if s.raftServer.IsLogEmpty() { // Initialize the server by joining itself. glog.V(0).Infoln("Initializing new cluster") _, err := s.raftServer.Do(&raft.DefaultJoinCommand{ Name: s.raftServer.Name(), ConnectionString: "http://" + s.httpAddr, }) if err != nil { glog.V(0).Infoln(err) return nil } } else { glog.V(0).Infoln("Old conf,log,snapshot should have been removed.") } return s } func (s *RaftServer) Peers() (members []string) { peers := s.raftServer.Peers() for _, p := range peers { members = append(members, strings.TrimPrefix(p.ConnectionString, "http://")) } return } func isPeersChanged(dir string, self string, peers []string) (oldPeers []string, changed bool) { confPath := path.Join(dir, "conf") // open conf file b, err := ioutil.ReadFile(confPath) if err != nil { return oldPeers, true } conf := &raft.Config{} if err = json.Unmarshal(b, conf); err != nil { return oldPeers, true } for _, p := range conf.Peers { oldPeers = append(oldPeers, strings.TrimPrefix(p.ConnectionString, "http://")) } oldPeers = append(oldPeers, self) sort.Strings(peers) sort.Strings(oldPeers) return oldPeers, reflect.DeepEqual(peers, oldPeers) } // Join joins an existing cluster. func (s *RaftServer) Join(peers []string) error { command := &raft.DefaultJoinCommand{ Name: s.raftServer.Name(), ConnectionString: "http://" + s.httpAddr, } var err error var b bytes.Buffer json.NewEncoder(&b).Encode(command) for _, m := range peers { if m == s.httpAddr { continue } target := fmt.Sprintf("http://%s/cluster/join", strings.TrimSpace(m)) glog.V(0).Infoln("Attempting to connect to:", target) err = postFollowingOneRedirect(target, "application/json", &b) if err != nil { glog.V(0).Infoln("Post returned error: ", err.Error()) if _, ok := err.(*url.Error); ok { // If we receive a network error try the next member continue } } else { return nil } } return errors.New("Could not connect to any cluster peers") } // a workaround because http POST following redirection misses request body func postFollowingOneRedirect(target string, contentType string, b *bytes.Buffer) error { backupReader := bytes.NewReader(b.Bytes()) resp, err := http.Post(target, contentType, b) if err != nil { return err } defer resp.Body.Close() reply, _ := ioutil.ReadAll(resp.Body) statusCode := resp.StatusCode if statusCode == http.StatusMovedPermanently { var urlStr string if urlStr = resp.Header.Get("Location"); urlStr == "" { return fmt.Errorf("%d response missing Location header", resp.StatusCode) } glog.V(0).Infoln("Post redirected to ", urlStr) resp2, err2 := http.Post(urlStr, contentType, backupReader) if err2 != nil { return err2 } defer resp2.Body.Close() reply, _ = ioutil.ReadAll(resp2.Body) statusCode = resp2.StatusCode } glog.V(0).Infoln("Post returned status: ", statusCode, string(reply)) if statusCode != http.StatusOK { return errors.New(string(reply)) } return nil }