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package weed_server
import ( "bytes" "encoding/json" "errors" "fmt" "io/ioutil" "math/rand" "net/http" "net/url" "os" "path" "strings" "time"
"github.com/chrislusf/weed-fs/go/glog" "github.com/chrislusf/weed-fs/go/topology" "github.com/goraft/raft" "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 set
if len(s.peers) > 0 { 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.
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) return nil } } } 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 }
// 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 }
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