package weed_server // https://yusufs.medium.com/creating-distributed-kv-database-by-implementing-raft-consensus-using-golang-d0884eef2e28 // https://github.com/Jille/raft-grpc-example/blob/cd5bcab0218f008e044fbeee4facdd01b06018ad/application.go#L18 import ( "fmt" transport "github.com/Jille/raft-grpc-transport" "github.com/hashicorp/raft" boltdb "github.com/hashicorp/raft-boltdb/v2" "github.com/seaweedfs/seaweedfs/weed/glog" "github.com/seaweedfs/seaweedfs/weed/pb" "google.golang.org/grpc" "math/rand" "os" "path" "path/filepath" "sort" "strings" "time" ) const ( ldbFile = "logs.dat" sdbFile = "stable.dat" updatePeersTimeout = 15 * time.Minute ) func getPeerIdx(self pb.ServerAddress, mapPeers map[string]pb.ServerAddress) int { peers := make([]pb.ServerAddress, 0, len(mapPeers)) for _, peer := range mapPeers { peers = append(peers, peer) } sort.Slice(peers, func(i, j int) bool { return strings.Compare(string(peers[i]), string(peers[j])) < 0 }) for i, peer := range peers { if string(peer) == string(self) { return i } } return -1 } func (s *RaftServer) AddPeersConfiguration() (cfg raft.Configuration) { for _, peer := range s.peers { cfg.Servers = append(cfg.Servers, raft.Server{ Suffrage: raft.Voter, ID: raft.ServerID(peer), Address: raft.ServerAddress(peer.ToGrpcAddress()), }) } return cfg } func (s *RaftServer) UpdatePeers() { for { select { case isLeader := <-s.RaftHashicorp.LeaderCh(): if isLeader { peerLeader := string(s.serverAddr) existsPeerName := make(map[string]bool) for _, server := range s.RaftHashicorp.GetConfiguration().Configuration().Servers { if string(server.ID) == peerLeader { continue } existsPeerName[string(server.ID)] = true } for _, peer := range s.peers { peerName := string(peer) if peerName == peerLeader || existsPeerName[peerName] { continue } glog.V(0).Infof("adding new peer: %s", peerName) s.RaftHashicorp.AddVoter( raft.ServerID(peerName), raft.ServerAddress(peer.ToGrpcAddress()), 0, 0) } for peer := range existsPeerName { if _, found := s.peers[peer]; !found { glog.V(0).Infof("removing old peer: %s", peer) s.RaftHashicorp.RemoveServer(raft.ServerID(peer), 0, 0) } } if _, found := s.peers[peerLeader]; !found { glog.V(0).Infof("removing old leader peer: %s", peerLeader) s.RaftHashicorp.RemoveServer(raft.ServerID(peerLeader), 0, 0) } } return case <-time.After(updatePeersTimeout): return } } } func NewHashicorpRaftServer(option *RaftServerOption) (*RaftServer, error) { s := &RaftServer{ peers: option.Peers, serverAddr: option.ServerAddr, dataDir: option.DataDir, topo: option.Topo, } c := raft.DefaultConfig() c.LocalID = raft.ServerID(s.serverAddr) // TODO maybee the IP:port address will change c.HeartbeatTimeout = time.Duration(float64(option.HeartbeatInterval) * (rand.Float64()*0.25 + 1)) c.ElectionTimeout = option.ElectionTimeout if c.LeaderLeaseTimeout > c.HeartbeatTimeout { c.LeaderLeaseTimeout = c.HeartbeatTimeout } if glog.V(4) { c.LogLevel = "Debug" } else if glog.V(2) { c.LogLevel = "Info" } else if glog.V(1) { c.LogLevel = "Warn" } else if glog.V(0) { c.LogLevel = "Error" } if option.RaftBootstrap { os.RemoveAll(path.Join(s.dataDir, ldbFile)) os.RemoveAll(path.Join(s.dataDir, sdbFile)) os.RemoveAll(path.Join(s.dataDir, "snapshots")) } if err := os.MkdirAll(path.Join(s.dataDir, "snapshots"), os.ModePerm); err != nil { return nil, err } baseDir := s.dataDir ldb, err := boltdb.NewBoltStore(filepath.Join(baseDir, ldbFile)) if err != nil { return nil, fmt.Errorf(`boltdb.NewBoltStore(%q): %v`, filepath.Join(baseDir, "logs.dat"), err) } sdb, err := boltdb.NewBoltStore(filepath.Join(baseDir, sdbFile)) if err != nil { return nil, fmt.Errorf(`boltdb.NewBoltStore(%q): %v`, filepath.Join(baseDir, "stable.dat"), err) } fss, err := raft.NewFileSnapshotStore(baseDir, 3, os.Stderr) if err != nil { return nil, fmt.Errorf(`raft.NewFileSnapshotStore(%q, ...): %v`, baseDir, err) } s.TransportManager = transport.New(raft.ServerAddress(s.serverAddr), []grpc.DialOption{option.GrpcDialOption}) stateMachine := StateMachine{topo: option.Topo} s.RaftHashicorp, err = raft.NewRaft(c, &stateMachine, ldb, sdb, fss, s.TransportManager.Transport()) if err != nil { return nil, fmt.Errorf("raft.NewRaft: %v", err) } if option.RaftBootstrap || len(s.RaftHashicorp.GetConfiguration().Configuration().Servers) == 0 { cfg := s.AddPeersConfiguration() // Need to get lock, in case all servers do this at the same time. peerIdx := getPeerIdx(s.serverAddr, s.peers) timeSleep := time.Duration(float64(c.LeaderLeaseTimeout) * (rand.Float64()*0.25 + 1) * float64(peerIdx)) glog.V(0).Infof("Bootstrapping idx: %d sleep: %v new cluster: %+v", peerIdx, timeSleep, cfg) time.Sleep(timeSleep) f := s.RaftHashicorp.BootstrapCluster(cfg) if err := f.Error(); err != nil { return nil, fmt.Errorf("raft.Raft.BootstrapCluster: %v", err) } } else { go s.UpdatePeers() } ticker := time.NewTicker(c.HeartbeatTimeout * 10) if glog.V(4) { go func() { for { select { case <-ticker.C: cfuture := s.RaftHashicorp.GetConfiguration() if err = cfuture.Error(); err != nil { glog.Fatalf("error getting config: %s", err) } configuration := cfuture.Configuration() glog.V(4).Infof("Showing peers known by %s:\n%+v", s.RaftHashicorp.String(), configuration.Servers) } } }() } return s, nil }