package exclusive_locks import ( "context" "sync/atomic" "time" "github.com/chrislusf/seaweedfs/weed/glog" "github.com/chrislusf/seaweedfs/weed/pb/master_pb" "github.com/chrislusf/seaweedfs/weed/wdclient" ) const ( RenewInteval = 4 * time.Second SafeRenewInteval = 3 * time.Second InitLockInteval = 1 * time.Second AdminLockName = "admin" ) type ExclusiveLocker struct { token int64 lockTsNs int64 isLocking bool masterClient *wdclient.MasterClient } func NewExclusiveLocker(masterClient *wdclient.MasterClient) *ExclusiveLocker { return &ExclusiveLocker{ masterClient: masterClient, } } func (l *ExclusiveLocker) IsLocking() bool { return l.isLocking } func (l *ExclusiveLocker) GetToken() (token int64, lockTsNs int64) { for time.Unix(0, atomic.LoadInt64(&l.lockTsNs)).Add(SafeRenewInteval).Before(time.Now()) { // wait until now is within the safe lock period, no immediate renewal to change the token time.Sleep(100 * time.Millisecond) } return atomic.LoadInt64(&l.token), atomic.LoadInt64(&l.lockTsNs) } func (l *ExclusiveLocker) RequestLock(clientName string) { if l.isLocking { return } ctx, cancel := context.WithCancel(context.Background()) defer cancel() // retry to get the lease for { if err := l.masterClient.WithClient(func(client master_pb.SeaweedClient) error { resp, err := client.LeaseAdminToken(ctx, &master_pb.LeaseAdminTokenRequest{ PreviousToken: atomic.LoadInt64(&l.token), PreviousLockTime: atomic.LoadInt64(&l.lockTsNs), LockName: AdminLockName, ClientName: clientName, }) if err == nil { atomic.StoreInt64(&l.token, resp.Token) atomic.StoreInt64(&l.lockTsNs, resp.LockTsNs) } return err }); err != nil { println("lock:", err.Error()) time.Sleep(InitLockInteval) } else { break } } l.isLocking = true // start a goroutine to renew the lease go func() { ctx2, cancel2 := context.WithCancel(context.Background()) defer cancel2() for l.isLocking { if err := l.masterClient.WithClient(func(client master_pb.SeaweedClient) error { resp, err := client.LeaseAdminToken(ctx2, &master_pb.LeaseAdminTokenRequest{ PreviousToken: atomic.LoadInt64(&l.token), PreviousLockTime: atomic.LoadInt64(&l.lockTsNs), LockName: AdminLockName, ClientName: clientName, }) if err == nil { atomic.StoreInt64(&l.token, resp.Token) atomic.StoreInt64(&l.lockTsNs, resp.LockTsNs) // println("ts", l.lockTsNs, "token", l.token) } return err }); err != nil { glog.Errorf("failed to renew lock: %v", err) return } else { time.Sleep(RenewInteval) } } }() } func (l *ExclusiveLocker) ReleaseLock() { l.isLocking = false ctx, cancel := context.WithCancel(context.Background()) defer cancel() l.masterClient.WithClient(func(client master_pb.SeaweedClient) error { client.ReleaseAdminToken(ctx, &master_pb.ReleaseAdminTokenRequest{ PreviousToken: atomic.LoadInt64(&l.token), PreviousLockTime: atomic.LoadInt64(&l.lockTsNs), LockName: AdminLockName, }) return nil }) atomic.StoreInt64(&l.token, 0) atomic.StoreInt64(&l.lockTsNs, 0) }