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package lock_manager
import ( "fmt" "github.com/seaweedfs/seaweedfs/weed/pb" "time" )
type DistributedLockManager struct { lockManager *LockManager LockRing *LockRing }
func NewDistributedLockManager() *DistributedLockManager { return &DistributedLockManager{ lockManager: NewLockManager(), LockRing: NewLockRing(time.Second * 5), } }
func (dlm *DistributedLockManager) Lock(host pb.ServerAddress, key string, expiredAtNs int64, token string) (renewToken string, movedTo pb.ServerAddress, err error) { servers := dlm.LockRing.GetSnapshot() if servers == nil { err = fmt.Errorf("no lock server found") return }
server := hashKeyToServer(key, servers) if server != host { movedTo = server return } renewToken, err = dlm.lockManager.Lock(key, expiredAtNs, token) return }
func (dlm *DistributedLockManager) Unlock(host pb.ServerAddress, key string, token string) (movedTo pb.ServerAddress, err error) { servers := dlm.LockRing.GetSnapshot() if servers == nil { err = fmt.Errorf("no lock server found") return }
server := hashKeyToServer(key, servers) if server != host { movedTo = server return } _, err = dlm.lockManager.Unlock(key, token) return }
// InsertLock is used to insert a lock to a server unconditionally
// It is used when a server is down and the lock is moved to another server
func (dlm *DistributedLockManager) InsertLock(key string, expiredAtNs int64, token string) { dlm.lockManager.InsertLock(key, expiredAtNs, token) } func (dlm *DistributedLockManager) SelectNotOwnedLocks(host pb.ServerAddress, servers []pb.ServerAddress) (locks []*Lock) { return dlm.lockManager.SelectLocks(func(key string) bool { server := hashKeyToServer(key, servers) return server != host }) } func (dlm *DistributedLockManager) CalculateTargetServer(key string, servers []pb.ServerAddress) pb.ServerAddress { return hashKeyToServer(key, servers) }
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