dsync

Documentation

Index

• Constants
• type DRWMutex
  • func NewDRWMutex(ctx context.Context, name string, clnt *Dsync) *DRWMutex
  • func (dm *DRWMutex) DRLocker() sync.Locker
  • func (dm *DRWMutex) GetLock(id, source string, timeout time.Duration) (locked bool)
  • func (dm *DRWMutex) GetRLock(id, source string, timeout time.Duration) (locked bool)
  • func (dm *DRWMutex) Lock(id, source string)
  • func (dm *DRWMutex) RLock(id, source string)
  • func (dm *DRWMutex) RUnlock()
  • func (dm *DRWMutex) Unlock()
• type Dsync
• type Granted
• type LockArgs
• type NetLocker

Constants

const DRWMutexAcquireTimeout = 1 * time.Second // 1 second.

DRWMutexAcquireTimeout - tolerance limit to wait for lock acquisition before.

const MaxJitter = 1.0

MaxJitter will randomize over the full exponential backoff time

const NoJitter = 0.0

NoJitter disables the use of jitter for randomizing the exponential backoff time

Types

type DRWMutex

type DRWMutex struct {
	Name string
	// contains filtered or unexported fields
}

A DRWMutex is a distributed mutual exclusion lock.

func NewDRWMutex

func NewDRWMutex(ctx context.Context, name string, clnt *Dsync) *DRWMutex

NewDRWMutex - initializes a new dsync RW mutex.

func (*DRWMutex) DRLocker

func (dm *DRWMutex) DRLocker() sync.Locker

DRLocker returns a sync.Locker interface that implements the Lock and Unlock methods by calling drw.RLock and drw.RUnlock.

func (*DRWMutex) GetLock

func (dm *DRWMutex) GetLock(id, source string, timeout time.Duration) (locked bool)

GetLock tries to get a write lock on dm before the timeout elapses.

If the lock is already in use, the calling go routine blocks until either the mutex becomes available and return success or more time has passed than the timeout value and return false.

func (*DRWMutex) GetRLock

func (dm *DRWMutex) GetRLock(id, source string, timeout time.Duration) (locked bool)

GetRLock tries to get a read lock on dm before the timeout elapses.

If one or more read locks are already in use, it will grant another lock. Otherwise the calling go routine blocks until either the mutex becomes available and return success or more time has passed than the timeout value and return false.

func (*DRWMutex) Lock

func (dm *DRWMutex) Lock(id, source string)

Lock holds a write lock on dm.

If the lock is already in use, the calling go routine blocks until the mutex is available.

func (*DRWMutex) RLock

func (dm *DRWMutex) RLock(id, source string)

RLock holds a read lock on dm.

If one or more read locks are already in use, it will grant another lock. Otherwise the calling go routine blocks until the mutex is available.

func (*DRWMutex) RUnlock

func (dm *DRWMutex) RUnlock()

RUnlock releases a read lock held on dm.

It is a run-time error if dm is not locked on entry to RUnlock.

func (*DRWMutex) Unlock

func (dm *DRWMutex) Unlock()

Unlock unlocks the write lock.

It is a run-time error if dm is not locked on entry to Unlock.

type Dsync

type Dsync struct {
	// List of rest client objects, one per lock server.
	GetLockersFn func() []NetLocker
}

Dsync represents dsync client object which is initialized with authenticated clients, used to initiate lock REST calls.

type Granted

type Granted struct {
	// contains filtered or unexported fields
}

Granted - represents a structure of a granted lock.

type LockArgs

type LockArgs struct {
	// Unique ID of lock/unlock request.
	UID string

	// Resource contains a entity to be locked/unlocked.
	Resource string

	// Source contains the line number, function and file name of the code
	// on the client node that requested the lock.
	Source string
}

LockArgs is minimal required values for any dsync compatible lock operation.

type NetLocker

type NetLocker interface {
	// Do read lock for given LockArgs.  It should return
	// * a boolean to indicate success/failure of the operation
	// * an error on failure of lock request operation.
	RLock(args LockArgs) (bool, error)

	// Do write lock for given LockArgs. It should return
	// * a boolean to indicate success/failure of the operation
	// * an error on failure of lock request operation.
	Lock(args LockArgs) (bool, error)

	// Do read unlock for given LockArgs. It should return
	// * a boolean to indicate success/failure of the operation
	// * an error on failure of unlock request operation.
	RUnlock(args LockArgs) (bool, error)

	// Do write unlock for given LockArgs. It should return
	// * a boolean to indicate success/failure of the operation
	// * an error on failure of unlock request operation.
	Unlock(args LockArgs) (bool, error)

	// Expired returns if current lock args has expired.
	Expired(args LockArgs) (bool, error)

	// Returns underlying endpoint of this lock client instance.
	String() string

	// Close closes any underlying connection to the service endpoint
	Close() error

	// Is the underlying connection online? (is always true for any local lockers)
	IsOnline() bool
}

NetLocker is dsync compatible locker interface.