class twisted.internet.defer.DeferredFilesystemLock(lockfile.FilesystemLock): (source)
A FilesystemLock that allows for a Deferred to be fired when the lock is acquired.
| Method | __init__ | |
| Method | deferUntilLocked | Wait until we acquire this lock. This method is not safe for concurrent use. |
| Instance Variable | _scheduler | The object in charge of scheduling retries. In this implementation this is parameterized for testing. |
| Instance Variable | _interval | The retry interval for an IReactorTime based scheduler. |
| Instance Variable | _tryLockCall | A DelayedCall based on _interval that will manage the next retry for acquiring the lock. |
| Instance Variable | _timeoutCall | A DelayedCall based on deferUntilLocked's timeout argument. This is in charge of timing out our attempt to acquire the lock. |
Inherited from FilesystemLock:
| Instance Variable | name | The name of the file associated with this lock. |
| Instance Variable | clean | Indicates whether this lock was released cleanly by its last owner. Only meaningful after lock has been called and returns True. |
| Instance Variable | locked | Indicates whether the lock is currently held by this object. |
| Method | lock | Acquire this lock. |
| Method | unlock | Release this lock. |
DelayedCall based on _interval that will manage the next retry for acquiring the lock.DelayedCall based on deferUntilLocked's timeout argument. This is in charge of timing out our attempt to acquire the lock.| Parameters | name | The name of the lock to acquire |
| scheduler | An object which provides IReactorTime |
Wait until we acquire this lock. This method is not safe for concurrent use.
| Parameters | timeout | the number of seconds after which to time out if the lock has not been acquired. (type: float or int) |
| Returns | a Deferred which will callback when the lock is acquired, or errback with a TimeoutError after timing out or an AlreadyTryingToLockError if the deferUntilLocked has already been called and not successfully locked the file. | |