ganeti.utils.filelock.FileLock

class documentation

class FileLock(object):

Utility class for file locks.

Class Method	`Open`	Creates and opens a file to be used as a file-based lock.
Method	`__del__`	Undocumented
Method	`__init__`	Constructor for FileLock.
Method	`Close`	Close the file and release the lock.
Method	`Exclusive`	Locks the file in exclusive mode.
Method	`Shared`	Locks the file in shared mode.
Method	`Unlock`	Unlocks the file.
Instance Variable	`fd`	Undocumented
Instance Variable	`filename`	Undocumented
Static Method	`_Lock`	Undocumented
Method	`_flock`	Wrapper for fcntl.flock.

@classmethod
def Open(cls, filename): ¶

Creates and opens a file to be used as a file-based lock.

Parameters
filename:string	path to the file to be locked

def __del__(self): ¶

Undocumented

def __init__(self, fd, filename): ¶

Constructor for FileLock.

def Close(self): ¶

Close the file and release the lock.

def Exclusive(self, blocking=False, timeout=None): ¶

Locks the file in exclusive mode.

Parameters
blocking:boolean	whether to block and wait until we can lock the file or return immediately
timeout:int or None	if not None, the duration to wait for the lock (in blocking mode)

def Shared(self, blocking=False, timeout=None): ¶

Locks the file in shared mode.

Parameters
blocking:boolean	whether to block and wait until we can lock the file or return immediately
timeout:int or None	if not None, the duration to wait for the lock (in blocking mode)

def Unlock(self, blocking=True, timeout=None): ¶

Unlocks the file.

According to flock(2), unlocking can also be a nonblocking operation:

  To make a non-blocking request, include LOCK_NB with any of the above
  operations.

Parameters
blocking:boolean	whether to block and wait until we can lock the file or return immediately
timeout:int or None	if not None, the duration to wait for the lock (in blocking mode)

Undocumented

filename = ¶

Undocumented

@staticmethod
def _Lock(fd, flag, timeout): ¶

Undocumented

def _flock(self, flag, blocking, timeout, errmsg): ¶

Wrapper for fcntl.flock.

Parameters
flag:int	operation flag
blocking:bool	whether the operation should be done in blocking mode.
timeout:None or float	for how long the operation should be retried (implies non-blocking mode).
errmsg:string	error message in case operation fails.