oauth2client.locked_file module

Locked file interface that should work on Unix and Windows pythons.

This module first tries to use fcntl locking to ensure serialized access to a file, then falls back on a lock file if that is unavialable.

Usage:

f = LockedFile('filename', 'r+b', 'rb')
f.open_and_lock()
if f.is_locked():
  print('Acquired filename with r+b mode')
  f.file_handle().write('locked data')
else:
  print('Acquired filename with rb mode')
f.unlock_and_close()

exception oauth2client.locked_file.AlreadyLockedException

Bases: exceptions.Exception

Trying to lock a file that has already been locked by the LockedFile.

exception oauth2client.locked_file.CredentialsFileSymbolicLinkError

Bases: exceptions.Exception

Credentials files must not be symbolic links.

class oauth2client.locked_file.LockedFile(*args, **kwargs)

Bases: object

Represent a file that has exclusive access.

file_handle()

Return the file_handle to the opened file.

filename()

Return the filename we were constructed with.

is_locked()

Return whether we successfully locked the file.

open_and_lock(timeout=0, delay=0.05)

Open the file, trying to lock it.

Parameters:

• timeout – float, The number of seconds to try to acquire the lock.
• delay – float, The number of seconds to wait between retry attempts.

Raises:

• AlreadyLockedException – if the lock is already acquired.
• IOError – if the open fails.

unlock_and_close()

Unlock and close a file.

oauth2client.locked_file.validate_file(filename)