get_lock

lockmgr.lockmgr.get_lock(name, expires: Optional[int] = 600, locked_by: str = None, lock_process: int = None) → lockmgr.models.Lock[source]

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Calls clean_locks() to remove any expired locks, checks for any existing locks using a FOR UPDATE transaction, then attempts to obtain a lock using the Lock model payments.models.Lock

If name is already locked, then Locked will be raised.

Otherwise, if it was successfully locked, a payments.models.Lock object for the requested lock name will be returned.

Usage:

>>> try:   # Obtain a lock on 'mylock', with an automatic expiry of 60 seconds.
...     mylock = get_lock('mylock', 60)
...     print('Successfully locked mylock')
... except Locked as e:
...     print('Failed to lock. Reason: ', type(e), str(e))
... finally:  # Regardless of whether there was an exception or not, remember to remove the lock!
...     print('Removing lock on "mylock"')
...     unlock(mylock)
Parameters

  • name (str) – A unique name to identify your lock

  • expires (int) – (Default: 600 sec) How long before this lock is considered stale and forcefully released? Set this to 0 for a lock which will never expire (must manually call unlock())

  • locked_by (str) – (Default: system hostname) What server/app is trying to obtain this lock?

  • lock_process (int) – (Optional) The process ID requesting the lock

Raises

Locked – If the requested lock name is already locked elsewhere, Locked will be raised

Return Lock lock

If successfully locked, will return the payments.models.Lock of the requested lock.