zc.lockfile Basic inter-process locks ************************* Basic inter-process locks ************************* The zc.lockfile package provides a basic portable implementation of interprocess locks using lock files. The purpose if not specifically to lock files, but to simply provide locks with an implementation based on file-locking primitives. Of course, these locks could be used to mediate access to *other* files. For example, the ZODB file storage implementation uses file locks to mediate access to file-storage database files. The database files and lock file files are separate files. .. contents:: Detailed Documentation ********************** Lock file support ================= The ZODB lock_file module provides support for creating file system locks. These are locks that are implemented with lock files and OS-provided locking facilities. To create a lock, instantiate a LockFile object with a file name: >>> import zc.lockfile >>> lock = zc.lockfile.LockFile('lock') If we try to lock the same name, we'll get a lock error: >>> import zope.testing.loggingsupport >>> handler = zope.testing.loggingsupport.InstalledHandler('zc.lockfile') >>> try: ... zc.lockfile.LockFile('lock') ... except zc.lockfile.LockError: ... print "Can't lock file" Can't lock file >>> for record in handler.records: ... print record.levelname, record.getMessage() ERROR Error locking file lock; pid=UNKNOWN To release the lock, use it's close method: >>> lock.close() The lock file is not removed. It is left behind: >>> import os >>> os.path.exists('lock') True Of course, now that we've released the lock, we can created it again: >>> lock = zc.lockfile.LockFile('lock') >>> lock.close() .. Cleanup >>> import os >>> os.remove('lock') Change History *************** 1.0.0 (2008-10-18) ==================== - Fixed a small bug in error logging. 1.0.0b1 (2007-07-18) ==================== Initial release Download ********************** Jim Fulton 0491e393764bbbfa13324a845db4ee27f7641b78 1.0.0