Mercurial > kallithea
view rhodecode/lib/pidlock.py @ 1039:51b70569c330 beta
extended admin rescan to show what repositories was added and what removed
fixed found bugs, added expunge to cached getter since it introduce some more problems.
Added some relationship to properly clean related objects from database.
author | Marcin Kuzminski <marcin@python-works.com> |
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date | Sun, 13 Feb 2011 01:38:39 +0100 |
parents | 5cc96df705b9 |
children | 07963dd1f0f1 |
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import os, time import sys from warnings import warn from multiprocessing.util import Finalize import errno class LockHeld(Exception):pass class DaemonLock(object): """daemon locking USAGE: try: l = DaemonLock(desc='test lock') main() l.release() except LockHeld: sys.exit(1) """ def __init__(self, file=None, callbackfn=None, desc='daemon lock', debug=False): self.pidfile = file if file else os.path.join(os.path.dirname(__file__), 'running.lock') self.callbackfn = callbackfn self.desc = desc self.debug = debug self.held = False #run the lock automatically ! self.lock() self._finalize = Finalize(self, DaemonLock._on_finalize, args=(self, debug), exitpriority=10) @staticmethod def _on_finalize(lock, debug): if lock.held: if debug: print 'leck held finilazing and running lock.release()' lock.release() def lock(self): """locking function, if lock is present it will raise LockHeld exception """ lockname = '%s' % (os.getpid()) if self.debug: print 'running lock' self.trylock() self.makelock(lockname, self.pidfile) return True def trylock(self): running_pid = False if self.debug: print 'checking for already running process' try: pidfile = open(self.pidfile, "r") pidfile.seek(0) running_pid = int(pidfile.readline()) pidfile.close() if self.debug: print 'lock file present running_pid: %s, checking for execution'\ % running_pid # Now we check the PID from lock file matches to the current # process PID if running_pid: try: os.kill(running_pid, 0) except OSError, exc: if exc.errno in (errno.ESRCH, errno.EPERM): print "Lock File is there but the program is not running" print "Removing lock file for the: %s" % running_pid self.release() else: raise else: print "You already have an instance of the program running" print "It is running as process %s" % running_pid raise LockHeld() except IOError, e: if e.errno != 2: raise def release(self): """releases the pid by removing the pidfile """ if self.debug: print 'trying to release the pidlock' if self.callbackfn: #execute callback function on release if self.debug: print 'executing callback function %s' % self.callbackfn self.callbackfn() try: if self.debug: print 'removing pidfile %s' % self.pidfile os.remove(self.pidfile) self.held = False except OSError, e: if self.debug: print 'removing pidfile failed %s' % e pass def makelock(self, lockname, pidfile): """ this function will make an actual lock :param lockname: acctual pid of file :param pidfile: the file to write the pid in """ if self.debug: print 'creating a file %s and pid: %s' % (pidfile, lockname) pidfile = open(self.pidfile, "wb") pidfile.write(lockname) pidfile.close self.held = True