Python BoundedSemaphore.locked方法代碼示例

# 需要導入模塊: from gevent.coros import BoundedSemaphore [as 別名]
# 或者: from gevent.coros.BoundedSemaphore import locked [as 別名]
class Lock:
    """ UNIX-specific exclusive file locks (released when the process ends).

    Based on
    http://blog.vmfarms.com/2011/03/cross-process-locking-and.html,
    adapted for context managers (the 'with' statement).

    Modified to be gevent-safe! Locks held by a given Greenlet may not be
    taken by other Greenlets until released, _as long as you only create one
    Lock object per lockfile_. THIS IS VERY IMPORTANT. *Make sure* that you're
    not creating multiple locks on the same file from the same process,
    otherwise you'll bypass the gevent lock!

    Parameters
    ----------
    f : file or str
        File handle or filename to use as the lock.
    block : bool
        Whether to block or throw IOError if the lock is grabbed multiple
        times.
    """
    TIMEOUT = 60

    def __init__(self, f, block=True):
        if isinstance(f, file):
            self.filename = f.name
            self.handle = f if not f.closed else open(f, 'w')
        else:
            self.filename = f
            mkdirp(os.path.dirname(f))
            self.handle = open(f, 'w')
        if block:
            self.lock_op = fcntl.LOCK_EX
        else:
            self.lock_op = fcntl.LOCK_EX | fcntl.LOCK_NB
        self.block = block
        self.gevent_lock = BoundedSemaphore(1)

    def acquire(self):
        got_gevent_lock = self.gevent_lock.acquire(blocking=self.block)
        if not got_gevent_lock:
            raise IOError("cannot acquire gevent lock")
        fcntl.flock(self.handle, self.lock_op)

    def release(self):
        fcntl.flock(self.handle, fcntl.LOCK_UN)
        self.gevent_lock.release()

    def locked(self):
        return self.gevent_lock.locked()

    def __enter__(self):
        self.acquire()
        return self

    def __exit__(self, type, value, traceback):
        self.release()

    def __del__(self):
        self.handle.close()

# 需要導入模塊: from gevent.coros import BoundedSemaphore [as 別名]
# 或者: from gevent.coros.BoundedSemaphore import locked [as 別名]

#.........這裏部分代碼省略.........
            # get position and set it in the API
            if self.cli_args['location']:
                position = get_location(self.cli_args['location'])
            else:
                position = get_location(self.config.location)
            self._origPosF = position
            if prev_location:
                position = prev_location
            self.api.set_position(*position)

            # retry login every 30 seconds if any errors
            self.log.info('Starting Login process...')
            login = False
            while not login:
                login = self.api.login(self.config.auth_service, self.config.username, self.config.get_password())
                if not login:
                    logger.error('Login error, retrying Login in 30 seconds')
                    self.sleep(30)
            self.log.info('Login successful')
            self._heartbeat(login, True)
        return True

    def reload_api(self, prev_location=None):
        self.api = None
        return self._load_api(prev_location)

    '''
    Blocking lock
        - only locks if current thread (greenlet) doesn't own the lock
        - persist=True will ensure the lock will not be released until the user
          explicitly sets self.persist_lock=False.
    '''
    def thread_lock(self, persist=False):
        if self.sem.locked():
            if self.locker == id(gevent.getcurrent()):
                self.log.debug("Locker is -- %s. No need to re-lock", id(gevent.getcurrent()))
                return False
            else:
                self.log.debug("Already locked by %s. Greenlet %s will wait...", self.locker, id(gevent.getcurrent()))
        self.sem.acquire()
        self.persist_lock = persist
        self.locker = id(gevent.getcurrent())
        self.log.debug("%s acquired lock (persist=%s)!", self.locker, persist)
        return True

    '''
    Releases the lock if needed and the user didn't persist it
    '''
    def thread_release(self):
        if self.sem.locked() and self.locker == id(gevent.getcurrent()) and not self.persist_lock:
            self.log.debug("%s is now releasing lock", id(gevent.getcurrent()))
            self.sem.release()

    def _callback(self, gt):
        try:
            if not gt.exception:
                result = gt.value
                logger.info('Thread finished with result: %s', result)
        except KeyboardInterrupt:
            return

        logger.exception('Error in main loop %s, restarting at location: %s',
                         gt.exception, self.get_position())
        # restart after sleep
        self.sleep(30)
        self.reload_config()