Provide functions for check if file is locked from fcntl import flock

"""
Provide functions for check if file is locked.
"""

from fcntl import flock, LOCK_EX, LOCK_NB
import os.path
import sys
import logging

import os.path

fh = None

def test_lock(fname):
    """
    Detect if file is locked.
    """

    global fh
    fh = open(fname, 'w')
    try:
        flock(fh.fileno(), LOCK_EX | LOCK_NB)
    except Exception, ex:
        return True
    return False


def test_lock_and_exit(fname):
    """
    If file is locked then terminate program.
    """

    logging.debug('Trying to lock: %s' % fname)
    if test_lock(fname):
        logging.error(u'%s is locked so I must die!' % fname)
        sys.exit()