common.py

import os
import sys
import fcntl
import errno


def lock(fd):
    try:
        fcntl.lockf(fd, fcntl.LOCK_EX | fcntl.LOCK_NB)
    except IOError, e:
        if e.errno in (errno.EACCES, errno.EAGAIN):
            sys.exit(0)
        else:
            raise


def single_process(fn):
    lock_file_name = 'the_same_lock_name.lock'
    lock_file_path = os.path.join('/tmp/', lock_file_name)

    def _(*a, **kw):
        fd = os.open(lock_file_path, os.O_CREAT | os.O_RDWR, 0660)
        try:
            lock(fd)
            return fn(*a, **kw)
        finally:
            os.close(fd)
    return _

script1.py

import time
from common import single_process


@single_process
def main():
    print 'begin script1'
    time.sleep(1)
    print 'end script1'


if __name__ == '__main__':
    main()

script2.py

import time
from common import single_process


@single_process
def main():
    print 'begin script2'
    time.sleep(1)
    print 'end script2'


if __name__ == '__main__':
    main()