Where do I change this Python code snippet to save the temp file in the tmp-folder?

this is a code example implementing a file lock, so the application can only open one instance. It currently works, but saves the the lock file in the Home-folder (Ubuntu). If the application crashes, the lock file does not get removed which is not good....

I can not easily see where I should change the code to save it in the c:/tmp-folder instead?

#!/usr/bin/python
# -*- coding: utf-8 -*-


#implements a lockfile if program already is open
import os
import socket
from fcntl import flock

class flock(object):
    '''Class to handle creating and removing (pid) lockfiles'''

开发者_如何学Go    # custom exceptions
    class FileLockAcquisitionError(Exception): pass
    class FileLockReleaseError(Exception): pass

    # convenience callables for formatting
    addr = lambda self: '%d@%s' % (self.pid, self.host)
    fddr = lambda self: '<%s %s>' % (self.path, self.addr())
    pddr = lambda self, lock: '<%s %s@%s>' %\
                              (self.path, lock['pid'], lock['host'])

    def __init__(self, path, debug=None):
        self.pid   = os.getpid()
        self.host  = socket.gethostname()
        self.path  = path
        self.debug = debug # set this to get status messages

    def acquire(self):
        '''Acquire a lock, returning self if successful, False otherwise'''
        if self.islocked():
            if self.debug:
                lock = self._readlock()
                print 'Previous lock detected: %s' % self.pddr(lock)
            return False
        try:
            fh = open(self.path, 'w')
            fh.write(self.addr())
            fh.close()
            if self.debug:
                print 'Acquired lock: %s' % self.fddr()
        except:
            if os.path.isfile(self.path):
                try:
                    os.unlink(self.path)
                except:
                    pass
            raise (self.FileLockAcquisitionError,
                   'Error acquiring lock: %s' % self.fddr())
        return self

    def release(self):
        '''Release lock, returning self'''
        if self.ownlock():
            try:
                os.unlink(self.path)
                if self.debug:
                    print 'Released lock: %s' % self.fddr()
            except:
                raise (self.FileLockReleaseError,
                       'Error releasing lock: %s' % self.fddr())
        return self

    def _readlock(self):
        '''Internal method to read lock info'''
        try:
            lock = {}
            fh   = open(self.path)
            data = fh.read().rstrip().split('@')
            fh.close()
            lock['pid'], lock['host'] = data
            return lock
        except:
            return {'pid': 8**10, 'host': ''}

    def islocked(self):
        '''Check if we already have a lock'''
        try:
            lock = self._readlock()
            os.kill(int(lock['pid']), 0)
            return (lock['host'] == self.host)
        except:
            return False

    def ownlock(self):
        '''Check if we own the lock'''
        lock = self._readlock()
        return (self.fddr() == self.pddr(lock))

    def __del__(self):
        '''Magic method to clean up lock when program exits'''
        self.release()

#now testing to see if file is locked = other instance of this program is running already

lock = flock('tmp.lock', True).acquire()
if lock:
    print 'doing stuff'
else:
    print 'locked!'
    exit()


#end of lockfile

Use tempfile

At the end of the script:

lock = flock('tmp.lock', True).acquire()

The 'tmp.lock' is the path to the file in the current directory. Change it to the path you need, i.e. 'c:/tmp-folder/tmp.lock'.

lock = flock('c:/tmp-folder/tmp.lock', True).acquire()

However, as @g19fanatic notes: are you on a Windows ('c:/...') or Linux (Ubuntu) system?