我在哪里更改此 Python 代码片段以将临时文件保存在 tmp 文件夹中？

Posted 2023-02-23

【中文标题】我在哪里更改此 Python 代码片段以将临时文件保存在 tmp 文件夹中？

【英文标题】：Where do I change this Python code snippet to save the temp file in the tmp-folder?

【发布时间】：2011-08-06 05:22:27

【问题描述】：

这是一个实现文件锁定的代码示例，因此应用程序只能打开一个实例。它目前可以工作，但将锁定文件保存在主文件夹（Ubuntu）中。如果应用程序崩溃，锁定文件不会被删除，这是不好的......

我不能轻易看到我应该更改代码以将其保存在 c:/tmp 文件夹中的位置吗？

#!/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'''

    # 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

【问题讨论】：

你说它是 ubuntu 的，然后又提到 c:/... 它是什么？

【参考方案1】：

使用tempfile

【参考方案2】：

在脚本的结尾：

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

'tmp.lock' 是当前目录中文件的路径。将其更改为您需要的路径，即'c:/tmp-folder/tmp.lock'。

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

但是，正如@g19fanatic 所说：您使用的是 Windows ('c:/...') 还是 Linux (Ubuntu) 系统？