从其他地方初始化的类中调用静态方法

Question

我有以下用于创建，写入和关闭LockFile的类。

class LockFileManager:
    def __init__(self,fname):
        """
        Create FileLock and Prepender objects.
        """
        self.fname = fname

        self.file_lock = FileLock(fname)
        self.file_lock.acquire()

        self.file_writer = Prepender(fname)

        print "LockFile: File lock and writer acquired!\n"

    @staticmethod
    def add_command(command):
        """
        Prepend a command to the LockFile
        """
        print "LockFile: Adding command: " + command + "\n"
        self.file_writer.write(command)

    def end(self):
        """
        Close and remove the LockFile
        """
        print "LockFile: Closing & Removing LockFile:\n"
        self.file_writer.close()
        self.file_lock.release()

        os.remove(self.fname)

在我的代码主体中，我将像这样初始化类：

lockfile = LockFileManager("lockfile.txt")

然后在代码的其他地方，我想写入文件：

LockFileManager.add_command("Write to LockFile provided at initialisation from some arbitrary point in the code ")

然后在代码主体的结尾，调用lockfile.exit()

当我尝试添加命令时， NameError occurred: global name 'self' is not defined 。 如果将self.file_writer.write(command)更改为file_writer.write(command)则它将不知道什么是file_writer 。

有人知道解决此问题的正确方法吗？ 干杯!

Answer 1

根据您所说的，我相信您正在寻找这样的东西：

from threading import Lock

class LockFile(file):
    def __init__(self, *args, **kwargs):
        super(LockFile, self).__init__(*args, **kwargs)
        self._lock = Lock()

    def write(self, *args, **kwargs):
        with self._lock:
            super(LockFile, self).write(*args, **kwargs)

log_file = LockFile('path/to/logfile', 'w')

然后，只需在需要写入log_file的类中导入log_file即可。

Answer 2

刚意识到一个模块可能是我最好的选择，我将类更改为下面的模块，并获得了想要的结果

def start(fname):
    """
    Create FileLock and Prepender objects.
    """
    global lockfile_name
    global file_lock
    global file_writer

    lockfile_name = fname

    file_lock = FileLock(fname)
    file_lock.acquire()

    file_writer = Prepender(fname)

    print "LockFile: File lock and writer acquired!\n"


def add_command(command):
    """
    Prepend a command to the LockFile
    """
    print "LockFile: Adding command: " + command + "\n"
    file_writer.write(command)

def end():
    """
    Close and remove the LockFile
    """
    print "LockFile: Closing & Removing LockFile:\n"
    file_writer.close()
    file_lock.release()

    os.remove(self.fname)