python - 如何知道对象在 Python 中实例化的位置？

Question

我在给定的 Python 模块中定义了一个类。从其他几个 python 文件中，我将创建所述类的实例。实例在对象创建时注册自己，即在 __init__() 期间，在单例注册表对象中。我想从第三种类型的 python 文件访问注册表，查看其中的对象，并能够找出这些对象是在哪些文件中预先创建的。

代码示例可能如下所示:

Python 模块文件:'/Users/myself/code/myobjectmodule.py':

@singleton
class Registry(object):
     def __init__(self):
         self.objects = {}

class MyObject(object):
    def __init__(self, object_name):
        self.object_name = object_name
        Registry().objects[self.object_name] = self

singleton 装饰器根据 http://www.python.org/dev/peps/pep-0318/#examples

实例创建 python 文件:'/Users/myself/code/instance_creation_python_file.py':

from myobjectmodule import MyObject

A = MyObject('Foo')

第三个 python 文件:'/Users/myself/code/registry_access.py':

from myobjectmodule import Registry

registry = Registry()
foo = registry.objects['Foo']

现在，我想要一个方法 foo.get_file_of_object_creation()。

如何实现这个方法？

编辑:

采用这种方法的原因是以下场景:
1. 框架定义了一组对象，这些对象应指定数据源并包含加载后的数据(MyObject)。
2. 使用此框架的应用程序应指定这些对象并使用它们。每个应用程序都保存在一个 .py 文件或一个文件夹中，该文件或文件夹还通过其名称指定应用程序的名称。
3. 引擎为所有应用程序提供功能，但对于某些功能，引擎需要知道哪些对象来自哪个应用程序/文件。

Answer 1

在不考虑为什么要这样做的优点的情况下，这里有一种方法可以做到:

# assume the file is saved as "temp.py"

import inspect

class RegisteredObject(object):
    def __new__(cls, *args, **kwargs):
        new_instance = super(RegisteredObject, cls).__new__(cls, *args, **kwargs)
        stack_trace = inspect.stack()
        created_at = '%s:%d' % (
            stack_trace[1][1], stack_trace[1][2])
        new_instance.created_at = created_at 
        return new_instance

    def get_file_of_object_creation(self):
        return self.created_at

class MyObject(RegisteredObject):
    pass

def create_A():
    return MyObject()

def create_B():
    return MyObject()

if __name__ == '__main__':
    t1 = create_A()
    t2 = create_B()
    t3 = create_A()
    t4 = create_B()
    t5 = MyObject()
    print '"t1" was created at "%s"' % t1.get_file_of_object_creation()
    print '"t2" was created at "%s"' % t2.get_file_of_object_creation()
    print '"t3" was created at "%s"' % t3.get_file_of_object_creation()
    print '"t4" was created at "%s"' % t4.get_file_of_object_creation()
    print '"t5" was created at "%s"' % t5.get_file_of_object_creation()

输出:

$ python temp.py
"t1" was created at "temp.py:19"
"t2" was created at "temp.py:22"
"t3" was created at "temp.py:19"
"t4" was created at "temp.py:22"
"t5" was created at "temp.py:29"