The singleton class has different assigned addresses

Question

In the a.py class, it's fetching values for the indicators dictionary. I'm trying to save those values to a global dictionary variable in container.py and then access them in b.py.

So, I declared a singleton called GlobalContainer in container.py and declared a dictionary inside it. Then, in a.py, I added the values fetched to that dictionary. However, when I tried to access the dictionary in the singleton from b.py, there were no values. Upon checking, I found that the memory address of GlobalContainer in container.py is different.

I need a single data storage accessible from a.py, b.py, c.py, etc. I don't understand why the singleton addresses are different.

container.py

class Singleton:
  def __init__(self, decorated):
    self._decorated = decorated
    self._initialized = False  # Flag for first instance creation

  def instance(self):
    if not self._initialized:
      self._instance = self._decorated()
      self._initialized = True
    return self._instance

  def __call__(self):
    raise TypeError('Singletons must be accessed through `instance()`.')

  def __instancecheck__(self, inst):
    return isinstance(inst, self._decorated)

  def __wrap__(self, instance, objtype, wrapper):
    # Allow access to class methods using the actual class object (cls)
    instance.__getattribute__ = lambda self, name: getattr(objtype, name, self.__dict__[name])
    return wrapper(instance)

@Singleton
class GlobalContainer:
    containers = {}

    def __init__(self):
    # No initialization check needed here
        print("### GlobalContainer created")  # This will print only once

    @classmethod
    def set_indicators(cls, symbol, indicators):
        if symbol not in cls.containers:
            cls.containers[symbol] = {'indicators': indicators}
        else:
            cls.containers[symbol]['indicators'] = indicators

    @classmethod
    def get_indicators(cls, symbol):
        container = cls.containers.get(symbol, {})
        return container.get('indicators', None)

in a.py

GlobalContainer.instance().set_indicators(self.symbol, self.indicators)

in b.py

GlobalContainer.instance().get_indicators(symbol)

The print('### GlobalContainer created') in the singleton's init part is executed twice. I want only one instance to be created and used as a global variable for GlobalContainer.

Answer 1

The "singleton" has two different addresses because you are executing two different scripts, each of which defines a new GlobalContainers class on start-up. The class is not shared between two separate processes.