Keep a class running in a python subprocess or thread or process

I am using Squish to automate a Qt-based GUI application. I look up qt objects in the application recursively. Since it's time-intensive, I would like to cache objects once found for later reuse. I have the below class to maintain a cache of objects in a dictionary -

    
    def __init__(self):
        self.object_store = {}
    
    @staticmethod
    def instance():
        if '_instance' not in ObjectCache.__dict__:
            ObjectCache._instance = ObjectCache()
        return ObjectCache._instance
    
    def set(self, object_name, obj):
        self.object_store[object_name] = obj
    
    def remove(self, object_name):
        del self.object_store[object_name]
    
    def exists(self, object_name):
        if object_name in self.object_store:
            return True
        return False
    
    def get(self, object_name):
        return self.object_store[object_name]
        
    def get_all(self):
        return self.object_store

I have below decorator for functions in my automation scripts to add/access/delete from this dictionary -

def object_caching_decorator(func):
    def wrapper(*args, **kwargs):
        object_cache = ObjectCache.instance()
        if object_cache.exists(func.__name__):
            try:
                if waitForObject(object_cache.get(func.__name__)):
                    return object_cache.get(func.__name__)
            except LookupError:
                object_cache.remove(func.__name__)
        obj = func(*args, **kwargs)
        object_cache.set(func.__name__, obj)
        return obj
    return wrapper

One might ask why can't all scripts share this class object? because the Squish tool resets the global symbol table before starting every test script hence I need a way to persist this object.

How do I keep this class running so that the scripts running on another process (Squish runner) can access it seamlessly?

Each Squish test case gets executed in a new instance (process) of the squishrunner and the script interpreter hosted within.

The object references that Squish gives you in the test script are actually proxy objects that transparently (behind the scenes) access the actual object inside of the application process for you, without you having to do anything for this "magic" to happen (or becoming aware of it, most of the time). Caching/persisting these objects across test case will not work and is not possible.

Also, caching object references is a notorious problem as the life-time of the objects referenced by these proxy objects may change if the AUT (Application Under Test) gets changed, or used in a different manner.

Instead of this, you should revisit the way that you look up objects. It is very likely that there is a better way that allows ad-hoc object lookup (as intended) that is fast enough. (If in doubt, I recommend to contact the vendor of Squish, since your maintenance contract or subscription of their product entitles you to technical support.)