Python functools lru_cache with instance methods: release object

by

This is not the cleanest solution, but it’s entirely transparent to the programmer:

import functools
import weakref

def memoized_method(*lru_args, **lru_kwargs):
    def decorator(func):
        @functools.wraps(func)
        def wrapped_func(self, *args, **kwargs):
            # We're storing the wrapped method inside the instance. If we had
            # a strong reference to self the instance would never die.
            self_weak = weakref.ref(self)
            @functools.wraps(func)
            @functools.lru_cache(*lru_args, **lru_kwargs)
            def cached_method(*args, **kwargs):
                return func(self_weak(), *args, **kwargs)
            setattr(self, func.__name__, cached_method)
            return cached_method(*args, **kwargs)
        return wrapped_func
    return decorator

It takes the exact same parameters as lru_cache, and works exactly the same. However it never passes self to lru_cache and instead uses a per-instance lru_cache.

More Related Contents:

  1. Make @lru_cache ignore some of the function arguments
  2. How to make function decorators and chain them together?
  3. How does the @property decorator work in Python?
  4. What’s with the integer cache maintained by the interpreter?
  5. What does functools.wraps do?
  6. Is there a decorator to simply cache function return values?
  7. Class method decorator with self arguments?
  8. How does functools partial do what it does?
  9. Expire a view-cache in Django?
  10. Decorating class methods – how to pass the instance to the decorator?
  11. How do I pass extra arguments to a Python decorator?
  12. How can I decorate an instance method with a decorator class?
  13. How do I force Django to ignore any caches and reload data?
  14. What is __pycache__?
  15. Decorator execution order
  16. Disabling caching in Flask [duplicate]
  17. Real world example about how to use property feature in python?
  18. How to use Python decorators to check function arguments?
  19. Why are some mysql connections selecting old data the mysql database after a delete + insert?
  20. How do I make function decorators and chain them together?
  21. How to make function decorators and chain them together in Python?
  22. @classmethod vs @staticmethod in Python
  23. Python decorator? – can someone please explain this? [duplicate]
  24. How to do a conditional decorator in python?
  25. Using a pip cache directory in docker builds
  26. How to create a custom decorator in Django?
  27. Decorator error: NoneType object is not callable
  28. How to count function calls using decorators?
  29. How to skip a pytest using an external fixture?
  30. Python decorator, self is mixed up [duplicate]

Leave a Comment