re: https://hachyderm.io/@glyph@mastodon.social/110692244224116619

audit_descriptor.py

from typing import Callable
class AuditDescriptor:
    def __init__(self, field_name, audit_action):
        self.field_name = field_name
        self.audit_action = audit_action

    def __get__(self, instance, owner):
        if instance is None:
            return self
        return instance.__dict__[self.field_name]

    def __set__(self, instance, value):
        self.audit_action((instance, self.field_name, value))
        instance.__dict__[self.field_name] = value


from dataclasses import dataclass
def audit_fields(audit_action: Callable):
    def make_auditable(cls):
        cls = dataclass(cls)  # or whatever you want to do here
        for k, v in cls.__annotations__.items():
            # Ommitted bookkeeping around class level defaults, inheritance of audited classes, etc.
            setattr(cls, k, AuditDescriptor(k, audit_action))
        return cls
    return make_auditable


audit_log = []

@audit_fields(audit_log.append)
class MyClass:
    name: str
    age: int

person = MyClass(name="John", age=30)
person.name = "Bob"
print(audit_log)