POC Python Change Monitor of generic nested data

change_monitor.py

from collections import namedtuple

ATTR_LOOKUP = 1
ITEM_LOOKUP = 2
Change = namedtuple("Change", "path to")


class Lookup(namedtuple("Lookup", "key lookup_type")):
    def __str__(self):
        if self.lookup_type == ATTR_LOOKUP:
            return u".{}".format(self.key)
        elif self.lookup_type == ITEM_LOOKUP:
            return u"[{}]".format(repr(self.key))
        else:
            raise Exception("Unknown lookup type: {}".format(self.lookup_type))


def monitor_value(v, path, root):
    if hasattr(v, "__getitem__") or hasattr(v, "__getattribute__"):
        return ChangeMonitor(v, path, root)
    else:
        return v


class ChangeMonitor(object):
    def __init__(self, data, path=None, root=None):
        self._data_ = data
        self._path_ = path or []
        self._changes_ = []
        self._root_ = root or self

    def __getattribute__(self, k):
        if k in ("_data_", "_path_", "_changes_", "_root_"):
            return object.__getattribute__(self, k)
        else:
            path = self._path_[:]
            path.append(Lookup(k, ATTR_LOOKUP))
            return monitor_value(getattr(self._data_, k), path, self._root_)

    def __getitem__(self, k):
        path = self._path_[:]
        path.append(Lookup(k, ITEM_LOOKUP))
        return monitor_value(self._data_[k], path, self._root_)

    def __setitem__(self, k, v):
        self._root_._changes_.append(
            Change(self._path_ + [Lookup(k, ITEM_LOOKUP)], v))
        self._data_[k] = v

    def __setattr__(self, k, v):
        if k in ("_data_", "_path_", "_changes_", "_root_"):
            return object.__setattr__(self, k, v)
        self._root_._changes_.append(
            Change(self._path_ + [Lookup(k, ATTR_LOOKUP)], v))
        object.__setattr__(self, k, v)

    def __repr__(self):
        return repr(self._data_)


class Model(object):
    name = "XXX"


m = Model()

# Wrap generic nested data in the change monitor.
x = ChangeMonitor({1: 2, 3: {4: 5, 6: {"7": {8: 9}}}, "m": m, "l": [1, 2, 3]})
x[3][4] = 42
x[3][6]["7"][8] = 9
x["m"].name = "YYY"
x["l"][1] = 999

print
print "The following is changed:"
for change in x._changes_:
    print "    DATA{} = {}".format(u"".join(unicode(x) for x in change.path),
                                   repr(change.to))

output.txt

The following is changed:
    DATA[3][4] = 42
    DATA[3][6]['7'][8] = 9
    DATA['m'].name = 'YYY'
    DATA['l'][1] = 999