Python class decorator to automatically add lock-protected setters to variables

add_lock_setters_getters.py

class AddLockSettersGetters(object):
    class add(object):
        def __init__(self, initial_value=None):
            self.initial_value = initial_value

    def __init__(self, lock_name):
        self.lock_name = lock_name

    def make_getter(self, name):
        def getter(self):
            return getattr(self, name)

        return getter

    def make_setter(self, name):
        lock_name = self.lock_name
        def setter(self, val):
            with getattr(self, lock_name):
                setattr(self, name, val)

        return setter

    def __call__(self, cls):
        for name in dir(cls):
            attr = getattr(cls, name)
            if isinstance(attr, self.add):
                assert (name.startswith('_'))
                setattr(cls, name, attr.initial_value)
                setattr(cls, 'set'+name, self.make_setter(name))
                setattr(cls, 'get'+name, self.make_getter(name))
        return cls

test_example.py

import threading
from add_lock_setters_getters import AddLockSettersGetters

# Instrumented lock class so you can see it actually works!
class OurLock(object):
    def __init__(self):
        self._lock = threading.Lock()

    def __enter__(self):
        print 'entering'
        self._lock.__enter__()
        print 'lock status: ', self._lock.locked()

    def __exit__(self, type, value, traceback):
        print 'exiting'
        self._lock.__exit__(type, value, traceback)
        print 'lock status: ', self._lock.locked()

@AddLockSettersGetters('locky')
class C(object):
    def __init__(self):
        self.locky = OurLock()

    _target_az = AddLockSettersGetters.add(1)
    _target_el = AddLockSettersGetters.add()


c = C()
print '_target_az: ', c._target_az
print '_target_el: ', c._target_el
c.set_target_az(10)
print c.get_target_az()
print c.get_target_el()
print '_target_az: ', c._target_az
print '_target_el: ', c._target_el
c.set_target_el(20)
print c.get_target_az()
print c.get_target_el()
print '_target_az: ', c._target_az
print '_target_el: ', c._target_el