Thread local and metaclass experiment

test_localmeta.py

import threading


class ThreadLocalMeta(type):
    """Metaclass to keep a single class instance per thread"""

    _local = threading.local()

    def __call__(cls, *args, **kwargs):
        try:
            return getattr(ThreadLocalMeta._local, cls.__name__.lower())
        except AttributeError:
            instance = super(ThreadLocalMeta, cls).__call__()
            setattr(ThreadLocalMeta._local, cls.__name__.lower(), instance)
            return instance


class MyClass(object):
    __metaclass__ = ThreadLocalMeta


def test():
    print "I'm thread %s" % threading.current_thread()
    obj1 = MyClass()
    obj2 = MyClass()
    assert(obj1 == obj2)


t1 = threading.Thread(target=test)
t2 = threading.Thread(target=test)

t1.start()
t2.start()

t1.join()
t2.join()