Metaclass to make all methods of a class thread-safe

[Irmen de Jong]

Hi,
I've developed the Metaclass below, because I needed a way
to make a bunch of classes thread-safe.
I didn't want to change every method of the class by adding
lock.aqcuire()..lock.release() around the existing code.
So I made a metaclass that essentially replaces every method
of a class with a 'wrapper' method, that does the locking,
invocation, unlocking.

Is this the right approach? It seems to work fine. But I have
very little experience with metaclass programming, so I'd like
to hear some feedback.

Thanks !!

--Irmen de Jong.


# ---- source below ----

from types import FunctionType
from threading import RLock

class ThreadSafeMethodsMetaClass(type):
     def __new__(meta, name, bases, dict):
         meta.convert_methods(dict)
         return super(ThreadSafeMethodsMetaClass, meta).__new__(meta, name, bases, dict)

     def makeThreadsafeMethod(func):
         def threadsafemethod(self, *args, **kwargs):
             self._monitor_lockObj.acquire()
             print ">>got lock"
             try:
                 return func(self, *args, **kwargs)
             finally:
                 self._monitor_lockObj.release()
                 print "<<released lock"
         return threadsafemethod
     makeThreadsafeMethod = staticmethod(makeThreadsafeMethod)

     def convert_methods(cls, dict):
         methods=[ v for k,v in dict.iteritems() if isinstance(v, FunctionType) ]
         for m in methods:
             dict[m.__name__]=cls.makeThreadsafeMethod(m)
         dict["_monitor_lockObj"] = RLock()

     convert_methods = classmethod(convert_methods)


class MyClass(object):
     __metaclass__=ThreadSafeMethodsMetaClass

     def __init__(self):
         print "init!"
     def method(self, a1, a2):
         print a1,a2

m=MyClass()
m.method("irmen",42)