from decorator import decorator
from twisted.python.threadpool import ThreadPool
from twisted.internet import threads

POOL_SIZE=5     #how many threads should the db connector pool should have

class Data:
    def __init__(self):
        self.pool =  ThreadPool(minthreads=1, maxthreads=POOL_SIZE, name='database')
        self.reactor = None

data = Data()
#a valid dbDefer decorator

def startPool(reactor): 
    data.pool.start()
    data.reactor = reactor
    data.reactor.addSystemEventTrigger('before', 'shutdown', data.pool.stop)

@decorator
def runInDBPool(f,*args,**kwargs):
    """Decorator to run DB queries in Twisted's thread pool"""
    return threads.deferToThreadPool(data.reactor, data.pool, f, *args, **kwargs)