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)