Paste the whole sauce. It's working, but I'm sorry for the various suitability. When connecting to RabbitMQ with pika, I used to rely on Blocking Connection, so It was my first time to use a generator to turn it.

win_notification.py

import logging
import logging.handlers

import pika
import win32serviceutil
import win32service
import win32event
import servicemanager
from gntp.notifier import GrowlNotifier

#log
LOG_FILE_PATH = 'C:\\tmp\win_notification_consumer.log'
LOG_BK_COUNT = 2
LOG_LEVEL = logging.INFO

# MQ
MQ_IP = "x.x.x.x"
MQ_QUEUE = "Queue2"

#notification
GROW_IP = "127.0.0.1"
GROW_PASS = None
GROW_APP_NAME = "amqp notif"
GROW_NOTIFS = ["Message"]
GROW_NOTE_TYPE = "Message"
GROW_TITLE = "Get Message"

#Windows service
WIN_SRV_NAME = "WinNotificationConsumer"
WIN_DISP_NAME = "WinNotificationConsumer"


class WinNotificationConsumer(win32serviceutil.ServiceFramework):

    # Required Attributes:
    _svc_name_ = WIN_SRV_NAME
    _svc_display_name_ = WIN_DISP_NAME

    def __init__(self, args):
        #Log initialization
        self.logger = logging.getLogger()
        self.logger.setLevel(LOG_LEVEL)
        formatter = logging.Formatter(
            '%(asctime)s - %(levelname)s - %(message)s')
        handler = logging.handlers.TimedRotatingFileHandler(
            filename=LOG_FILE_PATH,
            when='D',
            backupCount=LOG_BK_COUNT
        )
        handler.setLevel(logging.DEBUG)
        handler.setFormatter(formatter)
        self.logger.addHandler(handler)
        self.logger.debug('init log end.')

        #Initialize around Win32 API
        win32serviceutil.ServiceFramework.__init__(self, args)
        self.stop_event = win32event.CreateEvent(None, 0, 0, None)
        self.logger.debug('init win32 end.')

        #Notification initialization
        self.notifier = GrowlNotifier(
            applicationName=GROW_APP_NAME,
            notifications=GROW_NOTIFS,
            hostname=GROW_IP,
            password=GROW_PASS)
        self.notifier.register()
        self.logger.debug('init notif end.')

    def SvcDoRun(self):
        # service start
        self.logger.info('service starting...')
        #Event log output
        servicemanager.LogMsg(
            servicemanager.EVENTLOG_INFORMATION_TYPE,
            servicemanager.PYS_SERVICE_STARTED,
            (self._svc_name_, 'test')
        )
        self.consuming_and_notificate()

    def consuming_and_notificate(self):
        self.logger.debug('consuming and notificate starting...')

        #RabbitMQ connection settings
        self.connection = pika.BlockingConnection(
            pika.ConnectionParameters(host=MQ_IP)
        )
        self.channel = self.connection.channel()

        #Create if there is no queue
        self.channel.queue_declare(
            queue=MQ_QUEUE,
            durable=True
        )

        #The message obtained from the queue is turned by the generator.
        self.logger.info('start consuming message.')
        for msg in self.channel.consume(queue=MQ_QUEUE, no_ack=True):
            message_body = msg[2]
            self.logger.debug(message_body)
            self.notifier.notify(noteType=GROW_NOTE_TYPE,
                                 title=GROW_TITLE,
                                 description=message_body)

    def SvcStop(self):
        # service stop
        self.logger.info('service stopping...')

        #Use higher class methods
        self.ReportServiceStatus(
            win32service.SERVICE_STOP_PENDING)
        win32event.SetEvent(self.stop_event)

        #MQ disconnect
        self.channel.close()
        self.connection.close()
        self.logger.info('service stopped.')


def main():
    #argument('start','stop','install' etc.)Service start based on/Registration/Stop/Execute deletion etc.
    win32serviceutil.HandleCommandLine(WinNotificationConsumer)

if __name__ == '__main__':
    main()

</ i> Windows service registration

C:\\Python27\python.exe win_notification.py --auto install