#coding=utf-8
from google.gax.errors import GaxError
from google.pubsub.v1.subscriber_api import SubscriberApi
from grpc.framework.interfaces.face.face import ExpirationError


def main():
    api = SubscriberApi(timeout=5)
    subscription = api.subscription_path(<project>, <subscription-name>)

    for i in xrange(5):
        print('[PULL] Pull:ing data...')
        try:
            resp = api.pull(subscription, max_messages=5)
        except GaxError as e:
            if isinstance(e.cause, ExpirationError):
                print('[PULL] timed out!')
                continue
            raise e
        print(u'[PULL] ✉️  Got messages: {}'.format(resp))
        print(u'[ACK] Acknowledging ...')
        ack_ids = map(lambda msg: msg.ack_id, resp.received_messages)
        ackresp = api.acknowledge(subscription, ack_ids)
        print(u'[ACK] Done!')
    print('bye')

if __name__ == '__main__':
     main()