def pubsub_complete():


    project_id = "solwit-pjatk-arc-2018-gr4"
    topic_name = "projects/solwit-pjatk-arc-2018-gr4/topics/bookcovers"
    subscription_name = "bookcover"

    # Instantiates a publisher and subscriber client
    publisher = pubsub_v1.PublisherClient()
    subscriber = pubsub_v1.SubscriberClient()

    # The `topic_path` method creates a fully qualified identifier
    # in the form `projects/{project_id}/topics/{topic_name}`
    topic_path = subscriber.topic_path(project_id, topic_name)

    # The `subscription_path` method creates a fully qualified identifier
    # in the form `projects/{project_id}/subscriptions/{subscription_name}`
    subscription_path = subscriber.subscription_path(
        project_id, subscription_name)

    # Create the topic.
    topic = publisher.create_topic(topic_path)
    print('\nTopic created: {}'.format(topic.name))

    # Create a subscription.
    subscription = subscriber.create_subscription(
        subscription_path, topic_path)
    print('\nSubscription created: {}\n'.format(subscription.name))

    # Publish message.
    data = u'File size is above 10MB'
    # Data must be a bytestring
    data = data.encode('utf-8')
    # When you publish a message, the client returns a future.
    future = publisher.publish(topic_path, data=data)

    def callback(message):
        message.ack()
        messages.add(message)


    # Receive messages. The subscriber is nonblocking.
    subscriber.subscribe(subscription_path, callback=callback)

    print('\nListening for messages on {}...\n'.format(subscription_path))