pubsub.py

# pip install google-cloud-pubsub
import os, json
from google.cloud import pubsub_v1 
 
os.environ['GOOGLE_APPLICATION_CREDENTIALS'] = os.getcwd() + "/PubSubService.json" #import pubsub serveice credential json file

# The same for the publisher, except that the "audience" claim needs to be adjusted
# publisher_audience = "https://pubsub.googleapis.com/google.pubsub.v1.Publisher"
subscriber = pubsub_v1.SubscriberClient()
publisher = pubsub_v1.PublisherClient()


def publish_messages(project_id, topic_name):
    """Publishes multiple messages to a Pub/Sub topic."""
    # [START pubsub_quickstart_publisher]
    # [START pubsub_publish]
    project_id = "Your Google Cloud Project ID"
    topic_name = "Your Pub/Sub topic name"

    publisher = pubsub_v1.PublisherClient()
    # The `topic_path` method creates a fully qualified identifier
    # in the form `projects/{project_id}/topics/{topic_name}`
    topic_path = publisher.topic_path(project_id, topic_name)

    for n in range(1, 10):
        data = u'Message number {}'.format(n)
        # 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)
        print(future.result())

    print('Published messages.')

publish_messages("project_id","topic_name")


def list_subscriptions_in_topic(project_id, topic_name):
    """Lists all subscriptions for a given topic."""
    # [START pubsub_list_topic_subscriptions]

    # TODO project_id = "Your Google Cloud Project ID"
    # TODO topic_name = "Your Pub/Sub topic name"

    publisher = pubsub_v1.PublisherClient()
    topic_path = publisher.topic_path(project_id, topic_name)

    for subscription in publisher.list_topic_subscriptions(topic_path):
        print(subscription)
    # [END pubsub_list_topic_subscriptions]
list_subscriptions_in_topic("project_id","topic_name" )

def receive_messages(project_id, subscription_name):
    """Receives messages from a pull subscription."""
    # [START pubsub_subscriber_async_pull]
    # [START pubsub_quickstart_subscriber]


    # TODO project_id = "Your Google Cloud Project ID"
    # TODO subscription_name = "Your Pub/Sub subscription name"

    subscriber = pubsub_v1.SubscriberClient()
    # 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)

    def callback(message):
        print('Received message: {}'.format(message))
        message.ack()

    subscriber.subscribe(subscription_path, callback=callback)

    # The subscriber is non-blocking. We must keep the main thread from
    # exiting to allow it to process messages asynchronously in the background.
    print('Listening for messages on {}'.format(subscription_path))
    while True:
        time.sleep(60)
    # [END pubsub_subscriber_async_pull]
    # [END pubsub_quickstart_subscriber]


receive_messages("project_id", "subscription_name")