#!/usr/bin/env python

# Copyright 2019 Google LLC

#

# Licensed under the Apache License, Version 2.0 (the "License");

# you may not use this file except in compliance with the License.

# You may obtain a copy of the License at

#

# http://www.apache.org/licenses/LICENSE-2.0

#

# Unless required by applicable law or agreed to in writing, software

# distributed under the License is distributed on an "AS IS" BASIS,

# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

# See the License for the specific language governing permissions and

# limitations under the License.

# [START pubsub_quickstart_sub_all]

import argparse

import time

# [START pubsub_quickstart_sub_deps]

from google.cloud import pubsub_v1

# [END pubsub_quickstart_sub_deps]

def sub(project_id, subscription_name):

"""Receives messages from a Pub/Sub subscription."""

# [START pubsub_quickstart_sub_client]

# Initialize a Subscriber client

client = pubsub_v1.SubscriberClient()

# [END pubsub_quickstart_sub_client]

# Create a fully qualified identifier in the form of

# `projects/{project_id}/subscriptions/{subscription_name}`

subscription_path = client.subscription_path(

project_id, subscription_name)

def callback(message):

print('Received message {} of message ID {}'.format(

message, message.message_id))

# Acknowledge the message. Unack'ed messages will be redelivered.

message.ack()

print('Acknowledged message of message ID {}\n'.format(

message.message_id))

client.subscribe(subscription_path, callback=callback)

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

# Keep the main thread from exiting so the subscriber can

# process messages in the background.

while True:

time.sleep(60)

if __name__ == '__main__':

parser = argparse.ArgumentParser(

description=__doc__,

formatter_class=argparse.RawDescriptionHelpFormatter

)

parser.add_argument('project_id', help='Google Cloud project ID')

parser.add_argument('subscription_name', help='Pub/Sub subscription name')

args = parser.parse_args()

sub(args.project_id, args.subscription_name)

# [END pubsub_quickstart_sub_all]