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sub.py
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sub.py
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#!/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.
import argparse
from google.cloud import pubsub_v1
def sub(project_id, subscription_id, timeout=None):
"""Receives messages from a Pub/Sub subscription."""
# Initialize a Subscriber client
subscriber_client = pubsub_v1.SubscriberClient()
# Create a fully qualified identifier in the form of
# `projects/{project_id}/subscriptions/{subscription_id}`
subscription_path = subscriber_client.subscription_path(project_id, subscription_id)
def callback(message):
print(f"Received {message}.")
# Acknowledge the message. Unack'ed messages will be redelivered.
message.ack()
print(f"Acknowledged {message.message_id}.")
streaming_pull_future = subscriber_client.subscribe(
subscription_path, callback=callback
)
print(f"Listening for messages on {subscription_path}..\n")
try:
# Calling result() on StreamingPullFuture keeps the main thread from
# exiting while messages get processed in the callbacks.
streaming_pull_future.result(timeout=timeout)
except: # noqa
streaming_pull_future.cancel() # Trigger the shutdown.
streaming_pull_future.result() # Block until the shutdown is complete.
subscriber_client.close()
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_id", help="Pub/Sub subscription ID")
parser.add_argument(
"timeout", default=None, nargs="?", const=1, help="Pub/Sub subscription ID"
)
args = parser.parse_args()
sub(args.project_id, args.subscription_id, args.timeout)