publisher.py

#!/usr/bin/env python

# Copyright 2016 Google LLC. All Rights Reserved.
#
# 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.

"""This application demonstrates how to perform basic operations on topics
with the Cloud Pub/Sub API.

For more information, see the README.md under /pubsub and the documentation
at https://cloud.google.com/pubsub/docs.
"""

import argparse


def list_topics(project_id):
    """Lists all Pub/Sub topics in the given project."""
    # [START pubsub_list_topics]
    from google.cloud import pubsub_v1

    # TODO(developer)
    # project_id = "your-project-id"

    publisher = pubsub_v1.PublisherClient()
    project_path = f"projects/{project_id}"

    for topic in publisher.list_topics(request={"project": project_path}):
        print(topic)
    # [END pubsub_list_topics]


def create_topic(project_id, topic_id):
    """Create a new Pub/Sub topic."""
    # [START pubsub_quickstart_create_topic]
    # [START pubsub_create_topic]
    from google.cloud import pubsub_v1

    # TODO(developer)
    # project_id = "your-project-id"
    # topic_id = "your-topic-id"

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

    topic = publisher.create_topic(request={"name": topic_path})

    print(f"Created topic: {topic.name}")
    # [END pubsub_quickstart_create_topic]
    # [END pubsub_create_topic]


def delete_topic(project_id, topic_id):
    """Deletes an existing Pub/Sub topic."""
    # [START pubsub_delete_topic]
    from google.cloud import pubsub_v1

    # TODO(developer)
    # project_id = "your-project-id"
    # topic_id = "your-topic-id"

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

    publisher.delete_topic(request={"topic": topic_path})

    print(f"Topic deleted: {topic_path}")
    # [END pubsub_delete_topic]


def publish_messages(project_id, topic_id):
    """Publishes multiple messages to a Pub/Sub topic."""
    # [START pubsub_quickstart_publisher]
    # [START pubsub_publish]
    from google.cloud import pubsub_v1

    # TODO(developer)
    # project_id = "your-project-id"
    # topic_id = "your-topic-id"

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

    for n in range(1, 10):
        data = f"Message number {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)
        print(future.result())

    print(f"Published messages to {topic_path}.")
    # [END pubsub_quickstart_publisher]
    # [END pubsub_publish]


def publish_messages_with_custom_attributes(project_id, topic_id):
    """Publishes multiple messages with custom attributes
    to a Pub/Sub topic."""
    # [START pubsub_publish_custom_attributes]
    from google.cloud import pubsub_v1

    # TODO(developer)
    # project_id = "your-project-id"
    # topic_id = "your-topic-id"

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

    for n in range(1, 10):
        data = f"Message number {n}"
        # Data must be a bytestring
        data = data.encode("utf-8")
        # Add two attributes, origin and username, to the message
        future = publisher.publish(
            topic_path, data, origin="python-sample", username="gcp"
        )
        print(future.result())

    print(f"Published messages with custom attributes to {topic_path}.")
    # [END pubsub_publish_custom_attributes]


def publish_messages_with_error_handler(project_id, topic_id):
    # [START pubsub_publish_with_error_handler]
    """Publishes multiple messages to a Pub/Sub topic with an error handler."""
    from concurrent import futures
    from google.cloud import pubsub_v1

    # TODO(developer)
    # project_id = "your-project-id"
    # topic_id = "your-topic-id"

    publisher = pubsub_v1.PublisherClient()
    topic_path = publisher.topic_path(project_id, topic_id)
    publish_futures = []

    def get_callback(publish_future, data):
        def callback(publish_future):
            try:
                # Wait 100 ms for the publish call to succeed.
                print(publish_future.result(timeout=0.1))
            except futures.TimeoutError:
                print(f"Publishing {data} timed out.")

        return callback

    for i in range(10):
        data = str(i)
        # When you publish a message, the client returns a future.
        publish_future = publisher.publish(topic_path, data.encode("utf-8"))
        # Non-blocking. Publish failures are handled in the callback function.
        publish_future.add_done_callback(get_callback(publish_future, data))
        publish_futures.append(publish_future)

    # Wait for all the publish futures to resolve before exiting.
    futures.wait(publish_futures, return_when=futures.ALL_COMPLETED)

    print(f"Published messages with error handler to {topic_path}.")
    # [END pubsub_publish_with_error_handler]


def publish_messages_with_batch_settings(project_id, topic_id):
    """Publishes multiple messages to a Pub/Sub topic with batch settings."""
    # [START pubsub_publisher_batch_settings]
    from concurrent import futures
    from google.cloud import pubsub_v1

    # TODO(developer)
    # project_id = "your-project-id"
    # topic_id = "your-topic-id"

    # Configure the batch to publish as soon as there are 10 messages
    # or 1 KiB of data, or 1 second has passed.
    batch_settings = pubsub_v1.types.BatchSettings(
        max_messages=10,  # default 100
        max_bytes=1024,  # default 1 MiB
        max_latency=1,  # default 10 ms
    )
    publisher = pubsub_v1.PublisherClient(batch_settings)
    topic_path = publisher.topic_path(project_id, topic_id)
    publish_futures = []

    # Resolve the publish future in a separate thread.
    def callback(future):
        message_id = future.result()
        print(message_id)

    for n in range(1, 10):
        data = f"Message number {n}"
        # Data must be a bytestring
        data = data.encode("utf-8")
        publish_future = publisher.publish(topic_path, data)
        # Non-blocking. Allow the publisher client to batch multiple messages.
        publish_future.add_done_callback(callback)
        publish_futures.append(publish_future)

    futures.wait(publish_futures, return_when=futures.ALL_COMPLETED)

    print(f"Published messages with batch settings to {topic_path}.")
    # [END pubsub_publisher_batch_settings]


def publish_messages_with_flow_control_settings(project_id, topic_id):
    """Publishes messages to a Pub/Sub topic with flow control settings."""
    # [START pubsub_publisher_flow_control]
    from concurrent import futures
    from google.cloud import pubsub_v1
    from google.cloud.pubsub_v1.types import (
        LimitExceededBehavior,
        PublisherOptions,
        PublishFlowControl,
    )

    # TODO(developer)
    # project_id = "your-project-id"
    # topic_id = "your-topic-id"

    # Configure how many messages the publisher client can hold in memory
    # and what to do when messages exceed the limit.
    flow_control_settings = PublishFlowControl(
        message_limit=100,  # 100 messages
        byte_limit=10 * 1024 * 1024,  # 10 MiB
        limit_exceeded_behavior=LimitExceededBehavior.BLOCK,
    )
    publisher = pubsub_v1.PublisherClient(
        publisher_options=PublisherOptions(flow_control=flow_control_settings)
    )
    topic_path = publisher.topic_path(project_id, topic_id)
    publish_futures = []

    # Resolve the publish future in a separate thread.
    def callback(publish_future):
        message_id = publish_future.result()
        print(message_id)

    # Publish 1000 messages in quick succession to trigger flow control.
    for n in range(1, 1000):
        data = f"Message number {n}"
        # Data must be a bytestring
        data = data.encode("utf-8")
        publish_future = publisher.publish(topic_path, data)
        # Non-blocking. Allow the publisher client to batch messages.
        publish_future.add_done_callback(callback)
        publish_futures.append(publish_future)

    futures.wait(publish_futures, return_when=futures.ALL_COMPLETED)

    print(f"Published messages with flow control settings to {topic_path}.")
    # [END pubsub_publisher_flow_control]


def publish_messages_with_retry_settings(project_id, topic_id):
    """Publishes messages with custom retry settings."""
    # [START pubsub_publisher_retry_settings]
    from google import api_core
    from google.cloud import pubsub_v1

    # TODO(developer)
    # project_id = "your-project-id"
    # topic_id = "your-topic-id"

    # Configure the retry settings. Defaults shown in comments are values applied
    # by the library by default, instead of default values in the Retry object.
    custom_retry = api_core.retry.Retry(
        initial=0.250,  # seconds (default: 0.1)
        maximum=90.0,  # seconds (default: 60.0)
        multiplier=1.45,  # default: 1.3
        deadline=300.0,  # seconds (default: 60.0)
        predicate=api_core.retry.if_exception_type(
            api_core.exceptions.Aborted,
            api_core.exceptions.DeadlineExceeded,
            api_core.exceptions.InternalServerError,
            api_core.exceptions.ResourceExhausted,
            api_core.exceptions.ServiceUnavailable,
            api_core.exceptions.Unknown,
            api_core.exceptions.Cancelled,
        ),
    )

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

    for n in range(1, 10):
        data = f"Message number {n}"
        # Data must be a bytestring
        data = data.encode("utf-8")
        future = publisher.publish(topic=topic_path, data=data, retry=custom_retry)
        print(future.result())

    print(f"Published messages with retry settings to {topic_path}.")
    # [END pubsub_publisher_retry_settings]


def publish_with_ordering_keys(project_id, topic_id):
    """Publishes messages with ordering keys."""
    # [START pubsub_publish_with_ordering_keys]
    from google.cloud import pubsub_v1

    # TODO(developer): Choose an existing topic.
    # project_id = "your-project-id"
    # topic_id = "your-topic-id"

    publisher_options = pubsub_v1.types.PublisherOptions(enable_message_ordering=True)
    # Sending messages to the same region ensures they are received in order
    # even when multiple publishers are used.
    client_options = {"api_endpoint": "us-east1-pubsub.googleapis.com:443"}
    publisher = pubsub_v1.PublisherClient(
        publisher_options=publisher_options, client_options=client_options
    )
    # The `topic_path` method creates a fully qualified identifier
    # in the form `projects/{project_id}/topics/{topic_id}`
    topic_path = publisher.topic_path(project_id, topic_id)

    for message in [
        ("message1", "key1"),
        ("message2", "key2"),
        ("message3", "key1"),
        ("message4", "key2"),
    ]:
        # Data must be a bytestring
        data = message[0].encode("utf-8")
        ordering_key = message[1]
        # When you publish a message, the client returns a future.
        future = publisher.publish(topic_path, data=data, ordering_key=ordering_key)
        print(future.result())

    print(f"Published messages with ordering keys to {topic_path}.")
    # [END pubsub_publish_with_ordering_keys]


def resume_publish_with_ordering_keys(project_id, topic_id):
    """Resume publishing messages with ordering keys when unrecoverable errors occur."""
    # [START pubsub_resume_publish_with_ordering_keys]
    from google.cloud import pubsub_v1

    # TODO(developer): Choose an existing topic.
    # project_id = "your-project-id"
    # topic_id = "your-topic-id"

    publisher_options = pubsub_v1.types.PublisherOptions(enable_message_ordering=True)
    # Sending messages to the same region ensures they are received in order
    # even when multiple publishers are used.
    client_options = {"api_endpoint": "us-east1-pubsub.googleapis.com:443"}
    publisher = pubsub_v1.PublisherClient(
        publisher_options=publisher_options, client_options=client_options
    )
    # The `topic_path` method creates a fully qualified identifier
    # in the form `projects/{project_id}/topics/{topic_id}`
    topic_path = publisher.topic_path(project_id, topic_id)

    for message in [
        ("message1", "key1"),
        ("message2", "key2"),
        ("message3", "key1"),
        ("message4", "key2"),
    ]:
        # Data must be a bytestring
        data = message[0].encode("utf-8")
        ordering_key = message[1]
        # When you publish a message, the client returns a future.
        future = publisher.publish(topic_path, data=data, ordering_key=ordering_key)
        try:
            print(future.result())
        except RuntimeError:
            # Resume publish on an ordering key that has had unrecoverable errors.
            publisher.resume_publish(topic_path, ordering_key)

    print(f"Resumed publishing messages with ordering keys to {topic_path}.")
    # [END pubsub_resume_publish_with_ordering_keys]


def detach_subscription(project_id, subscription_id):
    """Detaches a subscription from a topic and drops all messages retained in it."""
    # [START pubsub_detach_subscription]
    from google.api_core.exceptions import GoogleAPICallError, RetryError
    from google.cloud import pubsub_v1

    # TODO(developer): Choose an existing subscription.
    # project_id = "your-project-id"
    # subscription_id = "your-subscription-id"

    publisher_client = pubsub_v1.PublisherClient()
    subscriber_client = pubsub_v1.SubscriberClient()
    subscription_path = subscriber_client.subscription_path(project_id, subscription_id)

    try:
        publisher_client.detach_subscription(
            request={"subscription": subscription_path}
        )
    except (GoogleAPICallError, RetryError, ValueError, Exception) as err:
        print(err)

    subscription = subscriber_client.get_subscription(
        request={"subscription": subscription_path}
    )
    if subscription.detached:
        print(f"{subscription_path} is detached.")
    else:
        print(f"{subscription_path} is NOT detached.")
    # [END pubsub_detach_subscription]


if __name__ == "__main__":
    parser = argparse.ArgumentParser(
        description=__doc__,
        formatter_class=argparse.RawDescriptionHelpFormatter,
    )
    parser.add_argument("project_id", help="Your Google Cloud project ID")

    subparsers = parser.add_subparsers(dest="command")
    subparsers.add_parser("list", help=list_topics.__doc__)

    create_parser = subparsers.add_parser("create", help=create_topic.__doc__)
    create_parser.add_argument("topic_id")

    delete_parser = subparsers.add_parser("delete", help=delete_topic.__doc__)
    delete_parser.add_argument("topic_id")

    publish_parser = subparsers.add_parser("publish", help=publish_messages.__doc__)
    publish_parser.add_argument("topic_id")

    publish_with_custom_attributes_parser = subparsers.add_parser(
        "publish-with-custom-attributes",
        help=publish_messages_with_custom_attributes.__doc__,
    )
    publish_with_custom_attributes_parser.add_argument("topic_id")

    publish_with_error_handler_parser = subparsers.add_parser(
        "publish-with-error-handler",
        help=publish_messages_with_error_handler.__doc__,
    )
    publish_with_error_handler_parser.add_argument("topic_id")

    publish_with_batch_settings_parser = subparsers.add_parser(
        "publish-with-batch-settings",
        help=publish_messages_with_batch_settings.__doc__,
    )
    publish_with_batch_settings_parser.add_argument("topic_id")

    publish_with_flow_control_settings_parser = subparsers.add_parser(
        "publish-with-flow-control",
        help=publish_messages_with_flow_control_settings.__doc__,
    )
    publish_with_flow_control_settings_parser.add_argument("topic_id")

    publish_with_retry_settings_parser = subparsers.add_parser(
        "publish-with-retry-settings",
        help=publish_messages_with_retry_settings.__doc__,
    )
    publish_with_retry_settings_parser.add_argument("topic_id")

    publish_with_ordering_keys_parser = subparsers.add_parser(
        "publish-with-ordering-keys",
        help=publish_with_ordering_keys.__doc__,
    )
    publish_with_ordering_keys_parser.add_argument("topic_id")

    resume_publish_with_ordering_keys_parser = subparsers.add_parser(
        "resume-publish-with-ordering-keys",
        help=resume_publish_with_ordering_keys.__doc__,
    )
    resume_publish_with_ordering_keys_parser.add_argument("topic_id")

    detach_subscription_parser = subparsers.add_parser(
        "detach-subscription",
        help=detach_subscription.__doc__,
    )
    detach_subscription_parser.add_argument("subscription_id")

    args = parser.parse_args()

    if args.command == "list":
        list_topics(args.project_id)
    elif args.command == "create":
        create_topic(args.project_id, args.topic_id)
    elif args.command == "delete":
        delete_topic(args.project_id, args.topic_id)
    elif args.command == "publish":
        publish_messages(args.project_id, args.topic_id)
    elif args.command == "publish-with-custom-attributes":
        publish_messages_with_custom_attributes(args.project_id, args.topic_id)
    elif args.command == "publish-with-error-handler":
        publish_messages_with_error_handler(args.project_id, args.topic_id)
    elif args.command == "publish-with-batch-settings":
        publish_messages_with_batch_settings(args.project_id, args.topic_id)
    elif args.command == "publish-with-flow-control":
        publish_messages_with_flow_control_settings(args.project_id, args.topic_id)
    elif args.command == "publish-with-retry-settings":
        publish_messages_with_retry_settings(args.project_id, args.topic_id)
    elif args.command == "publish-with-ordering-keys":
        publish_with_ordering_keys(args.project_id, args.topic_id)
    elif args.command == "resume-publish-with-ordering-keys":
        resume_publish_with_ordering_keys(args.project_id, args.topic_id)
    elif args.command == "detach-subscription":
        detach_subscription(args.project_id, args.subscription_id)