Python Client for Cloud Pub/Sub

Cloud Pub/Sub: Provides reliable, many-to-many, asynchronous messaging between applications.

Quick Start

In order to use this library, you first need to go through the following steps:

Installation

Install this library in a virtual environment using venv. venv is a tool that creates isolated Python environments. These isolated environments can have separate versions of Python packages, which allows you to isolate one project’s dependencies from the dependencies of other projects.

With venv, it’s possible to install this library without needing system install permissions, and without clashing with the installed system dependencies.

Code samples and snippets

Code samples and snippets live in the samples/ folder.

Supported Python Versions

Our client libraries are compatible with all current active and maintenance versions of Python.

Python >= 3.10, including 3.14

Unsupported Python Versions

Python <= 3.9

If you are using an end-of-life version of Python, we recommend that you update as soon as possible to an actively supported version.

Mac/Linux

python3 -m venv <your-env>
source <your-env>/bin/activate
pip install google-cloud-pubsub

Windows

py -m venv <your-env>
.\<your-env>\Scripts\activate
pip install google-cloud-pubsub

Example Usage

Publishing

To publish data to Cloud Pub/Sub you must create a topic, and then publish messages to it

import os
from google.cloud import pubsub_v1

publisher = pubsub_v1.PublisherClient()
topic_name = 'projects/{project_id}/topics/{topic}'.format(
    project_id=os.getenv('GOOGLE_CLOUD_PROJECT'),
    topic='MY_TOPIC_NAME',  # Set this to something appropriate.
)
publisher.create_topic(name=topic_name)
future = publisher.publish(topic_name, b'My first message!', spam='eggs')
future.result()

To learn more, consult the publishing documentation.

Subscribing

To subscribe to data in Cloud Pub/Sub, you create a subscription based on the topic, and subscribe to that, passing a callback function.

import os
from google.cloud import pubsub_v1

topic_name = 'projects/{project_id}/topics/{topic}'.format(
    project_id=os.getenv('GOOGLE_CLOUD_PROJECT'),
    topic='MY_TOPIC_NAME',  # Set this to something appropriate.
)

subscription_name = 'projects/{project_id}/subscriptions/{sub}'.format(
    project_id=os.getenv('GOOGLE_CLOUD_PROJECT'),
    sub='MY_SUBSCRIPTION_NAME',  # Set this to something appropriate.
)

def callback(message):
    print(message.data)
    message.ack()

with pubsub_v1.SubscriberClient() as subscriber:
    subscriber.create_subscription(
        name=subscription_name, topic=topic_name)
    future = subscriber.subscribe(subscription_name, callback)

The future returned by the call to subscriber.subscribe can be used to block the current thread until a given condition obtains:

try:
    future.result()
except KeyboardInterrupt:
    future.cancel()

It is also possible to pull messages in a synchronous (blocking) fashion. To learn more about subscribing, consult the subscriber documentation.

Authentication

It is possible to specify the authentication method to use with the Pub/Sub clients. This can be done by providing an explicit Credentials instance. Support for various authentication methods is available from the google-auth library.

For example, to use JSON Web Tokens, provide a google.auth.jwt.Credentials instance:

import json
from google.auth import jwt

service_account_info = json.load(open("service-account-info.json"))
audience = "https://pubsub.googleapis.com/google.pubsub.v1.Subscriber"

credentials = jwt.Credentials.from_service_account_info(
    service_account_info, audience=audience
)

subscriber = pubsub_v1.SubscriberClient(credentials=credentials)

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

Versioning

This library follows Semantic Versioning.

It is currently in major version one (1.y.z), which means that the public API should be considered stable.

Contributing

Contributions to this library are always welcome and highly encouraged.

See the CONTRIBUTING doc for more information on how to get started.

Community

The best place to ask questions is via Stackoverflow: https://stackoverflow.com/questions/tagged/google-cloud-pubsub

License

Apache 2.0 - See the LICENSE for more information.

Next Steps

Read the Client Library Documentation for Cloud Pub/Sub to see other available methods on the client.
Read the Cloud Pub/Sub Product documentation to learn more about the product and see How-to Guides.
View this README to see the full list of Cloud APIs that we cover.

Logging

This library uses the standard Python logging functionality to log some RPC events that could be of interest for debugging and monitoring purposes. Note the following:

Logs may contain sensitive information. Take care to restrict access to the logs if they are saved, whether it be on local storage or on Google Cloud Logging.
Google may refine the occurrence, level, and content of various log messages in this library without flagging such changes as breaking. Do not depend on immutability of the logging events.
By default, the logging events from this library are not handled. You must explicitly configure log handling using one of the mechanisms below.

Simple, environment-based configuration

To enable logging for this library without any changes in your code, set the GOOGLE_SDK_PYTHON_LOGGING_SCOPE environment variable to a valid Google logging scope. This configures handling of logging events (at level logging.DEBUG or higher) from this library in a default manner, emitting the logged messages in a structured format. It does not currently allow customizing the logging levels captured nor the handlers, formatters, etc. used for any logging event.

A logging scope is a period-separated namespace that begins with google, identifying the Python module or package to log.

Valid logging scopes: google, google.cloud.asset.v1, google.api, google.auth, etc.
Invalid logging scopes: foo, 123, etc.

NOTE: If the logging scope is invalid, the library does not set up any logging handlers.

Environment-Based Examples

Enabling the default handler for all Google-based loggers

export GOOGLE_SDK_PYTHON_LOGGING_SCOPE=google

Enabling the default handler for a specific Google module (for a client library called library_v1):

export GOOGLE_SDK_PYTHON_LOGGING_SCOPE=google.cloud.library_v1

Advanced, code-based configuration

You can also configure a valid logging scope using Python’s standard logging mechanism.

Code-Based Examples

Configuring a handler for all Google-based loggers

import logging

from google.cloud import library_v1

base_logger = logging.getLogger("google")
base_logger.addHandler(logging.StreamHandler())
base_logger.setLevel(logging.DEBUG)

Configuring a handler for a specific Google module (for a client library called library_v1):

import logging

from google.cloud import library_v1

base_logger = logging.getLogger("google.cloud.library_v1")
base_logger.addHandler(logging.StreamHandler())
base_logger.setLevel(logging.DEBUG)

Logging details

Regardless of which of the mechanisms above you use to configure logging for this library, by default logging events are not propagated up to the root logger from the google-level logger. If you need the events to be propagated to the root logger, you must explicitly set logging.getLogger("google").propagate = True in your code.
You can mix the different logging configurations above for different Google modules. For example, you may want use a code-based logging configuration for one library, but decide you need to also set up environment-based logging configuration for another library.
1. If you attempt to use both code-based and environment-based configuration for the same module, the environment-based configuration will be ineffectual if the code -based configuration gets applied first.
The Google-specific logging configurations (default handlers for environment-based configuration; not propagating logging events to the root logger) get executed the first time any client library is instantiated in your application, and only if the affected loggers have not been previously configured. (This is the reason for 2.i. above.)

Release files for google-cloud-pubsub 2.41.0

For a detailed explanation of source distributions (sdists) and built distributions (wheels), please see the package formats documentation.

Source distribution (sdist)

Source distribution for google-cloud-pubsub 2.41.0
File	Size	Uploaded
google_cloud_pubsub-2.41.0.tar.gz	397.7 kB	Sep 17, 2026	Details

Built distribution (wheel)

Table of built distributions (wheels) for google-cloud-pubsub 2.41.0
File	Interpreter	ABI	Platform	Reset
google_cloud_pubsub-2.41.0-py3-none-any.whl 322.3 kB Sep 17, 2026	Python 3	none	any	Details

Total release size: 720.1 kB

Release files / google_cloud_pubsub-2.41.0.tar.gz

Download URL	google_cloud_pubsub-2.41.0.tar.gz
Size	397.7 kB
Tags	Source
SHA-256 checksum How to use checksums	`4c7b42c23c1457543665ec162d75e0ba1b1d4c98adcc9c753f3517164f7937d7`
BLAKE2b-256 checksum How to use checksums	`1717a40387921a375c9cac6ec5e276c9ea7a756a7bbca94f4d5df9403bf5554b`
Upload date	Sep 17, 2026
Uploaded using Trusted Publishing? What is trusted publishing?	Yes
Uploaded via	`twine/6.2.0 CPython/3.11.2`

Provenance

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Identity

Publishing platform: Google Cloud
Publishing commit: /
Publisher account: google-cloud-sdk-py@oss-exit-gate-prod.iam.gserviceaccount.com

Workflow

Publishing configuration: /blob//

Artifact

Subject: google_cloud_pubsub-2.41.0.tar.gz
SHA-256 checksum: 4c7b42c23c1457543665ec162d75e0ba1b1d4c98adcc9c753f3517164f7937d7 Verifying attestations

Release files / google_cloud_pubsub-2.41.0-py3-none-any.whl

Download URL	google_cloud_pubsub-2.41.0-py3-none-any.whl
Size	322.3 kB
Tags	Python 3
SHA-256 checksum How to use checksums	`a71436ccc2ebe784d8c4d34c5e1395f6edaf4f560fa23a0b99f7ad846efd35aa`
BLAKE2b-256 checksum How to use checksums	`0e645b77fe420b382cf27c31e206a690c2ab2994035aeaa8900bdc82493794f9`
Upload date	Sep 17, 2026
Uploaded using Trusted Publishing? What is trusted publishing?	Yes
Uploaded via	`twine/6.2.0 CPython/3.11.2`

Provenance

Identity

Publishing platform: Google Cloud
Publishing commit: /
Publisher account: google-cloud-sdk-py@oss-exit-gate-prod.iam.gserviceaccount.com

Workflow

Publishing configuration: /blob//

Artifact

Subject: google_cloud_pubsub-2.41.0-py3-none-any.whl
SHA-256 checksum: a71436ccc2ebe784d8c4d34c5e1395f6edaf4f560fa23a0b99f7ad846efd35aa Verifying attestations