# Google Cloud Pub/Sub tool for ADK

Supported in ADKPython v1.22.0Experimental

The `PubSubToolset` allows agents to interact with [Google Cloud Pub/Sub](https://cloud.google.com/pubsub) service to publish, pull, and acknowledge messages.

Experimental

This feature is experimental and may be updated in future releases.

## Prerequisites

Before using the `PubSubToolset`, you need to:

1. **Enable the Pub/Sub API** in your Google Cloud project.
1. **Authenticate and authorize**: Ensure that the principal (e.g., user, service account) running the agent has the necessary IAM permissions to perform Pub/Sub operations. For more information on Pub/Sub roles, see the [Pub/Sub access control documentation](https://cloud.google.com/pubsub/docs/access-control).
1. **Create a topic or subscription**: [Create a topic](https://cloud.google.com/pubsub/docs/create-topic) to publish messages and [create a subscription](https://cloud.google.com/pubsub/docs/create-subscription) to receive them.

## Usage

```py
# Copyright 2025 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 asyncio
import os

from google.adk.agents import Agent
from google.adk.runners import Runner
from google.adk.sessions import InMemorySessionService
from google.adk.tools.pubsub.config import PubSubToolConfig
from google.adk.tools.pubsub.pubsub_credentials import PubSubCredentialsConfig
from google.adk.tools.pubsub.pubsub_toolset import PubSubToolset
from google.genai import types
import google.auth

# Define constants for this example agent
AGENT_NAME = "pubsub_agent"
APP_NAME = "pubsub_app"
USER_ID = "user1234"
SESSION_ID = "1234"
GEMINI_MODEL = "gemini-2.0-flash"

# Define Pub/Sub tool config.
# You can optionally set the project_id here, or let the agent infer it from context/user input.
tool_config = PubSubToolConfig(project_id=os.getenv("GOOGLE_CLOUD_PROJECT"))

# Uses externally-managed Application Default Credentials (ADC) by default.
# This decouples authentication from the agent / tool lifecycle.
# https://cloud.google.com/docs/authentication/provide-credentials-adc
application_default_credentials, _ = google.auth.default()
credentials_config = PubSubCredentialsConfig(
    credentials=application_default_credentials
)

# Instantiate a Pub/Sub toolset
pubsub_toolset = PubSubToolset(
    credentials_config=credentials_config, pubsub_tool_config=tool_config
)

# Agent Definition
pubsub_agent = Agent(
    model=GEMINI_MODEL,
    name=AGENT_NAME,
    description=(
        "Agent to publish, pull, and acknowledge messages from Google Cloud"
        " Pub/Sub."
    ),
    instruction="""\
        You are a cloud engineer agent with access to Google Cloud Pub/Sub tools.
        You can publish messages to topics, pull messages from subscriptions, and acknowledge messages.
    """,
    tools=[pubsub_toolset],
)

# Session and Runner
session_service = InMemorySessionService()
session = asyncio.run(
    session_service.create_session(
        app_name=APP_NAME, user_id=USER_ID, session_id=SESSION_ID
    )
)
runner = Runner(
    agent=pubsub_agent, app_name=APP_NAME, session_service=session_service
)


# Agent Interaction
def call_agent(query):
    """
    Helper function to call the agent with a query.
    """
    content = types.Content(role="user", parts=[types.Part(text=query)])
    events = runner.run(user_id=USER_ID, session_id=SESSION_ID, new_message=content)

    print("USER:", query)
    for event in events:
        if event.is_final_response():
            final_response = event.content.parts[0].text
            print("AGENT:", final_response)


call_agent("publish 'Hello World' to 'my-topic'")
call_agent("pull messages from 'my-subscription'")
```

## Tools

The `PubSubToolset` includes the following tools:

### `publish_message`

Publishes a message to a Pub/Sub topic.

| Parameter      | Type             | Description                                                                                              |
| -------------- | ---------------- | -------------------------------------------------------------------------------------------------------- |
| `topic_name`   | `str`            | The name of the Pub/Sub topic (e.g., `projects/my-project/topics/my-topic`).                             |
| `message`      | `str`            | The message content to publish.                                                                          |
| `attributes`   | `dict[str, str]` | (Optional) Attributes to attach to the message.                                                          |
| `ordering_key` | `str`            | (Optional) The ordering key for the message. If you set this parameter, messages are published in order. |

### `pull_messages`

Pulls messages from a Pub/Sub subscription.

| Parameter           | Type   | Description                                                                              |
| ------------------- | ------ | ---------------------------------------------------------------------------------------- |
| `subscription_name` | `str`  | The name of the Pub/Sub subscription (e.g., `projects/my-project/subscriptions/my-sub`). |
| `max_messages`      | `int`  | (Optional) The maximum number of messages to pull. Defaults to `1`.                      |
| `auto_ack`          | `bool` | (Optional) Whether to automatically acknowledge the messages. Defaults to `False`.       |

### `acknowledge_messages`

Acknowledges one or more messages on a Pub/Sub subscription.

| Parameter           | Type        | Description                                                                              |
| ------------------- | ----------- | ---------------------------------------------------------------------------------------- |
| `subscription_name` | `str`       | The name of the Pub/Sub subscription (e.g., `projects/my-project/subscriptions/my-sub`). |
| `ack_ids`           | `list[str]` | A list of acknowledgment IDs to acknowledge.                                             |