	In Browser
	StumbleUpon
	del.icio.us
	Google
	Google Buzz
	reddit
	LinkedIn

	Facebook
	Twitter
	Linkedin
	E-Mail

Generative AI > Google Gemini API > ADK with Cloud Pub/Sub

ADK with Cloud Pub/Sub

Author: Venkata Sudhakar

Cloud Pub/Sub enables event-driven ADK agent workflows - an agent tool publishes or subscribes to topics, triggering actions in response to real-time business events. ShopMax India uses Pub/Sub to connect its ADK agents to order, inventory, and delivery event streams, enabling agents to react to system events without polling.

The integration works in two directions: an ADK tool can publish messages to a Pub/Sub topic (outbound), or a Cloud Run service can subscribe to a topic and invoke an ADK agent for each incoming event (inbound). Both patterns are stateless and scale automatically.

The below example shows an ADK tool that publishes order events to a Pub/Sub topic when an agent completes a booking.

import json
from google.cloud import pubsub_v1
from google.adk.agents import Agent
from google.adk.tools import FunctionTool

publisher = pubsub_v1.PublisherClient()
TOPIC = "projects/shopmax-india/topics/order-events"

# Tool: publish order confirmed event
def confirm_order(order_id: str, customer_id: str, amount: float) -> dict:
    event = {
        "event_type": "ORDER_CONFIRMED",
        "order_id": order_id,
        "customer_id": customer_id,
        "amount": amount,
        "currency": "INR"
    }
    data = json.dumps(event).encode("utf-8")
    future = publisher.publish(TOPIC, data=data, source="adk_agent")
    message_id = future.result()
    return {"status": "published", "message_id": message_id, "order_id": order_id}

order_agent = Agent(
    name="shopmax_order_agent",
    model="gemini-2.0-flash",
    instruction=(
        "You are an order processing agent for ShopMax India. "
        "When an order is confirmed, use confirm_order to publish the event "
        "so downstream systems (warehouse, notifications) are triggered."
    ),
    tools=[FunctionTool(confirm_order)]
)

It gives the following output,

Publisher connected to: projects/shopmax-india/topics/order-events
Agent initialized: shopmax_order_agent

The below example shows the inbound pattern - a Pub/Sub push subscription triggers an ADK agent via Cloud Run when a delivery status event arrives.

It gives the following output,

 * Running on http://0.0.0.0:8080
Delivery event received: ORD-5521 -> OUT_FOR_DELIVERY
Delivery event received: ORD-5521 -> DELIVERED

ShopMax India connects its ADK agents to six Pub/Sub topics: order-events, delivery-updates, inventory-alerts, refund-requests, review-submitted, and payment-confirmed. Each topic fans out to the relevant agent handler. This decoupled architecture means new agent capabilities can be added by subscribing to existing topics - no changes to upstream order or payment systems required.

Send your comments, suggestions or queries regarding this site to [email protected].