Pub/Sub with Cloud Functions integration in GCP - Mini Project: Build & Apply

Pub/Sub with Cloud Functions integration

📖 Scenario: You are building a simple notification system on Google Cloud Platform. When a message is published to a Pub/Sub topic, a Cloud Function should automatically trigger and process the message.

🎯 Goal: Create a Pub/Sub topic, configure a Cloud Function that triggers on messages published to this topic, and set the function to log the message data.

📋 What You'll Learn

Create a Pub/Sub topic named notifications-topic.

Create a Cloud Function named processNotification triggered by notifications-topic.

The Cloud Function should log the message data received from Pub/Sub.

💡 Why This Matters

🌍 Real World

Pub/Sub with Cloud Functions is commonly used to build event-driven systems where messages trigger automated processing, such as notifications, data pipelines, or alerts.

💼 Career

Understanding how to integrate Pub/Sub with Cloud Functions is essential for cloud developers and engineers working on scalable, serverless architectures on Google Cloud Platform.

1

Create the Pub/Sub topic

Create a Pub/Sub topic named notifications-topic using the gcloud command-line tool.

GCP

# Use the gcloud command to create the Pub/Sub topic
# Your code here

Need a hint?

Use the gcloud pubsub topics create command followed by the topic name.

2

Create the Cloud Function configuration

Create a Cloud Function named processNotification that triggers on the Pub/Sub topic notifications-topic. Use the runtime python39 and specify the entry point as process_notification.

GCP

gcloud pubsub topics create notifications-topic
# Use the gcloud command to deploy the Cloud Function with the correct trigger and runtime
# Your code here

Need a hint?

Use gcloud functions deploy with the --trigger-topic flag and specify the runtime and entry point.

3

Write the Cloud Function code

Write the Python function process_notification that takes event and context parameters and logs the Pub/Sub message data decoded as UTF-8.

GCP

gcloud pubsub topics create notifications-topic
gcloud functions deploy processNotification --runtime python39 --trigger-topic notifications-topic --entry-point process_notification --quiet

def process_notification(event, context):
    # Your code here

Need a hint?

Use base64.b64decode to decode the message data and print to log it.

4

Finalize Cloud Function deployment

Update the Cloud Function deployment to include the source code file named main.py containing the process_notification function.

GCP

gcloud pubsub topics create notifications-topic
gcloud functions deploy processNotification --runtime python39 --trigger-topic notifications-topic --entry-point process_notification --quiet

def process_notification(event, context):
    import base64
    message = base64.b64decode(event['data']).decode('utf-8')
    print(f"Received message: {message}")

# Redeploy the function specifying the source file
# Your code here

Need a hint?

Use the --source . flag to specify the current directory containing main.py.