Cloud Functions with Pub/Sub triggers in GCP - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a Cloud Function triggered by Pub/Sub in Google Cloud?

It is a small piece of code that runs automatically when a message is published to a specific Pub/Sub topic.

beginner

How does Pub/Sub deliver messages to a Cloud Function?

Pub/Sub sends messages to the Cloud Function as events, which then processes the message data inside the function code.

intermediate

Why use Pub/Sub triggers for Cloud Functions instead of HTTP triggers?

Pub/Sub triggers are good for asynchronous, event-driven processing where messages are sent reliably and can be retried if processing fails.

intermediate

What happens if a Cloud Function fails to process a Pub/Sub message?

The message can be retried automatically by Pub/Sub until it is successfully processed or until it reaches a maximum retry limit.

advanced

How do you secure a Cloud Function triggered by Pub/Sub?

By setting proper IAM roles so only authorized services can publish messages to the Pub/Sub topic and invoke the function.

What triggers a Cloud Function when using Pub/Sub?

A A new message published to a Pub/Sub topic

B An HTTP request from a browser

C A scheduled timer event

D A file upload to Cloud Storage

Cloud Functions with Pub/Sub triggers run when a new message is published to the specified Pub/Sub topic.

What format does a Pub/Sub message have when received by a Cloud Function?

A Plain text only

B HTML document

C Binary file

D JSON object inside the event data

Pub/Sub messages are delivered as event data, often encoded as JSON, which the function can parse and use.

If a Cloud Function fails to process a Pub/Sub message, what happens next?

A The message is lost immediately

B The function restarts automatically

C Pub/Sub retries sending the message

D The message is sent to an email

Pub/Sub automatically retries delivering messages until successful or retry limits are reached.

Which Google Cloud service is responsible for sending messages to trigger Cloud Functions?

A Cloud Storage

B Cloud Pub/Sub

C Cloud SQL

D Cloud Run

Cloud Pub/Sub is the messaging service that triggers Cloud Functions when messages are published.

How can you restrict who can publish messages to a Pub/Sub topic?

A By setting IAM permissions on the topic

B By changing the Cloud Function code

C By disabling the topic

D By using a firewall rule

IAM permissions control which users or services can publish messages to a Pub/Sub topic.

Explain how a Cloud Function is triggered by a Pub/Sub message and what happens inside the function.

Think about the flow from message sending to function execution.

Describe how you would secure a Cloud Function that is triggered by Pub/Sub messages.

Focus on permissions and access control.