Pub/Sub vs Cloud Tasks in GCP - Practice Questions

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding Pub/Sub Message Delivery

Which statement best describes how Google Cloud Pub/Sub handles message delivery?

A Pub/Sub guarantees exactly-once delivery of messages to subscribers.

B Pub/Sub guarantees at-least-once delivery, so messages may be delivered more than once.

C Pub/Sub delivers messages only once and drops duplicates automatically.

D Pub/Sub does not retry message delivery if a subscriber fails to acknowledge.

💡 Hint

Think about how Pub/Sub ensures messages are not lost but might be repeated.

Pub/Sub guarantees at-least-once delivery, meaning messages can be delivered multiple times if acknowledgments are not received.

❓ Architecture

intermediate

Choosing Between Pub/Sub and Cloud Tasks for Task Execution

You need to design a system that processes user requests with guaranteed execution and ordered processing. Which service is more suitable?

A Use Pub/Sub because it guarantees ordered message processing and exactly-once delivery.

B Use Cloud Tasks because it supports task scheduling, retries, and ordered execution.

C Use Pub/Sub because it supports task scheduling and delayed execution natively.

D Use Cloud Tasks because it only supports fire-and-forget messaging without retries.

💡 Hint

Consider which service supports task ordering and retries explicitly.

Cloud Tasks supports scheduling, retries, and ordered execution, making it suitable for guaranteed task processing.

❓ service_behavior

advanced

Pub/Sub Subscription Acknowledgment Behavior

What happens if a Pub/Sub subscriber does not acknowledge a message within the ack deadline?

A The message is deleted and never redelivered.

B The message is redelivered to the same or another subscriber after the ack deadline expires.

C The message is moved to a dead-letter queue immediately.

D The subscriber is disconnected and must reconnect manually.

💡 Hint

Think about how Pub/Sub ensures message processing reliability.

If a message is not acknowledged in time, Pub/Sub redelivers it to ensure processing.

❓ security

advanced

Securing Cloud Tasks Execution

Which method is recommended to securely authenticate HTTP targets when Cloud Tasks dispatches tasks?

A Use API keys embedded in the task payload.

B Use OAuth 2.0 tokens or OIDC tokens generated by Cloud Tasks for authentication.

C Use basic authentication with username and password in the URL.

D No authentication is needed because Cloud Tasks runs inside Google Cloud.

💡 Hint

Consider secure token-based authentication methods supported by Cloud Tasks.

Cloud Tasks supports OAuth 2.0 and OIDC tokens to authenticate HTTP targets securely.

✅ Best Practice

expert

Handling High Throughput with Pub/Sub and Cloud Tasks

You have a system that must handle millions of user events per day with low latency and guaranteed processing. Which architecture best balances scalability and reliability?

A Use Pub/Sub to ingest events and Cloud Tasks to process critical tasks with retries and ordering.

B Use only Cloud Tasks for all events to ensure ordering and retries at scale.

C Use Pub/Sub with no retries and process events directly without task queues.

D Use Cloud Tasks to ingest events and Pub/Sub to process tasks asynchronously.

💡 Hint

Think about combining services to leverage their strengths for scale and reliability.

Pub/Sub handles high throughput event ingestion well, while Cloud Tasks manages critical task processing with retries and ordering.