Message ordering in GCP - Mini Project: Build & Apply

Message Ordering with Google Cloud Pub/Sub

📖 Scenario: You are building a messaging system where the order of messages is important. For example, a bank transaction system where deposits and withdrawals must be processed in the exact order they occur.

🎯 Goal: Set up a Google Cloud Pub/Sub topic and subscription that ensures messages are delivered in the order they were published.

📋 What You'll Learn

Create a Pub/Sub topic with message ordering enabled

Create a subscription to the topic with message ordering enabled

Publish messages with ordering keys

Ensure the subscription receives messages in the correct order

💡 Why This Matters

🌍 Real World

Message ordering is critical in systems like banking, inventory management, and event processing where the sequence of events affects the system state.

💼 Career

Understanding message ordering in Pub/Sub is essential for cloud engineers and developers building reliable, event-driven applications on Google Cloud.

1

Create a Pub/Sub topic with message ordering enabled

Create a Pub/Sub topic named bank-transactions with message ordering enabled by setting messageOrdering to true in the topic configuration.

GCP

# Create the Pub/Sub topic with message ordering enabled
# Your code here

Need a hint?

Use the gcloud pubsub topics create command with the --message-ordering flag.

2

Create a subscription with message ordering enabled

Create a subscription named bank-transactions-sub to the bank-transactions topic with message ordering enabled by setting --enable-message-ordering flag.

GCP

gcloud pubsub topics create bank-transactions --message-ordering
# Create the subscription with message ordering enabled
# Your code here

Need a hint?

Use the gcloud pubsub subscriptions create command with the --enable-message-ordering flag.

3

Publish messages with ordering keys

Publish two messages to the bank-transactions topic with the ordering key account-123. Use the --ordering-key=account-123 flag for both messages.

GCP

gcloud pubsub topics create bank-transactions --message-ordering
gcloud pubsub subscriptions create bank-transactions-sub --topic=bank-transactions --enable-message-ordering
# Publish first message with ordering key
# Your code here

Need a hint?

Use the gcloud pubsub topics publish command with the --ordering-key flag for each message.

4

Configure subscription to acknowledge messages in order

Ensure the subscription bank-transactions-sub is configured to acknowledge messages in order by setting --enable-message-ordering and verify the subscription is ready to process ordered messages.

GCP

gcloud pubsub topics create bank-transactions --message-ordering
gcloud pubsub subscriptions create bank-transactions-sub --topic=bank-transactions --enable-message-ordering
gcloud pubsub topics publish bank-transactions --message="Deposit $100" --ordering-key=account-123
gcloud pubsub topics publish bank-transactions --message="Withdraw $50" --ordering-key=account-123
# Confirm subscription is configured for message ordering
# Your code here

Need a hint?

Use gcloud pubsub subscriptions describe bank-transactions-sub to verify the subscription settings.