Publishing messages in GCP - Mini Project: Build & Apply

Publishing messages

📖 Scenario: You are working on a cloud project where you need to send messages to a messaging service for other parts of your application to process asynchronously.Google Cloud Pub/Sub is a service that lets you publish messages to a topic. Other services can subscribe to this topic to receive messages.

🎯 Goal: Create a simple Google Cloud Pub/Sub publisher that sends messages to a topic.

📋 What You'll Learn

Create a variable called project_id with the exact value "my-gcp-project".

Create a variable called topic_id with the exact value "my-topic".

Create a Pub/Sub client object called publisher.

Publish a message with the exact text "Hello, Pub/Sub!" to the topic.

Add a line to confirm the message was published by storing the message ID in a variable called message_id.

💡 Why This Matters

🌍 Real World

Publishing messages to a Pub/Sub topic is common in cloud applications to decouple components and enable asynchronous processing.

💼 Career

Understanding how to publish messages to Pub/Sub is essential for cloud engineers and developers working with event-driven architectures on Google Cloud.

1

Set up project and topic variables

Create a variable called project_id and set it to "my-gcp-project". Then create a variable called topic_id and set it to "my-topic".

GCP

# Your code here

Need a hint?

Use simple assignment to create the two variables with the exact names and values.

2

Create the Pub/Sub publisher client

Import the pubsub_v1 module from google.cloud. Then create a Pub/Sub publisher client object called publisher.

GCP

project_id = "my-gcp-project"
topic_id = "my-topic"
# Your code here

Need a hint?

Use from google.cloud import pubsub_v1 and then create publisher = pubsub_v1.PublisherClient().

3

Create the full topic path and publish a message

Use publisher.topic_path(project_id, topic_id) to create a variable called topic_path. Then publish the message "Hello, Pub/Sub!" to topic_path using publisher.publish(). Store the returned future in a variable called future.

GCP

from google.cloud import pubsub_v1

project_id = "my-gcp-project"
topic_id = "my-topic"

publisher = pubsub_v1.PublisherClient()
# Your code here

Need a hint?

Use publisher.topic_path() to get the full topic path string. Then publish the message as bytes with publisher.publish().

4

Get the message ID after publishing

Call future.result() and store the returned message ID string in a variable called message_id.

GCP

from google.cloud import pubsub_v1

project_id = "my-gcp-project"
topic_id = "my-topic"

publisher = pubsub_v1.PublisherClient()

topic_path = publisher.topic_path(project_id, topic_id)

future = publisher.publish(topic_path, b"Hello, Pub/Sub!")
# Your code here

Need a hint?

Use future.result() to wait for the publish to complete and get the message ID.