Create a topic
Create a subscription
Google Cloud Pub/Sub: Qwik Start - Python
The Google Cloud Pub/Sub service allows applications to exchange messages reliably, quickly, and asynchronously. To accomplish this, a data producer publishes messages to a Cloud Pub/Sub topic. A subscriber client then creates a subscription to that topic and consumes messages from the subscription. Cloud Pub/Sub persists messages that could not be delivered reliably for up to seven days.
In this lab, you will learn how to get started publishing messages with Cloud Pub/Sub using the Python client library.
What you'll do
In this lab, you'll do the following:
- Learn the basics of Pub/Sub.
- Create and list a Pub/Sub topic.
- Create and list a Pub/Sub subscription.
- Publish messages to a topic.
- Use a pull subscriber to output individual topic messages.
Setup and Requirements
Before you click the Start Lab button
Read these instructions. Labs are timed and you cannot pause them. The timer, which starts when you click Start Lab, shows how long Google Cloud resources will be made available to you.
This hands-on lab lets you do the lab activities yourself in a real cloud environment, not in a simulation or demo environment. It does so by giving you new, temporary credentials that you use to sign in and access Google Cloud for the duration of the lab.
To complete this lab, you need:
- Access to a standard internet browser (Chrome browser recommended).
- Time to complete the lab---remember, once you start, you cannot pause a lab.
How to start your lab and sign in to the Google Cloud Console
Click the Start Lab button. If you need to pay for the lab, a pop-up opens for you to select your payment method. On the left is the Lab Details panel with the following:
- The Open Google Console button
- Time remaining
- The temporary credentials that you must use for this lab
- Other information, if needed, to step through this lab
Click Open Google Console. The lab spins up resources, and then opens another tab that shows the Sign in page.
Tip: Arrange the tabs in separate windows, side-by-side.
Note: If you see the Choose an account dialog, click Use Another Account.
If necessary, copy the Username from the Lab Details panel and paste it into the Sign in dialog. Click Next.
Copy the Password from the Lab Details panel and paste it into the Welcome dialog. Click Next.
Important: You must use the credentials from the left panel. Do not use your Google Cloud Skills Boost credentials. Note: Using your own Google Cloud account for this lab may incur extra charges.
Click through the subsequent pages:
- Accept the terms and conditions.
- Do not add recovery options or two-factor authentication (because this is a temporary account).
- Do not sign up for free trials.
After a few moments, the Cloud Console opens in this tab.
Activate Cloud Shell
Cloud Shell is a virtual machine that is loaded with development tools. It offers a persistent 5GB home directory and runs on the Google Cloud. Cloud Shell provides command-line access to your Google Cloud resources.
- Click Activate Cloud Shell at the top of the Google Cloud console.
When you are connected, you are already authenticated, and the project is set to your PROJECT_ID. The output contains a line that declares the PROJECT_ID for this session:
gcloud is the command-line tool for Google Cloud. It comes pre-installed on Cloud Shell and supports tab-completion.
(Optional) You can list the active account name with this command:
Your output should now look like this:
(Optional) You can list the project ID with this command:
gcloud, in Google Cloud, refer to the gcloud CLI overview guide.
Task 1. Create a virtual environment
Python virtual environments are used to isolate package installation from the system.
Enter. If you get Permission denied error, then run the command
sudo apt-get install -y virtualenv.
Build the virtual environment:
Activate the virtual environment.
Task 2. Install the client library
Run the following to install the client library:
Get the sample code by cloning a GitHub repository:
Navigate to the directory:
Task 3. Pub/Sub - the Basics
Google Cloud Pub/Sub is an asynchronous global messaging service. There are three terms in Pub/Sub that appear often: topics, publishing, and subscribing.
A topic is a shared string that allows applications to connect with one another through a common thread.
Publishers push (or publish) a message to a Cloud Pub/Sub topic. Subscribers will then make a subscription to that thread, where they will either pull messages from the topic or configure webhooks for push subscriptions. Every subscriber must acknowledge each message within a configurable window of time.
In sum, a publisher creates and sends messages to a topic and a subscriber creates a subscription to a topic to receive messages from it.
Pub/Sub in Google CLoud
Pub/Sub comes preinstalled in the Cloud Shell, so there are no installations or configurations required to get started with this service. In this lab you use Python to create the topic, subscriber, and then view the message. You use a gcloud command to publish the message to the topic.
Task 4. Create a topic
To publish data to Cloud Pub/Sub you create a topic and then configure a publisher to the topic.
In Cloud Shell, your Project ID should automatically be stored in the environment variable
- Ensure the output is the same as the Project ID in your CONNECTION DETAILS.
publisher.py is a script that demonstrates how to perform basic operations on topics with the Cloud Pub/Sub API. View the content of publisher script:
For information about the publisher script:
Run the publisher script to create Pub/Sub Topic:
Test Completed Task
Click Check my progress to verify your performed task. If you have successfully created a Cloud Pub/Sub topic, you will see an assessment score.
This command returns a list of all Pub/Sub topics in a given project:
You can also view the topic you just made in the Cloud Console.
- Navigate to Navigation menu > Pub/Sub > Topics.
You should see
Task 5. Create a subscription
Create a Pub/Sub subscription for topic with
Test Completed Task
Click Check my progress to verify your performed task. If you have successfully created a Cloud Pub/Sub subscription, you will see an assessment score.
This command returns a list of subscribers in given project:
You'll see only one subscription because you've made only one subscription.
Check out the subscription you just made in the console. In the left pane, click Subscriptions. You should see the subscription name and other details.
For information about the
Task 6. Publish messages
Now that you've set up
MyTopic (the topic), a subscription to
MySub), see if you can use gcloud commands to publish a message to
Publish the message "Hello" to
Publish a few more messages to
MyTopic—run the following commands (replacing <YOUR NAME> with your name and <FOOD> with a food you like to eat):
Task 7. View messages
Now that you've published messages to MyTopic, pull and view the messages using MySub.
Use MySub to pull the message from MyTopic:
Click Ctrl+c to stop listening.
Task 8. Test your understanding
Below are multiple-choice questions to reinforce your understanding of this lab's concepts. Answer them to the best of your abilities.
You used Python to create a Pub/Sub topic, published to the topic, created a subscription, then used the subscription to pull data from the topic.
Finish your quest
This self-paced lab is part of the Baseline: Infrastructure quest. A quest is a series of related labs that form a learning path. Completing this quest earns you a badge to recognize your achievement. You can make your badge or badges public and link to them in your online resume or social media account. Enroll in this quest or any quest that contains this lab and get immediate completion credit. See the Google Cloud Skills Boost catalog to see all available quests.
Take your next lab
Pub/Sub Lite: Qwik Start. Complementing Pub/Sub, Pub/Sub Lite is a zonal service for messaging systems with predictable traffic patterns. If you publish 1 MiB-1 GiB of messages per second, Pub/Sub Lite is a low cost option for high-volume event ingestion.
Next steps /Learn more
This lab is part of a series of labs called Qwik Starts. These labs are designed to give you a little taste of the many features available with Google Cloud. Search for "Qwik Starts" in the Google Cloud Skills Boost catalog to find the next lab you'd like to take!
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Manual Last Updated July 13, 2022
Lab Last Tested February 28, 2022
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