PubSub Messaging Explained Simply for Everyone

PubSub

    PubSub, or Publish-Subscribe, is a messaging pattern that allows different parts of a system to communicate without directly talking to each other.

Publishers

    are entities responsible for sending messages (or events) to a central system, often referred to as a message broker or a topic. These messages contain information about events or updates that other parts of the system might be interested in.

Subscribers

     on the other hand, are entities that express interest in certain types of messages or events. They register with the message broker to receive notifications whenever a relevant message is published.

The key idea behind PubSub is decoupling. Publishers and subscribers are independent of each other and don't need to know about each other's existence. Publishers focus solely on producing messages, while subscribers focus on consuming messages that match their interests.

Lab :

Set up and Requirements

The set up of this lab is quite simple. Make sure you are performing the lab in an incognito window and using the latest version of Google Chrome. Follow the lab instructions to get into the Google Console. You can read through the instructions to be ready for the further steps in this lab.

The Pub/Sub basics

Have a look at the diagram below to take a look at the terms which you will be hearing often when you are dealing with this service.

Pub/Sub topics

Let’s now head to the first task of this lab which is to create a Pub/Sub topic.

Pub/Sub subscriptions

Now it is time to work with subscriptions. You will follow the same process which you followed above for the creation of topics. All you have to run is two commands

• To Create a subscription — gcloud pubsub subscriptions create — topic myTopic mySubscription
• To delete a subscription — gcloud pubsub subscriptions delete Test1

Pub/Sub Publishing and Pulling a Single Message

In this section you will publish and pull a single message on Pub/Sub. All you need to do is follow the instructions given carefully and fill in the blanks wherever necessary. 

Pub/Sub pulling all messages from subscriptions

In the above section you saw how to pull a single message. Now, you will see how you can pull multiple messages from subscriptions.