The Fan-Out architectural pattern is widely used in distributed systems to allow a single message or event to trigger multiple parallel actions. This concept is essential in modern architectures as it enables scalability, parallel processing, and decoupling between components.
According to the Cambridge Dictionary, fan-out means "spread out from a central point", which translates well the core idea of the pattern: a message originating from one point branches out to multiple destinations simultaneously.
In this article, I present a practical way to learn and apply this pattern using three AWS serverless services: Lambda, SQS, and SNS. The learning will be structured in three complementary articles that together form a practical challenge to understand and implement the Fan-Out concept.
How Will Fan-Out Be Explained?
To understand the Fan-Out pattern in practice, you will be guided through three articles. Each one covers a fundamental AWS service for implementing this pattern. It's important to follow the order to make the most of the learning:
1️⃣ Introduction to AWS Lambda
In this first article, you'll learn about AWS Lambda, AWS's serverless computing service. It will be used as the starting point for triggering events in the Fan-Out pattern. With Lambda, you'll create functions that process events and trigger messages to other services.
Note: It's important to highlight that the challenge consists of some reformulations of the initially proposed architecture design. Therefore, we'll reach a point in this first article, but in the second one, we'll start the first reformulation based on the new concepts added.
2️⃣ Introduction to Amazon Simple Queue Service (SQS)
In the second article, you'll learn about SQS, AWS's queue service. It will be used as one of the destinations for messages triggered by Lambda, allowing temporary storage and asynchronous message processing.
Note: returning to the initial observation, here we find the same scenario. We'll evolve to a point B of our architecture design, which will soon after be reformulated once again.
3️⃣ Introduction to Amazon Simple Notification Service (SNS)
Finally, the third article covers SNS, AWS's notification service. It will be used to distribute messages to multiple destinations simultaneously, completing the Fan-Out architecture.
The Practical Challenge
The goal of this challenge is to implement a Fan-Out architecture where:
An initial event triggers a Lambda function.
The Lambda function sends messages to an SNS topic.
SNS distributes these messages to different destinations, including an SQS queue.
A Lambda function receives the event from the queue.
With this practice, you'll understand how each service plays a fundamental role in building scalable, decoupled, and resilient systems.
Conclusion
The Fan-Out pattern is a powerful strategy in distributed systems, and by the end of this challenge, you'll have a clear vision of how to use it in AWS using Lambda, SQS, and SNS.
I hope these articles are helpful and help you explore serverless architecture concepts in practice. Don't forget to share your questions and results in the comments!
Happy reading and good studies! 🚀