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Cloudy Things: How to build on AWS

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Event-Driven Architectures in AWS

Event-Driven Architectures in AWS

Guillermo Ojeda's photo
Guillermo Ojeda
·Dec 8, 2022·

5 min read

Event-driven architectures are a type of architecture where components react to specific events or triggers. They have become increasingly popular in recent years, especially together with microservices. This is particularly true in cloud computing, where event-driven architectures are more easily built with managed services and serverless services.

In this blog post, we will explore event-driven architectures in Amazon Web Services (AWS), discuss some of the key benefits and challenges associated with using this approach, and go over an example implementation.

First, let's define what we mean by an event-driven architecture. In general, an event-driven architecture is a design pattern that allows for the creation of applications and components that are triggered by specific events. These events can be external, such as a user clicking on a button, or internal, such as a record being written into a database.

In AWS, event-driven architectures are built using a combination of AWS managed services, especially Amazon Simple Queue Service (SQS), Amazon Simple Notification Service (SNS), AWS Event Bridge and AWS Lambda.

This is an example of a more complex event-driven architecture in AWS:

AWS Serverless Architecture | Serverless Event Driven Architecture

One of the key benefits of using event-driven architectures in AWS is scalability. Because these architectures are triggered by specific events, they can automatically scale up or down to meet the demands of the application. More importantly, components can be scaled independently. This can save businesses a significant amount of money, as they only pay for the resources they actually use.

Additionally, event-driven architectures can help businesses to react to customer needs more quickly. Because components are decoupled and triggered by specific events, they can be updated independently.

Another benefit of event-driven architectures in AWS is the ability to integrate with a wide variety of other AWS services. This allows businesses to build complex applications that are able to process and analyze data from a variety of sources, providing valuable insights and enabling them to make more informed decisions.

Despite these benefits, there are also some challenges associated with using event-driven architectures in AWS. One of the biggest challenges is the complexity of the architecture itself. Because these architectures are built using a combination of different AWS services, they can be difficult to set up and manage, particularly for organizations that are not familiar with cloud computing.

Furthermore, event-driven architectures can be difficult to test and debug. Since they are triggered by specific events, it can be challenging to simulate these events in a testing environment, making it difficult to identify and fix issues before they impact production systems.

To implement an event-driven architecture in AWS, we will use a combination of Amazon Simple Queue Service (SQS), Amazon Simple Notification Service (SNS), and AWS Lambda.

First, we will create an SQS queue that will act as the central hub for our event-driven architecture. This queue will receive messages whenever a specific event occurs, such as a user clicking on a button or a database reaching a certain size.

Next, we will create an SNS topic that is subscribed to the SQS queue. Whenever a message is added to the queue, the SNS topic will be notified and will trigger an AWS Lambda function.

The AWS Lambda function will contain the logic for our event-driven architecture. This could include processing and analyzing data, making real-time decisions, and integrating with other AWS services.

To summarize, our event-driven architecture will work as follows:

  1. A specific event occurs, such as a user clicking on a button.

  2. This event adds a message to the SQS queue.

  3. The SNS topic is notified and triggers an AWS Lambda function.

  4. The AWS Lambda function processes and analyzes the data, and takes any necessary actions.

By using this approach, we can create a scalable and highly-responsive application that can react to specific events in real time. Additionally, by integrating with other AWS services, we can build complex applications that are able to process and analyze data from a variety of sources.

Below is an example CloudFormation template that creates an AWS Lambda function in Node.js that is triggered by an SNS topic, which is subscribed to an SQS queue.

Copy codeAWSTemplateFormatVersion: '2010-09-09'

Resources:
  MyLambdaFunction:
    Type: AWS::Lambda::Function
    Properties:
      FunctionName: MyLambdaFunction
      Runtime: nodejs12.x
      Code:
        ZipFile: |
          exports.handler = async (event) => {
            // Your function logic goes here
            return
          }

  MySQSQueue:
    Type: AWS::SQS::Queue

  MySNSTopic:
    Type: AWS::SNS::Topic
    Properties:
      Subscription:
        - Protocol: sqs
          Endpoint: !GetAtt MySQSQueue.Arn

This template creates an AWS Lambda function in Node.js named "MyLambdaFunction" and an SQS queue named "MySQSQueue". It also creates an SNS topic named "MySNSTopic" and subscribes the SQS queue to the topic.

Whenever a message is added to the SQS queue, the SNS topic will be notified and will trigger the Lambda function. The function will contain the logic for our event-driven architecture, which you can customize by modifying the code in the "ZipFile" property.

You can also customize the template by modifying the properties of the SQS queue and SNS topic. For example, you can specify the visibility timeout, message retention period, and other settings for the queue. Additionally, you can modify the runtime and code for the Lambda function, as well as other properties such as the memory and timeout settings.

In conclusion, event-driven architectures in AWS offer a number of benefits, including scalability, high responsiveness, and the ability to integrate with a wide variety of other AWS services. However, they also come with their own set of challenges, including complexity and difficulty in testing and debugging. Overall, event-driven architectures can be a valuable tool for businesses looking to build scalable and highly-responsive applications in the cloud.


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