AWS SNS SQS Fanout Notification System

This project implements an event-driven fan-out architecture using AWS CDK (TypeScript). It uses Amazon SNS to broadcast messages to multiple SQS queues, each processed by an independent Lambda consumer. Filtering is done via SNS message attributes, allowing each queue to selectively receive messages.

Project Structure

aws-fanout-notification-system/
├── bin                                             # CDK app definition
│   └──  aws-fanout-notification-system.ts
├── src
│   └──  constructs
│         └──  consumer-lambda.ts                   # Lambda function setup
│         └──  notification-queue.ts                # SQS + subscriptions setup
│         └──  notification-topic.ts                # SNS topic setup
│   └──  lambda
│         └──  emailHandler.ts                      # Email consumer
│         └──  pushHandler.ts                       # Push consumer
│         └──  smsHandler.ts                        # SMS consumer
├── stack/
│   └── aws-fanout-notification-system-stack.ts     # CDK root stack
├── cdk.json
└── package.json

Getting Started

Prerequisites

• Node.js
• AWS CDK v2
• AWS CLI configured with sufficient permissions

1. Install dependencies

npm install

2. Bootstrap and deploy the CDK stack

cdk bootstrap
cdk deploy

This will provision:

• 1 SNS Topic
  • NotificationTopic
• 3 SQS Queues (one per notification type)
  • EmailQueue
  • SmsQueue
  • PushQueue
• 3 Dead-Letter Queues (DLQs)
  • EmailDeadLetterQueue
  • SmsDeadLetterQueue
  • PushDeadLetterQueue
• 3 Lambda Functions
  • EmailLambda
  • SmsLambda
  • PushLambda
• 4 Log Groups (one per Lambda function + log retention):
  • /aws/lambda/EmailLambda
  • /aws/lambda/SmsLambda
  • /aws/lambda/PushLambda
  • log group for log retention

Working

Testing

I have created a simple Bash script to test the SNS → SQS → Lambda fan-out architecture by publishing messages to the SNS topic with different notification-type attributes.

You can find it in the project root as test-publish.sh.

Update your account-id in topic ARN before running the script.

chmod +x test-publish.sh
./test-publish.sh  # Sends all three notification
./test-publish.sh email sms # Sends notification through email & sms
./test-publish.sh push # Sends push notification

This script will:

• Publish a test message to the SNS topic
• Include a notification-type attribute (e.g., email)
• Trigger only the matching SQS queue and its corresponding Lambda function (due to SNS filter policies)

Open CloudWatch Logs for /aws/lambda/EmailLambda, SmsLambda, or PushLambda to verify processing.

Cleanup

If you're done testing or using this in a temporary environment:

cdk destroy

⚠️ Note: Since we are using CDK and logRetention, the log events inside CloudWatch log groups will expire automatically after the retention period (7 days). However, the log groups themselves are not deleted by default. To clean them up completely, you can use AWS CLI / AWS Console to delete all log groups with specific project tag (aws-fanout-notification-system).