Lessons

Practical Lesson on Troubleshooting SNS Delivery Failures

Introduction

In this practical lesson, we will explore troubleshooting SNS delivery failures in AWS. SNS (Simple Notification Service) is a fully managed messaging service that allows you to send messages to a variety of endpoints, such as email, SMS, and HTTP/S. However, sometimes messages may fail to be delivered for various reasons. In this lesson, we will learn how to identify and troubleshoot these delivery failures using AWS CDK with Typescript and AWS CLI commands.

Setting up the Environment

Before we can start troubleshooting SNS delivery failures, we need to set up our environment. We will be using AWS CDK with Typescript to deploy our infrastructure and AWS CLI commands to interact with our SNS topics. Make sure you have the AWS CLI installed and configured with your AWS credentials. Additionally, install the AWS CDK and set up a new project with Typescript.

Creating an SNS Topic

Let’s start by creating an SNS topic using AWS CDK with Typescript. Create a new file called sns-stack.ts and add the following code:

import * as cdk from '@aws-cdk/core';
import * as sns from '@aws-cdk/aws-sns';

export class SnsStack extends cdk.Stack {
  constructor(scope: cdk.Construct, id: string, props?: cdk.StackProps) {
    super(scope, id, props);

    const topic = new sns.Topic(this, 'MyTopic', {
      displayName: 'My SNS Topic'
    });
  }
}

This code will create a new SNS topic named ‘MyTopic’ with the display name ‘My SNS Topic’. Deploy the stack using the AWS CDK CLI:

cdk deploy

Subscribing to the SNS Topic

Next, let’s subscribe an endpoint to the SNS topic. For this example, we will subscribe an email address to receive notifications. Add the following code to your sns-stack.ts file:

import * as snsSubscriptions from '@aws-cdk/aws-sns-subscriptions';

const emailSubscription = new snsSubscriptions.EmailSubscription('your@email.com');
topic.addSubscription(emailSubscription);

This code will subscribe the email address ’your@email.com’ to the SNS topic. Deploy the stack again using the AWS CDK CLI.

Triggering a Delivery Failure

Now that we have set up our SNS topic and subscribed an endpoint, let’s trigger a delivery failure. You can do this by publishing a message to the SNS topic with an invalid endpoint. Add the following code to your sns-stack.ts file:

topic.publish({
  message: 'Test message',
  subject: 'Test subject',
  target: sns.TopicImportProps.fromTopicArn(this, 'InvalidEndpoint', 'arn:aws:sns:us-east-1:123456789012:InvalidEndpoint')
});

This code will publish a test message to the SNS topic with an invalid endpoint. Deploy the stack again using the AWS CDK CLI.

Troubleshooting SNS Delivery Failures

Now that we have triggered a delivery failure, let’s troubleshoot the issue using AWS CLI commands. Run the following command to list the delivery status of the messages in the SNS topic:

aws sns list-endpoints-by-platform-application --platform-application-arn <platform-application-arn>

Replace <platform-application-arn> with the ARN of the platform application associated with the invalid endpoint. This command will list all the endpoints registered with the platform application.

Next, run the following command to list the delivery status of the messages in the SNS topic:

aws sns list-subscriptions-by-topic --topic-arn <topic-arn>

Replace <topic-arn> with the ARN of the SNS topic. This command will list all the subscriptions associated with the SNS topic.

Conclusion

In this practical lesson, we learned how to troubleshoot SNS delivery failures using AWS CDK with Typescript and AWS CLI commands. We created an SNS topic, subscribed an endpoint, triggered a delivery failure, and used AWS CLI commands to identify and troubleshoot the issue. Key learnings from this lesson include understanding how to create SNS topics, subscribe endpoints, trigger delivery failures, and troubleshoot delivery issues using AWS CLI commands.

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