Lessons

Setting Up SNS Message Filtering

Introduction

In this lesson, we will explore how to set up SNS message filtering to efficiently manage and route messages within your AWS infrastructure. We will use AWS services such as Amazon SNS, AWS CDK, and Typescript to demonstrate the process. By the end of this lesson, you will have a clear understanding of how to implement message filtering in your AWS environment.

Prerequisites

Before we begin, make sure you have the following prerequisites in place:

  • An AWS account with permissions to create and manage SNS topics
  • Basic knowledge of AWS services and tools
  • AWS CDK and Typescript installed on your local machine

Setting Up SNS Topic

The first step in setting up message filtering is to create an SNS topic in your AWS account. You can do this using the AWS Management Console or the AWS CLI. Here is an example of how to create an SNS topic using the AWS CLI:

aws sns create-topic --name MySNSTopic

Once you have created the SNS topic, you can subscribe to it using various protocols such as HTTP, HTTPS, email, or SMS. For the purpose of this lesson, we will focus on setting up message filtering for the SNS topic.

Implementing Message Filtering

To implement message filtering for your SNS topic, you can use filter policies to define the criteria for filtering messages. Filter policies are JSON objects that specify the attributes and values that messages must match to be delivered to a subscription.

Here is an example of a filter policy that filters messages based on the “eventType” attribute:

const filterPolicy = {
  eventType: ['orderPlaced', 'orderCancelled']
};

You can then set the filter policy when subscribing to the SNS topic using the AWS CDK. Here is an example of how to subscribe to an SNS topic with a filter policy using Typescript:

const topic = new sns.Topic(this, 'MySNSTopic', {
  topicName: 'MySNSTopic'
});

topic.addSubscription(new subs.EmailSubscription('emailSubscription', {
  endpoint: 'example@example.com',
  filterPolicy: filterPolicy
}));

Testing Message Filtering

Once you have set up message filtering for your SNS topic, you can test it by publishing messages to the topic and observing which messages are delivered to the subscribed endpoints. You can use the AWS CLI to publish messages to the SNS topic:

aws sns publish --topic-arn <topic-arn> --message "{'eventType': 'orderPlaced'}"

By publishing messages with different attributes, you can verify that the filter policy is correctly filtering messages based on the specified criteria.

Conclusion

In this lesson, we have learned how to set up SNS message filtering using AWS services and tools such as AWS CDK and Typescript. By creating an SNS topic, implementing filter policies, and testing message filtering, you can efficiently manage and route messages within your AWS infrastructure. Key learnings from this lesson include:

  • Creating an SNS topic in AWS
  • Implementing filter policies for message filtering
  • Testing message filtering by publishing messages to the SNS topic

By applying these concepts in your own AWS environment, you can enhance the efficiency and reliability of message delivery within your applications.

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