Скачать или смотреть Unlocking Cross Account SNS Lambda Subscription using CDK

Learn how to set up a `cross-account SNS Lambda subscription` using AWS CDK. This step-by-step guide simplifies permission management for seamless communication between AWS accounts.
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Cross Account SNS Lambda Subscription using CDK

In the world of cloud computing, seamless integration between different services and accounts is essential for building flexible and responsive architectures. One common scenario is when you have multiple AWS accounts and want to connect AWS Lambda functions with SNS (Simple Notification Service) topics across these accounts. This guide explains how to achieve a cross account SNS Lambda subscription using AWS Cloud Development Kit (CDK).

The Problem

Imagine you have two AWS CDK applications running in separate AWS accounts:

Account A: This account owns the SNS topic.

Account B: This account hosts the Lambda function that needs to be triggered by notifications from the SNS topic in Account A.

Initially, you may try to add the subscription in the Lambda account (Account B) as shown below:

[[See Video to Reveal this Text or Code Snippet]]

However, you quickly realize this doesn't work because the SNS account in Account A does not grant the necessary permissions for the Lambda account to subscribe to it.

The Solution

Step 1: Grant Permissions in the SNS Account (Account A)

The first step to resolve this issue is granting the Lambda function in Account B permission to subscribe to the SNS topic in Account A. Here’s how you can implement this using CDK:

Define your SNS topic:

[[See Video to Reveal this Text or Code Snippet]]

Create a policy statement that allows the Lambda account to subscribe to your topic:

[[See Video to Reveal this Text or Code Snippet]]

Attach the policy statement to your SNS topic:

[[See Video to Reveal this Text or Code Snippet]]

Step 2: Subscribe Lambda in the Lambda Account (Account B)

Now that you have set the necessary permissions in Account A, proceed to configure the Lambda function to subscribe to the SNS topic:

Define your Lambda function:

[[See Video to Reveal this Text or Code Snippet]]

Import the SNS topic ARN and add the subscription:

[[See Video to Reveal this Text or Code Snippet]]

Important Notes

The AccountPrincipal in the policy statement of the SNS account must refer to the AWS account ID of the subscribing Lambda account.

This two-step process ensures that the SNS account correctly grants access to the Lambda account, allowing seamless communication.

Conclusion

In this guide, you successfully learned how to configure a cross account SNS Lambda subscription using AWS CDK. By granting the necessary permissions through resource policies, you can let your Lambda function respond to events from an SNS topic hosted in a different account. This not only enhances your application's capabilities but also ensures you adhere to best practices concerning security and permissions in AWS.

By following these steps, you can now set up integrations between AWS services across multiple accounts more effectively. Happy coding!