aws-cdk: NotificationArns as a construct prop, rather than read-only

[dzenana-s]

Describe the feature

We are exploring how we can integrate SNS with our CloudFormation stacks. We noticed that you can supply a notificationArns prop, which can include an SNS topic ARN, but only on the NestedStack construct, not the Stack construct.

Is there a reason why this prop cannot be supplied when creating deploying with the CDK without nesting? We are trying to find a way to automate adding SNS, without manually making the update to the stack so that it points notifications to the SNS topic in the console.

Use Case

We would like to monitor changes to certain CloudFormation stacks and send notifications through SNS when certain actions are taken on a stack.

Currently, we would have to deploy via CDK and then manually update the notification settings in the stack, but we would like to do this all via code.

Proposed Solution

No response

Other Information

No response

Acknowledgements

• I may be able to implement this feature request
• This feature might incur a breaking change

CDK version used

2.35.0

Environment details (OS name and version, etc.)

Mac OS

[kaizencc]

The reason is that NestedStack is built on top of the CfnStack cloudformation resource, which has the notificationArns property. A CDK Stack does not actually create a CfnStack afaik, so it doesn't have the opportunity to update the notificationArns property. How/why this is the case I'm not entirely sure; I did a little digging but came up with more questions than answers. Maybe @rix0rrr can help with answering that.

[peterwoodworth]

You can set the arns of SNS topics to notify on cdk deploy with the --notification-arns option.

@kaizencc you're right that Stack does not actually create a CfnStack - the CloudFormation::Stack resource is specifically for nested stacks. The way CDK accomplishes setting the notification arns on a non-nested stack is by passing them into the CreateChangeSet operation which is best configured through the CLI rather than the Stack construct, though I would think it's possible for us to design it such that it's configurable through the stack construct as well

@dzenana-s I hope configuring this through the CLI works for you! 🙂

[github-actions]

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[gricey432]

For people like me who find this in search, see #8581