👀 Views: 12 💬 Answers: 1 📅 Created: 2025-06-16

aws cloudformation sns lambda policies YAML

I'm trying to implement This might be a silly question, but I'm working on a project and hit a roadblock. I've been banging my head against this for hours. I'm running into an scenario when trying to update an AWS CloudFormation stack that includes an SNS topic. The stack update fails with the following behavior: `ResourceConflict: The operation could not be completed because the resource is in use.` This happens when I attempt to change the topic policy to allow a new Lambda function to publish messages. Here's the relevant part of my CloudFormation template: ```yaml Resources: MySNSTopic: Type: 'AWS::SNS::Topic' Properties: DisplayName: 'My SNS Topic' TopicName: 'my-sns-topic' MySNSPolicy: Type: 'AWS::SNS::TopicPolicy' Properties: Topics: - !Ref MySNSTopic PolicyDocument: Version: '2012-10-17' Statement: - Effect: Allow Principal: Service: lambda.amazonaws.com Action: 'SNS:Publish' Resource: !Ref MySNSTopic MyLambdaFunction: Type: 'AWS::Lambda::Function' Properties: FunctionName: 'MyPublishFunction' Handler: 'index.handler' Runtime: 'nodejs14.x' Role: !GetAtt MyLambdaExecutionRole.Arn Code: ZipFile: | exports.handler = async (event) => { // Lambda code to publish to SNS }; ``` I’ve attempted to delete the SNS topic policy manually via the AWS console and re-deploy the stack, but I still receive the same conflict behavior. I also tried to adjust the policy with an `AWS::SNS::TopicPolicy` directly in the stack, but that didn’t resolve the scenario either. Can anyone provide guidance on how to resolve this conflict behavior during the stack update? Are there best practices for managing SNS topic policies within CloudFormation stacks that I might be overlooking? I'm working on a service that needs to handle this. What's the best practice here? For context: I'm using Yaml on Ubuntu. Any help would be greatly appreciated! My development environment is macOS. What am I doing wrong?