Use EventBridge events to execute code when the CloudFormation stack itself is created

template.yaml

AWSTemplateFormatVersion: "2010-09-09"
Transform: "AWS::Serverless-2016-10-31"

Resources:

  LogGroup:
    Type: AWS::Logs::LogGroup
    Properties:
      LogGroupName: !Sub /aws/lambda/${StackCreatedFunction}
      RetentionInDays: 7
  
  StackCreatedFunction:
    Type: AWS::Serverless::Function
    Properties:
      FunctionName: !Sub "${AWS::StackName}-created"
      Handler: index.handler
      Runtime: nodejs16.x
      InlineCode: !Sub |-
        exports.handler = async (event) => {
          console.log(`Stack ${AWS::StackName} created!`)
        }
      Events:
        StackEvent:
          Type: EventBridgeRule
          Properties:
            EventBusName: default
            Pattern:
              source:
                - aws.cloudformation
              detail-type: 
                - CloudFormation Stack Status Change
              detail:
                stack-id:
                  - !Ref AWS::StackId
                status-details:
                  status:
                    - CREATE_COMPLETE

Outputs:
  LogGroupName:
    Description: "The name of the lambda function log group"
    Value: !Ref LogGroup