Attach Event to a bucket in a different stack, Sometimes you need to attach an event to a bucket that don't exist in your project stack, You can run this shell script to achieve that

attach_event_to_bucket_in_different_stack.sh

#!/bin/bash

# Get function ARN from stack
FUNCNAME="MyFunctionName"
FUNCARN=$(aws cloudformation describe-stacks \
  --stack-name "Stack-Name" \
  --query "Stacks[0].Outputs[?OutputKey==${FUNCNAME}].OutputValue" --output text
)

echo $FUNCARN

JSON=$(cat <<-EOF
  {
    "LambdaFunctionConfigurations": [
      {
        "Id": "EventName",
        "LambdaFunctionArn": ${FUNCARN},
        "Events": [
          "s3:ObjectCreated:*"
        ]
      }
    ]
  }
EOF
)

aws --profile sandbox s3api \
  put-bucket-notification-configuration \
  --bucket="bucket-name" \
  --notification-configuration "$JSON"

done