Amazon Simple Storage Service (Amazon S3) Event Notifications publishes notifications for certain events in your S3 bucket (for example, object created events, object removal events, or restore object events). You can use an AWS Lambda function to process these notifications according to your application’s requirements. However, the Lambda function can’t directly subscribe to notifications from S3 buckets that are hosted in different AWS Regions.
This pattern’s approach deploys a fanout scenario to process Amazon S3 notifications from cross-Region S3 buckets by using an Amazon Simple Notification Service (Amazon SNS) topic for each Region. These Regional SNS topics send the Amazon S3 event notifications to an Amazon Simple Queue Service (Amazon SQS) queue in a central Region that also contains your Lambda function. The Lambda function subscribes to this SQS queue and processes the event notifications according to your organization’s requirements.
