Integrating S3 Event Notifications with AWS Lambda

Overview of S3 Event Notifications

• S3 event notifications are used to receive alerts for various bucket events such as object creation, deletion, restoration, and replication.
• Notifications can be filtered by object key prefixes and suffixes.
• Common use case: Generating thumbnails for new images uploaded to S3.

Delivery Targets for S3 Events

• Amazon SNS: Events can be published to SNS topics to implement a fan-out pattern to multiple subscribers or Amazon SQS queues.
• Amazon SQS: Events can be sent to SQS queues for processing, and a Lambda function can poll the queue to process messages.
• AWS Lambda: S3 can directly invoke a Lambda function asynchronously to handle events.

Handling Failures

• Set up a dead-letter queue (DLQ), such as an SQS queue, to handle failed event processing.

Considerations

• S3 event notifications are typically delivered within seconds, but delays up to a minute or more can occur.
• Enable versioning on S3 buckets to prevent loss of notifications if multiple writes to the same object occur simultaneously.

Example Pattern

1. An S3 bucket receives a new file.
2. An event notification triggers a Lambda function.
3. The Lambda function processes the file and performs actions such as:
   • Inserting data into a DynamoDB table.
   • Updating a table in an RDS database.

Resoruce Based Policy