Setting Up Notification of Bucket Events

The Amazon S3 notifications feature enables you to configure a bucket so that Amazon S3 publishes a message to an Amazon Simple Notification Service (SNS) topic when Amazon S3 detects a key event on a bucket. Subscribers to this topic can have messages for bucket events delivered to an endpoint such as a web server, e-mail address, or an Amazon Simple Queue Service queue.

Note that Notification fees will be charged at the normal Amazon SNS rates. For details about pricing, go to http://aws.amazon.com/sns/#pricing. There are no additional Amazon S3 charges for publishing a message to an Amazon SNS topic beyond the request fee to enable and disable the feature. In order to receive notifications of a bucket's events, you must subscribe to the topic that has been configured for that bucket.

Currently, the s3:ReducedRedundancyLostObject event is the only event supported by Amazon S3. The s3:ReducedRedundancyLostObject event is triggered when Amazon S3 detects that it has lost all replicas of a Reduced Redundancy Storage (RRS) object and can no longer service requests for that object. Notification on this event can enable you to replace missing RRS objects proactively to ensure there is no customer impact.

Notifications are published to a specified Amazon SNS topic. Currently, only one topic can be configured for notifications. If the bucket owner and Amazon SNS topic owner are the same, the bucket owner has permission to publish notifications to the topic by default. Otherwise, the owner of the topic must create a policy to enable the bucket owner to publish to the topic. For more information about creating this policy, see Example Cases for Amazon SNS Access Control.

	Important
	The Amazon SNS topic specified for a bucket’s notification configuration must be in the same region as the bucket.

The following table lists the topic regions for the possible LocationContraint values for buckets.

By default, only the bucket owner has permission to set and view the notifications on a bucket. However, the bucket owner can use a bucket policy to grant permission to other users to set this configuration using the s3:PutBucketNotification permission or view this configuration via the s3:GetBucketNotification permission. For more information about bucket policy, see Using Bucket Policies.

Similar to other bucket settings, there is a sub-resource for each bucket enabling you to set or view that bucket's notification settings. To configure notifications on a bucket, use the bucket’s notification sub-resource with the Amazon S3 REST API. For more information about the notification sub-resource, see Put Bucket notification and Get Bucket notification.

After you call the PUT operation to configure notifications on a bucket, Amazon S3 publishes a test notification to ensure that the topic exists and that the bucket owner has permission to publish to the specified topic. If the notification is successfully published to the SNS topic, the PUT operation updates the bucket configuration and returns a 200 OK response with a x-amz-sns-test-message-id header containing the message ID of the test notification sent to the topic. For information about PUT operation errors, see Put Bucket notification.

The message published for an event to a topic contains the fields listed in the following table.

The following message is an example of a message publishing an s3:ReducedRedundancyLostObject event:

{
    "Service":"Amazon S3",
    "Event": "s3:ReducedRedundancyLostObject",
    "Time":"2010-02-11T23:48:22.000Z",
    "Bucket": "myphotos",
    "Key": "Home/2009/10/carvingpumpkins.jpg",
    "VersionId":"qfXHy5689N7n9mWVwanN_hIroMn_rzXl",
    "RequestId":"4442587FB7D0A2F9",
    "HostId":"fHZOHz+oQlKAFQ7RgVSklvcDNYI0v05gsOWWeJcyTTXWgGzI6CC5FZVICjD9bUzT"
}

The following message is an example of the test message that Amazon S3 sends when a bucket is enabled for notifications:

{
    "Service":"Amazon S3",
    "Event": "s3:TestEvent",
    "Time":"2010-02-11T23:48:22.000Z",
    "Bucket": "myphotos",
    "RequestId":"4442587FB7D0A2F9",
    "HostId":"fHZOHz+oQlKAFQ7RgVSklvcDNYI0v05gsOWWeJcyTTXWgGzI6CC5FZVICjD9bUzT"
}