Event notifications

Event notifications send messages to your queue when data in your R2 bucket changes. You can consume these messages with a consumer Worker or pull over HTTP from outside of Cloudflare Workers.

Open Beta

The event notifications feature is currently in open beta. To report bugs or request features, go to the #r2-storage channel in the Cloudflare Developer Discord ↗ or fill out the feedback form ↗.

Get started with event notifications

Prerequisites

Before getting started, you will need:

• An existing R2 bucket. If you do not already have an existing R2 bucket, refer to Create buckets.
• An existing queue. If you do not already have a queue, refer to Create a queue.
• A consumer Worker or HTTP pull enabled on your Queue.

Set up Wrangler

To begin, refer to Install/Update Wrangler to install Wrangler, the Cloudflare Developer Platform CLI. Log into Wrangler with the wrangler login command.

Enable event notifications on your R2 bucket

To enable event notifications, add an event notification rule to your bucket by running the r2 bucket notification create command. Event notification rules determine the event types that trigger notifications and enable filtering based on object prefix and suffix.

npx wrangler r2 bucket notification create <BUCKET_NAME> --event-type <EVENT_TYPE> --queue <QUEUE_NAME>

To add filtering based on prefix or suffix use the --prefix or --suffix flag, respectively.

# Filter using prefix
$ npx wrangler r2 bucket notification create <BUCKET_NAME> --event-type <EVENT_TYPE> --queue <QUEUE_NAME> --prefix "<PREFIX_VALUE>"

# Filter using suffix
$ npx wrangler r2 bucket notification create <BUCKET_NAME> --event-type <EVENT_TYPE> --queue <QUEUE_NAME> --suffix "<SUFFIX_VALUE>"

# Filter using prefix and suffix. Both the conditions will be used for filtering
$ npx wrangler r2 bucket notification create <BUCKET_NAME> --event-type <EVENT_TYPE> --queue <QUEUE_NAME> --prefix "<PREFIX_VALUE>" --suffix "<SUFFIX_VALUE>"

For a more complete step-by-step example, refer to the Log and store upload events in R2 with event notifications example.

Event types

Event type	Description	Trigger actions
object-create	Triggered when new objects are created or existing objects are overwritten.	PutObject CopyObject CompleteMultipartUpload
object-delete	Triggered when an object is explicitly removed from the bucket. Note: During the beta, deletes that occur as a result of object lifecycle policies will not trigger this event.	DeleteObject

Message format

Queue consumers receive notifications as Messages. The following is an example of the body of a message that a consumer Worker will receive:

{
  "account": "3f4b7e3dcab231cbfdaa90a6a28bd548",
  "action": "CopyObject",
  "bucket": "my-bucket",
  "object": {
    "key": "my-new-object",
    "size": 65536,
    "eTag": "c846ff7a18f28c2e262116d6e8719ef0"
  },
  "eventTime": "2024-05-24T19:36:44.379Z",
  "copySource": {
    "bucket": "my-bucket",
    "object": "my-original-object"
  }
}

Properties

Property	Type	Description
account	String	The Cloudflare account ID that the event is associated with.
action	String	The type of action that triggered the event notification. Example actions include: PutObject, CopyObject, CompleteMultipartUpload, DeleteObject.
bucket	String	The name of the bucket where the event occurred.
object	Object	A nested object containing details about the object involved in the event.
object.key	String	The key (or name) of the object within the bucket.
object.size	Number	The size of the object in bytes. Note: not present for object-delete events.
object.eTag	String	The entity tag (eTag) of the object. Note: not present for object-delete events.
eventTime	String	The time when the action that triggered the event occurred.
copySource	Object	A nested object containing details about the source of a copied object. Note: only present for events triggered by CopyObject.
copySource.bucket	String	The bucket that contained the source object.
copySource.object	String	The name of the source object.

Limitations

During the beta, event notifications has the following limitations:

• Queues per-queue message throughput is currently 400 messages per second. If your workload produces more than 400 notifications per second, messages may be dropped.
• For a given bucket, only one event notification rule can be created per queue.
• Each bucket can have up to 5 event notification rules.
• Deletes that occur as a result of object lifecycle policies will not trigger an event notification.
• Event notifications are not available for buckets with jursdictional restrictions.