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.
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>
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. |
|
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. |
|
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.