notification - Configure object change notification


gsutil notification create -f (json|none) [-p <prefix>] [-t <topic>] \
    [-m <key>:<value>]... [-e <eventType>]... gs://<bucket_name>
gsutil notification delete (<notificationConfigName>|gs://<bucket_name>)...
gsutil notification list gs://<bucket_name>...

gsutil notification watchbucket [-i <id>] [-t <token>] <app_url> gs://<bucket_name>
gsutil notification stopchannel <channel_id> <resource_id>


You can use the notification command to configure Pub/Sub notifications for Cloud Storage and Object change notification channels.

Cloud Pub/Sub

The "create", "list", and "delete" sub-commands deal with configuring Cloud Storage integration with Google Cloud Pub/Sub.


The create sub-command creates a notification config on a bucket, establishing a flow of event notifications from Cloud Storage to a Cloud Pub/Sub topic. As part of creating this flow, the create command also verifies that the destination Cloud Pub/Sub topic exists, creating it if necessary, and verifies that the Cloud Storage bucket has permission to publish events to that topic, granting the permission if necessary.

If a destination Cloud Pub/Sub topic is not specified with the -t flag, Cloud Storage chooses a topic name in the default project whose ID is the same as the bucket name. For example, if the default project ID specified is 'default-project' and the bucket being configured is gs://example-bucket, the create command uses the Cloud Pub/Sub topic "projects/default-project/topics/example-bucket".

In order to enable notifications, your project's Cloud Storage service agent must have the IAM permission "pubsub.topics.publish". This command checks to see if the destination Cloud Pub/Sub topic grants the service agent this permission. If not, the create command attempts to grant it.

A bucket can have up to 100 total notification configurations and up to 10 notification configurations set to trigger for a specific event.

Create Examples

Begin sending notifications of all changes to the bucket example-bucket to the Cloud Pub/Sub topic projects/default-project/topics/example-bucket:

gsutil notification create -f json gs://example-bucket

The same as above, but specifies the destination topic ID 'files-to-process' in the default project:

gsutil notification create -f json \
  -t files-to-process gs://example-bucket

The same as above, but specifies a Cloud Pub/Sub topic belonging to the specific cloud project 'example-project':

gsutil notification create -f json \
  -t projects/example-project/topics/files-to-process gs://example-bucket

Create a notification config that only sends an event when a new object has been created:

gsutil notification create -f json -e OBJECT_FINALIZE gs://example-bucket

Create a topic and notification config that only sends an event when an object beginning with "photos/" is affected:

gsutil notification create -p photos/ gs://example-bucket

List all of the notificationConfigs in bucket example-bucket:

gsutil notification list gs://example-bucket

Delete all notitificationConfigs for bucket example-bucket:

gsutil notification delete gs://example-bucket

Delete one specific notificationConfig for bucket example-bucket:

gsutil notification delete \


The create sub-command has the following options


Specify an event type filter for this notification config. Cloud Storage only sends notifications of this type. You may specify this parameter multiple times to allow multiple event types. If not specified, Cloud Storage sends notifications for all event types. The valid types are:

OBJECT_FINALIZE - An object has been created.
OBJECT_METADATA_UPDATE - The metadata of an object has changed.
OBJECT_DELETE - An object has been permanently deleted.
OBJECT_ARCHIVE - A live version of an object has become a
  noncurrent version.

Specifies the payload format of notification messages. Must be either "json" for a payload matches the object metadata for the JSON API, or "none" to specify no payload at all. In either case, notification details are available in the message attributes.


Specifies a key:value attribute that is appended to the set of attributes sent to Cloud Pub/Sub for all events associated with this notification config. You may specify this parameter multiple times to set multiple attributes.


Specifies a prefix path filter for this notification config. Cloud Storage only sends notifications for objects in this bucket whose names begin with the specified prefix.


Skips creation and permission assignment of the Cloud Pub/Sub topic. This is useful if the caller does not have permission to access the topic in question, or if the topic already exists and has the appropriate publish permission assigned.


The Cloud Pub/Sub topic to which notifications should be sent. If not specified, this command chooses a topic whose project is your default project and whose ID is the same as the Cloud Storage bucket name.

Next Steps

Once the create command has succeeded, Cloud Storage publishes a message to the specified Cloud Pub/Sub topic when eligible changes occur. In order to receive these messages, you must create a Pub/Sub subscription for your Pub/Sub topic. To learn more about creating Pub/Sub subscriptions, see the Pub/Sub Subscriber Overview.

You can create a simple Pub/Sub subscription using the gcloud command-line tool. For example, to create a new subscription on the topic "myNewTopic" and attempt to pull messages from it, you could run:

gcloud beta pubsub subscriptions create --topic myNewTopic testSubscription
gcloud beta pubsub subscriptions pull --auto-ack testSubscription


The list sub-command provides a list of notification configs belonging to a given bucket. The listed name of each notification config can be used with the delete sub-command to delete that specific notification config.

For listing Object Change Notifications instead of Cloud Pub/Sub notification subscription configs, add a -o flag.

List Examples

Fetch the list of notification configs for the bucket example-bucket:

gsutil notification list gs://example-bucket

The same as above, but for Object Change Notifications instead of Cloud Pub/Sub notification subscription configs:

gsutil notification list -o gs://example-bucket

Fetch the notification configs in all buckets matching a wildcard:

gsutil notification list gs://example-*

Fetch all of the notification configs for buckets in the default project:

gsutil notification list gs://*


The delete sub-command deletes notification configs from a bucket. If a notification config name is passed as a parameter, that notification config alone is deleted. If a bucket name is passed, all notification configs associated with that bucket are deleted.

Cloud Pub/Sub topics associated with this notification config are not deleted by this command. Those must be deleted separately, for example with the gcloud command gcloud beta pubsub topics delete.

Object Change Notification subscriptions cannot be deleted with this command. For that, see the command gsutil notification stopchannel.

Delete Examples

Delete a single notification config (with ID 3) in the bucket example-bucket:

gsutil notification delete projects/_/buckets/example-bucket/notificationConfigs/3

Delete all notification configs in the bucket example-bucket:

gsutil notification delete gs://example-bucket

Object Change Notifications

Object change notification is a separate, older feature within Cloud Storage for generating notifications. This feature sends HTTPS messages to a client application that you've set up separately. This feature is generally not recommended, because Pub/Sub notifications are cheaper, easier to use, and more flexible. For more information, see Object change notification.

The "watchbucket" and "stopchannel" sub-commands enable and disable Object change notifications.


The watchbucket sub-command can be used to watch a bucket for object changes. A service account must be used when running this command.

The app_url parameter must be an HTTPS URL to an application that will be notified of changes to any object in the bucket.

The optional id parameter can be used to assign a unique identifier to the created notification channel. If not provided, a random UUID string is generated.

The optional token parameter can be used to validate notifications events. To do this, set this custom token and store it to later verify that notification events contain the client token you expect.

Watchbucket Examples

Watch the bucket example-bucket for changes and send notifications to an application server running at

gsutil notification watchbucket \

Assign identifier my-channel-id to the created notification channel:

gsutil notification watchbucket -i my-channel-id \ gs://example-bucket

Set a custom client token that is included with each notification event:

gsutil notification watchbucket -t my-client-token \ gs://example-bucket


The stopchannel sub-command can be used to stop sending change events to a notification channel.

The channel_id and resource_id parameters should match the values from the response of a bucket watch request.

Stopchannel Examples

Stop the notification event channel with channel identifier channel1 and resource identifier SoGqan08XDIFWr1Fv_nGpRJBHh8:

gsutil notification stopchannel channel1 SoGqan08XDIFWr1Fv_nGpRJBHh8

Notifications And Parallel Composite Uploads

gsutil supports parallel composite uploads. If enabled, an upload can result in multiple temporary component objects being uploaded before the actual intended object is created. Any subscriber to notifications for this bucket then sees a notification for each of these components being created and deleted. If this is a concern for you, note that parallel composite uploads can be disabled by setting "parallel_composite_upload_threshold = 0" in your .boto config file. Alternately, your subscriber code can filter out gsutil's parallel composite uploads by ignoring any notification about objects whose names contain (but do not start with) the following string: