Bucket Notifications 

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Bucket Notifications

Bucket notifications provide a mechanism for sending information out of the radosgw when certain events are happening on the bucket. Currently, notifications could be sent to: HTTP, AMQP0.9.1 and Kafka endpoints.

Note, that if the events should be stored in Ceph, in addition, or instead of being pushed to an endpoint, the PubSub Module should be used instead of the bucket notification mechanism.

A user can create different topics. A topic entity is defined by its name and is per tenant. A user can only associate its topics (via notification configuration) with buckets it owns.

In order to send notifications for events for a specific bucket, a notification entity needs to be created. A notification can be created on a subset of event types, or for all event types (default). The notification may also filter out events based on prefix/suffix and/or regular expression matching of the keys. As well as, on the metadata attributes attached to the object, or the object tags. There can be multiple notifications for any specific topic, and the same topic could be used for multiple notifications.

REST API has been defined to provide configuration and control interfaces for the bucket notification mechanism. This API is similar to the one defined as the S3-compatible API of the pubsub sync module.

S3 Bucket Notification Compatibility

备注

To enable bucket notifications API, the rgw_enable_apis configuration parameter should contain: "notifications".

Notification Reliability 

Notifications may be sent synchronously, as part of the operation that triggered them. In this mode, the operation is acked only after the notification is sent to the topic's configured endpoint, which means that the round trip time of the notification is added to the latency of the operation itself.

备注

The original triggering operation will still be considered as successful even if the notification fail with an error, cannot be deliverd or times out

Notifications may also be sent asynchronously. They will be committed into persistent storage and then asynchronously sent to the topic's configured endpoint. In this case, the only latency added to the original operation is of committing the notification to persistent storage.

备注

If the notification fail with an error, cannot be deliverd or times out, it will be retried until successfully acked

小技巧

To minimize the added latency in case of asynchronous notifications, it is recommended to place the "log" pool on fast media

Topic Management via CLI 

Configuration of all topics, associated with a tenant, could be fetched using the following command:

# radosgw-admin topic list [--tenant={tenant}]

Configuration of a specific topic could be fetched using:

# radosgw-admin topic get --topic={topic-name} [--tenant={tenant}]

And removed using:

# radosgw-admin topic rm --topic={topic-name} [--tenant={tenant}]

Notification Performance Stats 

The same counters are shared between the pubsub sync module and the bucket notification mechanism.

pubsub_event_triggered: running counter of events with at least one topic associated with them
pubsub_event_lost: running counter of events that had topics associated with them but that were not pushed to any of the endpoints
pubsub_push_ok: running counter, for all notifications, of events successfully pushed to their endpoint
pubsub_push_fail: running counter, for all notifications, of events failed to be pushed to their endpoint
pubsub_push_pending: gauge value of events pushed to an endpoint but not acked or nacked yet

备注

pubsub_event_triggered and pubsub_event_lost are incremented per event, while: pubsub_push_ok, pubsub_push_fail, are incremented per push action on each notification

Bucket Notification REST API 

Topics 

备注

In all topic actions, the parameters are URL encoded, and sent in the message body using application/x-www-form-urlencoded content type

Create a Topic 

This will create a new topic. The topic should be provided with push endpoint parameters that would be used later when a notification is created. Upon a successful request, the response will include the topic ARN that could be later used to reference this topic in the notification request. To update a topic, use the same command used for topic creation, with the topic name of an existing topic and different endpoint values.

小技巧

Any notification already associated with the topic needs to be re-created for the topic update to take effect

POST

Action=CreateTopic
&Name=<topic-name>
[&Attributes.entry.1.key=amqp-exchange&Attributes.entry.1.value=<exchange>]
[&Attributes.entry.2.key=amqp-ack-level&Attributes.entry.2.value=none|broker|routable]
[&Attributes.entry.3.key=verify-ssl&Attributes.entry.3.value=true|false]
[&Attributes.entry.4.key=kafka-ack-level&Attributes.entry.4.value=none|broker]
[&Attributes.entry.5.key=use-ssl&Attributes.entry.5.value=true|false]
[&Attributes.entry.6.key=ca-location&Attributes.entry.6.value=<file path>]
[&Attributes.entry.7.key=OpaqueData&Attributes.entry.7.value=<opaque data>]
[&Attributes.entry.8.key=push-endpoint&Attributes.entry.8.value=<endpoint>]
[&Attributes.entry.9.key=persistent&Attributes.entry.9.value=true|false]
[&Attributes.entry.10.key=cloudevents&Attributes.entry.10.value=true|false]

Request parameters:

push-endpoint: URI of an endpoint to send push notification to
OpaqueData: opaque data is set in the topic configuration and added to all notifications triggered by the topic
persistent: indication whether notifications to this endpoint are persistent (=asynchronous) or not ("false" by default)
HTTP endpoint

URI: http[s]://<fqdn>[:<port]

port defaults to: 80/443 for HTTP/S accordingly

verify-ssl: indicate whether the server certificate is validated by the client or not ("true" by default)

cloudevents: indicate whether the HTTP header should contain attributes according to the S3 CloudEvents Spec ("false" by default)

AMQP0.9.1 endpoint

URI: amqp[s]://[<user>:<password>@]<fqdn>[:<port>][/<vhost>]

user/password defaults to: guest/guest

user/password may only be provided over HTTPS. If not, topic creation request will be rejected.

port defaults to: 5672/5671 for unencrypted/SSL-encrypted connections

vhost defaults to: "/"

verify-ssl: indicate whether the server certificate is validated by the client or not ("true" by default)

if ca-location is provided, and secure connection is used, the specified CA will be used, instead of the default one, to authenticate the broker

amqp-exchange: the exchanges must exist and be able to route messages based on topics (mandatory parameter for AMQP0.9.1). Different topics pointing to the same endpoint must use the same exchange

amqp-ack-level: no end2end acking is required, as messages may persist in the broker before delivered into their final destination. Three ack methods exist:

"none": message is considered "delivered" if sent to broker

"broker": message is considered "delivered" if acked by broker (default)

"routable": message is considered "delivered" if broker can route to a consumer

小技巧

The topic-name (see Create a Topic) is used for the AMQP topic ("routing key" for a topic exchange)

Kafka endpoint

URI: kafka://[<user>:<password>@]<fqdn>[:<port]

if use-ssl is set to "true", secure connection will be used for connecting with the broker ("false" by default)

if ca-location is provided, and secure connection is used, the specified CA will be used, instead of the default one, to authenticate the broker

user/password may only be provided over HTTPS. If not, topic creation request will be rejected.

user/password may only be provided together with use-ssl, if not, the connection to the broker would fail.

port defaults to: 9092

kafka-ack-level: no end2end acking is required, as messages may persist in the broker before delivered into their final destination. Two ack methods exist:

"none": message is considered "delivered" if sent to broker

"broker": message is considered "delivered" if acked by broker (default)

备注

The key/value of a specific parameter does not have to reside in the same line, or in any specific order, but must use the same index
Attribute indexing does not need to be sequential or start from any specific value
AWS Create Topic has a detailed explanation of the endpoint attributes format. However, in our case different keys and values are used

The response will have the following format:

<CreateTopicResponse xmlns="https://sns.amazonaws.com/doc/2010-03-31/">
    <CreateTopicResult>
        <TopicArn></TopicArn>
    </CreateTopicResult>
    <ResponseMetadata>
        <RequestId></RequestId>
    </ResponseMetadata>
</CreateTopicResponse>

The topic ARN in the response will have the following format:

arn:aws:sns:<zone-group>:<tenant>:<topic>

Get Topic Attributes 

Returns information about a specific topic. This includes push-endpoint information, if provided.

POST

Action=GetTopicAttributes
&TopicArn=<topic-arn>

Response will have the following format:

<GetTopicAttributesResponse>
    <GetTopicAttributesResult>
        <Attributes>
            <entry>
                <key>User</key>
                <value></value>
            </entry>
            <entry>
                <key>Name</key>
                <value></value>
            </entry>
            <entry>
                <key>EndPoint</key>
                <value></value>
            </entry>
            <entry>
                <key>TopicArn</key>
                <value></value>
            </entry>
            <entry>
                <key>OpaqueData</key>
                <value></value>
            </entry>
        </Attributes>
    </GetTopicAttributesResult>
    <ResponseMetadata>
        <RequestId></RequestId>
    </ResponseMetadata>
</GetTopicAttributesResponse>

User: name of the user that created the topic
Name: name of the topic
EndPoint: JSON formatted endpoint parameters, including:
- EndpointAddress: the push-endpoint URL
- EndpointArgs: the push-endpoint args
- EndpointTopic: the topic name that should be sent to the endpoint (may be different than the above topic name)
- HasStoredSecret: "true" if if endpoint URL contain user/password information. In this case request must be made over HTTPS. If not, topic get request will be rejected
- Persistent: "true" is topic is persistent
TopicArn: topic ARN
OpaqueData: the opaque data set on the topic

Get Topic Information 

Returns information about specific topic. This includes push-endpoint information, if provided. Note that this API is now deprecated in favor of the AWS compliant GetTopicAttributes API.

POST

Action=GetTopic
&TopicArn=<topic-arn>

Response will have the following format:

<GetTopicResponse>
    <GetTopicResult>
        <Topic>
            <User></User>
            <Name></Name>
            <EndPoint>
                <EndpointAddress></EndpointAddress>
                <EndpointArgs></EndpointArgs>
                <EndpointTopic></EndpointTopic>
                <HasStoredSecret></HasStoredSecret>
                <Persistent></Persistent>
            </EndPoint>
            <TopicArn></TopicArn>
            <OpaqueData></OpaqueData>
        </Topic>
    </GetTopicResult>
    <ResponseMetadata>
        <RequestId></RequestId>
    </ResponseMetadata>
</GetTopicResponse>

User: name of the user that created the topic
Name: name of the topic
EndpointAddress: the push-endpoint URL
EndpointArgs: the push-endpoint args
EndpointTopic: the topic name that should be sent to the endpoint (may be different than the above topic name)
HasStoredSecret: "true" if endpoint URL contain user/password information. In this case request must be made over HTTPS. If not, topic get request will be rejected
Persistent: "true" is topic is persistent
TopicArn: topic ARN
OpaqueData: the opaque data set on the topic

Delete Topic 

POST

Action=DeleteTopic
&TopicArn=<topic-arn>

Delete the specified topic.

备注

Deleting an unknown notification (e.g. double delete) is not considered an error
Deleting a topic does not automatically delete all notifications associated with it

The response will have the following format:

<DeleteTopicResponse xmlns="https://sns.amazonaws.com/doc/2010-03-31/">
    <ResponseMetadata>
        <RequestId></RequestId>
    </ResponseMetadata>
</DeleteTopicResponse>

List Topics 

List all topics associated with a tenant.

POST

Action=ListTopics

Response will have the following format:

<ListTopicsResponse xmlns="https://sns.amazonaws.com/doc/2010-03-31/">
    <ListTopicsResult>
        <Topics>
            <member>
                <User></User>
                <Name></Name>
                <EndPoint>
                    <EndpointAddress></EndpointAddress>
                    <EndpointArgs></EndpointArgs>
                    <EndpointTopic></EndpointTopic>
                </EndPoint>
                <TopicArn></TopicArn>
                <OpaqueData></OpaqueData>
            </member>
        </Topics>
    </ListTopicsResult>
    <ResponseMetadata>
        <RequestId></RequestId>
    </ResponseMetadata>
</ListTopicsResponse>

if endpoint URL contain user/password information, in any of the topic, request must be made over HTTPS. If not, topic list request will be rejected.

Notifications 

Detailed under: Bucket Operations.

备注

"Abort Multipart Upload" request does not emit a notification
Both "Initiate Multipart Upload" and "POST Object" requests will emit an s3:ObjectCreated:Post notification

Events 

The events are in JSON format (regardless of the actual endpoint), and share the same structure as the S3-compatible events pushed or pulled using the pubsub sync module. For example:

{"Records":[
    {
        "eventVersion":"2.1",
        "eventSource":"ceph:s3",
        "awsRegion":"us-east-1",
        "eventTime":"2019-11-22T13:47:35.124724Z",
        "eventName":"ObjectCreated:Put",
        "userIdentity":{
            "principalId":"tester"
        },
        "requestParameters":{
            "sourceIPAddress":""
        },
        "responseElements":{
            "x-amz-request-id":"503a4c37-85eb-47cd-8681-2817e80b4281.5330.903595",
            "x-amz-id-2":"14d2-zone1-zonegroup1"
        },
        "s3":{
            "s3SchemaVersion":"1.0",
            "configurationId":"mynotif1",
            "bucket":{
                "name":"mybucket1",
                "ownerIdentity":{
                    "principalId":"tester"
                },
                "arn":"arn:aws:s3:us-east-1::mybucket1",
                "id":"503a4c37-85eb-47cd-8681-2817e80b4281.5332.38"
            },
            "object":{
                "key":"myimage1.jpg",
                "size":"1024",
                "eTag":"37b51d194a7513e45b56f6524f2d51f2",
                "versionId":"",
                "sequencer": "F7E6D75DC742D108",
                "metadata":[],
                "tags":[]
            }
        },
        "eventId":"",
        "opaqueData":"me@example.com"
    }
]}

awsRegion: zonegroup
eventTime: timestamp indicating when the event was triggered
eventName: for list of supported events see: S3 Notification Compatibility. Note that the eventName values do not start with the s3: prefix.
userIdentity.principalId: user that triggered the change
requestParameters.sourceIPAddress: not supported
responseElements.x-amz-request-id: request ID of the original change
responseElements.x_amz_id_2: RGW on which the change was made
s3.configurationId: notification ID that created the event
s3.bucket.name: name of the bucket
s3.bucket.ownerIdentity.principalId: owner of the bucket
s3.bucket.arn: ARN of the bucket
s3.bucket.id: Id of the bucket (an extension to the S3 notification API)
s3.object.key: object key
s3.object.size: object size
s3.object.eTag: object etag
s3.object.versionId: object version in case of versioned bucket. When doing a copy, it would include the version of the target object. When creating a delete marker, it would include the version of the delete marker.
s3.object.sequencer: monotonically increasing identifier of the change per object (hexadecimal format)
s3.object.metadata: any metadata set on the object sent as: x-amz-meta- (an extension to the S3 notification API)
s3.object.tags: any tags set on the object (an extension to the S3 notification API)
s3.eventId: unique ID of the event, that could be used for acking (an extension to the S3 notification API)
s3.opaqueData: opaque data is set in the topic configuration and added to all notifications triggered by the topic (an extension to the S3 notification API)