CloudEvent Support

Experimental support for cloud events

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Subscribing to events with `CloudEventSource`

CloudEventSource resource can be used in KEDA for subscribing to events that are emitted to the user’s defined CloudEvent sink.

📝 When a CloudEventSource resource is created, KEDA continues to emit Kubernetes Events and will additionally emit CloudEvents for the supported event types listed in this document.

Here is a the schema of the CloudEventSource CRD:

apiVersion: eventing.keda.sh/v1alpha1
kind: CloudEventSource
metadata:
  name: {cloud-event-name}
spec:
  clusterName: {cluster-name} #Optional. Will be used in the source/subject to specify where the event comes from. The default value is 'kubernetes-default' and it can also be set during the installation of KEDA with --k8sClusterName. This one will overwrite others if set.
  authenticationRef: 
    name: {trigger-authentication-name} #Optional. Used to reference a `TriggerAuthentication` for authentication. 
    kind: TriggerAuthentication # Optional. Used to choose the authentication scopes. https://keda.sh/docs/latest/concepts/authentication/#authentication-scopes-namespace-vs-cluster
  destination:
    http:
      uri: http://foo.bar
    azureEventGridTopic:
      endpoint: https://my-topic.eastus-1.eventgrid.azure.net/api/events

  eventSubscription: #Optional. Submit included/excluded event types will filter events when emitting events. 
    includedEventTypes: #Optional. Only events in this section will be emitted.
    - keda.scaledobject.failed.v1
    excludedEventTypes: #Optional. Events in this section will not be emitted.       
    - keda.scaledobject.ready.v1

In general, an event emitted by KEDA would fundamentally come down to the following structure:

{
    "specversion" : "1.0",
    "type" : "com.cloudeventsource.keda",
    "source" : "/{cluster-name}/{keda-namespace}/keda",
    "subject" : "/{cluster-name}/{namespace}/{object-type}/{object-name}",
    "id" : "<guid>",
    "time" : "2018-04-05T17:31:00Z",
    "datacontenttype" : "application/json",
    "data" : {
      "reason":"<event-reason>",
      "message":"<event-message>"
   }
}

Event Sinks

There will be multiple types of destination to emit KEDA events to.

Here is an overview of the supported destinations:

HTTP endpoint.
Azure Event Grid endpoint.

HTTP endpoint

  destination:
    http:
      uri: http://foo.bar  #An http endpoint that can receive cloudevent

Azure Event Grid

  destination:
    azureEventGrid:
      endpoint: foo.bar #endpoint from AzureEventGrid Topic

Authentication information must be provided by using authenticationRef which allows you to provide the access key or managed identity for Azure Event Grid authentication by providing a TriggerAuthentication.

Here is an overview of the supported authentication types:

Connection String Authentication

accessKey - Access key string for the Azure Event Grid connection auth.

Pod identity based authentication

Azure AD Workload Identity provider can be used.

apiVersion: keda.sh/v1alpha1
kind: TriggerAuthentication
metadata:
  name: nameOfTriggerAuth
  namespace: default
spec:
  podIdentity:
    provider: azure-workload

Event Filter

You can include filter(s) to define what event types you are interested in, or want to ignore. This is done by using includedEventTypes or excludedEventTypes respectively for a given sink.

eventSubscription: #Optional. Submit included/excluded event types will filter events when emitting events. 
  includedEventTypes: #Optional. Only events in this section will be emitted.
  - keda.scaledobject.failed.v1
  excludedEventTypes: #Optional. Events in this section will not be emitted.       
  - keda.scaledobject.ready.v1

Supported Event List

Event Type	Scenario Description
`keda.scaledobject.ready.v1`	On the first time a ScaledObject is ready, or if the previous ready condition status of the object was `Unknown` or `False`
`keda.scaledobject.failed.v1`	If the check validation for a ScaledObject fails
`keda.scaledobject.removed.v1`	When a ScaledObject is deleted
`keda.scaledobject.paused.v1`	When a ScaledObject is paused
`keda.scaledobject.unpaused.v1`	When a ScaledObject is unpaused
`keda.scaledjob.ready.v1`	On the first time a ScaledJob is ready, or if the previous ready condition status of the object was `Unknown` or `False`
`keda.scaledjob.failed.v1`	If the check validation for a ScaledJob fails
`keda.scaledjob.removed.v1`	When a ScaledJob is deleted
`keda.scaledjob.paused.v1`	When a ScaledJob is paused
`keda.scaledjob.unpaused.v1`	When a ScaledJob is unpaused
`keda.scaledjob.rolloutcleanup.started.v1`	When KEDA starts cleaning up Jobs owned by the previous version of a ScaledJob
`keda.scaledjob.rolloutcleanup.completed.v1`	When KEDA completes cleanup of Jobs owned by the previous version of a ScaledJob
`keda.scaledjob.rolloutcleanup.failed.v1`	When KEDA fails to delete a Job owned by the previous version of a ScaledJob
`keda.authentication.triggerauthentication.created.v1`	On the first time a TriggerAuthentication is created
`keda.authentication.triggerauthentication.updated.v1`	When a TriggerAuthentication is updated
`keda.authentication.triggerauthentication.removed.v1`	When a TriggerAuthentication is deleted
`keda.authentication.clustertriggerauthentication.created.v1`	On the first time a ClusterTriggerAuthentication is created
`keda.authentication.clustertriggerauthentication.updated.v1`	When a ClusterTriggerAuthentication is updated
`keda.authentication.clustertriggerauthentication.removed.v1`	When a ClusterTriggerAuthentication is deleted

Subscribing to events with CloudEventSource