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Subscribing to Events

Optional Feature

Event support is an optional feature of the Control Plane. It must be explicitly enabled by a platform administrator through an EventConfig resource for each zone. If events are not enabled in your environment, you can skip this page.

Prerequisites

Before subscribing to an event, the event type must already be exposed by another team. The provider must have completed both the event specification registration and the event exposure. See Exposing Events for details on the full exposure process.

Subscribing to an event grants your application access to events published by another team. The subscription process is managed through Rover files and may require approval depending on the event provider's configuration.

Defining an Event Subscription​

Event subscriptions are declared in the subscriptions section of your Rover file:

apiVersion: tcp.ei.telekom.de/v1
kind: Rover
metadata:
  name: analytics-service
spec:
  zone: dataplane1
  subscriptions:
    - type: event
      eventType: de.telekom.orders.created.v1
      deliveryType: callback
      payloadType: Data
      callback: https://analytics.internal:8080/events

Key Fields​

FieldDescription
eventTypeThe event type you want to subscribe to. This must match an existing exposed event type.
deliveryTypeConfigures how events are delivered to your application. See below.

What Happens When You Subscribe​

When you apply a Rover file with an event subscription, the Control Plane:

  1. Creates an EventSubscription resource linking your application to the target event type
  2. The EventSubscription handler verifies that both an active EventType and an active EventExposure exist for the requested event type
  3. Creates an Approval resource (if the event requires approval)
  4. Waits for approval to be granted (for simple or foureyes strategies)
  5. Once approved, creates a Subscriber in the PubSub domain, registering your application with the Horizon runtime
caution

If no active EventType or EventExposure exists for the requested event type, your subscription will remain in a pending state. Verify that the event provider has completed both the specification registration and the exposure.

note

If the event uses the auto approval strategy, access is granted immediately. For simple or foureyes strategies, you will need to wait for the event provider to approve your request. See Approvals for details.

Event Delivery Methods​

The Control Plane supports multiple event delivery methods:

MethodDescription
CallbackEvents are delivered to a URL endpoint you specify. The platform pushes events to your service.
SSE (Server-Sent Events)Your service opens a persistent connection and receives events as a stream in real time.

Additional Features​

Beyond the basic subscription, you can customize event delivery and filtering with additional features.

tip

See Additional Features for the full list of features and detailed configuration examples.

FeatureDescription
Event Delivery SettingsCustomize payload format, retention time, circuit breaker behavior, retry logic, and health checks.
Subscriber TriggersFilter which events are delivered to your application based on CloudEvents attributes and payload content.
Scope SelectionChoose which publisher-defined scopes you want to receive.

Checking Subscription Status​

You can check the status of your subscriptions using Rover-CTL:

roverctl get-info

The output will show the status of each subscription, including whether it is pending approval, granted, or rejected. See the Rover-CTL CLI Reference for more commands and options.

Next Steps​