Azure Event Hubs

Component format

To setup Azure Event Hubs pubsub create a component of type pubsub.azure.eventhubs. See this guide on how to create and apply a pubsub configuration.

apiVersion: dapr.io/v1alpha1
kind: Component
metadata:
  name: eventhubs-pubsub
  namespace: default
spec:
  type: pubsub.azure.eventhubs
  version: v1
  metadata:
  - name: connectionString
    value: "Endpoint=sb://{EventHubNamespace}.servicebus.windows.net/;SharedAccessKeyName={PolicyName};SharedAccessKey={Key};EntityPath={EventHub}"
  - name: storageAccountName
    value: "myeventhubstorage"
  - name: storageAccountKey
    value: "112233445566778899"
  - name: storageContainerName
    value: "myeventhubstoragecontainer"

Spec metadata fields

Create an Azure Event Hub

Follow the instructions here on setting up Azure Event Hubs. Since this implementation uses the Event Processor Host, you will also need an Azure Storage Account. Follow the instructions here to manage the storage account access keys.

See here on how to get the Event Hubs connection string. Note this is not the Event Hubs namespace.

Create consumer groups for each subscriber

For every Dapr app that wants to subscribe to events, create an Event Hubs consumer group with the name of the dapr id. For example, a Dapr app running on Kubernetes with dapr.io/app-id: "myapp" will need an Event Hubs consumer group named myapp.

Note: Dapr passes the name of the Consumer group to the EventHub and so this is not supplied in the metadata.

Subscribing to Azure IoT Hub Events

Azure IoT Hub provides an endpoint that is compatible with Event Hubs, so the Azure Event Hubs pubsub component can also be used to subscribe to Azure IoT Hub events.

The device-to-cloud events created by Azure IoT Hub devices will contain additional IoT Hub System Properties, and the Azure Event Hubs pubsub component for Dapr will return the following as part of the response metadata:

For example, the headers of a delivered HTTP subscription message would contain:

{
  'user-agent': 'fasthttp',
  'host': '127.0.0.1:3000',
  'content-type': 'application/json',
  'content-length': '120',
  'iothub-connection-device-id': 'my-test-device',
  'iothub-connection-auth-generation-id': '637618061680407492',
  'iothub-connection-auth-method': '{"scope":"module","type":"sas","issuer":"iothub","acceptingIpFilterRule":null}',
  'iothub-connection-module-id': 'my-test-module-a',
  'iothub-enqueuedtime': '2021-07-13T22:08:09Z',
  'message-id': 'my-custom-message-id',
  'x-opt-sequence-number': '35',
  'x-opt-enqueued-time': '2021-07-13T22:08:09Z',
  'x-opt-offset': '21560',
  'traceparent': '00-4655608164bc48b985b42d39865f3834-ed6cf3697c86e7bd-01'
}

Related links

• Basic schema for a Dapr component
• Read this guide for instructions on configuring pub/sub components
• Pub/Sub building block