Default Hub connection - 2023

The automatically created connection named Devices via Bosch IoT Hub connects the connectivity layer to the digital twin layer.

You can see it in the UI at Connections > Devices via Bosch IoT Hub.

The connection type Bosch IoT Hub determines this connection's underlying transport protocol.
While the connections of older subscriptions worked based on the Apache Kafka 2.x protocol binding, the new ones are based on Eclipse Hono binding.

However, in the background the connection is handled exactly as the Apache Kafka type.

In detail, the differences are:

• The Bosch IoT Hub messaging endpoint and credentials (uri) are hidden.

• The sources and targets now display in the UI the logical addresses (aliases).
  

  • E.g. Sources: shows telemetry, event and command_response
    instead of displaying hono.telemetry.serviceInstanceId etc.
    
    

  • E.g. Targets: shows command
    instead of displaying hono.command.t73cdbbe564224aea8882f477fbc6cf05_hub/{{ thing:id }}
    

• The header mappings in Targets are automatically generated.

  • Details are documented in Eclipse Ditto - https://www.eclipse.org/ditto/connectivity-protocol-bindings-hono.html#source-addresses

  • You can still add other header mappings you need, but the generated mappings cannot be overwritten
    By default the UI will not show the entries like the examples

    •   old source example header mapping

      Source

      Header mappings

      • correlation-id ⇾ {{ header:correlation-id }}

      • status ⇾ {{ header:status }}

    •   old target example header mapping

      Target

      Header mappings

      • device_id ⇾ {{ thing:id }}

      • subject ⇾ {{ header:subject | fn:default(topic:action-subject) }}

      • correlation-id ⇾ {{ header:correlation-id }}

• Further, some properties are generated automatically:

  • specificConfig - see https://www.eclipse.org/ditto/connectivity-protocol-bindings-hono.html#specific-configuration-properties

  • validateCertificates - see https://www.eclipse.org/ditto/connectivity-protocol-bindings-hono.html#certificate-validation