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BaSyx / Documentation / Components / Registry / Features / Hierarchical MQTT

Hierarchical MQTT Eventing

User Story & Use Case

As AAS Components user

I want hierarchical MQTT topics in the AAS Registry Component

so that I can subscribe precisely to the topics of interest without having to filter on client side

MQTT supports hierarchical topics with wildcard subscription support. For example, if the topics a/b/x and a/b/y exist, subscribing to a/b/+ subscribes to all events broadcasted on both topics.

Feature Overview

The following hierarchical topics with their respective payloads are implemented:

  • aas-registry/<reg-id>/shells/created
  • aas-registry/<reg-id>/shells/updated
    • Payload: New AAS-Descriptor

  • aas-registry/<reg-id>/shells/removed
    • Payload: Old AAS-Descriptor

  • aas-registry/<reg-id>/submodels/added
  • aas-registry/<reg-id>/submodels/updated
    • Payload: New SM-Descriptor

  • aas-registry/<reg-id>/submodels/deleted
    • Payload: Old SM-Descriptor

  • aas-registry/<reg-id>/shells/<encoded-aas-identifier>/submodels/added
  • aas-registry/<reg-id>/shells/<encoded-aas-identifier>/submodels/deleted
    • Payload: New SM-Descriptor

  • /aas-registry/<reg-id>/shells/<encoded-aas-identifier>/submodels/deleted
    • Payload: Old SM-Descriptor

For AAS-Identifier encoding, Base64URL encoding and URL encoding are available.

Feature Configuration

The feature can be configured in the file by setting = MQTTV2 for Base64URL encoding or = MQTTV2_SIMPLE_ENCODING for URL encoding. Additionally, the Registry id needs to be configured via = <repo-id>.

An example configuration for this feature could be: = MQTTV2 = product-aas-registry

The MQTT broker connectivity is configured via

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