DigitalTwin

Kafka Bridges

1. Alerta bridge, a service which listens at a specific Kafka topic and forwards the data to Alerta.
2. NgsildUpdates bride, a service which listens at a specific Kafka topic and forwards data to the scorpio/Ngsild broker.
3. DebeziumBridge, a service which listens to debezium updates on ngsild entities and forward them to specific topics.
4. Timescaledb Bridge, a service which listens at specific Kafka topic and forwards data to timescaledb(tsdb) running in postgres database

Alerta Bridge

This service listens to the topic defined in the values file of helmfile in kafkaBridge.ngsildUpdates.listenTopic adn defaults to iff.alerts. Example message is shown below:

{
    "resource": "test",
    "event": "test",
    "environment": "Development",
    "service": [ "Digital Twin" ],
    "severity": "critical",
    "customer": "customerB"
}

Note that the object has to be sent to kafka without \n, e.g. assuming that this is stored in alerta.json you can send it with kafkacat like this:

cat alerta.json | tr -d '\n' | kafkacat -P -t iff.alerts -b my-cluster-kafka-bootstrap:9092

NgsildUpdates Bridge

This service listen to the topic defined in the values file of helmfile in kafkaBridge.ngsildUpdates.listenTopic and defaults to iff.ngsildUpdates. The JSON object expects 3 fields:

• op - can be “update” or “upsert”
  • update is using the entitiyOperations/update NGSI-LD endpoint. With this endpoint existing entities can be updated.
  • upsert is using the entitiyOperations/upsert NGSI-LD endpoint. With this endpoint new entities can be created or an existing one can be updated.
• overwriteOrReplace - “true” or true, “false” or fals
  • This flag influences the behavior of the update or upsert operation. If op=update then it sets the options=overwrite parameter if it is true. If op=upsert then it sets the options=replace parameter if false and the options=update parameter if true.
• entities: Array of valid NGSI-LD entities

Example request

{
    "op": "update",
    "overwriteOrReplace": "true",
    "entities": [
      {
        "@context": "https://uri.etsi.org/ngsi-ld/v1/ngsi-ld-core-context.jsonld",
        "id": "urn:filter:1",
        "type": "https://industry-fusion.com/types/v0.9/filter",
        "https://industry-fusion.com/types/v0.9/state": {
          "type": "Property",
          "value": "OFF"
        },
        "https://industry-fusion.com/types/v0.9/strength": {
          "type": "Property",
          "value": "0.4"
        },
        "https://industry-fusion.com/types/v0.9/hasCartridge": {
          "type": "Relationship",
          "object": "urn:filterCartridge:1"
        }
      }
    ]
}

Note that the object has to be sent to kafka without \n, e.g. assuming that this is stored in ngsildUpdates.json you can send it with kafkacat like this:

cat ngsildUpdates.json | tr -d '\n' | kafkacat -P -t iff.alerts -b my-cluster-kafka-bootstrap:9092

Debezium Bridge

The debezium bridge maps the updates from the NGSILD entity tabe to StreamingSQL tables. Concept TBD.

TimescaledDB Bridge

This service which listens at specific Kafka topic (iff.ngsild.attributes) and forwards NGSI-LD data to timescaledb(tsdb) running in postgres database.

• Currently it is disabled by default. To enable please remove timescaledb deployment file link from .helmignore of kafkabridge charts

• entities: Array of valid NGSI-LD entities

Data stored in the hypertable “entityhistory” of timescaledb database “tsdb” in below format:

tsdb=# select * from entityhistory;
         observedAt         |         modifiedAt         |      entityId      |                    attributeId                    |               attributeType                |                              datasetId                              | nodeType |                      value                       | index 
----------------------------+----------------------------+--------------------+--------------------------------------------------+-------------------------------------------+---------------------------------------------------------------------+----------+--------------------------------------------------+-------
 2023-07-18 09:40:24.22+00  | 2023-07-18 09:40:24.22+00  | urn:plasmacutter:1 | https://industry-fusion.com/types/v0.9/state     | https://uri.etsi.org/ngsi-ld/Property     | urn:plasmacutter:1\https://industry-fusion.com/types/v0.9/state     | @value   |  https://industry-fusion.com/types/v0.9/state_OFF                                         |     0
 2023-07-18 09:38:15.559+00 | 2023-07-18 09:38:15.559+00 | urn:plasmacutter:1 | https://industry-fusion.com/types/v0.9/hasFilter | https://uri.etsi.org/ngsi-ld/Relationship | urn:plasmacutter:1\https://industry-fusion.com/types/v0.9/hasFilter | @id      | urn:filter:1                                     |     0
   

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