How to type and model telemetry from IOT Central data export, routed through Event Hub and consumed in TSI?

Question

When using IOT Central data export to Event Hub, you have a message format which is:

{
"applicationId": "A-GUID",
"component": null,
"deviceId": "AN-ID",
"enqueuedTime": "2022-02-23T20:34:11.0400000Z",
"enrichments": {},
"messageProperties": {},
"messageSource": "telemetry",
"module": null,
"schema": "default@v1",
"telemetry": [
{
"label": "temp",
"value": "33"
},
{
"label": "watts",
"value": 2183
}
...
"templateId": "A-TEMPLATE-ID",
"ts": "2022-02-23T20:26:39.0000000Z",
"EventProcessedUtcTime": "2022-02-23T20:37:53.1779856Z",
"PartitionId": 0,
"EventEnqueuedUtcTime": "2022-02-23T20:34:12.5810000Z"
}

My question is how do you unpack the Telemetry property into something which TSI can see as Types?

The Type seems to rely on a flatter naming structure, like $event.telemety.watts, and there is no way to query for $event.telemetrty.label == "watts.

My one thought is that I may need to transform this data before it gets to TSI by using an inbound event hub, then a function to flatten the schema and an outbound event hub which is what TSI reads from.

Answer 1

Figured it out. There's a new (to me) Transform feature in IoT Central Data Export.

We used the following rule to transform the telemetry.

telemetry: .telemetry | map({ (.name|tostring): .value }) | add