TwinMaker: using lambda to fetch data for non-timeSeries properties

Question

Hello!
I've been trying to use IoT RoboRunner + IoT TwinMaker + AWS Grafana to create a dashboard.
As one of the most basic things to show is a list of the current workers/robots.

Take the following `componentTypes`:
(parent, to be inherited from, to keep the lambda function common)
Ideally, the lambda function would be able to see the event, and the associated `telemetryAssetId`, and reply with an appropriate payload.
```json
{
  "componentTypeId": "com.example.lambda_reader",
  "workspaceId": "MyWorkspace",
  "functions": {
    "dataReader": {
      "implementedBy": {
        "lambda": {
          "arn": "arn:aws:lambda:us-east-1::function:RoboRunnerWorkerInfo"
        }
      }
    }
  },
  "propertyDefinitions": {
    "telemetryAssetId": {
      "dataType": {
        "type": "STRING"
      },
      "isExternalId": true,
      "isStoredExternally": false,
      "isTimeSeries": false,
      "isRequiredInEntity": true
    }
  }
}
```
and the child, which inherits from the above
```
{
    "componentTypeId": "com.example.myworkspace.worker_list",
    "extendsFrom": [
        "com.example.lambda_reader"
    ],
    "propertyDefinitions": {
        "telemetryAssetId": {
            "defaultValue" : { "stringValue": "WorkerList" }
        },
        "workerList": {
            "dataType": {
              "type": "LIST",
              "netstedType": {
                "type": "STRING"
              }
            },
            "isTimeSeries": false,
            "isStoredExternally": true
        }
    }
}
```
When adding these two `componentType`s, the latter shows up as abstract unless `isTimeSeries` is set to `true`. Is this intended behavior? Seems like I should be able to do this?
Any help is appreciated!

Accepted Answer

I was able to fetch non-timeseries properties by specifying a function under a different name than `dataReader`.

So, instead of 
```
  "functions": {
    "dataReader": {
      "implementedBy": {
        "lambda": {
          "arn": "arn:aws:lambda:us-east-1::function:RoboRunnerWorkerInfo"
        }
      }
    }
```
for non-timeseries properties, it should be 
```
  "functions": {
    "attributePropertyValueReaderByEntity": {
      "implementedBy": {
        "lambda": {
          "arn": "arn:aws:lambda:us-east-1::function:RoboRunnerWorkerInfo"
        }
      }
    }
```
Which is absolutely nowhere in the documentation. I arrived at it by sifting through github and finding https://github.com/aws-samples/aws-iot-twinmaker-samples/blob/main/src/modules/s3/component-types/s3_component_type.json

Answer

Hi, to explain little bit more into the detail, if a property is marked as `IsStoredExternally` means TwinMaker will only keep the property schema but not the value. So to access the property value you'll need to invoke the unified data access APIs with a defined connector.

For time-series property, you can use [GetPropertyValueHistory](https://docs.aws.amazon.com/iot-twinmaker/latest/apireference/API_GetPropertyValueHistory.html) API to access the property value, you need to define `dataReader` connector and while querying the property value in runtime, TwinMaker will forward the request to your connector to resolve it.

For non-time-series property, you can use [GetPropertyValue](https://docs.aws.amazon.com/iot-twinmaker/latest/apireference/API_GetPropertyValue.html) API to access, and as you already found out, you need to define `attributePropertyValueReaderByEntity` connector for that.

We'll continue polishing our documentation to make it clear. Let us know if you are interested in more details on the topic.

Best,

Answer

Are you unblocked?

TwinMaker: using lambda to fetch data for non-timeSeries properties

Relevant questions

When should I use IoT Core?

TwinMaker: using lambda to fetch data for non-timeSeries properties

IoT Core pricing of basic ingest and QoS 1 combination

Publishing messages to IoT core using an imported lambda in greengrassv2

3D Models added to AWS TwinMaker Scene Lost colors

Which AWS service(s) is cheaper to use to decode and view graphs corresponding to the payload emitted from Helium?

Launch Announcement: AWS IoT TwinMaker is now generally available

Greengrass vs. IoT Core

IoT TwinMaker and Grafana integration where component has multiple list properties

unable to Sub scribing with Mqtt data in AWS IoT core with greengrass deployment