How to create a IoT Core Rule to save a JSON list of objects to timestream

Question

Hi,

I run a RaspberryPi with different temperature sensors on it. I collect all sensor data and send them to IoT Core. In the MQTT Test-Client I can also subscribe to the message and see the following output:

`[
  {
    "sensor_id": "28-011921dac0de",
    "value": 20.937
  },
  {
    "sensor_id": "28-3ce10457469c",
    "value": 59.5
  },
  {
    "sensor_id": "28-011921d74ee8",
    "value": 46.812
  },
  {
    "sensor_id": "28-3ce104579319",
    "value": 45.375
  }
]`

1) Is it a bad idea to send all sensore datas in one message?
2) How do I have to define the rule to send this message to TimeStream? At the end I want to visualize/analyze each temperature value.

Thank you

Answer

Hi Philipp, 
1. It is not a bad idea, quite the contrary. By batching the readings from multiple sensors in one single message you are reducing the amount of message considerably 
2. The IoT Rule Timestream action does not support inserting records with different dimensions (in your case the `sensor_id` would be a dimension), but you can send the message payload to a Lambda function and have the Lambda function write the records in Timestream. You can have a look at this repo on how to write such Lambda function: https://github.com/massi-ang/amazon-timestream-app

Answer

Regarding the first question, there is no right way to send the data, it all depends on your use case and your expected results. Regarding the second question. Check this tutorial about [Ingesting Data into Amazon Timestream with AWS IoT Core](https://www.youtube.com/watch?v=00Wersoz2Q4).

Answer

It seems to be impossible with just a SQL statement:

See here for more details: https://stackoverflow.com/questions/74090199/aws-iot-rule-sql-republish-get-thing-name-as-json-object-key

How to create a IoT Core Rule to save a JSON list of objects to timestream

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