Trigger a lambda function based on thing type

Hi janpoltan,

Today, the rules engine cannot fetch thing type, thing group, or registry attributes for a thing when processing a message. You could write a Lambda function to fetch these kinds of metadata and evaluate that at runtime with the aws_lambda() function: https://docs.aws.amazon.com/iot/latest/developerguide/iot-sql-functions.html#iot-func-aws-lambda

The other way to achieve that is as you describe, with a Step Functions solution.

A third way to achieve this, if it makes sense for your solution, is to store the thing type in the device shadow. The shadow can be referenced by the rules engine at runtime today. The main concern is whether this leaks inappropriate control plane info to your data plane, or whether there is risk of your device or other actors accidentally clearing this type from the shadow.

Ryan

Ive tried using the aws_lambda

https://docs.aws.amazon.com/iot/latest/developerguide/iot-sql-functions.html#iot-func-aws-lambda

It looks like the sql dont support passing topic vars?

SELECT topic(3) as id, aws_lambda("arn:aws:lambda:eu-west-1:xxxx:function:xxxx", {"payload": id}) as deviceEnv FROM 'device/test'

or

SELECT aws_lambda("arn:aws:lambda:eu-west-1:xxxx:function:xxxx", {"payload": topic(3)}) as deviceEnv FROM 'device/test'

I'm a little surprised the second approach didn't work. If the topic() function is not evaluated first before sending the value to Lambda, you can write this in a nested way to work around:

SELECT aws_lambda("arn:aws:lambda:eu-west-1:xxxx:function:xxxx", {"payload": topic}) as deviceEnv FROM (SELECT *, topic(3) as topic FROM 'device/test')

Admittedly I did not test the above SQL, but this is how I've solved past similar issues where values needed be generated and bubbled up to a secondary query.

HTH,
Ryan

Actually the second option worked. My mistake not updating the topic filter to

device/test/+

SELECT * FROM 'device/test/+' WHERE (SELECT aws_lambda("arn:aws:lambda:region:accountId:function:functionName", {"deviceId": topic(3)}).env as env FROM 'device/test/+') = "dev"

The where clause doesnt seem to work

Edited by: janpoltan on Apr 3, 2019 1:44 AM

It seems it wont work

Moved to other post