CODEWITHSUNDEEP
aws-lambdaaws-iot
user11207695
user11207695

Reputation:

Triggering Lambda when a device Shadow updates

I've set up a rule

SELECT * FROM '$aws/things/+/shadow/update/accepted'

This rule triggers my lambda function when the shadow of any thing in my AWS IoT updates.

Instead I want it to get triggered only when the shadows of some things are updated, not all of them. Any way I can do that?

Upvotes: 3

Views: 1449

Answers (2)

Theo
Theo

Reputation: 132862

I recently learned that you can use functions to filter on parts of the topic, and something like this could potentially work for you:

SELECT *
FROM '$aws/things/+/shadow/update/accepted'
WHERE startswith(topic(3), 'someprefix-')

This would only trigger the action(s) when the part of the topic captured by the + started with "someprefix-". You can use other functions to filter in other ways if a prefix does not work for you.

Upvotes: 2

Bob
Bob

Reputation: 9

Each individual device you have registered will have a specific /shadow/update/accepted topic that you can subscribe to. It should be easy as replacing the '+' in your topic with the name of the device.

The same topic is also listed in the 'Interact' section of each device in IoT Core.

Upvotes: 0

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