适用于所有Thing Shadow更新的单一AWS IoT规则

Got it, let's break down why your wildcard approach isn't working and get you set up correctly to handle all Thing Shadow update successes with a single Lambda function.

The Problem with Your Current Wildcard #

Your rule uses # which is a multi-level wildcard in AWS IoT MQTT topics, but it's not the right fit here. The # wildcard matches all remaining levels of a topic starting from its position. While $aws/things/# would technically match your target topics, it would also match every other topic under $aws/things/ (like shadow get requests, delete events, etc.)—and more importantly, the way you structured it ($aws/things/#/shadow/update/accepted) is invalid syntax because # must be the final segment in a topic filter. That's why your rule wasn't triggering as expected.

The Correct Wildcard Syntax #

To specifically target all Thing Shadow update accepted events (and nothing else), use the + wildcard instead. The + matches exactly one topic level, which is perfect for replacing the specific thing name:

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

This will reliably match any topic like:

• $aws/things/testThing/shadow/update/accepted
• $aws/things/device001/shadow/update/accepted
• $aws/things/sensor-abc/shadow/update/accepted

Additional Steps to Ensure It Works #

• Verify Lambda Permissions
  Make sure your AWS IoT rule has permission to invoke the Lambda function. When you create the rule action to trigger Lambda, AWS usually auto-creates the necessary IAM role, but double-check that the role includes the lambda:InvokeFunction permission for your target Lambda. If your Lambda needs to interact with IoT Shadows (like reading/writing back), ensure it has permissions like iot:GetThingShadow or iot:UpdateThingShadow attached to its execution role.

• Extract the Thing Name in Lambda
  If you need to know which specific Thing triggered the Lambda, modify the SQL to include the thing name directly in the payload:

  SELECT topic(2) AS thingName, * FROM '$aws/things/+/shadow/update/accepted'
  

  The topic(2) function extracts the 3rd segment of the topic (counting starts at 0: segment 0 = $aws, segment 1 = things, segment 2 = the thing name). Your Lambda will then receive a thingName field in the event payload, making per-device logic straightforward.

• Test the Rule
  Use the AWS IoT Console's Test client to publish a sample message to a test Thing's shadow update accepted topic. Check Lambda logs to confirm it's invoked and receiving the expected payload.

内容的提问来源于stack exchange，提问作者tharun