Boto3 Lambda - Existing custom IoT Rule as event source


Hello forum,

We know and are able to set existing custom IoT Rule as a Trigger for AWS Lambda.

We are currently using boto3 to create lambda function.

After creating lambda function we tried to set an existing custom IoT Rule as trigger using create_event_source_mapping().

This is resulting in below error -

An error occurred (InvalidParameterValueException) when calling the CreateEventSourceMapping operation: Unrecognized event source, must be kinesis, dynamodb stream or sqs. Unsupported source arn : arn:aws:iot:xx-xx-1:xxxxxxxxxxxx:rule/ruleName

Please find the code for the same below -

import boto3
import botocore.exceptions

function_name = sample_function
trigger_arn = arn:aws:iot:xx-xx-1:xxxxxxxxxxxx:rule/ruleName

client = boto3.client('lambda')

Is this not supported or possible using boto3?

How to fix this?

  • Hi edgegoldberg, Did you figure out or solve this issue? I am struggling with the same error when trying to set up an IoT Rule as a trigger to a lambda function in a cloudformation template, and using the EventSourceMapping resource.

asked 2 years ago412 views
1 Answer

Lambda event source mapping is used only for the event sources that Lambda needs to poll such as SQS, Kinesis, Kafka, etc. IoT Rules are different. In order to trigger a Lambda function from an IoT rule you need to use the create_topic_rule in the IoT client.

profile pictureAWS
answered 2 years ago
  • Hi Uri, Thank you for the response. Yes I checked that earlier and I knew that I can use create_topic_rule to create new rule and set an action to trigger lambda. But I don't think I could use create_topic_rule to set an action to trigger lambda for an already created rule. Could you please point out which API I should use for the same? (I am expecting that I just have to pass the ARN of the existing rule and ARN of the lambda)

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