Sync between publish and subscribe to iot topic in AWS Lambda


Hi folks, Hope you are well and safe and also hope that this questions don't gonna be an already asked question.

I'm here to ask a brief explanation on how can I write in AWS Lambda function a sync mechanism. I mean: I'm writing a .py script that, when is triggered, publish a message to a topic. When the IoT things receive the message on published on this topic, react publishing response on another topic. Well, at this point, I want to receive the published message from IoT thing in same lambda function that was firstly triggered from outside. Is it possible or I need to use AWS IoT rules in order to trigger a different AWS Lambda function?

Best regards.

1 Answer

If by "same lambda function" you mean the same invokation of a function, then no. But you could trigger a different invokation of the same function for this different purpose. Usually though you would trigger a different function for better code structure and least-privilege security configuration. Either way it sounds like you might want to share state between invokations - DynamoDB is a common way to do it.

answered 2 years ago
  • Thanks @skinsman.

    Yes, trigger different invokation of the same function seems the solution. The next problem, in this approach, could be: how can I hold the context that invoke firstly the Lambda function in order to give a response to it when I receive the second trigger?

    I mean, how can I keep the http connection alive, and reuse after second trigger?

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