feature request: awslambda.streamifyResponse support for lambda

[aravindjaimon]

Is there an existing issue for this?

• I have searched the existing issues

Feature description

AWS introduced streaming responses.

https://docs.aws.amazon.com/lambda/latest/dg/configuration-response-streaming.html

This comes in handy when creating handlers working with LLM's.
Other middleware like Middy also supports response streaming.
https://middy.js.org/docs/intro/streamify-response/

As of now, these streamed lambdas are not working in localstack. Getting an internal server error for the same.

It would be good to have the feature as LLM-based applications are growing.

Another approach will be to use websockets. But a clean approach will always be to use streams for pushing out each response piece by piece for faster resolution.

🧑‍💻 Implementation

No response

Anything else?

No response

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[ptfpinho23]

I'd be happy to take this one as I'd really like to see this implemented & have been in the same situation

[joe4dev]

I'd be happy to take this one as I'd really like to see this implemented & have been in the same situation

Thank you for @ptfpinho23 for letting us know you are interested in this feature. We have an internal backlog item for this feature and are happy to prioritize highly requested features (also see support depending on our subscription plans).

This feature is quite complex because it requires a deep understanding of:

• our custom Rolo HTTP framework
• our custom lambda-runtime-init written in Golang
• LocalStack development and Parity Testing in particular covered in CONTRIBUTING (ideally demonstrated through successfully merged PRs)
• our LocalStack Lambda implementation

If you are confident in all these areas, feel free to give it a try and demonstrate a working implementation covered by an AWS Parity test.

[ptfpinho23]

Thank you for @ptfpinho23 for letting us know you are interested in this feature. We have an internal backlog item for this feature and are happy to prioritize highly requested features (also see support depending on our subscription plans).

This feature is quite complex because it requires a deep understanding of:

• our custom Rolo HTTP framework
• our custom lambda-runtime-init written in Golang
• LocalStack development and Parity Testing in particular covered in CONTRIBUTING (ideally demonstrated through successfully merged PRs)
• our LocalStack Lambda implementation

If you are confident in all these areas, feel free to give it a try and demonstrate a working implementation covered by an AWS Parity test.

Thanks for the breakdown @joe4dev . I've been taking a closer look in the meantime & will definitely give it a try.