How to combine streaming with HTTP invocation?

[jpenwith]

Expected behavior

Is it possible to stream a full HTTP response (with custom headers and status code), when the function is invoked via its function URL (https://123xyz.lambda-url.us-east-1.on.aws/)?

Specifically, this code already works:

struct EchoStreamer: StreamingLambdaHandler {
    // Raw event (from the URL request) we don’t need here
    typealias Event = String
    // Per-chunk type; ByteBuffer keeps allocations low
    typealias StreamChunk = ByteBuffer

    func handle(_ event: ByteBuffer, responseWriter: some LambdaResponseStreamWriter, context: LambdaContext) async throws {
        let eventString = String(buffer: event)

        for character in eventString {
            try await responseWriter.write(.init(string: String(character)))
            try await Task.sleep(nanoseconds: 10_000_000)
        }
        
        try await responseWriter.finish()

    }
}

try await LambdaRuntime(handler: EchoStreamer()).run()

but, is it possible to set the status code and headers of the response?

Currently, running

curl -N -v --header "Content-Type:\ application/json" --data "{\"name\":\"Alice\"}" https://123xyz.lambda-url.us-east-1.on.aws/

does echo the request body back as a stream, but the status code and headers are set by AWS

Actual behavior

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Steps to reproduce

_

If possible, minimal yet complete reproducer code (or URL to code)

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What version of this project (swift-aws-lambda-runtime) are you using?

main

Swift version

6.0

Amazon Linux 2 docker image version

amazonlinux2

[sebsto]

Thank you for bringing this to my attention.
I don't think this is currently supported by the runtime.
I'm investigating and checking what changes would be needed

[jpenwith]

Thanks very much, appreciate it

[sebsto]

I confirmed this is not possible at the moment. I saw this is supported in JS and Python, but the Lambda Runtime API Specifciation doesn't share too much details.

I engaged with AWS Specialist to understand what needs to be done.

I opened a separate issue to keep track of this.
#520

I'm closing this issue. Thank you again for having brought this to my attention.