Can we allow customisation of local server port

[adam-fowler]

Expected behavior

Add environment variable LOCAL_LAMBDA_PORT to customise port local server binds to.

Actual behavior

Airplay can use port 7000

Steps to reproduce

Run local lambda on Mac with setting General -> AirDrop & Handoff -> AirPlay receiver enabled
Check server response using curl -I localhost:7000

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

No response

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

2.0.0-beta.2

Swift version

Apple Swift version 6.1 (swift-6.1-RELEASE)
Target: arm64-apple-macosx15.0
Darwin Adams-Mac-mini.local 24.6.0 Darwin Kernel Version 24.6.0: Mon Jul 14 11:30:40 PDT 2025; root:xnu-11417.140.69~1/RELEASE_ARM64_T6041 arm64

Amazon Linux 2 docker image version

No response

[sebsto]

I know TCP port conflicts with Airplay.

However, it never really caused problems. Somehow the runtime binds TCP port 7000 even when AirPlay is configured. I had problems when the server stops and the runtime continues trying polling events, which causes a nextInvocationMissingHeaders error (because Airplay doesn't send expected headers)

I'm curious to learn in which context it prevents running.

Anyway, I think it's better to address this once for all and allow users to select their port.

Can you please review #557 ?

[sebsto]

fixed by #557