Lamdbda with Daemon: Python

We occassionally have need to run a Daemon in Lambda that our event handler talks to.

• My Diazo in Lambda does this: a docker-packaged lambda gets a URL on the event, and sends it to an Nginx daemon running Diazo.
• I want to run GitHub prerender/prerender, but have to run the rendering service on localhost:3000, and have our event handler grab the desired URL and send it to the service like http://localhost:3000/render?url=https://example.com

But I'm finding the Prerender service case difficult; maybe it's my lack of NodeJS-fu: I get connection refused:

• is the service really starting? There's no ps on Lambda.
• Is it listening on localhost, and what's that addr?
• Is the event GET happening before the service is starting?

Test a simple case with Python Lambda: a service listening on localhost:3000, queried by a event handler.

Deploy and invoke it with the Serverless Framework:

sls deploy
sls invoke --function app

CloudWatch logs will be in /aws/lambda/lambda-with-daemon-dev-app/.