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
pson 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/.