Ok got this working, I used the curl API before so I must have done something weird, but here is a simple reduced working example for anyone else who needs it:
Dockerfile
:
FROM node:18-alpine
# Create app directory
WORKDIR /usr/src/app
COPY src ./src
CMD [ "node", "src/index.js" ]
src/index.js
:
console.log('hello world')
Then create/run the machine:
fly machine run .
Follow the prompts, create an app, check your logs:
hello world
Thanks again @jerome