I can get the example working that Docker provides and just about every blog is just a variation of it: just printing out the secret value in the build output.
Cool... but I need to get it into my app that is looking for it and failing to build because it doesn't exist. That much isn't clear to me and I've been unable to figure it out myself.
This is the project structure:
project-root/
api/
docker/
Dockerfile
mysecret.txt
src/
... …