How should the docker compose variables work?

[krasi-georgiev]

@janvda

Not clear to me how multiline env variables might also solve this issue.

I have developped a simple tool that converts an env variable into a file which is than used in the AlertManager container. Allowing multiline env variables would make it possible to NOT add the env variable directly in the compose file and pass it vie the cli

balena push --env ALERTMANAGER_CONFIG="$ALERTMANAGER_CONFIG" 192.168.0.113

or set it via the balena portal GUI.
I currently can’t use the gui due to this bug:

Use pre build multiarch image from docker hub

Trying to use my own multi-arch image that I have built with the new docker buildx command and pushed to docker hub. From the docs so far I understand that I need to use belena push, but it seems that doesn’t use the existing image, but still somehow builds a new image as when running the logs show standard_init_linux.go:207: exec user process caused "exec format error". I can run this image fine on another Rpi with Hypriot OS docker-compose file version: "2.1" services: lora-connect: …

P.S I have now added suport to the envToFile tool to expand the env vars so will test shortly and will let you know if it worked.