Environment Variable in docker compose

Question

I wanted to create a docker-compose file, but the following seems to fail:

...
services:
  test:
    ...
    volumes:
      - ${FOO}:/bar
...

I've read that environment variables are not evaluated in keys, only in values. But since the $FOO is a value, I thought this would work?

Answer 1

This works. You have to declare FOO somewhere to get the result. Following code will work:

caller.sh

#!/bin/sh
export FOO=/home
docker-compose up