What is the correct way to use environment for docker-compose?

Question

ubuntu

I can't figure out if I can make my own idea.
There is an OSRM service that I want to run in a container. It has 2 important parameters, TAG, and the card it works with.
I want to use this data as parameters so that I can change it in 1 place, and you can switch to the new version, do not change it in commands, docker-compose files, etc.
I thought to do it through environment. Created a file osrm.env with the content:

OSRM_TAG=v5.22.0
OSRM_MAP=/maps/russia.osrm

Created docker-compose:

version: '2'
services:
 osrm:
  env_file:
   - ./osrm.env
  image: osrm/osrm-backend:${OSRM_TAG}
  volumes:
   - /home/djonik/maps:/maps
  ports:
   - "5000:5000"
  container_name: osrm-routed

  command: osrm-routed --algorithm mld ${OSRM_MAP}

Made export OSRM_TAG=v5.21.0to check which value will be used.
But with the docker-compose config command, I get the following output:

[email protected]:~/sedi-docker/osrm$ docker-compose config
WARNING: The OSRM_MAP variable is not set. Defaulting to a blank string.
services:
  osrm:
    command: 'osrm-routed --algorithm mld '
    container_name: osrm-routed
    environment:
      OSRM_MAP: /maps/ru_az_am_kg_ge_by_ua_cz.osrm
      OSRM_TAG: v5.22.0
    image: osrm/osrm-backend:v5.21.0
    ports:
    - 5000:5000/tcp
    volumes:
    - /home/djonik/maps:/maps:rw
version: '2.0'

Either I do not understand something correctly, or tell me how to do it better?
Or is it better not to use environment?

Answer 1

If I remember correctly, the env config passed to the composer and the envs in the container itself are not related. Try passing the value of ${OSRM_TAG} to the env of the container:

environment:
  - OSRM_TAG=${OSRM_TAG}