Using environment variable for volume name in docker compose

This is expected behavior – Compose only does variable interpolation in values, not keys. See here.

In my project I use external structure:

version: '3.1'
services:
### Code from branch develop ###
  applications:
    image: registry.gitlab.lc:5000/develop/ed/develop.sources:latest
    volumes:
      - developcode:/var/www/develop
    deploy:
      replicas: 1
      update_config:
        parallelism: 1
        delay: 5s
      restart_policy:
        condition: on-failure
      placement:
        constraints: [node.role == manager]
### PHP-FPM ###
  php-fpm:
    image: registry.gitlab.lc:5000/develop/ed/php-fpm-ed-sq:latest
    volumes:
      - developcode:/var/www/develop
    expose:
      - "9000"
    deploy:
      replicas: 2
      update_config:
        parallelism: 1
        delay: 5s
      restart_policy:
        condition: on-failure
      placement:
        constraints: [node.role == manager]
    logging:
      driver: gelf
      options:
        gelf-address: "udp://${GRAYLOG_ADDR}:12201"
        tag: "php-fpm"
### Nginx ###
  nginx:
    image: registry.gitlab.lc:5000/develop/ed/nginx-ed-sq:staging
    volumes:
      - developcode:/var/www/develop
    ports:
      - "80:80"
      - "443:443"
    deploy:
      replicas: 2
      update_config:
        parallelism: 1
        delay: 5s
      restart_policy:
        condition: on-failure
      placement:
        constraints: [node.role == manager]
### Volumes Setup ###
volumes:
  developcode:
    external:
      name: code-${VER}

but first of all I need create external volume manually, e. g.:

export VER=1.1 && docker volume create --name code-$VER

You can see created volume:

docker volume ls
DRIVER              VOLUME NAME
local               code-1.0
local               code-1.1

And after that, deploy services using:

env $(cat .env | grep ^[A-Z] | xargs) docker stack deploy --with-registry-auth --compose-file docker-compose.yml MY_STACK