Docker-compose env_file behavior is confusing

General
,
11

So, docker-compose config output as is:

services:
  debug:
    build:
      context: /home/flint/services/debug
    command:
    - bash
    - -c
    - echo "$${LISTEN_ADDRESS}:$${LISTEN_PORT}"
    container_name: debug
    environment:
      LISTEN_ADDRESS: 192.168.1.74
      LISTEN_PORT: '9090'
    image: debug
    network_mode: host
    volumes:
    - read_only: true
      source: /home/flint/services/debug/conf.d/debug.conf
      target: /etc/debug/debug.conf
      type: bind

and the docker inspect is correct too:

        "Config": {
            "Hostname": "cmc01.flint.net",
            "Domainname": "",
            "User": "",
            "AttachStdin": false,
            "AttachStdout": false,
            "AttachStderr": false,
            "Tty": false,
            "OpenStdin": false,
            "StdinOnce": false,
            "Env": [
                "LISTEN_ADDRESS=192.168.1.74",
                "LISTEN_PORT=9090",
                "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
                "DHCPD_PROTOCOL=4",
                "DHCPD_INTERFACE=eth0",
                "DHCPD_DEFAULT_CONFIG=/etc/dhcpd/dhcpd.conf"
            ],

What’s really weird is when using .env or --env-file command line with the Prometheus container it works, only env_file variable injection seems to be not correctly interpreted.