docker-compose env_file

console log

$ cat docker-compose.env.yml
version: '2'

services:
  test:
    image: busybox
    command: env
    env_file: ./env.data
    environment:
      - VAL="from compose"


$ cat env.data
HELLO=world
TEST=123

$ cat .env
ENV=default

$ docker-compose -f docker-compose.env.yml up
WARNING: The Docker Engine you're using is running in swarm mode.

Compose does not use swarm mode to deploy services to multiple nodes in a swarm. All containers will be scheduled on the current node.

To deploy your application across the swarm, use the bundle feature of the Docker experimental build.

More info:
https://docs.docker.com/compose/bundles

Starting test_test_1
Attaching to test_test_1
test_1  | PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
test_1  | HOSTNAME=f5d3d0a14087
test_1  | TEST=123
test_1  | HELLO=world
test_1  | VAL="from compose"
test_1  | HOME=/root
test_test_1 exited with code 0