docker-compose/pkg/e2e/fixtures/configs/compose.yaml

services:
  from_env:
    image: alpine
    configs:
      - source: from_env
        target: /from_env
    command: cat /from_env

  from_file:
    image: alpine
    configs:
      - source: from_file
        target: /from_file
    command: cat /from_file

  inlined:
    image: alpine
    configs:
      - source: inlined
        target: /inlined
    command: cat /inlined

configs:
  from_env:
    environment: CONFIG
  from_file:
    file: config.txt
  inlined:
    content: This is my $CONFIG