homeserver/docker/stacks/collabora/collabora.yml

services:
  collabora:
    image: collabora/code
    container_name: collabora
    environment:
      - password=${COLLABORA_PASSWORD}
      - username=${COLLABORA_USERNAME}
      - aliasgroup1=${COLLABORA_DOMAIN}  
      - extra_params=--o:ssl.enable=true
    networks:
      - proxy
      - collabora
    ports:
      - "9980:9980"
    restart: on-failure

networks:
   proxy:
      external:
         name: proxy
   collabora:
      name: collabora