Using YAML to reuse parts of existing docker-compose configuration

docker-compose.yml

version: "3"
services:
  apache: &apacheConfig
    build: .
    volumes:
      - ./:/var/www/html:cached
      - ./docker/php-apache/php.ini:/usr/local/etc/php/php.ini
      - ./docker/php-apache/ssl-local:/etc/httpd/ssl
    working_dir: /var/www/html
    ports:
      - "8700:443"
      - "8800:80"
    links:
      - elasticsearch

  apache-xdebug:
    <<: *apacheConfig
    build: docker/xdebug
    volumes:
      - ./:/var/www/html:cached
      - ./docker/php-apache/php.ini:/usr/local/etc/php/php.ini
      - ./docker/php-apache/ssl-local:/etc/httpd/ssl
      - ./docker/xdebug/xdebug.ini:/usr/local/etc/php/conf.d/xdebug.ini

A variation of this:

api:
    environment: &app-variable-environments
      - FS_AWS_S3_ACCESS_KEY_ID
      - FS_AWS_S3_SECRET_ACCESS_KEY
      - FS_AWS_S3_REGION
      - FS_AWS_S3_BUCKET
      - MONGO_URL
      - MONGO_DB
      - REDIS_HOST
      - REDIS_PORT
      - REDIS_DB
      - UI_PORT
      - API_PORT
      - DOMAIN_NAME
      - APP_SECRET
      - SMTP_HOST
      - SMTP_PORT
      - SMTP_SECURED
      - SMTP_USER
      - SMTP_PASS
    build:
      context: ./app

worker:
    environment: *app-variable-environments