提高我的docker-compose.yaml的适应性

Question

I am using docker-compose for my open-source web application. In the process of publishing my project on github I wanted to make my docker-compose.yaml file easier to understand and adapt. I'm still a beginner with Docker but the file works as intended. I just want to improve the readability and changeability of the volumes used by the containers. The values a/large/directory/or/disk:/var/lib/postgresql/data and /another/large/disk/:/something will most likely need to be adapted to the system the user is running my application on. Can I introduce variables for these? How can I make it more obvious that these values are to be changed by the person running my application?

My current docker-compose.yaml file

version: '3'
services:
  postgres:
    image: postgres:latest
    restart: always
    expose:
      - 5432
    ports:
      - 5432:5432
    environment:
      POSTGRES_USER: 'postgres'
      POSTGRES_PASSWORD: 'password'
      POSTGRES_DB: 'sample'
    volumes:
      - /a/large/directory/or/disk:/var/lib/postgresql/data
    networks:
      - mynetwork
  mysql:
    image: mysql:5.7
    restart: always
    environment:
      MYSQL_DATABASE: 'db'
      MYSQL_USER: 'user'
      MYSQL_PASSWORD: 'password'
      MYSQL_ROOT_PASSWORD: 'password'
    expose:
      - 3306
    ports:
      - 3306:3306
    volumes:
      - ~/data/mysql:/var/lib/mysql
    networks:
      - mynetwork
    depends_on:
      - postgres
  core:
    restart: always
    build: core/
    environment:
      SPRING_APPLICATION_JSON: '{
        "database.postgres.url": "postgres:5432/sample",
        "database.postgres.user": "postgres",
        "database.postgres.password": "password",
        "database.mysql.host": "mysql",
        "database.mysql.user": "root",
        "database.mysql.password": "password"
      }'
    volumes:
      - ~/data/core:/var
      - /another/large/disk/:/something  
    networks:
      - mynetwork
    depends_on:
      - mysql
    ports:
      - 8080:8080
  web:
    restart: always
    build: web/
    networks:
      - mynetwork
    depends_on:
      - core
    ports:
      - 3000:3000
networks:
  mynetwork:
    driver: bridge
volumes:
    myvolume:

(I'd also appreciate any other suggestions for improvements to my file!)

Answer 1

Docker Compose supports variable interpolation. But then you need to document those values, and people might just assume docker compose up and have it work without extra setup.

Compose typically isn't used for production deployment, so you wouldn't use a real volume. That being said, you can simply use relative directories rather than home folder or absolute path ( ./data/app:/mount ) to the file itself, or a Docker managed volume.