如何在docker-compose文件中将links替换为depends_on？

Hey there! Let's fix that deprecated links config in your Docker Compose file and swap it out for the recommended depends_on—it's simpler and aligns with current Docker best practices.

First, a quick background: links was phased out because Docker Compose now automatically creates a dedicated bridge network for your project by default. On this network, every service name acts as a resolvable hostname, so you don't need the alias mapping that links provided. depends_on takes care of the startup dependency order instead.

Here's your updated, fully functional docker-compose.yml #

I've filled in the missing parts for your Node.js and PHP services and replaced the links with proper depends_on setup:

version: "3.1"
services:
  nginx:
    image: nginx:alpine
    ports:
      - "8000:80"
    volumes:
      - ./php/content:/srv/www/content
      - ./static:/srv/www/static
      - ./nginx/default.conf:/etc/nginx/conf.d/default.conf
    # Replace deprecated links with depends_on to define startup order
    depends_on:
      - node-app
      - php-api
    # Pro tip: In Nginx's default.conf, use the service names as hostnames!
    # Example: proxy_pass http://node-app:3000; or fastcgi_pass php-api:9000;

  node-app:
    image: node:18-alpine
    volumes:
      - ./node-app:/app
    working_dir: /app
    command: npm start
    # Add depends_on here if this service relies on another (e.g., a database)

  php-api:
    image: php:8.2-fpm-alpine
    volumes:
      - ./php/content:/srv/www/content
    # Same here—add depends_on if you have a database or other dependencies

Key things to keep in mind #

• depends_on only manages startup order: It ensures node-app and php-api start before Nginx, but it won't wait for those services to be fully ready (e.g., Node.js finishing its init, PHP-FPM accepting connections). If you need to wait for readiness, add healthcheck to your services and use condition: service_healthy in depends_on, like this:

  depends_on:
    php-api:
      condition: service_healthy
  

• Update your Nginx config: If you were using the alias from links (like php-a), replace that with the service name (php-api) in your Nginx upstream definitions—this works because of the default Compose network's DNS resolution.
• No more aliases needed: If you relied on links to create custom host aliases, you can define them in a custom network's aliases section, but in most cases, using the service name directly is cleaner.

内容的提问来源于stack exchange，提问作者François Romain