生产服务器Docker部署MySQL无法与Django连接问题求助

Alright, let's figure out why your Django app can't connect to the MySQL container in GitLab CI, and fix this step by step.

1. Fix Syntax Errors in Django Settings #

First off, I notice a basic syntax mistake in your settings.py database config—your string values aren’t wrapped in quotes! Python will throw an error when trying to read mydb, root, etc., as unquoted identifiers. Update your config to:

DATABASES = {
  'default': {
    'ENGINE': 'django.db.backends.mysql',
    'NAME': 'mydb',
    'USER': 'root',
    'PASSWORD': 'root',
    'HOST': 'db',
    'PORT': 3306,
  }
}

2. Ensure Network Connectivity in GitLab CI #

In GitLab CI, Docker containers need to be on the same network to resolve each other by service name (like db).

• If you’re using a single docker-compose.yml for both your Django app and MySQL service, Docker automatically creates a shared network, so db should be resolvable. Double-check that your Django service is part of the same compose file.
• If you’re starting containers separately, manually create a Docker network and attach both containers to it. For example, in your CI script:

  docker network create myapp-network
  docker run --network myapp-network --name db ... mysql:5.7
  docker run --network myapp-network --name web ... your-django-image
  

3. Fix MySQL User Permissions #

By default, MySQL’s root user is restricted to local (localhost) connections only. Since your Django app is connecting from another container, you need to grant root access from any host:

• Add a command to your MySQL service in docker-compose.yml to set this up on startup:

  db:
    image: mysql:5.7
    restart: always
    env_file:
      - ./app/app/.env
    volumes:
      - ./mysql-data:/var/lib/mysql
    ports:
      - "3302:3306"
    command: --bind-address=0.0.0.0 --default-authentication-plugin=mysql_native_password
  

• Alternatively, if you need to fix an existing container, run these commands:

  docker exec -it <your-mysql-container-id> mysql -uroot -proot
  mysql> GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' IDENTIFIED BY 'root';
  mysql> FLUSH PRIVILEGES;
  

4. Wait for MySQL to Fully Start #

In CI environments, Django often tries to connect before MySQL has finished initializing. Add a wait step to your GitLab CI job to ensure MySQL is ready:

• Use nc (netcat) to poll the port until it’s open:

  until nc -z db 3306; do sleep 1; echo "Waiting for MySQL..."; done
  

• Or use the wait-for-it script (you can include it in your Docker image or fetch it in the CI job):

  wait-for-it db:3306 --timeout=30 -- python manage.py migrate
  

5. Verify Environment Variables Are Loaded #

Double-check that your .env variables are correctly passed to the MySQL container. Run this command in your CI pipeline (or locally) to confirm:

docker exec -it <your-mysql-container-id> sh -c 'echo $MYSQL_DATABASE && echo $MYSQL_ROOT_PASSWORD'

Make sure mydb and root are printed—if not, your env_file path might be incorrect in docker-compose.yml.

Start with fixing the syntax error first, then work through the other steps—this should get your connection working.

内容的提问来源于stack exchange，提问作者TNN