'Can\'t connect to MySQL server on \'db\' Django-Restframework with Mysql in docker

问题

I have dockerized my existing Django Rest project which uses MySQL database.

Dockefile

FROM python:3.6

ENV PYTHONUNBUFFERED 1
RUN mkdir /code
WORKDIR /code
COPY . /code/
RUN pip install -r requirements.txt

requirements.txt

django
djongo
django-rest-framework
wheel
pillow
mysqlclient
django-cors-headers

docker-compose.yml

version: '3'
volumes:
    portainer:

services:
  db:
    image: mysql
    environment:
      MYSQL_ROOT_PASSWORD: docker
      MYSQL_DATABASE: docker
      MYSQL_USER: docker
      MYSQL_PASSWORD: docker
    ports:
      - "3306:3306"

  web:
    build: .
    command: bash -c "python manage.py makemigrations && python manage.py migrate && python manage.py runserver 0.0.0.0:8000 "
    volumes: 
      - .:/code
    ports:
      - "8000:8000"
    links:
     - db
  portainer:
   image: portainer/portainer
   ports:
   - "9000:9000"
   volumes:
    - /var/run/docker.sock:/var/run/docker.sock
    - portainer:/data

setting.py

        'ENGINE': 'django.db.backends.mysql', #django.db.backends.mysql 
        'NAME': 'docker', #local: libraries #server: 
        'USER': 'docker', #root #root
        'PASSWORD': 'docker', #local: root #server: 
        'HOST': 'db', #local: localhost  #server:
        'PORT': '3306',

My command 'docker-compose up -d --build' are successful but the restapp container was not started so while checking logs it was showing this error django.db.utils.OperationalError: (2003, 'Can\'t connect to MySQL server on \'db\' (111 "Connection refused")').

回答1:

This may happen if your application container (web here) starts before your database is fully initialized.

You must wait until db service is started (more precisely, until mysql is accepting connections) before starting your application (python manage.py makemigrations && python manage.py migrate && python manage.py runserver 0.0.0.0:8000).

For that, you can use wait-for-it.sh script (check https://docs.docker.com/compose/startup-order/) before running your python commands. Alternatively, you could use a restart policy on your web service (https://docs.docker.com/compose/compose-file/#restart_policy) to automatically restart your service (until database is up).

来源：https://stackoverflow.com/questions/53129271/can-t-connect-to-mysql-server-on-db-django-restframework-with-mysql-in-doc

标签

python

mysql

django

Docker

django-rest-framework