如何在 Dockerized Django 中运行迁移? [英] How do I run migrations in Dockerized Django?

问题描述

我遵循了 Docker + Django 教程 很棒，因为我可以按照说明成功构建和运行网站.但是，我终生无法弄清楚如何在更改模型后成功运行数据库迁移.

I followed a Docker + Django tutorial which was great, in that I could successfully build and run the website following the instructions. However, I can't for the life of me figure out how to successfully run a database migration after changing a model.

以下是我采取的步骤:

1. 克隆关联的 git repo

2. 设置一个名为dev

• with docker-machine create -d virtualbox dev
• 并用 eval $(docker-machine env dev)
指向它

构建并启动它:

• docker-compose build
• 和docker-compose up -d

运行初始迁移(这是我唯一一次能够运行看起来成功的迁移):

• docker-compose run web python manage.py migrate

通过导航到返回的 IP 地址来检查网站是否正常工作:

Checked that the website works by navigating to the IP address returned by:

• docker-machine ip dev

对模型进行更改.我刚刚将它添加到 web/docker_django/apps/todo/models.py 文件中的 Item 模型中.:

Make a change to a model. I just added this to the Item model in web/docker_django/apps/todo/models.py file.:

• name = models.CharField(default='Unnamed', max_length=50, null=False)

更新镜像并重启容器:

• docker-compose down --volumes
• 然后 docker-compose build
• 然后 docker-compose up --force-recreate -d

第 1 次迁移尝试:

我用过:

docker-compose run web python manage.py makemigrations todo

那么:

docker-compose run web python manage.py migrate

在 makemigrations 命令之后，它说:

After the makemigrations command, it said:

Migrations for 'todo':
  0001_initial.py:
    - Create model Item

当我运行 migrate 命令时，它给出了以下消息:

When I ran the migrate command, it gave the following message:

Operations to perform: 
  Synchronize unmigrated apps: messages, todo, staticfiles 
  Apply all migrations: contenttypes, admin, auth, sessions 
Synchronizing apps without migrations: 
  Creating tables... 
    Running deferred SQL... 
  Installing custom SQL... 
Running migrations: 
  No migrations to apply. 

所以那没有用.

这次我尝试直接从正在运行的 Web 容器内部运行迁移.这看起来像这样:

This time I tried running migrations from directly inside the running web container. This looked like this:

(macbook)$ docker exec -it dockerizingdjango_web_1 bash
root@38f9381f179b:/usr/src/app# ls
Dockerfile  docker_django  manage.py  requirements.txt  static  tests
root@38f9381f179b:/usr/src/app# python manage.py makemigrations todo
Migrations for 'todo':
  0001_initial.py:
    - Create model Item
root@38f9381f179b:/usr/src/app# python manage.py migrate
Operations to perform:
  Synchronize unmigrated apps: staticfiles, messages
  Apply all migrations: contenttypes, todo, admin, auth, sessions
Synchronizing apps without migrations:
  Creating tables...
    Running deferred SQL...
  Installing custom SQL...
Running migrations:
  Rendering model states... DONE
  Applying todo.0001_initial...Traceback (most recent call last):
  File "/usr/local/lib/python3.5/site-packages/django/db/backends/utils.py", line 62, in execute
    return self.cursor.execute(sql)
psycopg2.ProgrammingError: relation "todo_item" already exists

此外，我在该容器中找不到任何 migrations 文件夹.

Moreover, I couldn't find any migrations folders in that container.

我显然不知道这里发生了什么，所以如果有人能告诉我如何成功更改模型和运行数据库迁移，我将不胜感激.如果你能帮助我概念化当我运行这些必须让 web 和 postgres 图像协同工作的命令时发生了什么，那就加分.

I clearly have very little idea what's happening under the hood here, so if someone could show me how to successfully change models and run database migrations I would much appreciate it. Bonus points if you can help me conceptualize what's happening where when I run these commands that have to get the web and postgres images to work together.

@MazelTov 的建议都有助于自动化流程，因为我越来越习惯于使用 Docker 进行开发，但是我缺少的东西，@MazelTov 在一个非常有用的讨论中让我补充，正在安装，以便迁移显示在我的本地机器上.

@MazelTov's suggestions will all be helpful for automating the process as I get more used to developing with Docker, but the thing I was missing, that @MazelTov filled me in on in a very helpful discussion, was mounting so that migrations show up in my local machine.

所以基本上，我的迁移尝试 1 如果不是，例如:

So basically, my Migration Attempt 1 would have worked just fine if instead of, for example:

docker-compose run web python manage.py makemigrations todo

...我用过:

docker-compose run --service-ports -v $(pwd)/web:/usr/src/app web python manage.py makemigrations todo

推荐答案

有很多方法可以实现这一点.

There are many ways how to achieve this.

1) 在 bash 脚本中启动应用程序(uwsgi、runserver...)之前运行 ./manage.py migrate

1) Run ./manage.py migrate before you start your app (uwsgi, runserver,...) in bash script

Dockerfile

FROM debian:latest

...

# entrypoint, must be executable file chmod +x entrypoint.sh
COPY entrypoint.sh /home/docker/entrypoint.sh

# what happens when I start the container
CMD ["/home/docker/entrypoint.sh"]

入口点.sh

#!/bin/bash

./manage.py collectstatic --noinput
# i commit my migration files to git so i dont need to run it on server
# ./manage.py makemigrations app_name
./manage.py migrate

# here it start nginx and the uwsgi
supervisord -c /etc/supervisor/supervisord.conf -n

2) 如果您有很多迁移文件并且不想停机，您可以从单独的 docker-compose 服务运行 migrate 命令

2) If you have a lot of migration files and you dont want any downtime, you could run the migrate command from seperate docker-compose service

docker-compose.yml

docker-compose.yml

version: '3.3'

services:  

  # starts the supervisor (uwsgi + nginx)
  web:
    build: .
    ports: ["80:80"]

  # this service will use same image, and once the migration is done it will be stopped
  web_migrations:
    build: .
    command: ./manage.py migrate

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