带有 Postgres 的 Django 应用程序上的 Docker 映像返回 django.db.utils.OperationalError

我想为我的 Django 项目 mysite 创建一个 Docker 映像，它有两个应用程序轨道和用户。我使用 docker build -t mysite 来构建我的 docker 镜像。我写了一个 Dockerfile 就像它在 dockerhub 上所说的那样。然后我创建了 docker-compose.yml 文件和我在 docker-compose 文件中使用的 bash 脚本entypoint.sh。

这些是我的文件：

Dockerfile：

FROM django:onbuild

COPY entrypoint.sh /entrypoint.sh
RUN chmod +x /entrypoint.sh

docker-compose.yml：

version: '3'

services:
  db:
    image: postgres
    container_name: postgres_container
    environment:
     - POSTGRES_USER=postgres
     - POSTGRES_PASSWORD=postgres
     - POSTGRES_DB=postgres
    ports:
     - 5432:5432
  web:
    image: mysite:latest
    build:
     context: .
     dockerfile: Dockerfile
    container_name: mysite_container
    ports:
      - "8000:8000"
    depends_on:
      - db
    entrypoint: /entrypoint.sh

入口点.sh

#!/bin/sh

python manage.py makemigrations
python manage.py migrate
python manage.py runserver 0.0.0.0:8000
exec "$@"

所以当我想启动整个容器时，我使用了以下命令

docker build .
docker-compose build
docker-compose up

而我的 postgres_containter 启动成功，但是 mysite_container 抛出以下错误：

mysite_container | Traceback (most recent call last):
mysite_container |   File "manage.py", line 22, in <module>
mysite_container |     execute_from_command_line(sys.argv)
mysite_container |   File "/usr/local/lib/python3.4/site-packages/django/core/management/__init__.py", line 371, in execute_from_command_line
mysite_container |     utility.execute()
mysite_container |   File "/usr/local/lib/python3.4/site-packages/django/core/management/__init__.py", line 365, in execute
mysite_container |     self.fetch_command(subcommand).run_from_argv(self.argv)
mysite_container |   File "/usr/local/lib/python3.4/site-packages/django/core/management/base.py", line 288, in run_from_argv
mysite_container |     self.execute(*args, **cmd_options)
mysite_container |   File "/usr/local/lib/python3.4/site-packages/django/core/management/base.py", line 335, in execute
mysite_container |     output = self.handle(*args, **options)
mysite_container |   File "/usr/local/lib/python3.4/site-packages/django/core/management/commands/migrate.py", line 79, in handle
mysite_container |     executor = MigrationExecutor(connection, self.migration_progress_callback)
mysite_container |   File "/usr/local/lib/python3.4/site-packages/django/db/migrations/executor.py", line 18, in __init__
mysite_container |     self.loader = MigrationLoader(self.connection)
mysite_container |   File "/usr/local/lib/python3.4/site-packages/django/db/migrations/loader.py", line 49, in __init__
mysite_container |     self.build_graph()
mysite_container |   File "/usr/local/lib/python3.4/site-packages/django/db/migrations/loader.py", line 207, in build_graph
mysite_container |     self.applied_migrations = recorder.applied_migrations()
mysite_container |   File "/usr/local/lib/python3.4/site-packages/django/db/migrations/recorder.py", line 61, in applied_migrations
mysite_container |     if self.has_table():
mysite_container |   File "/usr/local/lib/python3.4/site-packages/django/db/migrations/recorder.py", line 44, in has_table
mysite_container |     return self.Migration._meta.db_table in self.connection.introspection.table_names(self.connection.cursor())
mysite_container |   File "/usr/local/lib/python3.4/site-packages/django/db/backends/base/base.py", line 255, in cursor
mysite_container |     return self._cursor()
mysite_container |   File "/usr/local/lib/python3.4/site-packages/django/db/backends/base/base.py", line 232, in _cursor
mysite_container |     self.ensure_connection()
mysite_container |   File "/usr/local/lib/python3.4/site-packages/django/db/backends/base/base.py", line 216, in ensure_connection
mysite_container |     self.connect()
mysite_container |   File "/usr/local/lib/python3.4/site-packages/django/db/utils.py", line 89, in __exit__
mysite_container |     raise dj_exc_value.with_traceback(traceback) from exc_value
mysite_container |   File "/usr/local/lib/python3.4/site-packages/django/db/backends/base/base.py", line 216, in ensure_connection
mysite_container |     self.connect()
mysite_container |   File "/usr/local/lib/python3.4/site-packages/django/db/backends/base/base.py", line 194, in connect
mysite_container |     self.connection = self.get_new_connection(conn_params)
mysite_container |   File "/usr/local/lib/python3.4/site-packages/django/db/backends/postgresql/base.py", line 168, in get_new_connection
mysite_container |     connection = Database.connect(**conn_params)
mysite_container |   File "/usr/local/lib/python3.4/site-packages/psycopg2/__init__.py", line 130, in connect
mysite_container |     conn = _connect(dsn, connection_factory=connection_factory, **kwasync)
mysite_container | django.db.utils.OperationalError: could not connect to server: Connection refused
mysite_container |      Is the server running on host "localhost" (127.0.0.1) and accepting
mysite_container |      TCP/IP connections on port 5432?
mysite_container | could not connect to server: Cannot assign requested address
mysite_container |      Is the server running on host "localhost" (::1) and accepting
mysite_container |      TCP/IP connections on port 5432?

我在 settings.py 中的数据库是

DATABASES = {
        'default': {
            'ENGINE': 'django.db.backends.postgresql_psycopg2',
            'NAME': 'postgres',
            'USER': 'postgres',
            'PASSWORD': 'postgres',
            'HOST': 'localhost',
            'PORT': '5432',
        }
}

那么，有谁知道我为什么会收到此错误？当我执行 docker-compose up 时，我的 postgres 在端口 5432 上的本地主机上成功运行，但似乎我的 web 容器没有检测到。我应该在 Docker 文件中更改什么才能正确运行 mysite_container？

编辑：现在我添加了新的 settings_docker.py，我将我的主机设置为 'db' 文件，并将环境变量 DOCKER_SETTINGS_MODULE=mysite.settins_docker 添加到我在 docker-compose.yml 中的 Web 服务，并且容器正常启动，但我没有我的数据库关系。那么，如何将这些关系迁移到 docker？