了解 django.db.utils.OperationalError: 连接错误：未提供节点名或服务名，或未知错误

问题描述 投票：0回答：1

我正在尝试使用 Postgress 数据库创建一个 Django 网站。当我运行 python manage.py runserver 命令来启动网站时，我收到以下错误消息。

回溯错误消息

Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/django/db/backends/base/base.py", line 275, in ensure_connection
    self.connect()
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/django/utils/asyncio.py", line 26, in inner
    return func(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/django/db/backends/base/base.py", line 256, in connect
    self.connection = self.get_new_connection(conn_params)
                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/django/utils/asyncio.py", line 26, in inner
    return func(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/django/db/backends/postgresql/base.py", line 275, in get_new_connection
    connection = self.Database.connect(**conn_params)
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/psycopg/connection.py", line 750, in connect
    raise last_ex.with_traceback(None)
psycopg.OperationalError: connection is bad: nodename nor servname provided, or not known

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/threading.py", line 1038, in _bootstrap_inner
    self.run()
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/threading.py", line 975, in run
    self._target(*self._args, **self._kwargs)
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/django/utils/autoreload.py", line 64, in wrapper
    fn(*args, **kwargs)
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/django/core/management/commands/runserver.py", line 136, in inner_run
    self.check_migrations()
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/django/core/management/base.py", line 574, in check_migrations
    executor = MigrationExecutor(connections[DEFAULT_DB_ALIAS])
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/django/db/migrations/executor.py", line 18, in __init__
    self.loader = MigrationLoader(self.connection)
                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/django/db/migrations/loader.py", line 58, in __init__
    self.build_graph()
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/django/db/migrations/loader.py", line 235, in build_graph
    self.applied_migrations = recorder.applied_migrations()
                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/django/db/migrations/recorder.py", line 89, in applied_migrations
    if self.has_table():
       ^^^^^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/django/db/migrations/recorder.py", line 63, in has_table
    with self.connection.cursor() as cursor:
         ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/django/utils/asyncio.py", line 26, in inner
    return func(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/django/db/backends/base/base.py", line 316, in cursor
    return self._cursor()
           ^^^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/django/db/backends/base/base.py", line 292, in _cursor
    self.ensure_connection()
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/django/utils/asyncio.py", line 26, in inner
    return func(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/django/db/backends/base/base.py", line 274, in ensure_connection
    with self.wrap_database_errors:
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/django/db/utils.py", line 91, in __exit__
    raise dj_exc_value.with_traceback(traceback) from exc_value
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/django/db/backends/base/base.py", line 275, in ensure_connection
    self.connect()
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/django/utils/asyncio.py", line 26, in inner
    return func(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/django/db/backends/base/base.py", line 256, in connect
    self.connection = self.get_new_connection(conn_params)
                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/django/utils/asyncio.py", line 26, in inner
    return func(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/django/db/backends/postgresql/base.py", line 275, in get_new_connection
    connection = self.Database.connect(**conn_params)
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/psycopg/connection.py", line 750, in connect
    raise last_ex.with_traceback(None)
django.db.utils.OperationalError: connection is bad: nodename nor servname provided, or not known

为了解决这个问题，我尝试做的第一件事就是检查 Django 文档中的错误消息。在这篇[文章]中，它引用了该错误，但没有详细介绍如何解决该错误。 （https://docs.djangoproject.com/en/5.0/ref/exceptions/#django.db.OperationalError）

我还查看了有关将 Postgress 数据库连接到 Django 的 Django 文档，但它没有回答我的问题。 [关于 Postgress 的 Django 文档。] (https://docs.djangoproject.com/en/5.0/ref/databases/#postgresql-notes)

我还在堆栈溢出中搜索了错误消息，找到了这篇文章和其他人，但他们没有解决我的问题。

我还检查了 Docker 论坛和 Django 论坛以获取答案，但没有文章可以回答我的问题。我报名了 Docker 课程并观看了视频并完成了官方教程，但我仍然不明白为什么我的数据库无法连接。

至于我的尝试，我尝试更改django_project settings.py中的数据库名称以及用户和密码。我尝试将 PORT 更改为 8000，然后又改回来。

对于 Dockerfile 的故障排除，我通过建立一条路径来更改卷设置以反映计算机上存储的内容。我使用 :latest 更改了 Postgress 图像设置，以尝试告诉 docker 使用最新的 Postgress 进行构建。

我的问题是节点名或服务器名是什么？为什么我的 Django 项目无法连接到 postgress？

django_project/settings.py

# django_project/settings.py
DATABASES = {
    "default": {
        "ENGINE": "django.db.backends.postgresql",
        "NAME": "postgres",
        "USER": "postgres",
        "PASSWORD": "postgres",
        "HOST": "db",  # set in docker-compose.yml
        "PORT": 5432,  # default postgres port
    }
}

我还查看了我的 Dockerfile 和 docker compose 文件。

Dockerfile

# Pull base image from docker hub. by not specifying a version I tell the hub to pull the latest file. 
FROM python
# Set environment variables
ENV PIP_DISABLE_PIP_VERSION_CHECK 1
ENV PYTHONDONTWRITEBYTECODE 1
ENV PYTHONUNBUFFERED 1
# Set work directory
WORKDIR /Users/andrewstribling/Desktop/dev/code/ch4-bookstore
# Install dependencies
COPY ./requirements.txt .
RUN pip install -r requirements.txt
# Copy project
COPY . .

docker-compose.yml

version: "3"

services:
  web:
    build: "."
    command: python manage.py runserver 0.0.0.0:8000
    volumes:
      - /dev/code/ch4-bookstore/
    ports:
      - "8000:8000"
    depends_on:
      - "db"

  db:
    image: postgres:latest
    volumes:
      - postgres_data:/var/lib/postgresql/data/
    environment:
      - "POSTGRES_HOST_AUTH_METHOD=trust"

volumes:
  postgres_data:
python django docker
1个回答
0
投票

您的 Postgres 容器未按照最低要求运行。更新你的 postgres 容器块，你应该可以开始了。我建议您阅读 docker hub 来选择您选择的镜像 https://hub.docker.com/_/postgres.

  postgres:
    image: postgres:latest
    networks:
      - mynet
    restart: always
    volumes:
      - postgres-data:/var/lib/postgresql/data
    environment:
      - POSTGRES_USER=test
      - POSTGRES_PASSWORD=password
      - POSTGRES_DB=test
      - PGDATA=/var/lib/postgresql/data
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