postgresql - 为什么我的Flask服务器无法使用docker-compose与postgres数据库对话？

Question

我已经在下面发布了相关文件。一切都按预期构建，但是当尝试使用SQLAlchemy进行数据库调用时，我总是遇到以下错误:
OperationalError: (psycopg2.OperationalError) could not translate host name "db" to address: Name or service not known
sqlalchemy使用的字符串是(如.env.web.dev中给出的):postgres://postgres:postgres@db:5432/spaceofmotion。

我究竟做错了什么？

docker-compose.yml:

version: '3'

services:
  db:
    container_name: db
    ports:
      - '5432:5432'
    expose:
      - '5432'
    build:
      context: ./
      dockerfile: Dockerfile.postgres
    networks:
      - db_web

  web:
    container_name: web
    restart: always
    build:
      context: ../
      dockerfile: Dockerfile.web
    ports:
      - '5000:5000'
    env_file:
      - ./.env.web.dev
    networks:
      - db_web
    depends_on:
      - db
      - redis
      - celery

  redis:
    image: 'redis:5.0.7-buster'
    container_name: redis
    command: redis-server
    ports:
      - '6379:6379'

  celery:
    container_name: celery
    build:
      context: ../
      dockerfile: Dockerfile.celery
    env_file:
      - ./.env.celery.dev
    command: celery worker -A a.celery --loglevel=info
    depends_on:
      - redis

  client:
    container_name: react-app
    build:
      context: ../a/client
      dockerfile: Dockerfile.client
    volumes:
      - '../a/client:/src/app'
      - '/src/app/node_modules'
    ports:
      - '3000:3000'
    depends_on:
      - "web"
    environment:
      - NODE_ENV=development
      - HOST_URL=http://localhost:5000

networks:
  db_web:
    driver: bridge

Dockerfile.postgres:

FROM postgres:latest

ENV POSTGRES_DB spaceofmotion
ENV POSTGRES_USER postgres
ENV POSTGRES_PASSWORD postgres

COPY ./spaceofmotion-db.sql /
COPY ./docker-entrypoint-initdb.d/restore-database.sh /docker-entrypoint-initdb.d/

restore-database.sh:

file="/spaceofmotion-db.sql"
psql -U postgres spaceofmotion < "$file"

Dockerfile.web:

FROM python:3.7-slim-buster

RUN apt-get update
RUN apt-get -y install python-pip libpq-dev python-dev && \
    pip install --upgrade pip && \
    pip install psycopg2

ENV PYTHONDONTWRITEBYTECODE 1
ENV PYTHONUNBUFFERED 1

COPY . /app
WORKDIR /app

RUN pip install -r requirements.txt

CMD ["python", "manage.py", "runserver"]

.env.web.dev:

DATABASE_URL=postgres://postgres:postgres@db:5432/spaceofmotion
... <other config vars> ...

Answer 1

这是您的celery容器专用的吗？

您的db容器声明

networks:
  - db_web

但是 celery容器没有这样的声明；那意味着 it will be on the default network Compose creates for you。由于这两个容器不在同一网络上，因此它们无法相互连接。

使用Compose管理的 default网络没有任何问题，尤其是对于常规Web应用程序，我建议删除整个文件中的所有 networks:块。 (您也不需要指定 container_name:，因为Compose会自行提供合​​理的名称。)