Docker: Is the server running on host localhost error

Question

I am new to Docker and I am trying to dockerize an application for the first time by following a variety of tutorials on the internet and I'm getting this error that I am unable to resolve.

I searched around, tried different things but have not found something that would help me resolve the problem.

ERROR MESSAGE : Is the server running on host "localhost" (::1) and accepting TCP/IP connections on port 5432?

Here is my docker-compose file. The error comes from jobsite.

jobsite:
    container_name: job_startup
    build: .
    # command: ["./docker_compose/django/wait_for_postgres.sh"]
    volumes:
      - .:/code
    environment:
      PRODUCTION: 'False'
    ports:
      - "8000:8000"
    # depends_on:
    #   - "db"
    # links:
    #   - "db"

  enginx:
    build: ./nginx
    container_name: job_nginx
    restart: always
    environment:
      - NGINX_PORT=80
    ports:
      - "80:80"
   depends_on:
      - "jobsite"

Here is the main Dockerfile:

    FROM python:3
ENV PYTHONUNBUFFERED 1
ENV PYTHONDONTWRITEBYTECODE 1

RUN mkdir /code
WORKDIR /code

COPY requirements.txt /code/
RUN pip install -r requirements.txt

COPY . /code/

EXPOSE 8000

CMD python manage.py runserver 0.0.0.0:8000

The screenshot of the error message:

Error message screenshot

UPDATE

db:
    # image: postgres:latest
    build: ./database
    container_name: postgres_database
    # ports:
    #   - "8000:5432"
    restart: always
    environment:
      - DOCKER=True
      - POSTGRES_USER=postgres
      - POSTGRES_DB=jobs_data1
      - POSTGRES_PASSWORD=''
      - POSTGRES_HOST=127.0.0.1
      - DB_USER=john
      - DB_PASSWORD=''
      - DB_DATABASE=jobs_data1
    volumes:
      - ./postgres_database:/docker-entrypoint-initdb.d/
      - postgres_data:/var/lib/postgresql/data/

Answer 1

Your application tries to connect to PostgreSQL running on localhost. PostgreSQL, though, is obviously not running on localhost. You'll have to add a container to your docker compose configuration that starts PostgreSQL. Then, configure your Python application to use that name instead of localhost.

Answer 2

The application job_startup tries to connect to a postgres database running on localhost.

Your docker-compose file is missing the db service. Also the connection string in your python script should be db as hostname, as described by your commented out links and depends_on lines.