Django connection with postgres by docker-compose

Question

My django project cannot connect to the postgres database container. What should I do?

python manage.py collectstatic --noinput && python manage.py makemigrations blog && python manage.py migrate . I know that the docker launch command creates a new container, but I have more commands as one on bash in docker-compose.yml. It should work, right?

my Dockerfile :

 FROM python:3.6-alpine MAINTAINER Name < name@domain > ENV PYTHONUNBUFFERED 1 ENV INSTALL_PATH /heckblog RUN mkdir -p $INSTALL_PATH WORKDIR $INSTALL_PATH COPY requirements.txt requirements.txt # make available run pip install psycopg2 RUN apk update && \ apk add --virtual build-deps gcc python3-dev musl-dev && \ apk add postgresql-dev RUN pip3 install -r requirements.txt # add bash into alpine linux RUN apk add --update bash && rm -rf /var/cache/apk/* COPY ./heckblog . #RUN pip install . CMD gunicorn -b 0.0.0.0:8000 --access-logfile - "config.wsgi:application" 

my docker-compose.yml :

 version: '2' services: db: image: postgres:alpine environment: POSTGRES_USER: blogdmin POSTGRES_PASSWORD: password POSTGRES_DB: heckblog PGDATA: /tmp/pgdata volumes: - postgres_data:/tmp/pgdata web: build: . command: > bash -c "sleep 10 && python manage.py collectstatic --noinput && python manage.py makemigrations blog && python manage.py migrate && echo \"from django.contrib.auth.models import User; User.objects.create_superuser('admin', ' [e-mail] ', 'pass')\" | python manage.py shell && gunicorn -b 0.0.0.0:8000 --access-logfile - --reload \"config.wsgi:application\"" volumes: - ./heckblog:/heckblog depends_on: - db environment: IN_DOCKER: 1 ports: - "80:8000" volumes: postgres_data: 

settings.py :

 ... DATABASES = { 'default': { 'ENGINE': 'django.db.backends.postgresql_psycopg2', 'NAME': 'heckblog', 'USER': 'blogdmin', 'PASSWORD': 'password', 'HOST': 'localhost', 'PORT': '', # default port } } ... 

The output of docker-compose up --build :

 web_1 | TCP/IP connections on port 5432? web_1 | could not connect to server: Connection refused web_1 | Is the server running on host "localhost" (127.0.0.1) and accepting web_1 | TCP/IP connections on port 5432? web_1 | heckblog_web_1 exited with code 1 

I use: Windows 10 Docker 17.03.0-ce-win1- (10296) docker-compose version 1.11.2 Django == 1.10.6 psycopg2 == 2.7.1.

thanks for answers

Answer 1

Each container in docker gets its own hostname and IP by default. When compose spins containers for you, it also puts all containers on the default network to allow DNS-based discovery.

This means that your database is not accessible on localhost, but you can contact it by the service name "db". Change this line in settings.py parameters:

  'HOST': 'localhost', 

in

  'HOST': 'db',