Cannot connect to postgres db using docker build - postgresql

Question

I am trying to build an image and deploy it to a VPS.
I am running the app successfully with
docker-compose up
Then I build it with
docker build -t mystore .
When I try to run it for a test locally or on the VPS trough docker cloud:
docker run -p 4000:8000 mystore
The container works fine, but when I hit http://0.0.0.0:4000/
I am getting:
OperationalError at /
could not translate host name "db" to address: Name or service not known
I have changed the postgresql.conf listen_addresses to "*", nothing changes. The posgresql logs are empty. I am running MacOS.
Here is my DATABASE config:
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.postgresql_psycopg2',
'NAME': 'postgres',
'USER': 'user',
'PASSWORD': 'password',
'HOST': 'db',
'PORT': '5432',
}
}
This is the Dockerfile
FROM python:3.5
ENV PYTHONUNBUFFERED 1
RUN \
apt-get -y update && \
apt-get install -y gettext && \
apt-get clean
ADD requirements.txt /app/
RUN pip install -r /app/requirements.txt
ADD . /app
WORKDIR /app
EXPOSE 8000
ENV PORT 8000
CMD ["uwsgi", "/app/saleor/wsgi/uwsgi.ini"]
This is the docker-compose.yml file:
version: '2'
services:
db:
image: postgres
environment:
- POSTGRES_USER=user
- POSTGRES_PASSWORD=password
ports:
- '5432:5432'
redis:
image: redis
ports:
- '6379:6379'
celery:
build:
context: .
dockerfile: Dockerfile
env_file: common.env
command: celery -A saleor worker --app=saleor.celeryconf:app --loglevel=info
volumes:
- .:/app:Z
links:
- redis
depends_on:
- redis
search:
image: elasticsearch:5.4.3
mem_limit: 512m
environment:
- "ES_JAVA_OPTS=-Xms512m -Xmx512m"
ports:
- '127.0.0.1:9200:9200'
web:
build: .
command: python manage.py runserver 0.0.0.0:8000
env_file: common.env
depends_on:
- db
- redis
- search
ports:
- '8000:8000'
volumes:
- .:/app:Z
makemigrations:
build: .
command: python manage.py makemigrations --noinput
volumes:
- .:/app:Z
migration:
build: .
command: python manage.py migrate --noinput
volumes:
- .:/app:Z

Answer 1

You forgot to add links to your web image
web:
build: .
command: python manage.py runserver 0.0.0.0:8000
env_file: common.env
depends_on:
- db
- redis
- search
links: # <- here
- db
- redis
- search
ports:
- '8000:8000'
volumes:
- .:/app:Z

Answer 2

Check the available networks. There are 3 by default:
$ docker network ls
NETWORK ID NAME DRIVER SCOPE
db07e84f27a1 bridge bridge local
6a1bf8c2d8e2 host host local
d8c3c61003f1 none null local
I've a simplified setup of your docker compose. Only postgres:
version: '2'
services:
postgres:
image: postgres
name: postgres
environment:
- POSTGRES_USER=user
- POSTGRES_PASSWORD=password
ports:
- '5432:5432'
networks:
random:
networks:
random:
I gave the postgres container the name postgres and called the service postgres, I created a network called 'random' (last commands), and I've added the service postgres to the network random. If you don't specify a network you will see that docker-compose creates its a selfnamed network.
After starting docker-compose, you will have 4 networks. A new bridge network called random.
Check in which network your docker compose environment is created by inspecting for example your postgres container:
Mine is created in the network 'random':
$ docker inspect postgres
It's in the network 'random'.
"Networks": {
"random": {..
Now start your mystore container in the same network:
$ docker run -p 4000:8000 --network=random mystore
You can check again with docker inspect. To be sure you can exec inside your mystore container and try to ping postgres. They are deployed inside the same network so this should be possible and your container should be able to translate the name postgres to an address.

Answer 3

in your docker-compose.yml, add a network and add your containers to it like so:
to each container definition add:
networks:
- mynetwork
and then, at the end of the file, add:
networks:
mynetwork: