Struggling with connection between Django and Postgres within Docker containers - django

Question

I've been hitting the following error for awhile now and can't seem to fix it...
django.db.utils.OperationalError: could not connect to server: Connection refused
Is the server running on host "127.0.0.1" and accepting
TCP/IP connections on port 5432?
Multiple resources stated it was simply due to the HOST setting within my DATABASES, but the following is what I am working with and still can't get it to work:
DATABASES = {
'default': {
'HOST': 'db',
'ENGINE': 'django_postgrespool2',
'NAME': os.environ.get('PROJECT_HEARSAY_DB_NAME'),
'USER': os.environ.get('PROJECT_HEARSAY_DB_USER'),
'PASSWORD': os.environ.get('PROJECT_HEARSAY_DB_PASSWORD'),
'PORT': os.environ.get('PROJECT_HEARSAY_DB_PORT'),
}
}
Here is the Dockerfile for my Django app:
FROM python:3
ENV PYTHONUNBUFFERED 1
COPY . /app
WORKDIR /app
RUN pip install --upgrade pip
RUN pip install -r requirements.txt
Here is the Dockerfile for my Postgresql DB:
FROM postgres
And here is the docker-compose.yml that I am working with:
version: "3"
services:
postgresql:
build:
context: ./db
container_name: db.postgresql
ports:
- 5432:5432
environment:
POSTGRES_DB: "db_name"
POSTGRES_USER: "username"
POSTGRES_PASSWORD: "password"
django:
restart: always
build:
context: ./api
command: bash -c "./manage.py migrate && ./manage.py runserver 0.0.0.0:8000"
container_name: api.django
ports:
- 8000:8000
depends_on:
- postgresql
I'm curious if anyone here could shed some light on what I am doing wrong.
Thank you.

Answer 1

Your container name is db.postgresql, so your connection string should be db.postgresql or postgresql in the host name.
DATABASES = {
'default': {
'HOST': 'db.postgresql',
'ENGINE': 'django_postgrespool2',
'NAME': os.environ.get('PROJECT_HEARSAY_DB_NAME'),
'USER': os.environ.get('PROJECT_HEARSAY_DB_USER'),
'PASSWORD': os.environ.get('PROJECT_HEARSAY_DB_PASSWORD'),
'PORT': os.environ.get('PROJECT_HEARSAY_DB_PORT'),
}
}
you can verify the connection
docker exec api.django bash -c "nslookup db.postgresql"
You will get the Postgres container IP inside your Django container.