Running Django migrations on dockerized project - django

I have a Django project running in multiple Docker containers with help of docker-compose. The source code is attached from directory on my local machine. Here's the compose configuration file:
version: '3'
services:
db:
image: 'postgres'
ports:
- '5432:5432'
core:
build:
context: .
dockerfile: Dockerfile
command: python3 manage.py runserver 0.0.0.0:8000
ports:
- '8001:8000'
volumes:
- .:/code
depends_on:
- db
Although the application starts as it should, I can't run migrations, because every time I do manage.py makemigrations ... I receive:
django.db.utils.OperationalError: could not translate host name "db" to address: nodename nor servname provided, or not known
Obviously I can open bash inside the core container and run makemigrations from there, but then the migration files are created inside the container which is very uncomfortable.
In my project's settings the database is configured as:
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.postgresql',
'NAME': 'postgres',
'USER': 'postgres',
'HOST': 'db',
'PORT': '5432',
}
}
As docker postgres image is accessible at localhost:5432 I tried changing database host in settings to:
'HOST': '0.0.0.0'
But then when firing up the containers with docker-compose up I'm receiving:
...
django.db.utils.OperationalError: could not connect to server:
Connection refused
Is the server running on host "0.0.0.0" and accepting
TCP/IP connections on port 5432?
...
How should I configure database in settings.py so that Django can access it to create migrations?

Your docker-compose configurations are not correct. You forgot to link services
version: '3'
services:
db:
image: 'postgres'
ports:
- '5432:5432'
core:
build:
context: .
dockerfile: Dockerfile
command: python3 manage.py runserver 0.0.0.0:8000
ports:
- '8001:8000'
volumes:
- .:/code
depends_on:
- db
links: # <- here
- db

Related

failed to connect with Postgres container in Django

django.db.utils.OperationalError: connection to server at "db" (172.18.0.2), port 5432 failed: FATAL: the database system is starting up
I have an issue connecting to the Postgres contaner. I was trying in different ways like setting passwords only in the docker-compose file. Still am stuck.
docker-compose.yml
version: '3'
services:
db:
image: postgres:alpine
environment:
- POSTGRES_PASSWORD=password
- POSTGRES_USER=user
- POSTGRES_DB=userdb
volumes:
- django_db:/var/lib/postgresql/data
container_name: db
singup:
build: .
command: python manage.py runserver 0.0.0.0:8000
ports:
- 8000:8000
container_name: singup
depends_on:
- db
volumes:
django_db:
database setting
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.postgresql',
'NAME': 'userdb',
'USER': 'user',
'PASSWORD': 'password',
'HOST': 'db',
}
}
This is a timing issue, even thought you have the below line
singup:
depends_on:
- db
It's just waiting for db container to be up and running, not neccessarily Postgres.
To avoid this, use a tool such as wait-for-it, dockerize, sh-compatible wait-for, or RelayAndContainers template. These are small wrapper scripts which you can include in your application’s image to poll a given host and port until it’s accepting TCP connections.
For example, to use wait-for-it.sh or wait-for to wrap your service’s command:
singup:
depends_on:
- db
command: ["./wait-for-it.sh", "db:5432", "--", "python", "app.py"]
Repo of wait-for-it: https://github.com/vishnubob/wait-for-it

Cannot connect django to postgres running inside docker container

My django app is not dockerized, but I run postgres inside docker container using docker-compose.yml script. After docker-compose up I can connect to db with dbeaver, but not with django app. Every time I'm getting an error:
django.db.utils.OperationalError: could not translate host name "db" to address:
Temporary failure in name resolution
File docker-compose.yml:
version: "3.9"
services:
db:
image: postgres:13
volumes:
- postgres_data:/var/lib/postgresql/data/
environment:
- "POSTGRES_HOST_AUTH_METHOD=trust"
- POSTGRES_USER="postgres"
- POSTGRES_PASSWORD="postgres"
- POSTGRES_DB="postgres"
ports:
- 5432:5432
volumes:
postgres_data
Django project file config/settings.py:
...
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.postgresql_psycopg2',
'NAME': env.str("DB_NAME"),
'USER': env.str("DB_USER"),
'PASSWORD': env.str("DB_PASS"),
'HOST': env.str("DB_HOST"),
'PORT': env.decimal("DB_PORT")
}
}
It was some kind of pipenv error. When I restarted terminal and executed pipenv shell again and then python manage.py runserver everything worked just fine

could not translate host name to "db" to address: Unknown host

I'm attempting to follow the guide provided by: https://docs.docker.com/compose/django/
Whenever I attempt to makemigrations, it gives me the Unknown host error given in the title. I'm trying to use PostgreSQL with Django and Wagtail as its CMS
My docker-compose.yml looks like:
version: "3.9"
services:
db:
image: postgres
environment:
- POSTGRES_DB=postgres
- POSTGRES_USER=postgres
- POSTGRES_PASSWORD=postgres
web:
build: .
command: python manage.py runserver 0.0.0.0:8000
volumes:
- .:/code
ports:
- "8000:8000"
depends_on:
- db
and my settings in the settings.py file look like:
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.postgresql',
'NAME': 'postgres',
'USER': 'postgres',
'PASSWORD': 'postgres',
'HOST': 'db',
'PORT': 5432,
}
}
Am I missing anything?
Your code can run in two different environments, and hard-coding the connection information might not be correct.
You mention in a comment that you're running something like:
docker-compose up -d db
python manage.py makemigrations
In this environment python is running outside of Docker. If you add ports: [5432:5432] to the database configuration in the docker-compose.yml file, the database will be accessible via (probably) localhost. On the other hand, when you run docker-compose up, the application runs inside Docker and the database will be reachable at db.
You can use an environment variable to configure this. I find it useful to give these variables default values that would be useful for a developer, and set them to different values in my deployment setup (the docker-compose.yml).
DATABASES = {
'default': {
...
'HOST': os.getenv('DB_HOST', 'localhost'),
...
}
}
version: "3.9"
services:
db:
ports:
- '5432:5432' # makes this accessible from your development environment
...
web:
environment:
- DB_HOST=db
...

Struggling with connection between Django and Postgres within Docker containers

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.
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.

Django docker - could not translate host name "db" to address: nodename nor servname provided, or not known

I'm relatively new to Django and Docker and am following a tutorial to build a mini application. However, I'm getting stuck with the following error:
django.db.utils.OperationalError: could not translate host name "db" to address: nodename nor servname provided, or not known
My docker-compose file looks as follows:
version: '3'
services:
db:
image: 'postgres'
ports:
- '5432'
core:
build:
context: .
dockerfile: Dockerfile
command: python3 manage.py runserver 0.0.0.0:8000
ports:
- '8000:8000'
volumes:
- .:/code
depends_on:
- db
links:
- db:db
My settings.py file contains the database:
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.postgresql',
'NAME': 'postgres',
'USER': 'postgres',
'HOST': 'db',
'PORT': 5432,
}
}
I've seen the post here and here however both have not fixed the issue.
Would appreciate some guidance. Thanks.
So you are trying to reach the db which is running in one container from another container? If yes - the following could potentially help, at least it helped me when I had similar issues.
Try to define networks config in addition to links in your compose file, create a network with some name and define it in both services. Like described here, as the docks on links config recommend to do that.
Something like this for your case:
version: '3'
services:
db:
image: 'postgres'
ports:
- '5432'
networks:
some_network:
core:
build:
context: .
dockerfile: Dockerfile
command: python3 manage.py runserver 0.0.0.0:8000
ports:
- '8000:8000'
volumes:
- .:/code
depends_on:
- db
links:
- db:db
networks:
some_network:
networks:
some_network:
It helped me to resolve the host name to connect to the db.
I had to use docker-compose up to make sure my db container was running.
Instead of redefining the networks, use
docker-compose down -v
to stop all containers and remove all cached data.
Then
docker-compose up
to restart from scratch.
I've been searching for several days for the solution to this issue. Here's what I did:
1 - I copied the postgresql.conf.sample file from my postgres container to my project folder
you must get in to cd usr/share/postgresql
with docker exec -it yourcontainer bash
2 - I changed its name to postgresql.conf
3 - I modified these variables in postgresql.conf
listen_addresses = '*'
port = 5432
max_connections = 100
superuser_reserved_connections = 3
unix_socket_directories = '/tmp'
4 - I added it to my Dockerfile
COPY postgresql.conf /tmp/postgresql.conf
5 - settings.py
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.postgresql',
'NAME': 'test',
'USER': 'testing',
'PASSWORD': 'tests',
'HOST': 'localhost',
'PORT': 5432,
}
}
6 - I did docker-compose up -build again
I came across this issue recently, i solved it by adding postgres environment variables to db in my docker-compose.yml file like so
version: '3'
services:
db:
image: 'postgres'
ports:
- '5432'
environment:
- POSTGRES_DB=booksdb
- POSTGRES_USER=postgres
- POSTGRES_PASSWORD=postgres
core:
build:
context: .
dockerfile: Dockerfile
command: python3 manage.py runserver 0.0.0.0:8000
ports:
- '8000:8000'
volumes:
- .:/code
depends_on:
- db
links:
- db:db
In my specific case, I had postgres without any version, so postgres image gets updated and the db (postgres) container won't get up
The following configuration works for me from official documentation
version: "3.8"
services:
db:
image: postgres
environment:
- POSTGRES_DB=postgres
- POSTGRES_USER=postgres
- POSTGRES_PASSWORD=postgres
web:
build: .
command: python /code/manage.py runserver 0.0.0.0:8000
volumes:
- .:/code
ports:
- "8000:8000"
depends_on:
- db
then run those commands:
docker-compose up -d --build
docker-compose logs
docker exec -it "container_name" python3 manage.py migrate
This works for me. Make sure of the path to the manage.py file is correct.