Django project with PostgreSQL database in Docker container - directory /var/lib/postgresql/data exists but is not empty

Question

I try to run Django project in Docker container. Until now, everything was working fine. I didn't change anything but I get error shown at the bottom. Any ideas what is wrong? My PostgreSQL settings look in this way:

DATABASES = {
 "default":
 {
  'ENGINE': 'django.db.backends.postgresql',
  "NAME": 'myproject',
  "HOST": "db",
  "PORT": "5432",
 }
 }

DATABASES = {'default': dj_database_url.config(default='postgres://addw...@ec2-31-11-107-127.compute-1.amazonaws.com:5432/qdsfks')}

docker-compose.yml:

version: '3'

services:
  db:
    image: postgres
    environment:
      POSTGRES_USER: myproject
      POSTGRES_PASSWORD: somepass
    volumes:
      - "./local_pgdata:/var/lib/postgresql/data/pgdata"
  django:
    build: .
    command: python3 manage.py runserver 0.0.0.0:8001
    volumes:
      - .:/code
    ports:
      - "8001:8001"
    depends_on:
      - db

Logs:

db_1      | The files belonging to this database system will be owned by user "postgres".
db_1      | This user must also own the server process.
db_1      | 
db_1      | The database cluster will be initialized with locale "en_US.utf8".
db_1      | The default database encoding has accordingly been set to "UTF8".
db_1      | The default text search configuration will be set to "english".
db_1      | 
db_1      | Data page checksums are disabled.
db_1      | 
db_1      | initdb: directory "/var/lib/postgresql/data" exists but is not empty
db_1      | If you want to create a new database system, either remove or empty
db_1      | the directory "/var/lib/postgresql/data" or run initdb
db_1      | with an argument other than "/var/lib/postgresql/data".

According to the error you need to delete the content of "/var/lib/postgresql/data" to create a new database system there. Can you show us the content of your postgres Dockerfile? Why are you mapping "./local_pgdata" to "/var/lib/postgresql/data/pgdata"? — Tobias Ernst, Dec 17 '17 at 01:00
@TobiasErnst how can I do this? I am mapping "./local_pgdata" to "/var/lib/postgresql/data/pgdata" because I can import then files from this directory to my PostgreSQL database in Docker container. — , Dec 17 '17 at 01:01
How are you importing the files? Please share the command with us. — Tobias Ernst, Dec 17 '17 at 01:07
@TobiasErnst `\copy backend_table (field1,field2) FROM '/var/lib/postgresql/data/pgdata/file.csv' CSV HEADER;` — , Dec 17 '17 at 01:17

score 1 · Answer 1 · answered Dec 17 '17 at 01:38

You should only map the host file system to your docker container if you want to use the existing host database. Otherwise I suggest to remove the volume mapping and use a custom Dockerfile to load existing content as described below.

./web/proj/settings.py

Improvement: You also need to set USER and PASSWORD in your settings.py

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.postgresql',
        'NAME': os.environ['POSTGRES_NAME'],
        'USER': os.environ['POSTGRES_USER'],
        'PASSWORD': os.environ['POSTGRES_PASSWORD'],
        'HOST': os.environ['POSTGRES_HOST'],
        'PORT': os.environ['POSTGRES_PORT'],
    }
}

./docker-compose.yml

db:
    restart: always
    build:
      context: ./db
      dockerfile: Dockerfile
    env_file: .env
    expose:
      - "5432"

django:
    restart: always
    build:
      context: ./web
      dockerfile: Dockerfile
    volumes:
      - .:/app
    command: bash -c "cd ./web && ./manage.py makemigrations && ./manage.py migrate && ./manage.py runserver"
    expose:
      - "8000"
    env_file: .env
    depends_on:
      - db
    links:
      - db

./.env

POSTGRES_NAME=db_name
POSTGRES_USER=db_user
POSTGRES_PASSWORD=password
POSTGRES_HOST=db
POSTGRES_PORT=5432

./db/Dockerfile

FROM postgres
RUN mkdir /app
WORKDIR /app
ADD ./ /app/ # add all sources if you need them
ADD ./path-to-your-csv.csv /app/
RUN [import content here]

Here you can find a way how you load custom sql code via initdb: Load custom sql script. You will also find a way to load the content of your csv file.

Moreover you should consider using fixtures instead of loading csv or sql scripts. This will be easier.

Hope this will help solving your problem.

And if I did not have to copy data to the database from the file, what would be the simplest way to fix this problem? — , Dec 17 '17 at 03:40
Just remove the volumes mapping of your db container and start the project by calling: ´docker-compose --project-name projectname up --build´. — Tobias Ernst, Dec 17 '17 at 10:19
Do you mean commenting this `volumes: - "./local_pgdata:/var/lib/postgresql/data/pgdata"`? — , Dec 18 '17 at 22:48
Yes. I would say there is no reason to map the host file system data. — Tobias Ernst, Dec 19 '17 at 01:20

Django project with PostgreSQL database in Docker container - directory /var/lib/postgresql/data exists but is not empty

1 Answers1