AWS Postgresql RDS instance "does not exist" with docker-compose and Django

Question

My RDS and web container are not connected.

But I did all the database-related settings in Django's settings, and I also set up AWS RDS properly.

What should I do more?

This is DATABASES of settings file of Django.

DATABASES = {
    "default": {
        "ENGINE": "django.db.backends.postgresql",
        "NAME": env("SQL_DATABASE"),
        "USER": env("SQL_USER"),
        "PASSWORD": env("SQL_PASSWORD"),
        "HOST": env("SQL_HOST"),
        "PORT": env("SQL_PORT"),
    }
}

I skipped the docker-compose.yml with nginx-proxy or TLS.

When I tested in local, I made and mounted DB containers on docker-compose, but in prod environments, I didn't make DB containers because I use AWS RDS. Will this be a problem?

Please help me.

(ps.All of PROJECT_NAME replaced the actual project name.)

This is my docker-compose.yml

version: '3.8'

services:

  web:
    build:
      context: .
      dockerfile: prod.Dockerfile
    image: project:web
    command: gunicorn PROJECT_NAME.wsgi:application --bind 0.0.0.0:8000
    env_file:
      - envs/.env.prod
    volumes:
      - static_volume:/home/app/web/static
      - media_volume:/home/app/web/media
    expose:
      - 8000
    entrypoint:
      - sh
      - config/docker/entrypoint.prod.sh

volumes:
  static_volume:
  media_volume:

This is what I've got error from docker

Waiting for postgres...
PostgreSQL started

Traceback (most recent call last):
  File "/usr/local/lib/python3.8/site-packages/django/db/backends/base/base.py", line 219, in ensure_connection
    self.connect()
  File "/usr/local/lib/python3.8/site-packages/django/utils/asyncio.py", line 26, in inner
    return func(*args, **kwargs)
  File "/usr/local/lib/python3.8/site-packages/django/db/backends/base/base.py", line 200, in connect
    self.connection = self.get_new_connection(conn_params)
  File "/usr/local/lib/python3.8/site-packages/django/utils/asyncio.py", line 26, in inner
    return func(*args, **kwargs)
  File "/usr/local/lib/python3.8/site-packages/django/db/backends/postgresql/base.py", line 187, in get_new_connection
    connection = Database.connect(**conn_params)
  File "/usr/local/lib/python3.8/site-packages/psycopg2/__init__.py", line 127, in connect
    conn = _connect(dsn, connection_factory=connection_factory, **kwasync)
psycopg2.OperationalError: FATAL:  database "db-PROJECT_NAME-ec2" does not exist


The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "manage.py", line 22, in <module>
    main()
  File "manage.py", line 18, in main
    execute_from_command_line(sys.argv)
  File "/usr/local/lib/python3.8/site-packages/django/core/management/__init__.py", line 401, in execute_from_command_line
    utility.execute()
  File "/usr/local/lib/python3.8/site-packages/django/core/management/__init__.py", line 395, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/usr/local/lib/python3.8/site-packages/django/core/management/base.py", line 330, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/usr/local/lib/python3.8/site-packages/django/core/management/base.py", line 371, in execute
    output = self.handle(*args, **options)
  File "/usr/local/lib/python3.8/site-packages/django/core/management/base.py", line 85, in wrapped
    res = handle_func(*args, **kwargs)
  File "/usr/local/lib/python3.8/site-packages/django/core/management/commands/migrate.py", line 92, in handle
    executor = MigrationExecutor(connection, self.migration_progress_callback)
  File "/usr/local/lib/python3.8/site-packages/django/db/migrations/executor.py", line 18, in __init__
    self.loader = MigrationLoader(self.connection)
  File "/usr/local/lib/python3.8/site-packages/django/db/migrations/loader.py", line 53, in __init__
    self.build_graph()
  File "/usr/local/lib/python3.8/site-packages/django/db/migrations/loader.py", line 216, in build_graph
    self.applied_migrations = recorder.applied_migrations()
  File "/usr/local/lib/python3.8/site-packages/django/db/migrations/recorder.py", line 77, in applied_migrations
    if self.has_table():
  File "/usr/local/lib/python3.8/site-packages/django/db/migrations/recorder.py", line 55, in has_table
    with self.connection.cursor() as cursor:
  File "/usr/local/lib/python3.8/site-packages/django/utils/asyncio.py", line 26, in inner
    return func(*args, **kwargs)
  File "/usr/local/lib/python3.8/site-packages/django/db/backends/base/base.py", line 259, in cursor
    return self._cursor()
  File "/usr/local/lib/python3.8/site-packages/django/db/backends/base/base.py", line 235, in _cursor
    self.ensure_connection()
  File "/usr/local/lib/python3.8/site-packages/django/utils/asyncio.py", line 26, in inner
    return func(*args, **kwargs)
  File "/usr/local/lib/python3.8/site-packages/django/db/backends/base/base.py", line 219, in ensure_connection
    self.connect()
  File "/usr/local/lib/python3.8/site-packages/django/db/utils.py", line 90, in __exit__
    raise dj_exc_value.with_traceback(traceback) from exc_value
  File "/usr/local/lib/python3.8/site-packages/django/db/backends/base/base.py", line 219, in ensure_connection
    self.connect()
  File "/usr/local/lib/python3.8/site-packages/django/utils/asyncio.py", line 26, in inner
    return func(*args, **kwargs)
  File "/usr/local/lib/python3.8/site-packages/django/db/backends/base/base.py", line 200, in connect
    self.connection = self.get_new_connection(conn_params)
  File "/usr/local/lib/python3.8/site-packages/django/utils/asyncio.py", line 26, in inner
    return func(*args, **kwargs)
  File "/usr/local/lib/python3.8/site-packages/django/db/backends/postgresql/base.py", line 187, in get_new_connection
    connection = Database.connect(**conn_params)
  File "/usr/local/lib/python3.8/site-packages/psycopg2/__init__.py", line 127, in connect
    conn = _connect(dsn, connection_factory=connection_factory, **kwasync)
django.db.utils.OperationalError: FATAL:  database "db-PROJECT_NAME-ec2" does not exist

[2021-09-18 15:09:21 +0000] [1] [INFO] Starting gunicorn 20.0.4
[2021-09-18 15:09:21 +0000] [1] [INFO] Listening at: http://0.0.0.0:8000 (1)
[2021-09-18 15:09:21 +0000] [1] [INFO] Using worker: sync
[2021-09-18 15:09:21 +0000] [12] [INFO] Booting worker with pid: 12

Answer 1

Highly likely the reason is that the AWS RDS DB instance name differs from PostgreSQL DB name.

As per AWS RDS manual

For Databases, choose the name of the new DB instance.

On the RDS console, the details for the new DB instance appear. The DB instance has a status of creating until the DB instance is created and ready for use. When the state changes to available, you can connect to the DB instance. Depending on the DB instance class and storage allocated, it can take several minutes for the new instance to be available.

As per PostgreSQL: Documentation

dbname

Specifies the name of the database to be created. The name must be unique among all PostgreSQL databases in this cluster. The default is to create a database with the same name as the current system user.

Default dbname is postgres

So, you may want to try postgres instead db-PROJECT_NAME-ec2 as a DB name.