django quickstart fail "Database is uninitialized and superuser password is not specified."

[snoop2head]

Greetings, I am new to docker.

Situation

• I am following Quickstart guide of django which is stated in compose/django.md
• I've been following the walkthrough exactly the same, yet it seems like the guide has omitted postgres initialization.
• Mac OS Cattalina 10.15.3 / pipenv virtual environment / python 3.8

Problem

docker-compose up

fails with

db_1   | Error: Database is uninitialized and superuser password is not specified.
db_1   |        You must specify POSTGRES_PASSWORD to a non-empty value for the
db_1   |        superuser. For example, "-e POSTGRES_PASSWORD=password" on "docker run".
db_1   | 
db_1   |        You may also use "POSTGRES_HOST_AUTH_METHOD=trust" to allow all
db_1   |        connections without a password. This is *not* recommended.
db_1   | 
db_1   |        See PostgreSQL documentation about "trust":
db_1   |        https://www.postgresql.org/docs/current/auth-trust.html
docker-docs-example_db_1 exited with code 1
web_1  | Watching for file changes with StatReloader
web_1  | Performing system checks...
web_1  | 
web_1  | System check identified no issues (0 silenced).
web_1  | Exception in thread django-main-thread:
web_1  | Traceback (most recent call last):
web_1  |   File "/usr/local/lib/python3.8/site-packages/django/db/backends/base/base.py", line 217, in ensure_connection
web_1  |     self.connect()
web_1  |   File "/usr/local/lib/python3.8/site-packages/django/db/backends/base/base.py", line 195, in connect
web_1  |     self.connection = self.get_new_connection(conn_params)
web_1  |   File "/usr/local/lib/python3.8/site-packages/django/db/backends/postgresql/base.py", line 178, in get_new_connection
web_1  |     connection = Database.connect(**conn_params)
web_1  |   File "/usr/local/lib/python3.8/site-packages/psycopg2/__init__.py", line 126, in connect
web_1  |     conn = _connect(dsn, connection_factory=connection_factory, **kwasync)
web_1  | psycopg2.OperationalError: could not translate host name "db" to address: Name or service not known
web_1  | 
web_1  | 
web_1  | The above exception was the direct cause of the following exception:
web_1  | 
web_1  | Traceback (most recent call last):
web_1  |   File "/usr/local/lib/python3.8/threading.py", line 932, in _bootstrap_inner
web_1  |     self.run()
web_1  |   File "/usr/local/lib/python3.8/threading.py", line 870, in run
web_1  |     self._target(*self._args, **self._kwargs)
web_1  |   File "/usr/local/lib/python3.8/site-packages/django/utils/autoreload.py", line 54, in wrapper
web_1  |     fn(*args, **kwargs)
web_1  |   File "/usr/local/lib/python3.8/site-packages/django/core/management/commands/runserver.py", line 120, in inner_run
web_1  |     self.check_migrations()
web_1  |   File "/usr/local/lib/python3.8/site-packages/django/core/management/base.py", line 453, in check_migrations
web_1  |     executor = MigrationExecutor(connections[DEFAULT_DB_ALIAS])
web_1  |   File "/usr/local/lib/python3.8/site-packages/django/db/migrations/executor.py", line 18, in __init__
web_1  |     self.loader = MigrationLoader(self.connection)
web_1  |   File "/usr/local/lib/python3.8/site-packages/django/db/migrations/loader.py", line 49, in __init__
web_1  |     self.build_graph()
web_1  |   File "/usr/local/lib/python3.8/site-packages/django/db/migrations/loader.py", line 212, in build_graph
web_1  |     self.applied_migrations = recorder.applied_migrations()
web_1  |   File "/usr/local/lib/python3.8/site-packages/django/db/migrations/recorder.py", line 73, in applied_migrations
web_1  |     if self.has_table():
web_1  |   File "/usr/local/lib/python3.8/site-packages/django/db/migrations/recorder.py", line 56, in has_table
web_1  |     return self.Migration._meta.db_table in self.connection.introspection.table_names(self.connection.cursor())
web_1  |   File "/usr/local/lib/python3.8/site-packages/django/db/backends/base/base.py", line 256, in cursor
web_1  |     return self._cursor()
web_1  |   File "/usr/local/lib/python3.8/site-packages/django/db/backends/base/base.py", line 233, in _cursor
web_1  |     self.ensure_connection()
web_1  |   File "/usr/local/lib/python3.8/site-packages/django/db/backends/base/base.py", line 217, in ensure_connection
web_1  |     self.connect()
web_1  |   File "/usr/local/lib/python3.8/site-packages/django/db/utils.py", line 89, in __exit__
web_1  |     raise dj_exc_value.with_traceback(traceback) from exc_value
web_1  |   File "/usr/local/lib/python3.8/site-packages/django/db/backends/base/base.py", line 217, in ensure_connection
web_1  |     self.connect()
web_1  |   File "/usr/local/lib/python3.8/site-packages/django/db/backends/base/base.py", line 195, in connect
web_1  |     self.connection = self.get_new_connection(conn_params)
web_1  |   File "/usr/local/lib/python3.8/site-packages/django/db/backends/postgresql/base.py", line 178, in get_new_connection
web_1  |     connection = Database.connect(**conn_params)
web_1  |   File "/usr/local/lib/python3.8/site-packages/psycopg2/__init__.py", line 126, in connect
web_1  |     conn = _connect(dsn, connection_factory=connection_factory, **kwasync)
web_1  | django.db.utils.OperationalError: could not translate host name "db" to address: Name or service not known
web_1  | 

[VTRyo]

I had a similar problem.
I'm sure it will be fixed in the following way.

# docker-compose.yml

 version: '3'

 services:
   db:
     image: postgres
     ports:                       #add line.
       - '5432'
     environment:           # add line.
       - 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

# setting.py

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.postgresql',
        'NAME': 'postgres',
        'USER': 'postgres',
        'PASSWORD': 'postgres',  #add line.
        'HOST': 'db',
        'PORT': 5432,
    }
}

Result

docker-compose up
Recreating compose-test_db_1 ... done
Recreating compose-test_web_1 ... done
Attaching to compose-test_db_1, compose-test_web_1
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".

.   .   .

web_1  | April 12, 2020 - 09:20:06
web_1  | Django version 2.2.12, using settings 'composeexample.settings'
web_1  | Starting development server at http://0.0.0.0:8000/
web_1  | Quit the server with CONTROL-C.

[snoop2head]

Thanks for your help! I am closing down the issue

[docker-robott]

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