Django doesn't connect to postgresql database using docker – Debian

I am pretty new to Django and very new to docker. This is my first time using docker. I am trying to connect my django app in one docker container to postgreSQL database in another docker container. I was following a youtube tutorial when I encountered this problem. I wasn’t following the tutorial exactly as shown in the video though. I am using Docker on Windows 10.

My ‘docker-compose.yml’ file:

    version: '3.8'
    
    services:
      db:
        container_name: db_ramrobazar
        image: postgres
        restart: always
        environment:
          - POSTGRES_DB=postgres
          - POSTGRES_USER=postgres
          - POSTGRES_PASSWORD=postgres
        ports:
          - '5432:5432'
        volumes:
          - postgres_data:/var/lib/postgresql/data/
        # env_file: .env
        networks:
          - djangonetwork
    
      web:
        container_name: web_ramrobazar
        build:
          context: .
        depends_on:
          - db
        command: >
          sh -c "python manage.py makemigrations && 
                 python manage.py migrate &&
                 python manage.py runserver 0.0.0.0:8000"
        ports:
          - "8000:8000"
        env_file: .env
        links:
          - db:db
        networks:
          - djangonetwork
        volumes: 
          - .:/usr/src/app
    
    volumes:
      postgres_data:
    
    networks:
      djangonetwork:
        driver: bridge

My Dockerfile file:

    FROM python:3.8-slim-buster
    
    
    # setting work directory
    WORKDIR /usr/src/app
    
    
    # env variables
    ENV PYTHONUNBUFFERED 1
    ENV PYTHONDONTWEITEBYTECODE 1
    
    # install psycopg dependencies
    RUN apt-get update && apt-get install -y 
        build-essential 
        libpq-dev 
        && rm -rf /var/lib/apt/lists/*
    
    
    # install dependencies
    RUN pip install --upgrade pip
    COPY requirements.txt .
    RUN pip install -r requirements.txt
    
    
    COPY . .

My .env file:

    DEBUG=True
    SECRET_KEY=mysecretkey
    ALLOWED_HOSTS=*
    DATABASE_URL=postgres://postgres:postgres@localhost:5432/postgres
    
    # postgres
    POSTGRES_USER=postgres
    POSTGRES_PASSWORD=postgres
    POSTGRES_DB=postgres
    ENGINE=django.db.backends.postgresql_psycopg2
    HOST=localhost
    PORT=5432

My settings.py file:

    # DATABASES = {
    #     'default': {
    #         'ENGINE': 'django.db.backends.sqlite3',
    #         'NAME': BASE_DIR / 'db.sqlite3',
    #     }
    # }
    
     DATABASES = {
         'default': {
             'ENGINE': config('ENGINE'),
             'NAME': config('POSTGRES_DB'),
             'USER': config('POSTGRES_USER'),
             'PASSWORD': 'postgres',
             'HOST': config('HOST'),
             'PORT': config('PORT'),
         }
     }
    
    # DATABASE_URL = config('DATABASE_URL').replace("'", "")
    # DATABASES = {
    #    'default': dj_database_url.parse(DATABASE_URL, conn_max_age=600)
    # }

When I delete all the migration files (like 0001_initial.py) and execute docker-compose up --build, I get the following:

    (venv) C:UsersashutDesktopramrobazar>docker-compose up --build
    [+] Building 7.8s (12/12) FINISHED
     => [internal] load build definition from Dockerfile                                                               0.0s
     => => transferring dockerfile: 32B                                                                                0.0s
     => [internal] load .dockerignore                                                                                  0.0s
     => => transferring context: 2B                                                                                    0.0s
     => [internal] load metadata for docker.io/library/python:3.8-slim-buster                                          3.0s
     => [1/7] FROM docker.io/library/python:3.8-slim-buster@sha256:234da35e659c02a785a1e9d2002e386bea80f293572f90ad0c  0.0s
     => [internal] load build context                                                                                  1.3s
     => => transferring context: 1.01MB                                                                                1.2s
     => CACHED [2/7] WORKDIR /usr/src/app                                                                              0.0s
     => CACHED [3/7] RUN apt-get update && apt-get install -y     build-essential     libpq-dev     && rm -rf /var/li  0.0s
     => CACHED [4/7] RUN pip install --upgrade pip                                                                     0.0s
     => CACHED [5/7] COPY requirements.txt .                                                                           0.0s
     => CACHED [6/7] RUN pip install -r requirements.txt                                                               0.0s
     => [7/7] COPY . .                                                                                                 2.0s
     => exporting to image                                                                                             1.5s
     => => exporting layers                                                                                            1.4s
     => => writing image sha256:c1c5807098513138a5cf51f8c690c8ba8636f078ab32d6e9bcdf9930c670995a                       0.0s
     => => naming to docker.io/library/ramrobazar_web                                                                  0.0s
    
    Use 'docker scan' to run Snyk tests against images to find vulnerabilities and learn how to fix them
    [+] Running 2/2
     - Container db_ramrobazar   Created                                                                               0.0s
     - Container web_ramrobazar  Recreated                                                                             0.1s
    Attaching to db_ramrobazar, web_ramrobazar
    db_ramrobazar   |
    db_ramrobazar   | PostgreSQL Database directory appears to contain a database; Skipping initialization
    db_ramrobazar   |
    db_ramrobazar   | 2022-05-20 07:11:29.657 UTC [1] LOG:  starting PostgreSQL 14.3 (Debian 14.3-1.pgdg110+1) on x86_64-pc-linux-gnu, compiled by gcc (Debian 10.2.1-6) 10.2.1 20210110, 64-bit
    db_ramrobazar   | 2022-05-20 07:11:29.657 UTC [1] LOG:  listening on IPv4 address "0.0.0.0", port 5432
    db_ramrobazar   | 2022-05-20 07:11:29.657 UTC [1] LOG:  listening on IPv6 address "::", port 5432
    db_ramrobazar   | 2022-05-20 07:11:29.670 UTC [1] LOG:  listening on Unix socket "/var/run/postgresql/.s.PGSQL.5432"
    db_ramrobazar   | 2022-05-20 07:11:29.680 UTC [26] LOG:  database system was shut down at 2022-05-20 06:52:31 UTC
    db_ramrobazar   | 2022-05-20 07:11:29.688 UTC [1] LOG:  database system is ready to accept connections
    web_ramrobazar  | /usr/local/lib/python3.8/site-packages/django/core/management/commands/makemigrations.py:121: RuntimeWarning: Got an error checking a consistent migration history performed for database connection 'default': could not connect to server: Connection refused
    web_ramrobazar  |       Is the server running on host "localhost" (127.0.0.1) and accepting
    web_ramrobazar  |       TCP/IP connections on port 5432?
    web_ramrobazar  | could not connect to server: Cannot assign requested address
    web_ramrobazar  |       Is the server running on host "localhost" (::1) and accepting
    web_ramrobazar  |       TCP/IP connections on port 5432?
    web_ramrobazar  |
    web_ramrobazar  |   warnings.warn(
    web_ramrobazar  | Migrations for 'account':
    web_ramrobazar  |   ramrobazar/account/migrations/0001_initial.py
    web_ramrobazar  |     - Create model User
    web_ramrobazar  |     - Create model UserProfile
    web_ramrobazar  | Migrations for 'inventory':
    web_ramrobazar  |   ramrobazar/inventory/migrations/0001_initial.py
    web_ramrobazar  |     - Create model Brand
    web_ramrobazar  |     - Create model Category
    web_ramrobazar  |     - Create model Product
    web_ramrobazar  |     - Create model ProductAttribute
    web_ramrobazar  |     - Create model ProductAttributeValue
    web_ramrobazar  |     - Create model ProductInventory
    web_ramrobazar  |     - Create model ProductType
    web_ramrobazar  |     - Create model Stock
    web_ramrobazar  |     - Create model SoldStatus
    web_ramrobazar  |     - Add field product_type to productinventory
    web_ramrobazar  |     - Create model Media
    web_ramrobazar  | Traceback (most recent call last):
    web_ramrobazar  |   File "/usr/local/lib/python3.8/site-packages/django/db/backends/base/base.py", line 244, in ensure_connection
    web_ramrobazar  |     self.connect()
    web_ramrobazar  |   File "/usr/local/lib/python3.8/site-packages/django/utils/asyncio.py", line 26, in inner
    web_ramrobazar  |     return func(*args, **kwargs)
    web_ramrobazar  |   File "/usr/local/lib/python3.8/site-packages/django/db/backends/base/base.py", line 225, in connect
    web_ramrobazar  |     self.connection = self.get_new_connection(conn_params)
    web_ramrobazar  |   File "/usr/local/lib/python3.8/site-packages/django/utils/asyncio.py", line 26, in inner
    web_ramrobazar  |     return func(*args, **kwargs)
    web_ramrobazar  |   File "/usr/local/lib/python3.8/site-packages/django/db/backends/postgresql/base.py", line 203, in get_new_connection
    web_ramrobazar  |     connection = Database.connect(**conn_params)
    web_ramrobazar  |   File "/usr/local/lib/python3.8/site-packages/psycopg2/__init__.py", line 122, in connect
    web_ramrobazar  |     conn = _connect(dsn, connection_factory=connection_factory, **kwasync)
    web_ramrobazar  | psycopg2.OperationalError: could not connect to server: Connection refused
    web_ramrobazar  |       Is the server running on host "localhost" (127.0.0.1) and accepting
    web_ramrobazar  |       TCP/IP connections on port 5432?
    web_ramrobazar  | could not connect to server: Cannot assign requested address
    web_ramrobazar  |       Is the server running on host "localhost" (::1) and accepting
    web_ramrobazar  |       TCP/IP connections on port 5432?
    web_ramrobazar  |
    web_ramrobazar  |
    web_ramrobazar  | The above exception was the direct cause of the following exception:
    web_ramrobazar  |
    web_ramrobazar  | Traceback (most recent call last):
    web_ramrobazar  |   File "manage.py", line 22, in <module>
    web_ramrobazar  |     main()
    web_ramrobazar  |   File "manage.py", line 18, in main
    web_ramrobazar  |     execute_from_command_line(sys.argv)
    web_ramrobazar  |   File "/usr/local/lib/python3.8/site-packages/django/core/management/__init__.py", line 446, in execute_from_command_line
    web_ramrobazar  |     utility.execute()
    web_ramrobazar  |   File "/usr/local/lib/python3.8/site-packages/django/core/management/__init__.py", line 440, in execute
    web_ramrobazar  |     self.fetch_command(subcommand).run_from_argv(self.argv)
    web_ramrobazar  |   File "/usr/local/lib/python3.8/site-packages/django/core/management/base.py", line 414, in run_from_argv
    web_ramrobazar  |     self.execute(*args, **cmd_options)
    web_ramrobazar  |   File "/usr/local/lib/python3.8/site-packages/django/core/management/base.py", line 460, in execute
    web_ramrobazar  |     output = self.handle(*args, **options)
    web_ramrobazar  |   File "/usr/local/lib/python3.8/site-packages/django/core/management/base.py", line 98, in wrapped
    web_ramrobazar  |     res = handle_func(*args, **kwargs)
    web_ramrobazar  |   File "/usr/local/lib/python3.8/site-packages/django/core/management/commands/migrate.py", line 91, in handle
    web_ramrobazar  |     self.check(databases=[database])
    web_ramrobazar  |   File "/usr/local/lib/python3.8/site-packages/django/core/management/base.py", line 487, in check
    web_ramrobazar  |     all_issues = checks.run_checks(
    web_ramrobazar  |   File "/usr/local/lib/python3.8/site-packages/django/core/checks/registry.py", line 88, in run_checks
    web_ramrobazar  |     new_errors = check(app_configs=app_configs, databases=databases)
    web_ramrobazar  |   File "/usr/local/lib/python3.8/site-packages/django/core/checks/model_checks.py", line 36, in check_all_models
    web_ramrobazar  |     errors.extend(model.check(**kwargs))
    web_ramrobazar  |   File "/usr/local/lib/python3.8/site-packages/django/db/models/base.py", line 1461, in check
    web_ramrobazar  |     *cls._check_indexes(databases),
    web_ramrobazar  |   File "/usr/local/lib/python3.8/site-packages/django/db/models/base.py", line 1864, in _check_indexes
    web_ramrobazar  |     connection.features.supports_covering_indexes
    web_ramrobazar  |   File "/usr/local/lib/python3.8/site-packages/django/utils/functional.py", line 49, in __get__
    web_ramrobazar  |     res = instance.__dict__[self.name] = self.func(instance)
    web_ramrobazar  |   File "/usr/local/lib/python3.8/site-packages/django/db/backends/postgresql/features.py", line 84, in is_postgresql_11
    web_ramrobazar  |     return self.connection.pg_version >= 110000
    web_ramrobazar  |   File "/usr/local/lib/python3.8/site-packages/django/utils/functional.py", line 49, in __get__
    web_ramrobazar  |     res = instance.__dict__[self.name] = self.func(instance)
    web_ramrobazar  |   File "/usr/local/lib/python3.8/site-packages/django/db/backends/postgresql/base.py", line 354, in pg_version
    web_ramrobazar  |     with self.temporary_connection():
    web_ramrobazar  |   File "/usr/local/lib/python3.8/contextlib.py", line 113, in __enter__
    web_ramrobazar  |     return next(self.gen)
    web_ramrobazar  |   File "/usr/local/lib/python3.8/site-packages/django/db/backends/base/base.py", line 639, in temporary_connection
    web_ramrobazar  |     with self.cursor() as cursor:
    web_ramrobazar  |   File "/usr/local/lib/python3.8/site-packages/django/utils/asyncio.py", line 26, in inner
    web_ramrobazar  |     return func(*args, **kwargs)
    web_ramrobazar  |   File "/usr/local/lib/python3.8/site-packages/django/db/backends/base/base.py", line 284, in cursor
    web_ramrobazar  |     return self._cursor()
    web_ramrobazar  |   File "/usr/local/lib/python3.8/site-packages/django/db/backends/base/base.py", line 260, in _cursor
    web_ramrobazar  |     self.ensure_connection()
    web_ramrobazar  |   File "/usr/local/lib/python3.8/site-packages/django/utils/asyncio.py", line 26, in inner
    web_ramrobazar  |     return func(*args, **kwargs)
    web_ramrobazar  |   File "/usr/local/lib/python3.8/site-packages/django/db/backends/base/base.py", line 244, in ensure_connection
    web_ramrobazar  |     self.connect()
    web_ramrobazar  |   File "/usr/local/lib/python3.8/site-packages/django/db/utils.py", line 91, in __exit__
    web_ramrobazar  |     raise dj_exc_value.with_traceback(traceback) from exc_value
    web_ramrobazar  |   File "/usr/local/lib/python3.8/site-packages/django/db/backends/base/base.py", line 244, in ensure_connection
    web_ramrobazar  |     self.connect()
    web_ramrobazar  |   File "/usr/local/lib/python3.8/site-packages/django/utils/asyncio.py", line 26, in inner
    web_ramrobazar  |     return func(*args, **kwargs)
    web_ramrobazar  |   File "/usr/local/lib/python3.8/site-packages/django/db/backends/base/base.py", line 225, in connect
    web_ramrobazar  |     self.connection = self.get_new_connection(conn_params)
    web_ramrobazar  |   File "/usr/local/lib/python3.8/site-packages/django/utils/asyncio.py", line 26, in inner
    web_ramrobazar  |     return func(*args, **kwargs)
    web_ramrobazar  |   File "/usr/local/lib/python3.8/site-packages/django/db/backends/postgresql/base.py", line 203, in get_new_connection
    web_ramrobazar  |     connection = Database.connect(**conn_params)
    web_ramrobazar  |   File "/usr/local/lib/python3.8/site-packages/psycopg2/__init__.py", line 122, in connect
    web_ramrobazar  |     conn = _connect(dsn, connection_factory=connection_factory, **kwasync)
    web_ramrobazar  | django.db.utils.OperationalError: could not connect to server: Connection refused
    web_ramrobazar  |       Is the server running on host "localhost" (127.0.0.1) and accepting
    web_ramrobazar  |       TCP/IP connections on port 5432?
    web_ramrobazar  | could not connect to server: Cannot assign requested address
    web_ramrobazar  |       Is the server running on host "localhost" (::1) and accepting
    web_ramrobazar  |       TCP/IP connections on port 5432?
    web_ramrobazar  |
    web_ramrobazar exited with code 1

When only the database ‘db_ramrobazar’ is running in docker and I try to execute python manage.py makemigrations, I get the following:

    (venv) C:UsersashutDesktopramrobazar>python manage.py makemigrations
    C:UsersashutDesktopramrobazarvenvlibsite-packagesdjangocoremanagementcommandsmakemigrations.py:121: 
    RuntimeWarning: Got an error checking a consistent migration history performed for database connection 'default': connection to server at "localhost" (::1), port 5432 failed: FATAL:  password authentication failed for user "postgres"
    
      warnings.warn(
    Migrations for 'account':
      ramrobazaraccountmigrations001_initial.py
        - Create model User
        - Create model UserProfile
    Migrations for 'inventory':
      ramrobazarinventorymigrations001_initial.py
        - Create model Brand
        - Create model Category
        - Create model Product
        - Create model ProductAttribute
        - Create model ProductAttributeValue
        - Create model ProductInventory
        - Create model ProductType
        - Create model Stock
        - Create model SoldStatus
        - Add field product_type to productinventory
        - Create model Media

After getting the above result from makemigrations, when I execute python manage.py migrate, I get the following:

    (venv) C:UsersashutDesktopramrobazar>python manage.py migrate
    Traceback (most recent call last):
      File "C:UsersashutDesktopramrobazarvenvlibsite-packagesdjangodbbackendsbasebase.py", line 244, in ensure_connection
        self.connect()
      File "C:UsersashutDesktopramrobazarvenvlibsite-packagesdjangoutilsasyncio.py", line 26, in inner
        return func(*args, **kwargs)
      File "C:UsersashutDesktopramrobazarvenvlibsite-packagesdjangodbbackendsbasebase.py", line 225, in connect
        self.connection = self.get_new_connection(conn_params)
      File "C:UsersashutDesktopramrobazarvenvlibsite-packagesdjangoutilsasyncio.py", line 26, in inner
        return func(*args, **kwargs)
      File "C:UsersashutDesktopramrobazarvenvlibsite-packagesdjangodbbackendspostgresqlbase.py", line 203, in get_new_connection
        connection = Database.connect(**conn_params)
      File "C:UsersashutDesktopramrobazarvenvlibsite-packagespsycopg2__init__.py", line 122, in connect
        conn = _connect(dsn, connection_factory=connection_factory, **kwasync)
    psycopg2.OperationalError: connection to server at "localhost" (::1), port 5432 failed: FATAL:  password authentication failed for user "postgres"
    
    
    The above exception was the direct cause of the following exception:
    
    Traceback (most recent call last):
      File "C:UsersashutDesktopramrobazarmanage.py", line 22, in <module>
        main()
      File "C:UsersashutDesktopramrobazarmanage.py", line 18, in main
        execute_from_command_line(sys.argv)
      File "C:UsersashutDesktopramrobazarvenvlibsite-packagesdjangocoremanagement__init__.py", line 446, in execute_from_command_line
        utility.execute()
      File "C:UsersashutDesktopramrobazarvenvlibsite-packagesdjangocoremanagement__init__.py", line 440, in execute
        self.fetch_command(subcommand).run_from_argv(self.argv)
      File "C:UsersashutDesktopramrobazarvenvlibsite-packagesdjangocoremanagementbase.py", line 414, in run_from_argv
        self.execute(*args, **cmd_options)
      File "C:UsersashutDesktopramrobazarvenvlibsite-packagesdjangocoremanagementbase.py", line 460, in execute
        output = self.handle(*args, **options)
      File "C:UsersashutDesktopramrobazarvenvlibsite-packagesdjangocoremanagementbase.py", line 98, in wrapped
        res = handle_func(*args, **kwargs)
      File "C:UsersashutDesktopramrobazarvenvlibsite-packagesdjangocoremanagementcommandsmigrate.py", line 91, in handle
        self.check(databases=[database])
      File "C:UsersashutDesktopramrobazarvenvlibsite-packagesdjangocoremanagementbase.py", line 487, in check
        all_issues = checks.run_checks(
      File "C:UsersashutDesktopramrobazarvenvlibsite-packagesdjangocorechecksregistry.py", line 88, in run_checks
        new_errors = check(app_configs=app_configs, databases=databases)
      File "C:UsersashutDesktopramrobazarvenvlibsite-packagesdjangocorechecksmodel_checks.py", line 36, in check_all_models
        errors.extend(model.check(**kwargs))
      File "C:UsersashutDesktopramrobazarvenvlibsite-packagesdjangodbmodelsbase.py", line 1461, in check
        *cls._check_indexes(databases),
      File "C:UsersashutDesktopramrobazarvenvlibsite-packagesdjangodbmodelsbase.py", line 1864, in _check_indexes
        connection.features.supports_covering_indexes
      File "C:UsersashutDesktopramrobazarvenvlibsite-packagesdjangoutilsfunctional.py", line 49, in __get__
        res = instance.__dict__[self.name] = self.func(instance)
      File "C:UsersashutDesktopramrobazarvenvlibsite-packagesdjangodbbackendspostgresqlfeatures.py", line 84, in is_postgresql_11
        return self.connection.pg_version >= 110000
      File "C:UsersashutDesktopramrobazarvenvlibsite-packagesdjangoutilsfunctional.py", line 49, in __get__
        res = instance.__dict__[self.name] = self.func(instance)
      File "C:UsersashutDesktopramrobazarvenvlibsite-packagesdjangodbbackendspostgresqlbase.py", line 354, in pg_version
        with self.temporary_connection():
      File "C:Program FilesPython310libcontextlib.py", line 135, in __enter__
        return next(self.gen)
      File "C:UsersashutDesktopramrobazarvenvlibsite-packagesdjangodbbackendsbasebase.py", line 639, in temporary_connection
        with self.cursor() as cursor:
      File "C:UsersashutDesktopramrobazarvenvlibsite-packagesdjangoutilsasyncio.py", line 26, in inner
        return func(*args, **kwargs)
      File "C:UsersashutDesktopramrobazarvenvlibsite-packagesdjangodbbackendsbasebase.py", line 284, in cursor
        return self._cursor()
      File "C:UsersashutDesktopramrobazarvenvlibsite-packagesdjangodbbackendsbasebase.py", line 260, in _cursor
        self.ensure_connection()
      File "C:UsersashutDesktopramrobazarvenvlibsite-packagesdjangoutilsasyncio.py", line 26, in inner
        return func(*args, **kwargs)
      File "C:UsersashutDesktopramrobazarvenvlibsite-packagesdjangodbbackendsbasebase.py", line 243, in ensure_connection
        with self.wrap_database_errors:
      File "C:UsersashutDesktopramrobazarvenvlibsite-packagesdjangodbutils.py", line 91, in __exit__
        raise dj_exc_value.with_traceback(traceback) from exc_value
      File "C:UsersashutDesktopramrobazarvenvlibsite-packagesdjangodbbackendsbasebase.py", line 244, in ensure_connection
        self.connect()
      File "C:UsersashutDesktopramrobazarvenvlibsite-packagesdjangoutilsasyncio.py", line 26, in inner
        return func(*args, **kwargs)
      File "C:UsersashutDesktopramrobazarvenvlibsite-packagesdjangodbbackendsbasebase.py", line 225, in connect
        self.connection = self.get_new_connection(conn_params)
      File "C:UsersashutDesktopramrobazarvenvlibsite-packagesdjangoutilsasyncio.py", line 26, in inner
        return func(*args, **kwargs)
      File "C:UsersashutDesktopramrobazarvenvlibsite-packagesdjangodbbackendspostgresqlbase.py", line 203, in get_new_connection
        connection = Database.connect(**conn_params)
      File "C:UsersashutDesktopramrobazarvenvlibsite-packagespsycopg2__init__.py", line 122, in connect
        conn = _connect(dsn, connection_factory=connection_factory, **kwasync)
    django.db.utils.OperationalError: connection to server at "localhost" (::1), port 5432 failed: FATAL:  password authentication failed for user "postgres"

I have tried changing the password of the ‘postgres’ user using the CLI like below but it doesn’t do anything.

    # psql -U postgres -d postgres
    psql (14.3 (Debian 14.3-1.pgdg110+1))
    Type "help" for help.
    
    postgres=# ALTER USER postgres WITH PASSWORD 'postgres';
    ALTER ROLE
    postgres=#

Please let me know if anything else is needed.

Edit

I replaced localhost with db. But then I got the error mentioned in this link. I tried the solution in one of the comments which said that managements commands like python manage.py makemigrations should be run from the web container using the command docker-compose run --rm web python manage.py makemigrations. But when I do that I get the following.

    (venv) C:UsersashutDesktopramrobazar>docker-compose run --rm web python manage.py makemigrations
    [+] Running 1/0
     - Container db_ramrobazar  Created                                                                                0.0s
    [+] Running 2/2
     - Container db_ramrobazar   Started                                                                               3.2s
     - Container web_ramrobazar  Started                                                                               1.4s
    /usr/local/lib/python3.8/site-packages/django/core/management/commands/makemigrations.py:121: RuntimeWarning: Got an error checking a consistent migration history performed for database connection 'default': 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?
    
      warnings.warn(
    No changes detected

This is the same error I get when I run docker-compose up --build or docker-compose up mentioned above.

Edit Again

As suggested by Sardar Faisal, I removed

    command: >
          sh -c "python manage.py makemigrations && 
                 python manage.py migrate &&
                 python manage.py runserver 0.0.0.0:8000"

and ran docker-compose run -p 8000:8000 web_ramrobazar sh but I got the error no such service: web_ramrobazar. So I ran docker-compose run -p 8000:8000 web sh instead and I got the following:

    [+] Running 1/0
     - Container db_ramrobazar  Created                                                                                0.0s
    [+] Running 2/2
     - Container db_ramrobazar   Started                                                                               3.1s
     - Container web_ramrobazar  Started                                                                               1.5s
    # python manage.py makemigrations
    /usr/local/lib/python3.8/site-packages/django/core/management/commands/makemigrations.py:121: RuntimeWarning: Got an error checking a consistent migration history performed for database connection 'default': 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?
    
      warnings.warn(
    No changes detected
    #

This is the same error mentioned above in the first edit.

Updated settings.py:

    # DATABASES = {
    #     'default': {
    #         'ENGINE': 'django.db.backends.sqlite3',
    #         'NAME': BASE_DIR / 'db.sqlite3',
    #     }
    # }
    
    # DATABASES = {
    #     'default': {
    #         'ENGINE': config('ENGINE'),
    #         'NAME': config('POSTGRES_DB'),
    #         'USER': config('POSTGRES_USER'),
    #         'PASSWORD': 'postgres',
    #         'HOST': config('HOST'),
    #         'PORT': config('PORT'),
    #     }
    # }
    
    DATABASE_URL = config('DATABASE_URL').replace("'", "")
    DATABASES = {
        'default': dj_database_url.parse(DATABASE_URL, conn_max_age=600)
    }

Updated .env:

    DEBUG=True
    SECRET_KEY=mysecretkey
    ALLOWED_HOSTS=*
    DATABASE_URL=postgres://postgres:postgres@db:5432/postgres
    
    # postgres
    POSTGRES_USER=postgres
    POSTGRES_PASSWORD=postgres
    POSTGRES_DB=postgres
    ENGINE=django.db.backends.postgresql_psycopg2
    HOST=localhost
    PORT=5432