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I'm trying to dockerize my django app whilst following a tutorial, and nothing goes as planned. Could you help me understand what's going on and how to fix it? This is what I did:

  1. I made my dockerfile
FROM python:3.8-slim-buster
ENV PYTHONUNBUFFERED 1 

WORKDIR /app
COPY requirements.txt .
RUN pip install -r requirements.txt
RUN pip install psycopg2-binary
COPY . .
CMD python manage.py runserver 0.0.0.0:80
  1. I ran docker build -t app . which worked
  2. I ran docker run -p 8888:80 app but that's when the following issue popped up:
Watching for file changes with StatReloader
Performing system checks...

System check identified no issues (0 silenced).
Exception in thread django-main-thread:
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 122, in connect
    conn = _connect(dsn, connection_factory=connection_factory, **kwasync)
psycopg2.OperationalError: connection to server at "localhost" (127.0.0.1), port 5432 failed: Connection refused
        Is the server running on that host and accepting TCP/IP connections?
connection to server at "localhost" (::1), port 5432 failed: Cannot assign requested address
        Is the server running on that host and accepting TCP/IP connections?


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

Traceback (most recent call last):
  File "/usr/local/lib/python3.8/threading.py", line 932, in _bootstrap_inner
    self.run()
  File "/usr/local/lib/python3.8/threading.py", line 870, in run
    self._target(*self._args, **self._kwargs)
  File "/usr/local/lib/python3.8/site-packages/django/utils/autoreload.py", line 53, in wrapper
    fn(*args, **kwargs)
  File "/usr/local/lib/python3.8/site-packages/django/core/management/commands/runserver.py", line 121, in inner_run
    self.check_migrations()
  File "/usr/local/lib/python3.8/site-packages/django/core/management/base.py", line 459, in check_migrations
    executor = MigrationExecutor(connections[DEFAULT_DB_ALIAS])
  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 122, in connect
    conn = _connect(dsn, connection_factory=connection_factory, **kwasync)
django.db.utils.OperationalError: connection to server at "localhost" (127.0.0.1), port 5432 failed: Connection refused
        Is the server running on that host and accepting TCP/IP connections?
connection to server at "localhost" (::1), port 5432 failed: Cannot assign requested address
        Is the server running on that host and accepting TCP/IP connections?
Zeitounator
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Gabriel
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  • Django running in the container can't access the database using `localhost`, due to Docker networking configuration. I would suggest looking at this kind of answers https://stackoverflow.com/questions/52011129/access-database-that-is-outside-the-docker-environment – DuGabiche May 09 '23 at 13:19
  • set `db host = postgres` instead `localhost` and give a try. – Hemal Patel May 09 '23 at 13:23
  • Thanks guys! where do i set that? Im new to all this – Gabriel May 09 '23 at 13:25
  • You can probably find that information faster than writing the above comment by typing "django database settings" in your favorite search engine. Moreover, don't blindly change the current setting (i.e. localhost) to a random name before you know exactly where your db is actually running and how to access it (i.e. with which exact name) from your running container. You need to read some basic documentation about docker networking and you probably want to deploy all your services (django, postgres, memory cache....) with something like `docker-compose` to ease their management. – Zeitounator May 09 '23 at 13:43

0 Answers0