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Django app while dockerizing gives "Starting development server at http://0.0.0.0:8000/" but doesn't show up on browser

So I am a beginner in docker and Django. What I have here is a django app which I am trying to dockerize and run. My requirements.txt has only django and gunicorn as the packages.
I am getting the below in terminal after building and running the docker image:
Watching for file changes with StatReloader
Performing system checks...
System check identified no issues (0 silenced).
August 26, 2021 - 06:57:22
Django version 3.2.6, using settings 'myproject.settings'
Starting development server at http://0.0.0.0:8000/
Quit the server with CONTROL-C.
Below is my Dockerfile:
FROM python:3.6-slim
ENV PYTHONUNBUFFERED=1
RUN mkdir /Django
WORKDIR /Django
ADD . /Django
RUN pip install -r requirements.txt
EXPOSE 8000
CMD python manage.py runserver 0.0.0.0:8000
The commands I am using are:
docker build . -t myproj
docker run -p 8000:8000 myproj
I have tried adding allowedhosts = ['127.0.0.1'] in settings.py but still I am getting "The site can't be reached. 127.0.0.1 refused to connect.
Not able to see the "Congratulations" screen.
Please help me out with this.
P.s: I am using windows machine
Updates
I tried running the below line and got the following output:
docker exec 8e6c4e4a58db curl 127.0.0.1:8000
OCI runtime exec failed: exec failed: container_linux.go:349: starting container process caused "exec: \"curl\": executable file not found in $PATH": unknown

Without your settings.py, this can be hard to figure out. You say you have allowedhosts = ['127.0.0.1'] in there and that should definitely not be necessary. It might actually be what's blocking your host, since requests from your host come from a different IP address.
I've made the following Dockerfile that creates a starter project and runs it
FROM python:latest
RUN python -m pip install Django
RUN django-admin startproject mysite
WORKDIR /mysite
EXPOSE 8000
CMD python manage.py runserver 0.0.0.0:8000
If I build it and run it with
docker build -t mysite .
docker run -d -p 8000:8000 mysite
I can connect to http://localhost:8000/ on my machine and get the default page (I'm on Windows too).
I hope that helps you to locate your issue.
PS: Your curl command fails because curl isn't installed in your image, so it failing has nothing to do with your issue.

Hypercorn with "--reload" and Docker volumes

I am running Hypercorn with --reload inside a Docker container. The file I am running is kept in a volume managed by Docker Compose.
When I change the file on my system, I can see that the change is reflected in the volume, e.g. with docker compose exec myapp /bin/cat /app/runtime/service.py.
However, when I change a file in this way, Hypercorn does not restart as I would have expected. Is there some adverse interaction between Hypercorn and the Docker volume? Or am I expecting something from the --reload option that I should not expect?
Example files are below. My expectation was that modifying runtime/service.py from outside the container would trigger Hypercorn to restart the server with the modified version of the file. But this does not occur.
Edit: I should add that I am using Docker 20.10.5 via Docker Desktop for Mac, on MacOS 10.14.6.
Edit 2: This might be a Hypercorn bug. If I add uvicorn[standard] in requirements.txt and run python -m uvicorn --reload --host 0.0.0.0 --port 8001 service:app, the reloading works fine. Possibly related: https://gitlab.com/pgjones/hypercorn/-/issues/185
entrypoint.sh:
#!/bin/sh
cd /app/runtime
/opt/venv/bin/python -m hypercorn --reload --bind 0.0.0.0:8001 service:app
Dockerfile:
FROM $REDACTED
RUN /opt/venv/bin/python -m pip install -U pip
RUN /opt/venv/bin/pip install -U setuptools wheel
COPY requirements.txt /app/requirements.txt
RUN /opt/venv/bin/pip install -r /app/requirements.txt
COPY requirements-dev.txt /app/requirements-dev.txt
RUN /opt/venv/bin/pip install -r /app/requirements-dev.txt
COPY entrypoint.sh /app/entrypoint.sh
EXPOSE 8001/tcp
CMD ["/app/entrypoint.sh"]
docker-compose.yml:
version: "3.8"
services:
api:
container_name: api
hostname: myapp
build:
context: .
ports:
- 8001:8001
volumes:
- ./runtime:/app/runtime
runtime/service.py:
import logging
import quart
logger = logging.getLogger(__name__)
logging.basicConfig(level=logging.INFO)
app = quart.Quart(__name__)
#app.route('/')
async def handle_hello():
logger.info('Handling request.')
return 'Hello, world!\n'
#app.route('/bad')
async def handle_bad():
logger.critical('Bad request.........')
raise RuntimeError('Oh no!!!')

Here is a minimal, fully working example which does auto-reload using hypercorn:
docker-compose.yaml
services:
app:
build: .
# Here --reload is used which works as intended!
command: hypercorn --bind 0.0.0.0:8080 --reload src:app
ports:
- 8080:8080
volumes:
- ./src:/app/src
Dockerfile
FROM python:3.10-slim-bullseye
WORKDIR /app
RUN pip install hypercorn==0.14.3 quart==0.18.0
COPY src ./src
EXPOSE 8080
ENV QUART_APP=src:app
# This is the production command; docker-compose.yaml overwrites it for local development
CMD hypercorn --bind 0.0.0.0:8080 src:app
src/__init__.py
from quart import Quart
app=Quart(__name__)
#app.route('/', methods=['GET'])
def get_root():
return "Hello world!"
Run via docker-compose up and notice how hypercorn reloads once __init__.py got modified.

You likely need to use a volume mount to get the reload functionality!
This is because when you build the container, it bakes whatever you have locally into it. Further changes only affect your local filesystem.
This is arguably not intended-use (as the container becomes dependent on external files!), but likely useful for faster testing/debugging
You could also directly edit the container by connecting to it, which you may find suits your needs.

http://localhost/5000 not working in docker flask

can't open file '/web/manage.py': [Errno 2] No such file or directory
exited with code 2
NOTE: Tried all similar problems solution posted, did not work.
No matter what I do, not able to get http://localhost/5000 to work. Even if the above error goes away by removing volume and command from docker-container.
Below is docker-compose.yml
services:
web:
build: ./web
command: python /web/manage.py runserver 0.0.0.0:8000
volumes:
- './users:/usr/src/app'
ports:
- 5000:5000
env_file:
- ./.env.dev
Below is Dockerfile:
# pull official base image
FROM python:3.9.5-slim-buster
# set work directory
WORKDIR /usr/src/app
# set environment variables
ENV PYTHONDONTWRITEBYTECODE 1
ENV PYTHONUNBUFFERED 1
# install dependencies
RUN pip install --upgrade pip
COPY ./requirements.txt /usr/src/app/requirements.txt
RUN pip install -r requirements.txt
# copy project
COPY . /usr/src/app/
BELOW IS manage.py:
from flask.cli import FlaskGroup
from project import app
cli = FlaskGroup(app)
if __name__ == "__main__":
cli()
BELOW IS init.py:
from flask import Flask, jsonify
app = Flask(__name__)
#app.route("/")
def hello_world():
return jsonify(hello="world")
Below is the structure:
The ones marked in red appeared when I ran this command: docker-compose build
enter image description here

A couple of changes to do.
The cli command in your docker-compose.yml file needs to be:
command: python /usr/src/app/manage.py run -h 0.0.0.0 -p 8000
There the command name is run and not runserver. Also the host ip to bind and port to listen are configured as different command options.
Also the configured port mapping for the service needs to map to the container port from the command:
ports:
- 5000:8000
In your manage.py module, FlaskGroup should be provided create_app option which is factory not the app instance.
You can implement this as a lambda function.
cli = FlaskGroup(create_app=(lambda:app))
Edit
The source files are not mounted in the container volume that why you're getting "no such file manage.py".
You need to mount your source files in the container volume under /usr/src/app.
volumes:
- './web:/usr/src/app'

Docker: Running a Flask app via Gunicorn - Worker timeouts? Poor performance?

I am trying to create a new app that is written in Python Flask, run by gunicorn and then dockerised.
The problem I have is the performance inside the docker container is very poor, inconsistent and I do eventually get a response but I can't understand why the performance is decreasing. Sometimes I see in the logs [CRITICAL] WORKER TIMEOUT (pid:9).
Here is my app:
server.py
from flask import Flask
app = Flask(__name__)
#app.route('/')
def index():
return "The server is running!"
if __name__ == '__main__':
app.run()
Dockerfile
FROM python:3.6.9-slim
# Copy all the files to the src folder
COPY build/ /usr/src/
# Create the virtual environment
RUN python3 -m venv /usr/src/myapp_venv
# Install the requirements
RUN /usr/src/myapp_venv/bin/pip3 install -r /usr/src/requirements.txt
# Runs gunicorn
# --chdir sets the directory where gunicorn should look for the server files
# server:app means run the "server.py" file and look for the "app" constructor within that
ENTRYPOINT ["/usr/src/myapp/bin/gunicorn", "--bind", "0.0.0.0:5000", "--workers", "1", "--chdir", "/usr/src/", "server:app"]
# Expose the gunicorn port
EXPOSE 5000
requirements.txt
Click==7.0
Flask==1.1.1
gunicorn==20.0.0
itsdangerous==1.1.0
Jinja2==2.10.3
MarkupSafe==1.1.1
Werkzeug==0.16.0
I run the docker container like this:
docker build -t killerkode/myapp .
docker run --name myapp -p 5000:5000 killerkode/myapp

I managed to find this helpful article which explains why Gunicorn hangs.
https://pythonspeed.com/articles/gunicorn-in-docker/
The solution for me was to change the worker temp directory and increase the minimum workers to 2. I still see workers being killed off but there is no longer any delays / slowness. I suspect adding in the gthread will improve things further.
Here is my updated Dockerfile:
FROM python:3.6.9-slim
# Copy all the files to the src folder
COPY build/ /usr/src/
# Create the virtual environment
RUN python3 -m venv /usr/src/myapp_venv
# Install the requirements
RUN /usr/src/myapp_venv/bin/pip3 install -r /usr/src/requirements.txt
# Runs gunicorn
# --chdir sets the directory where gunicorn should look for the server files
# server:app means run the "server.py" file and look for the "app" constructor within that
ENTRYPOINT ["/usr/src/myapp/bin/gunicorn", "--bind", "0.0.0.0:5000", "--worker-tmp-dir", "/dev/shm", "--workers", "2", "--chdir", "/usr/src/", "server:app"]
# Expose the gunicorn port
EXPOSE 5000

django runserver hangs in docker-compose up but runs correctly in docker-compose run

Edit
Adding --ipv6 to the command, while not properly configured for, seem to surpass the point where the process hangs.
Problem
Calling docker-compose up executes runserver but hangs at some point after printing the current time.
Calling docker-compose run -p 8000:8000 web python manage.py runserver 0.0.0.0:8000 also execute the server, but does so succesfully and can be reached at 192.168.99.100:8000.
Questions
How come I can run the server directly from docker-compose in my shell but not from the .yml file?
To me, the content of the .yml file and the docker-compose run line from the shell are strikingly similar.
The only difference I can think of would perhaps be permissions at some level required to properly start a django server, but I don't know how to address that. Docker runs on a windows 8.1 machine. The shared folder for my virtual machine is the default c:\Users.
Files
My folder contain a fresh django project as well as these docker files. I've tampered with different versions of python and django but the result is the same. I've cleaned up my images and containers between attempts using
docker rm $(docker ps -a -q)
docker rmi $(docker images -q)
docker-compose.yml
version: '3'
services:
web:
build: .
command: python manage.py runserver 0.0.0.0:8000
volumes:
- .:/code
ports:
- "8000:8000"
Dockerfile
FROM python:3.6-alpine
ENV PYTHONUNBUFFERED 1
RUN mkdir /code
WORKDIR /code
ADD requirements.txt /code/
RUN pip install -r requirements.txt
ADD . /code/
requirements.txt
Django>=1.8,<2.0
System
My operative system is windows 8.1

I was hit by this issue myself and it seems that you need to allocate a tty and a stdin to your container in order to make runserver work:
python:
image: my-image:latest
stdin_open: true # docker run -i
tty: true # docker run -t
build:
context: ..
dockerfile: docker/Dockerfile

I had the same issue and could not get it to do anything else. However when i went to the ip of the docker machine docker-machine ip it returned 192.168.99.100, then by going to 192.168.99.100:8000 my docker container started receiving the requests