What is the docker command to run my Django server? - django

Question

I'm trying to Dockerize my local Django/MySql setup. I have this directory and file structure ...
apache
docker-compose.yml
web
- manage.py
- venv
- requirements.txt
- ...
Below is the docker-compose.yml file I'm using ...
version: '3'
services:
web:
restart: always
build: ./web
expose:
- "8000"
links:
- mysql:mysql
volumes:
- web-django:/usr/src/app
- web-static:/usr/src/app/static
#env_file: web/venv
environment:
DEBUG: 'true'
command: [ "python", "./web/manage.py runserver 0.0.0.0:8000" ]
mysql:
restart: always
image: mysql:5.7
environment:
MYSQL_DATABASE: 'maps_data'
# So you don't have to use root, but you can if you like
MYSQL_USER: 'chicommons'
# You can use whatever password you like
MYSQL_PASSWORD: 'password'
# Password for root access
MYSQL_ROOT_PASSWORD: 'password'
ports:
- "3406:3406"
expose:
# Opens port 3406 on the container
- '3406'
volumes:
- my-db:/var/lib/mysql
volumes:
web-django:
web-static:
my-db:
However when I run
docker-compose up
I get errors like the below
maps_web_1 exited with code 2
web_1 | python: can't open file './web/manage.py runserver 0.0.0.0:8000': [Errno 2] No such file or directory
maps_web_1 exited with code 2
maps_web_1 exited with code 2
web_1 | python: can't open file './web/manage.py runserver 0.0.0.0:8000': [Errno 2] No such file or directory
maps_web_1 exited with code 2
Is there another way I'm supposed to be referencing the manage.py file?
Edit: Added info requested in comments ...
FROM python:3.7-slim
RUN apt-get update && apt-get install
RUN apt-get install -y libmariadb-dev-compat libmariadb-dev
RUN apt-get update \
&& apt-get install -y --no-install-recommends gcc \
&& rm -rf /var/lib/apt/lists/*
RUN python -m pip install --upgrade pip
COPY requirements.txt requirements.txt
RUN python -m pip install -r requirements.txt
COPY . .

Answer 1

As others suggested, this is most probably because of running the manage.py runserver from a wrong directory or something very similar to this.
You are not using WORKDIR directive in your Dockerfile, at all. It is much safer if you do use them. Change your Dockerfile and docker-compose.yml files as below, and you problem should be solved.
Dockerfile
FROM python:3.7-slim
RUN apt-get update && apt-get install
RUN apt-get install -y libmariadb-dev-compat libmariadb-dev
RUN apt-get update \
&& apt-get install -y --no-install-recommends gcc \
&& rm -rf /var/lib/apt/lists/*
RUN python -m pip install --upgrade pip
RUN mkdir -p /app/
WORKDIR /app/
COPY requirements.txt requirements.txt
RUN python -m pip install -r requirements.txt
COPY . /app/
docker-compose.yml
version: '3'
services:
web:
restart: always
build: ./web
expose:
- "8000"
links:
- mysql:mysql
volumes:
- web-django:/usr/src/app
- web-static:/usr/src/app/static
#env_file: web/venv
environment:
DEBUG: 'true'
command: [ "python", "manage.py", "runserver", "0.0.0.0:8000" ]
...
Notice
You should be able to fix the problem by simply deleting web from your command for running the server. That's because when you are building the Dockerfile, you are inside the web directory. So when you do COPY . . you are copying contents inside web directory, and not the web directory itself. Actually, your file structure inside the docker image, should look something similar to this:
- root
- home
- var
- ...
- manage.py
- venv
- requirements.txt
- ...

Answer 2

In the command: directive, if you're using the array syntax, you're responsible for breaking up the command into words. As you've shown it you're running the equivalent of python "manage.py runserver 0.0.0.0:8000" at the shell prompt, and it's dutifully considering the entire command and options as the filename of a script to be run, including spaces. If you break this up into single words it will work better
command: ["python", "manage.py", "runserver", "0.0.0.0:8000"]
But there's not really a reason to specify this in docker-compose.yml at all. This is the default command you'd want to run to launch the container no matter how you ran it, so it should be the default command in your image's Dockerfile
...
EXPOSE 8000
CMD ["python", "manage.py", "runserver", "0.0.0.0:8000"]
You don't need links: at all on modern Docker (Docker Compose automatically sets up inter-container networking for you). You definitely don't want to mount named volumes over your application code: this hides what's in your image, and (since you've told Docker this is critical user data) it forces Docker to use an old version of your application if you try to update your image.
That leaves you with a simpler docker-compose.yml file:
version: '3'
services:
web:
restart: always
build: ./web
ports: # to access the container from outside
- "8000:8000"
environment:
DEBUG: 'true'
mysql:
restart: always
image: mysql:5.7
environment:
MYSQL_DATABASE: 'maps_data'
MYSQL_USER: 'chicommons'
MYSQL_PASSWORD: 'password'
MYSQL_ROOT_PASSWORD: 'password'
ports:
- "3406:3306" # second port is always container-internal port
volumes:
- my-db:/var/lib/mysql
volumes:
my-db:

Answer 3

Let us try to debug this error:
maps_web_1 exited with code 2
web_1 | python: can't open file './web/manage.py runserver 0.0.0.0:8000': [Errno 2] No such file or directory
Looks like either code is not not copied to container (named 'web') or command is triggered from root/home directory, where manage.py is not accessible.
1. Is the code available on container? How to check?
Usually, docker will just commands in container execute and exit unless there is unfinished running task (like server running in background).
To stop exiting and enable debugging it, let us add a running command, so that you can login to container and see if code is present.
command: tail -f /dev/null #trick to keep the docker alive for debug mode.
docker-compose.yml
web:
restart: always
build: ./web
expose:
- "8000"
links:
- mysql:mysql
volumes:
- web-django:/usr/src/app
- web-static:/usr/src/app/static
#env_file: web/venv
environment:
DEBUG: 'true'
command: tail -f /dev/null #trick to keep the docker alive for debug mode.
Login to container 'web', from command line run docker exec -it web bash
Check if project files are present, now you can run python manage.py runserver 8000 command manually. If it works, then we can be sure of that the server can be run on container. Now, we can analyse initial working directory.
If code is present, check why manage.py is not found? Is the working directory set? meaning, does the container know what is the base directory to run command?
Specify which is the working directory, in Dockerfile, before you copy the project files in to container.
Dockerfile in web directory
ENV PYTHONUNBUFFERED 1
ARG PROJ_DIR=/usr/project/web
RUN mkdir -p $PROJ_DIR
WORKDIR $PROJ_DIR
COPY . $WORKDIR
docker-compose.yml
restart: always
build: ./web
expose:
- "8000"
links:
- mysql:mysql
volumes:
- web-django:/usr/src/app
- web-static:/usr/src/app/static
#env_file: web/venv
environment:
DEBUG: 'true'
command: python manage.py runserver 0.0.0.0:8000 #note this command is triggered from $WORKDIR that we set in Dockerfile.
I think this should resolve the issue or help you to figure out the problem.