Building on Docker Hub ignores context path when copying files - django

Question

I am trying to upload a Django app to Docker Hub. On the local machine (Ubuntu 18.04) everything works fine, but on Docker Hub there is an issue that the requirements.txt file cannot be found.
Local machine:
sudo docker-compose build --no-cache
Result (it's okay):
Step 5/7 : COPY . .
---> 5542d55caeae
Step 6/7 : RUN file="$(ls -1 )" && echo $file
---> Running in b85a55aa2640
Dockerfile db.sqlite3 hello_django manage.py requirements.txt venv
Removing intermediate container b85a55aa2640
---> 532e91546d41
Step 7/7 : RUN pip install -r requirements.txt
---> Running in e940ebf96023
Collecting Django==3.2.2....
But, Docker Hub:
Step 5/7 : COPY . .
---> 852fa937cb0a
Step 6/7 : RUN file="$(ls -1 )" && echo $file
---> Running in 281d9580d608
README.md app config docker-compose.yml
Removing intermediate container 281d9580d608
---> 99eaafb1a55d
Step 7/7 : RUN pip install -r requirements.txt
---> Running in d0e180d83772
[91mERROR: Could not open requirements file: [Errno 2] No such file or directory: 'requirements.txt'
Removing intermediate container d0e180d83772
The command '/bin/sh -c pip install -r requirements.txt' returned a non-zero code: 1
app/Dockerfile
FROM python:3.8.3-alpine
ENV PYTHONDONTWRITEBYTECODE 1
ENV PYTHONUNBUFFERED 1
WORKDIR /code
COPY . .
RUN file="$(ls -1 )" && echo $file
RUN pip install -r requirements.txt
docker-composer.yml
version: '3'
services:
web:
build:
context: app
dockerfile: Dockerfile
volumes:
- ./app/:/code/
ports:
- "8000:8000"
env_file:
- ./config/.env.dev
command: python manage.py runserver 0.0.0.0:8000
Project Structure:
UPDATE:
Docker is building from Github.
File requirements.txt is in the GitHub repository (app folder), but for some reason during build Docker Hub copies files from the project root folder and not the contents of the app folder.
Github:
https://github.com/sigalglebru/django-on-docker

Answer 1

The problem is that you need to tell Docker Hub where to find your build context.
When you run docker-compose build locally, docker-compose reads your docker-compose.yml file and knows to build inside the app directory, because you've explicitly set the build context:
build:
context: app
dockerfile: Dockerfile
When you build on Docker Hub, by default it will assume the build
context is the top level of your repository. If you set the path to
your Dockerfile to, e.g., app/Dockerfile, this is equivalent to
running:
docker build -f app/Dockerfile .
If you try that, you'll see if fail the same way. Rather than setting
the path to the Dockerfile, you need to set the path to the build
context to the app directory. For example:
(Look at the "Build Context" column).
When configured correct, your repository builds on Docker Hub without errors.

Answer 2

Thank you, I found solution:
I just copied files from./app to the mounted volume, and little changed context, but still don't understand why it worked fine on the local machine
Dockerfile:
FROM python:3.8.3-alpine
ENV PYTHONDONTWRITEBYTECODE 1
ENV PYTHONUNBUFFERED 1
WORKDIR /code
COPY ./app .
RUN pip install -r requirements.txt
docker-compose.yml
version: "3.6"
services:
python:
restart: always
build:
context: .
dockerfile: docker/Dockerfile
expose:
- 8000
ports:
- 8000:8000
command: "python manage.py runserver 0.0.0.0:8000"