docker-compose how to reference files in other directories - django

Question

Having this dockerfile:
FROM python:3.8.3-alpine
ENV MICRO_SERVICE=/home/app/microservice
# RUN addgroup -S $APP_USER && adduser -S $APP_USER -G $APP_USER
# set work directory
RUN mkdir -p $MICRO_SERVICE
RUN mkdir -p $MICRO_SERVICE/static
# where the code lives
WORKDIR $MICRO_SERVICE
# set environment variables
ENV PYTHONDONTWRITEBYTECODE 1
ENV PYTHONUNBUFFERED 1
# install psycopg2 dependencies
RUN apk update \
&& apk add --virtual build-deps gcc python3-dev musl-dev \
&& apk add postgresql-dev gcc python3-dev musl-dev \
&& apk del build-deps \
&& apk --no-cache add musl-dev linux-headers g++
# install dependencies
RUN pip install --upgrade pip
# copy project
COPY . $MICRO_SERVICE
RUN pip install -r requirements.txt
COPY ./entrypoint.sh $MICRO_SERVICE
CMD ["/bin/bash", "/home/app/microservice/entrypoint.sh"]
and the following docker-compose.yml file:
version: "3.7"
services:
nginx:
build: ./nginx
ports:
- 1300:80
volumes:
- static_volume:/home/app/microservice/static
depends_on:
- web
restart: "on-failure"
web:
build: . #build the image for the web service from the dockerfile in parent directory
command: sh -c "python manage.py collectstatic --no-input &&
gunicorn djsr.wsgi:application --bind 0.0.0.0:${APP_PORT}"
volumes:
- .:/microservice:rw # map data and files from parent directory in host to microservice directory in docker containe
- static_volume:/home/app/microservice/static
env_file:
- .env
image: wevbapp
expose:
- ${APP_PORT}
restart: "on-failure"
volumes:
static_volume:
I need to reference the following files (in the docker-compose.yml file) being in other directories rather than the .devcontainer:
manage.py
requirements.txt
.env
This is my folder structure:
An easy solution would be to move the dockerfile, docker-compose.yml, and .env in the django directory djsr, but I am trying to keep the files structured like this. How can I do reference those files in docker-compose.yml?

Answer 1

It is fairly common to put the couple of Docker-related files in the project root directory, and that can potentially save you some trouble; I'd recommend that as a first choice.
If you do want to keep it all in a subdirectory, it's possible, though. When you run docker-compose, you can specify the location of the configuration file. It will consider all paths as relative to this file's directory.
# Either:
docker-compose -f .devcontainer/docker-compose.yml up
cd .devcontainer && docker-compose up
When you go to build the image, the build reads in a context directory, and COPY statements are always interpreted relative to this directory. For your setup, you need the context directory to be the top of your source tree, and then specify an alternate Dockerfile in a subdirectory.
services:
web:
build:
context: ..
dockerfile: .dockerenv/Dockerfile
For the most part the Dockerfile itself is fine, but where the entrypoint script is in a subdirectory, the COPY command needs to reflect that too. Since you're copying the entire source directory, you could also rearrange things inside the image to be the layout you want.
COPY requirements.txt ./
RUN pip install -r requirements.txt
COPY . ./
# Either:
COPY .dockerenv/entrypoint.sh ./
# Or:
RUN mv .dockerenv/entrypoint.sh .
# Or:
CMD ["./dockerenv/entrypoint.sh"]
I don't recommend the volume structure you have, but if you want to keep it, you also need to change the source path of the bind mount to be the parent directory. (Note particularly, in the previous Dockerfile fragment, a couple of the options involve moving files inside the image, and a bind mount will hide that change.)
services:
web:
volumes:
# Ignore the application built into the container, and use
# whatever's checked out on the host system instead.
- ..:/home/app/microservice
# Further ignore the static assets on the host system and
# use the content in a named volume instead.
- static_volume:/home/app/microservice/static

Answer 2

why don't you mount the same as you did with the folders only for these files?
The source of the mount. For bind mounts, this is the path to the file or directory on the
Docker daemon host. May be specified as source or src.