How to do it...

With Docker and Compose installed, we will start by creating a myproject_docker directory. Within this, create subdirectories named apps, config, media, project, static, and templates. Then, we will create three configuration files:

• A requirements.txt file defining Python dependencies, under the config directory
• Dockerfile for the Django application container, in the myproject_docker root
• A docker-compose.yml file identifying all of the services making up the application environment, also in the myproject_docker root

The requirements.txt, which lives under the config subdirectory, is much the same as if using a virtual environment (see the Working with a virtual environment recipe), though we will include all dependencies here, not just those that differ from other projects. Because we are likely trying to match our Docker environment to that of the production server, we will generally require very specific versions of each module. In this case, we limit to the latest patch within a minor version range. For example, here, we would prefer mysqlclient 1.3.13 over mysqlclient 1.3.3, but we would not yet upgrade to mysqlclient 1.4.0:

# config/requirements.txt
Pillow~=5.2.0
mysqlclient~=1.3.0
Django~=2.1.0

Dockerfile will define how to build the environment within the container:

# Dockerfile
FROM python:3
RUN apt-get update \
    && apt-get install -y --no-install-recommends \
        mysql-client libmysqlclient-dev
WORKDIR /usr/src/app
ADD config/requirements.txt ./
RUN pip3 install --upgrade pip; \
    pip3 install -r requirements.txt
RUN django-admin startproject myproject .; \
    mv ./myproject ./origproject

We start with the official image for Python 3, install some dependencies for MySQL, set our working directory, add and install Python requirements, and then start a Django project.

Finally, docker-compose.yml puts together the Django application container with other services, such as a MySQL database, so that we can run them together with ease:

# docker-compose.yml
version: '3'
services:
  db:
    image: 'mysql:5.7'
  app:
    build: .
    command: python3 manage.py runserver 0.0.0.0:8000
    volumes:
      - './project:/usr/src/app/myproject'
      - './media:/usr/src/app/media'
      - './static:/usr/src/app/static'
      - './templates:/usr/src/app/templates'
      - './apps/external:/usr/src/app/external'
      - './apps/myapp1:/usr/src/app/myapp1'
      - './apps/myapp2:/usr/src/app/myapp2'
    ports:
      - '8000:8000'
    links:
      - db

As we can see in the volumes section, we will also need to add subdirectories within myproject_docker named project, media, static, and templates, plus each of the apps for the project. These directories will house the code, configuration, and other resources that are exposed within the container.