Django development using Docker as host - Part 4: docker-compose

In the previous step, we initialized the Django application using the docker image.

In this part, we will be creating the docker-compose.yml file and define the required services to run the application.

TOC

1. Create directories
2. Create docker-compose.yml
3. Define database (MySQL) service
4. Define adminer server (Database management)
5. Define app service
6. Run docker-compose

Let's start

1. Create directories

Create two directories at the root of the project, src and static_my_project in the host where source code of the Django application will reside in the src directory and the static files in the static_my_project directory.
The directory structure will look like

- /
  | - scripts
  | - src
  | - static_my_project
  | - docker-compose.yml
  | - Dockerfile
  | - requirements.txt

2. Create dokcer-compose.yml

Create the docker-compose.yml file in the host with the content

version: '3.7'

3. Define database service

Let's define a database service that will be consumed by the Django application.
Add the following to the docker-compose.yml

services:
  database:
    image: mysql:8.0
    container_name: app__database
    command: --default-authentication-plugin=mysql_native_password
    restart: always
    volumes:
    - app_db:/var/lib/mysql
    environment:
      - MYSQL_ROOT_PASSWORD=app_db
      - MYSQL_DATABASE=app_db
      - MYSQL_USER=app_db
      - MYSQL_PASSWORD=app_db
    ports:
    - 3306:3306

volumes:
  app_db:

• We are using mysql version 8.0 image for the database.
• We have also defined a docker volume to store database files inside app_db.
• The database will be running on port 3306.

4. Define adminer server (optional)

Adminer is a web-based database management service. Using this service we can directly access the database in the browser.
Add the following content to the docker-compose.yml file

services:
  adminer:
    image: adminer:latest
    restart: always
    ports:
    - 8080:8080

The adminer services will be running on port 8080.

5. Define app service

Let's create an application service. We will use the Dockerfile to build the image.
Add the following content to the docker-compose.yml

services:
  app:
    build:
      context: .
      dockerfile: Dockerfile
    container_name: app_image
    command: ["/scripts/docker/wait_for_it.sh", "database:3306", "--", "/scripts/docker/docker_start.sh"]
    depends_on:
      - database
    ports:
    - 8000:8000
    volumes:
    - ./requirements.txt:/app/requirements.txt
    - ./static_my_project:/static_my_project
    - ./src:/app

• The application will be build using the Dockerfile we created in step 1
• When running, the application container will be named app_image
• Django by default runs on port 8000, we have mapped the port 8000 of the host to the container so that the server can be accessed from the host browser.
• We have mapped the following host volumes to the container files/folder.
  • requirements.txt -- Any modification to the requirements.txt file in the container will be updated to the host requirements.txt file
  • The static_my_project directory of the host will be mapped to the static_my_project directory in the container.
  • The /app directory is mapped to the ./src directory in the container. Any changes to the host ./src or container /app directory will be synced.

The contents of the docker-compose.yml

version: '3.7'

services:

  app:
    build:
      context: .
      dockerfile: Dockerfile
    container_name: app_image
    command: ["/scripts/docker/wait_for_it.sh", "database:3306", "--", "/scripts/docker/docker_start.sh"]
    depends_on:
      - database
    ports:
    - 8000:8000
    volumes:
    - ./requirements.txt:/app/requirements.txt
    - ./static_my_project:/static_my_project
    - ./src:/app

  database:
    image: mysql:8.0
    container_name: app__database
    command: --default-authentication-plugin=mysql_native_password
    restart: always
    volumes:
    - app_db:/var/lib/mysql
    environment:
      - MYSQL_ROOT_PASSWORD=app_db
      - MYSQL_DATABASE=app_db
      - MYSQL_USER=app_db
      - MYSQL_PASSWORD=app_db
    ports:
    - 3306:3306

  adminer:
    image: adminer:latest
    restart: always
    ports:
    - 8080:8080

volumes:
  app_db:

6. Run docker-compose

To run the defined services inside the docker-compose.yml file, let's run the services by executing

docker-compose up --build

It will build the application image and run the services.

Let's verify first if database and adminer services are running. Open the following link in the browser

http://localhost:8080

If the adminer login page appears, enter the following details

• Server: database
• Username: app_db
• Password: app_db
• Database: app_db

If the login works, the database and the adminer services are successfully running.