Django development using Docker as host - Part 5: Django development

Till now we covered application setup and docker services running via docker-compose. In this step, we will use the docker container to develop the Django application.

TOC

1. Start docker-compose services
2. Django settings
3. Run Django application
4. Live reload Django changes
5. Sync python dependencies
6. Create Django app

Let's dive-in

1. Start docker-compose services

Before we start with the Django development, we need to run the docker containers with the required services.
Execute the following command to run the services defined in the docker-compose.yml file

docker-compose up --build

After the service has been started, execute the below command in a new terminal to see the running containers

docker ps

You will see the list of running containers.

2. Django settings

When the docker-compose runs for the first time, you will see a Django exception

django.core.exceptions.ImproperlyConfigured: You're using the staticfiles app without having set the STATIC_ROOT setting to a filesystem path.

This is because we have not yet configured the STATIC_ROOT settings where the static files are copied on running collectstatic management command.
Add the following settings to the src/my_app/settings.py file.

Static file settings

STATICFILES_DIRS = [
    os.path.join(os.path.dirname(BASE_DIR), 'static_my_project')
]

STATIC_ROOT = os.path.join(os.path.dirname(BASE_DIR), 'static_cdn', 'static_root')

MEDIA_URL = '/media/'
MEDIA_ROOT = os.path.join(os.path.dirname(BASE_DIR), 'static_cdn', 'media_root')

• The STATICFILES_DIRS setting defines where the static files will be kept. While development, we will keep the static files inside the static_my_project directory.
• STATIC_ROOT is the path where the static files are copied on collectstatic management command

Database settings

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.mysql',
        'HOST': 'database',
        'PORT': '3306',
        'NAME': 'app_db',
        'USER': 'app_db',
        'PASSWORD': 'app_db'
    }
}

Where database is the service inside the docker-compose.

Template directory

In order to allow the creation of the template files inside the application directory, add the following to the TEMPLATES.DIRS settings

[
   os.path.join(BASE_DIR, 'templates')
]

This allows us to add the template files inside the src/templates directory and also in the app's templates/ directory.

3. Run Django application

After adding the settings, run the following to start the docker services

docker-compose up --build

After the services have been started, let's verify the following:

• Django database has been migrated to the MySQL database. Visit http://localhost:8080 and use the database credentials to log in to the database management.
• Open http://localhost:8000 to see the Django application running.

4. Live reload Django changes

As we have the .src/ directory mapped to the /app directory, the host .src/ directory will work as the container's /app directory. Any changes in the .src/ directory files will reload the Django application.
Check the docker-compose logs for the logs.

4. Sync python dependencies

We do not have python installed in our system instead we are using python using Dockerfile container. So the python dependencies should be installed in the container.

• Open a bash shell in the running container

docker exec -it app_image bash

• Install the dependency using pip

pip install requests

This dependency can be used until the container is running. Once stopped, re-running the container, it will be removed.
It is required to sync the requirements.txt file in the host with the latest dependencies in the container to keep both in sync.

This can be achieved in two ways:

1. Add the requests dependency with the version number in the host's requirements.txt file

requests==<version>

1. Freeze the pip dependencies from container to the host:

pip freeze > /requirements.txt

Note, since the requirements.txt in the host is mapped to the same file in the root of the container, the path should start with /. Without / it will create a requirements.txt file inside the src/ directory.

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You can create the Django applications by running the manage.py management commands inside the container and edit the source code in the ./src directory.

6. Create Django app

Let's create a Django app

Run the following in the container bash

python manage.py startapp home

It will create a home directory in the ./src directory.

Add view

Add the following content to the ./src/home/views.py file

from django.views.generic import TemplateView


class IndexView(TemplateView):
    template_name = "home/index.html"

Add template

Create a template file index.html inside the templates/home directory with the following content

<html>
<head>
    <title>Index page</title>
</head>

<body>
    <h2>Welcome to the Index page</h2>
</body>
</html>

Add routing

Add the following to the home/urls.py file

from django.urls import path
from home.views import IndexView

app_name = 'home'
urlpatterns = [
    path('', IndexView.as_view()),
]

Include the URLs to the application urls.py file

path('home/', include('home.urls', namespace='home'))

Include the app to the settings.py file

INSTALLED_APPS = [
   'home'
]

Open in browser

In the browser, open the following URL

http://localhost:8000/home/

You will see the index page content.

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Congratulations, we have completed the setup of Django project using the docker as host.
Now you can develop the Django application without depending on the host system.

😊 😍 💻

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Check complete source code on Github

anuj9196 / django-docker-host

Docker host for the Django development. http://bit.ly/django-docker-host