Docker and Django REST Framework

Docker

Source: WSVincent - A Beginner’s Guide to Docker

Docker is an alternative to virtual environments, which encapsulates an application completely. It is system agnostic, so you can ensure that everyone on a team is working with the same setup, regardless of OS.

The downside to all of this is that Docker is a complex tool. That said, let’s get into it.

Linux Containers

At it’s core, Docker is just a tool used to implement virtual Linux containers. Most computers rely on Linux at some level, so Docker builds from that level up, ensuring that a container is built a specific way.

Linux containers differ from virtual environments in that virtual environments only isolate Python packages. A Linux container is an entire system isolation.

Using Docker

docker run hello-world will run our first demo container. It downloads an official image and creates a container from it.

docker info can be used to inspect Docker.

ls -la will inspect containers. -la is required to include stopped containers.

Images and Containers

The reading uses the following analogy to explain images and containers:

• A Dockerfile is the recipe for a cake
• An image is a snapshot of the recipe at a given time
• A docker-compose.yml says how to make the cake
• And the container is the actual, baked cake

Docker Hub can be used to get official images.

Dockerfile must be built manually and must start with a FROM command. They are read from top to bottom.

#Reading example:

# Dockerfile
FROM python:3.7-alpine

After creating the Dockerfile an image can be built using docker image build ..

docker-compose.yml defines our container. Order of code here is also important (top-to-bottom).

#Reading example:

# docker-compose.yml
version: '3.7'

services:
  web:
    build: .
    command: python /code/manage.py runserver 0.0.0.0:8000
    volumes:
      - .:/code
    ports:
      - 8000:8000

Once you’ve defined your image and container, docker-compose up --build can be used to run build and run both in one command.

Django REST Framework

Source: Django for APIs

Django REST Framework is a tool that works alongside Django to create web APIs. It is not standalone, and must be added on top of Django.

Start by creating a Django project and app as usual, performing migrations and updating settings as needed.

Create a model, superuser, and basic display using views and templates.

Once your basic Django site is up, it’s time to get into the REST framework.

Using Django REST Framework

Start by installing Django REST Framework

$ pipenv install djangorestframework~=3.11.0

and add 'rest_framework' to your INSTALLED_APPS in settings.py.

Create a new api app, and also add that to INSTALLED_APPS.

API endpoints are added just like traditional routes, inside of urls.py.

The View

Once the urls are set up, we’ll need our view. Create an API view extending the proper generic view:

#Reading example:

# api/views.py
from rest_framework import generics

from books.models import Book
from .serializers import BookSerializer


class BookAPIView(generics.ListAPIView):
    queryset = Book.objects.all()
    serializer_class = BookSerializer

The Serializers

A serializer translates data into a web friendly format, usually JSON, to be sent from our endpoint.

Create a serializers.py file within the api app:

#From reading:

# api/serializers.py
from rest_framework import serializers

from books.models import Book


class BookSerializer(serializers.ModelSerializer):
    class Meta:
        model = Book
        fields = ('title', 'subtitle', 'author', 'isbn')

It’s fairly straightforward, but we need to import from rest_framework, extend the ModelSerializer class and then define the Meta class that states our model and fields to be serialized.

That’s all set.

cURL

Now we can run our server, and open another terminal.

curl can be used to make a basic GET request to a url.

$ curl http://127.0.0.1:8000/api/

This should reach out and touch our API, getting our model data back as JSON! Unsurprisingly for Django, it really is that simple.

Additional Resources

Official Django REST Framework Tutorial