Django REST Framework & Docker

Docker

• Installation and running means for applications.

• With Docker it doesn’t matter if you are using a Mac, Windows, or Linux computer anymore. The entire development environment is isolated: programming language, software packages, databases, and more.

• Docker is really just Linux containers which are a type of virtualization.

• Size and speed, are affected when it comes to virtualization.

Vitruals machines are homes, Docker containers are apartments

• Analogy

  Virtual Machines are like homes: stand-alone buildings with their own infrastructure including plumbing and heating, as well as a kitchen, bathrooms, bedrooms, and so on. Docker containers are like apartments: they share common infrastructure like plumbing and heating, but come in various sizes that match the exact needs of an owner.

Containers vs Virtual Environments

• Virtual environments locally isolate Python software packages.

• rely on a global, system-level installation of Python albeit they can refer to the proper version

• we can’t run a production database or other services within virtual environments so compared to Docker containers they are far more limited

Install Docker

• Docker’s version should be at least 19

  $ docker –version Docker version 19.03.5, build 633a0ea

Installation Check

• $ docker run hello-world
• $ docker info
• $ docker image ls

Images and Containers

Definitions

• An image is a snapshot in time of what a project contains.

• A container is a running instance of the image.

• Analogy

  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

Images

• defining the image with a Dockerfil, is very much like Pipenv or a requirements.txt file.

• # Dockerfile
    FROM python:3.7-alpine
  

• Dockerfiles are read from top-to-bottom.

Image Builds

• $ docker image build .

Image Layers

• Image consist of multuple layers, such that the base layer is often a flavor of Linux, like alpine.
• Why Image Layering>

  • Each image layer is immutable–unchanged–like a git commit. This helps ensure consistency when two developers build the same image.

  • The second reason is performance. Docker caches the steps in a Dockerfile to speed up subsequent builds.

Django REST Framework

• Used with Django web framework to create web APIs.

• Must be added to added to the project after Django itself has been installed and configured.

• (library) $ pipenv install djangorestframework~=3.11.0

• The following apps must be added to the installed apps:

  # 3rd party   'rest_framework', # new
  

   # Local    'books',
  

  ‘api’, # new

• The api app will not have its own database models so there is no need to create a migration file and run migrate to update the database.

• An end point shall be added to the api

  urlpatterns = [ path(‘admin/’, admin.site.urls), path(‘api/’, include(‘api.urls’)), # new path(‘’, include(‘books.urls’)),]

Views

 # 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

Serializers

• A serializer translates data into a format that is easy to consume over the internet, typically JSON, and is displayed at an API endpoint.

Browsable API

• http://127.0.0.1:8000/api/