Beginner Django API using the Django REST framework

This repo contains a very basic Django API using the Django REST framework with four endpoints (ADD, SUB, MUL, DIV) that support both GET and PUT requests.

Environement Setup

• conda create -n django_tutorial python=3.7
• conda activate django_tutorial
• pip install Django djangorestframework
• or simply install requirements.txt file

  conda install --file requirements.txt
  

Clone this Repo

git clone https://github.com/mlDaddy/Calculator_API_Backend.git

Initialize Django App from Scratch (If not interested in cloning)

• mkdir Calculator_API_Backend
• cd Calculator_API_Backend
• django-admin startproject calculator_project
• copy fol code in calculator_app/views.py

  from rest_framework.views import APIView
  from rest_framework.response import Response
  from rest_framework import status
  
  class CalculatorView(APIView):
      def get(self, request, operation):
          instructions = f"Please send a PUT request with the 'a' and 'b' parameters to perform {operation} operation."
          return Response(instructions, status=status.HTTP_200_OK)
  
      def put(self, request, operation):
          if operation not in ['add', 'sub', 'mul', 'div']:
              return Response("Invalid operation.", status=status.HTTP_400_BAD_REQUEST)
  
          a = float(request.data.get('a'))
          b = float(request.data.get('b'))
  
          if operation == 'add':
              result = a + b
          elif operation == 'sub':
              result = a - b
          elif operation == 'mul':
              result = a * b
          elif operation == 'div':
              if b == 0:
                  return Response("Division by zero is not allowed.", status=status.HTTP_400_BAD_REQUEST)
              result = a / b
  
          return Response(f"Result of {operation}: {result}", status=status.HTTP_200_OK)
  
  

  • copy fol code in calculator_project/urls.py

  from django.urls import path
  from calculator_app.views import CalculatorView
  
  urlpatterns = [
      path('add/', CalculatorView.as_view(), {'operation': 'add'}),
      path('sub/', CalculatorView.as_view(), {'operation': 'sub'}),
      path('mul/', CalculatorView.as_view(), {'operation': 'mul'}),
      path('div/', CalculatorView.as_view(), {'operation': 'div'}),
  ]
  

  • calculator_project/settings.py, add your app to the INSTALLED_APPS list and configure the REST framework settings:

  INSTALLED_APPS = [
      # ...
      'rest_framework',
      'calculator_app',
  ]
  

  • Append fol code to calculator_project/settings.py file

  REST_FRAMEWORK = {
      'DEFAULT_PERMISSION_CLASSES': (
          'rest_framework.permissions.AllowAny',
      ),
      'DEFAULT_AUTHENTICATION_CLASSES': (
          'rest_framework.authentication.SessionAuthentication',
          'rest_framework.authentication.TokenAuthentication',
      ),
  }
  

  • Add allowed hosts in calculator_project/settings.py file

  ALLOWED_HOSTS = ['127.0.0.1', 'localhost']
  

Starting Django App

• python manage.py makemigrations
• python manage.py migrate
• python manage.py runserver

Testing using Postman

• install postman on ubuntu

  sudo snap install postman
  

• Launch Postman on ubuntu
• Import tests/Calculator_API_Backend.postman_collection.json file in Postman
• Test each call one by one (total 8 calls)

Deployment on AWS/EC2

• Launch your EC2 instance with following settings (leave everything else as default)
  • Amazon Machine Image (AMI): Ubuntu Server
  • Instance type: t2.micro
  • Allow SSH traffic from: Anywhere
  • Allow HTTPS traffic from the internet: Yes
  • Allow HTTP traffic from the internet: Yes
• Update the public IP of your EC2 instance in calculator_project/settings.py file

  ALLOWED_HOSTS = ['127.0.0.1:8000/', 'localhost:8000']
  

• Install conda and setup environment on EC2 using SSH
• Clone github repo
• Start Django app in a manner similar to the one used previously on local machine.
• Test using Postman (You may have to change the urls in previousely imported json file)
• Make sure you turn off your EC2 instance once you are done to avoid billing.

Deployment using Docker

• Installing Docker on Ubuntu (Local or EC2 wherever you are trying to Deploy your api)
  • Update Package Lists by opening a terminal and ensuring your package lists are up-to-date:

  sudo apt update
  

  • Install the necessary packages to allow apt to use a repository over HTTPS:

  sudo apt install -y apt-transport-https ca-certificates curl software-properties-common
  

  • Add Docker's official GPG key:

  curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /usr/share/keyrings/docker-archive-keyring.gpg
  

  • Add the Docker repository to your system:

  echo "deb [arch=amd64 signed-by=/usr/share/keyrings/docker-archive-keyring.gpg] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null
  

  • Install Docker from the Docker repository:

  sudo apt update
  sudo apt install -y docker-ce docker-ce-cli containerd.io
  

  • Start the Docker service and enable it to start on boot:

  sudo systemctl start docker
  sudo systemctl enable docker
  

  • Verify that Docker is installed and running by running the following command. You should see the Docker version information.

  sudo docker --version
  

Deploying Your Django API with Docker

• Create Dockerfile
• Build the Docker image using the docker build command.

  sudo docker build -t calculator_app .
  

• Run a Docker container based on the image you built. Map the host port to the container's port, and provide any environment variables as needed:

  sudo docker run -p 8000:8000 --name calculator_app_container calculator_app
  

  This command runs a container named calculator_app_container based on the calculator_app image, exposing the Django application on port 8000. You will see 'Watching for file changes with StatReloader' from django server on your terminal.
• Access Your API using the previousely defined urls and test them using Postman as done earlier.

Continuous Deployment (CD) on EC2 using Github Actions

• sudo snap install aws-cli
• create IAM user
• aws configure (using your IAM keys)
• store IAM keys in github actions secrets
• aws ecr create-repository --repository-name calculator_app --region ap-south-1
• Create a cluster calculator_app
• aws ecs register-task-definition --generate-cli-skeleton > ECS_TASK_DEFINITION.json
• update this json file.
• check if json file is correctly configured using aws ecs register-task-definition ECS_TASK_DEFINITION.json