yapp-backend-dev

Yapp Backend Developer code challenge

This project demonstrates a simple implementation of a Serverless API that implements simple CRUD methods for a MySQL DataBase. It makes use of AWS SAM CLI deploying serverless functions as API endpoint handlers.

Description

This project contains source code and supporting files for a serverless application that you can deploy with the SAM CLI. It includes the following files and folders.

• .env.example - A template that defines the project needed environment variables.
• template.yaml - A template that defines the application's AWS resources.
• docker-compose.yml - A containerized MySQL DataBase to help with fast deployment.
• yapp_backend/ - Code for the application's Lambda function.
  • tests/ - Unit tests for the application code.
  • app.py - Serverless API handlers.
  • db.py - Database connection and session setup.
  • models.py - Movie SQLAlchemy model.
  • data.csv - Kaggle data for movies and ratings.
  • seed.py - Script to populate blank DataBase.

Requirements

This project assumes the following requirements are met.

• Python3.7+ - Lambda functions use Python runtime environment.
• Docker and docker-compose - Needed for AWS SAM CLI and MySQL DataBase.
• AWS SAM CLI - AWS Serverless Application Model framework.

Deployment

• Clone this repo

$ git clone https://github.com/delta575/yapp-backend-dev.git  # Clone this repo
$ cd yapp-backend-dev  # Change directory to project root folder

• Set environment variables

Edit file following this specifications:

$ cp .env.example .env  # Copy example
$ nano .env  # Edit file

Important: Set the same DATABASE_URL environment variable for SAM Global configs located on template.yaml file.

• Setup virtual environment and install requirements:

Install development requirements, poetry is used as the preferred package manager.
Follow the install instructions for your enviroment.

Then install the project local dependencies:

$ poetry install  # Create virtual env and install dependencies

• Deploy MySQL DataBase

If you already have MySQL deployed you can skip this step, just make sure to point the DATABASE_URL env var correctly.

For easy deployment, a MySQL DataBase was containerized with a docker-compose.yml which also sets the needed environment variables for authentication.

$ docker-compose up --build -d  # Deploys MySQL database as a docker container

• Seed Data

Run the script seed.py which will create the Movie table from it's model and populate the DataBase with data.csv content.
data.csv follows this Kaggle repository structure.

$ poetry shell  # activate virtual environment
$ python yapp_backend/seed.py  # run seed script

• Run Unit Tests

Tests are defined in the tests folder in this project. Use pytest to run unit tests.

poetry shell  # activate virtual environment
python -m pytest -v  # run unit tests

• Deploy SAM Local Server

sam build --use-container && sam local start-api

You can test the API visiting a GET method on your browser, by default SAM runs at http://localhost:3000/.

Postman is recommended for fully featured testing.

SAM API:

Simple CRUD methods: