# Review APP Low level design system

### Content index

- [Definitions and requirements of business](./RequirementsOfBusiness.md)
- [Requirements of the system](#requirements-of-the-system)
- [Architecture of the system](#architecture-of-the-system)
- [Modeling of data](#modeling-of-data)
- [Testing](#testing)
- [CI/CD Integration](#cd-integration)

### Requirements of the system

Just design the system of backend, not the frontend

**Review reader**
- Just get content of reviews **GET**
- ***Thousand of users(1000+ readers)*** can see the reviews
- They must be able to see the reviews around the world
- Response time must be less than **10 seconds**
- In case, the reviews is more  than **100** reviews, the response should be paginated
- What's going on if the server is down? (Cache, CDN, etc)

**Review publisher**
- Create, edit and remove reviews of cameras (**POST**, **PUT**, **DELETE**)
- **10 Users** can create reviews
- Service must be available 24/7 
- Review publisher must be able to authenticate (**Login** and **Logout**, **JWT**, **Register**)
- Review publisher must be able to upload images
- Response time must be less than **300 seconds**
- **10 and 20 reviews** per day (No needs a lot of resources)
- Publishers just can create reviews in **America Sur**


### Architecture of the system

**Load Balancer**
- [Nginx](https://docs.nginx.com/nginx/admin-guide/load-balancer/http-load-balancer/) or HAProxy
- Local: Nginx with Docker
- Production: Azure Load Balancer

**Horizontal Container**
- Local: [Docker](https://www.docker.com/)
- Production: Azure Container App

**ReviewReader**:
- Tecnologies: [FastAPI](https://fastapi.tiangolo.com/lo/), [Pydantic](https://docs.pydantic.dev/latest/#example), [Python 3.11](https://docs.python.org/3/) and [aioredis](https://aioredis.readthedocs.io/en/latest/)
- Local: Python with Docker
- Production: Azure container App
- Cache
  - Local: [Redis](https://redis.io/) with Docker
  - Production: Azure Cache for redis
- Database
  - Local: [MongoDB](https://www.mongodb.com/) NoSQL with Docker
  - Production: MongoDB NoSQL

**ReviewPublisher**:
- Technologies: [Django Rest Framework](https://www.django-rest-framework.org/), [Django](https://www.djangoproject.com/) and [Python 3.10](https://docs.python.org/3/), [Django redis](https://github.com/jazzband/django-redis)
- Local: Python with Docker
- Production: Azure app service
- Cache
  - Local: [Redis](https://redis.io/) with Docker
	- Production: Azure Cache for redis
- Database:
	- Local: [MySQL](https://dev.mysql.com/doc/refman/8.0/en/) with Docker
	- Production: Azure MySQL Database
  
**Authentication**:
- Technologies: [Django Rest Framework](https://www.django-rest-framework.org/), [Django](https://www.djangoproject.com/) and [Python 3.10](https://docs.python.org/3/), [Django redis](https://github.com/jazzband/django-redis) and [JWT authentication](https://github.com/jazzband/djangorestframework-simplejwt)
- Local: Python with Docker
- Production: Azure functions
- Cache
  - Local: [Redis](https://redis.io/) with Docker
	- Production: Azure Cache for redis
- Database:
	- Local: [MySQL](https://dev.mysql.com/doc/refman/8.0/en/) with Docker
	- Production: Azure MySQL Database


**Service of migration**:
- Technologies: [PHP 8.2](https://www.php.net/), [Mongo PHP Library](https://github.com/mongodb/mongo-php-library), [MySQL PHP Library](https://github.com/abhishekgahlot/mysql-to-mongo) and [Composer](https://getcomposer.org/)
- Local: PHP with Docker
- Production: Azure functions

### Modeling of data


### Testing


### CI/CD Integration