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juadaz edited this page Jun 15, 2023 · 9 revisions

Review APP High level system design

Content index

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

Definitions and Acronyms

  • API: application program interface
  • Readers: Users that just read the reviews
  • Publishers: Users that create, edit and remove reviews
  • API Management Azure: Azure API Management is a service that you can use to publish, secure, transform, maintain, and monitor APIs.
  • Azure Load Balancer: Azure Load Balancer delivers high availability and network performance to your applications.
  • Azuer App Service: Azure App Service is an HTTP-based service for hosting web applications, REST APIs, and mobile back ends.
  • Azure Functions: Azure Functions is a serverless compute service that enables you to run code on-demand without having to explicitly provision or manage infrastructure.
  • Azure Database for MySQL: Azure Database for MySQL is a relational database service based on the open-source MySQL Server engine.
  • Azure Cache for redis: Azure Cache for Redis is a fully managed, open-source compatible in-memory data store that powers fast, high-performing applications.
  • Azure Container APPs: Azure Container Apps is a fully managed service that allows you to deploy and run containerized apps without having to manage servers or clusters.

Overview

The CamereReviews company needs a system to allow that photografers proffesionals upload and publish reviews of cameras for anywhere can research and purcharse the review through the portal. The company has a team of developers specialized in frontend that will develop a portal to allow that editors upload the reviews and the users can see them, and they have requested that you as a backend specialist, provide a system, including API that allow to do the following:

  • Upload reviews of cameras
  • Get the content of reviews to show them in the portal view in web and mobile versions
  • Handle of users for editors (not include visitors)
  • It's planned to distribute mostly in America Sur where is the biggest market, but also has sales in North America, Europe and very few in Asia.

Scope

Uses cases

  • As a publisher I want to login and logout in the system
  • As a publisher I want to recover my password if I forgot it
  • As a publisher I want to create and upload a review of a camera
  • As a publisher I want to edit reviews of a camera after I published it
  • As a publisher I want to delete reviews of a camera after I published it
  • As a publisher admin I want to create, edit and remove users
  • As a publisher admin I want to create, edit and remove roles (Publisher and Publisher admin)
  • As a publisher I want to publish my reviews in less than 300 seconds
  • As a reader I want to se reviews of a camera in less than 10 seconds
  • As a reader I want to read reviews of a camera
  • As a reader I don't need to login to read reviews
  • As a reader I want to filter through categories of cameras

Out of Scope (Not supported)

  • No needs to support users(readers) to create reviews - Review publisher
  • Not support users(publishers) to create reviews in another continent = Review publisher
  • As a publisher I'd like to get analytics of my reviews
  • As a publisher admin I want to have more roles than just Publisher and Publisher admin
  • As a publisher I'd like to give feedback to reviews
  • As a reader I'd like to register, login and logout
  • As a reader I'd like to recover my password if I forgot it
  • As a reader I'd like to save reviews as favorites
  • As a reader and publisher I'd like to see the reviews in my language
  • As a reader and publisher I'd like to comment reviews

Architecture

Architecture willd developed in multiples phases. The first step will be developed the archicture without mention any tecnologie DevOps.

Phase 1 Description General without Technologies Review app will have a API gateway(management) as a main service to handle access, auth and the unique endpoint amound services ReviewReader and ReviewPublisher will implement a database MySQL to make queries as fast as it can, actually it will be cache and database, otherwise it will have a service to authenticate users and their own database and cache too. Also we have to talk about ReviewReader, it will get more complexity to improve performance and scability for the future. This service will be handle by a load balancer to distribute the traffic and a Horizontal scaling or Horizontal container to improve performance and scability. How you can looks in the diagram below.

Architecture Diagram

Phase 1

Something really important is other service that architecture will have, it'll be a service to migrate data from database MySQL (ReviewPublisher) to database NoSQL (Review Reader).

Phase 2 Description Specific without Technologies

  • API Gateway: It'll be a service intermediary between the client and the server (ReviewPublisher and Load Balancer (ReviewReader)), this will handle all request HTTP.
  • Load balancer: It'll handle incomin traffic accross services just for ReviewReader.
  • ReviewPublisher: It'll be a service that allows publishers to create, edit and remove reviews of cameras.
  • Auth: It'll work as a service to authenticate users and it'll be used just by ReviewPublisher.
    • Cache
    • Database
  • Service of Migration: It'll migrate data from NoSQL Database (ReviewPublisher) to SQL Database (ReviewReader).
  • Review Reader: It'll be a service that allows readers to get content of reviews of cameras.
    • Cache
    • Database

Phase 3 Description with technologies DevOps

Architecture Diagram

Phase 2

Phase 4 End to End flow between services

Flow Diagram as Publisher Auth

  • User as a publisher
    1. User as a publisher will access to ReviewPublisher through API Management Azure or API Gateway.
    2. Then API Management Azure will redirect the request to ReviewPublisher. Request will be handle first by API Management Azure and then by ReviewPublisher.
    3. ReviewPublisher will handle the request; the first step will be authenticate the user through Auth service.
    4. So ReviewPublisher will send a request to Auth service to authenticate the user. Auth service will handle the request and will send a response to ReviewPublisher.
    5. Auth service looks into Azure Cache for redis if the user is authenticated or already exists.
    6. If the user is authenticated or already exists, Auth service will send a response to ReviewPublisher.
    7. If the user is not into Azure Cache for redis, Auth service will do a query to MySQL Database and will send a response to ReviewPublisher.
    8. ReviewPublisher will handle the response and will send a response to API Management Azure.
    9. User as a publisher will get a response from ReviewPublisher through API Management Azure and will be able to create, edit and remove reviews of cameras if the user is authenticated.

Flow diagram as a publisher

Flow Diagram as Publisher Create, Edit and Remove review

  • User as a publisher
    1. User as a publisher have to be authenticated to create, edit and remove reviews of cameras. If the user is not authenticated, look at the flow diagram as a publisher auth.
    2. User as a publisher will create, edit and remove reviews of cameras through API Management Azure or API Gateway.
    3. Then request will be handle first by API Management Azure and then by ReviewPublisher.
    4. If the request is Get reviews, ReviewPublisher looks into Azure Cache for redis if the review already there and if so, ReviewPublisher will send a response to API Management Azure. Otherwise, ReviewPublisher will do a query to MySQL Database, save it in Azure Cache for redis and return the response to API Management Azure.
    5. If the request is Create review, ReviewPublisher looks into Azure Cache for redis if the review already exists and otherwise, ReviewPublisher will do a query to MySQL Database, save it in Azure Cache for redis and return the response to API Management Azure.
    6. If the request is Edit review, ReviewPublisher will do a query to MySQL Database, update it in Azure Cache for redis and return the response to API Management Azure
    7. If the request is Remove review, ReviewPublisher will do a query to MySQL Database, delete it in Azure Cache for redis and return the response to API Management Azure

Flow diagram as a publisher create, edit and remove review

Flow diagram as a reader

  • User as a reader
    1. User as a reader doesn't have access or be authenticated, so it'll be able to get content of reviews of cameras.
    2. User as a reader will get content of reviews of cameras through API Management Azure or API Gateway.
    3. Then request will be sent to Azure Load Balancer and it'll redirect some server into horizontal container about their criterion.
    4. ReviewPublisher get the request, get the response from Redis or MongoDB and return the response to API Management Azure.
    5. Finally user as a reader get response from API Management Azure.

Flow diagram as a reader

Flow diagram as a publisher Auth in local soon

Flow diagram as a reader in local soon

Data model

Soon

Limitations & Unknowns

  • Email notifications
  • Not support Review publisher to create reviews in another continent
  • Users(readers) can't login and register
  • Payment gateway to pay for the reviews
  • Search|Lookup functionality for reviews
  • Not authentication to get reviews
  • Migrate a lot of data from NoSQL Database when Horizontal scaling will get many instances of MySQL Database, Will it be a problem? Will it be slower?

Data structures

Costs

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