Microservices Project

Environment variables

.env file must be created in the root folder

Running via NPM

PORT_1=3000 # PORT to run content service on
PORT_2=3001 # PORT to run user interaction service on
PORT_3=3002 # PORT to run user service on
DB_1=mongodb://127.0.0.1:27017/ContentService
DB_2=mongodb://127.0.0.1:27017/userInteractionService
DB_3=mongodb://127.0.0.1:27017/userService
TOTP_KEY=EFSYLHHHABKPIDKIYWCTLYXROROFVERXDJCM # api key generated using nanoid for accessing user interaction service internal api
HOST=localhost

Running via Docker

Everything remains same as above. Only change is to replace 127.0.0.1 to mongo for the DB URIs like this:

DB_1=mongodb://mongo:27017/ContentService
DB_2=mongodb://mongo:27017/userInteractionService
DB_3=mongodb://mongo:27017/userService

Installation

via NPM

git clone https://github.com/Aditya-ds-1806/microservices.git
cd microservices
npm i
npm start

via Docker

git clone https://github.com/Aditya-ds-1806/microservices.git
cd microservices
docker-compose build
docker-compose up

HLD

• DBConnection class - handle DB connection
• UserSchema, ContentSchema, UserInteractionSchema - define schemas for DB
• UserInteractionService, ContentService and UserService - 3 workers to handle service registration
• ContentRoutes, UserRoutes, UserInteractionRoutes - define endpoints for microservices
• ContentControllers, UserControllers, UserInteractionControllers - handle business logic and return responses; if error forward to error handler
• ContentMiddleware, UserMiddleware, UserInteractionMiddleware to manipulate and validate requests; don't return responses, forward errors to error handler
• APiError - Error handler; extends native Error; Single point of entry for sending 4xx and 5xx errors

LLD

Content Service

• Middlewares

  • check if userId is valid and user exists by contacting user service
  • check if contentId is valid and content exists
  • error handler

• Controllers

  • a controller each for CRUD on contents
  • sort contents by top and new
  • contact user interaction service's internal API that is secured via TOTP, to fetch likes and reads, and sort contents by top defined as (reads + likes)
  • TOTP_KEY used for generating TOTPs is agreed upon before hand by the 2 services and TOTP sent in headers
  • controller for inserting documents to DB from csv file
  • internal method to sort by new, result is reused for sorting by top

User Service

• Middlewares

  • check if userId is valid and user exists
  • check if contentId is valid and content exists by contacting content service
  • error handler

• Controllers

  • a controller each for CRUD on User

User Interaction Service

• Middlewares

  • check if userId is valid and user exists by contacting user service
  • check if contentId is valid and content exists by contacting content service
  • validate recieved TOTP for content/stats endpoint, send 401 if the TOTPs don't match
  • error handler

• Controllers

  • read and update likes count
  • read and update reads count
  • internal API for returning likes and reads count on content to assist in sorting by top

Developer Empathy

• Used conventional commits, husky and commitlint to write meaningful and organized commit messages
• Used eslint to enforce code style and check for errors