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microservices-architectured-app

An event-driven asynchronous communication based microservices architectured e-commerce app created using express, typescript, nats-streaming and next.js

What is this ?

It's an e-commerce based web app for buying and selling tickets of different live and fun events happening around the city based on microservices architecture. The app is broken down into multiple individual services that talk to each other through publishing events via an event bus. Each service is responsible for handling and implementing a specific feature of the app like auth service handles authentication, orders service handles orders, payments service implements user payments and all these services work and communicate asynchronously through an event bus(nats-streaming) to run the entire app

Why microservices ?

Using microservices architecture and not relying on the monoloith pattern makes the app more durable, fault tolerant, highly available and increases the up time of the app. So if one of the services crashes, other parts of the app will still be functional and available to the users. Microservices and distributed systems is the heart of modern software and backend engineering.

Technologies used

• Next.js for server side rendering and building frontend
• Express.js is used for building backend
• Mongodb as database
• Mongoose as an ORM
• Typescript , backend is written entirely in typescript to prevent headaches you get when infinte number of events are flowing around with no hints
• Stripe for handling payments
• Jest and Supertest for testing
• Docker for containerization
• Kubernetes for conatiner orchestration
• Skaffold command line tool that facilitates continuous development for Kubernetes-native applications. Makes working with and managing kubernetes and different kubernetes services and deploymets a lot easier.
• NATS Streaming is used as an event bus or message queue for publisihing and handling the events emitted by different services.
• Bull.js is a fast and robust queue system. It is used to implement the payment expiration timer.

App Architecture

The app is divided into 7 services that handle and implement a specific feature and functionality of the app:

• auth handles the entire app authentication and authorization. JWT and cookie based authentication is used.
• expiration handles the payment expiration timer to make sure user pays within a specified time frame.
• orders for handling user orders
• payments for handling stripe payments
• tickets for handling tickets(creating, updating, fetching). Instead of selling products, this e-commerce app sells tickets of different live events happening around the city.
• common all the common functionality like requireAuth, error handling, and other middlewares and functions shared by different services are grouped together. This service is published as an npm package and installed in other services to be used.
• client handles and implements the frontend of the app.
• infra manages all the kubernetes deployment and service (.yaml) files that run run the app

Kubernetes and Docker Architecture

Each service, mogongodb database and nats-streaming server is dockerized as a docker container. The docker conatiners are managed and orchestrated by their respective kubernetes deployment.yaml files inside the infra directory. The communication between different kuberentes deployments is governed by service ObjectType. Finally ingress-service, which uses ingress-nginx (an Ingress controller for Kubernetes using NGINX) as a reverse proxy and a load balancer to proxy or direct incoming requests to their respective services under the ticketing.dev hostname. Skaffold is used to get all the kubernetes deployments and services up and running with a single command skaffold dev which uses skaffold.yaml file.

Installation

Getting this project up and running on your local machine is a notoriously dfficult task. It requires some knowlege of docker and kubernetes ecosystem. If you are still up for the challenge, or if you don't have a life, try getting it work. Make sure you have docker, kubernetes and skaffold installed. Set the required envirenmental variables and run the following command:

skaffold dev

And boom app will be up and running, no extra setup and dependencies required.

To delete any resources deployed by Skaffold and stop all the deployments, services and containers run

skaffold delete

Suggestion

Try running and testing it locally only if you don't have a life. Otherwise I'm not the one to blame for you scratching your head 😫 while trying to understand this microservices mess of event-driven communication betweewn the services 😑

Note

I did this project as a part of Stephen Grider's Udemy Course. Thanks to him 😊