Ticketing App - Microservices & Event Driven Architecture

Local Dev

Set up ingress-nginx controller

• This is required for both local dev K8s cluster and DigitalOcean K8s cluster

Check ingress-nginx documentation: https://kubernetes.github.io/ingress-nginx/

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Create secret tokens in k8s cluster

• This is required for both local dev k8s and DigitalOcean k8s

e.g. To create a secret token in k8s cluster that is used for stripe payment service:

kubectl create secret generic stripe-secret --from-literal STRIPE_KEY=[YOUR_STRIPE_SECRET_KEY]

And inside payment service k8s deployment config file (payments-depl.yaml):

- name: STRIPE_KEY
  valueFrom:
    secretKeyRef:
      name: stripe-secret
      key: STRIPE_KEY
      
And for the confirmation service: 
kubectl create secret generic sendgrid-secret --from-literal SENDGRID_API_KEY=[YOUR_SENDGRID_API_KEY]

And inside confirmation service k8s deployment config file (confirmation-depl.yaml):

- name: SENDGRID_API_KEY
  valueFrom:
    secretKeyRef:
      name: sendgrid-secret
      key: SENDGRID_API_KEY
      

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Set up mock host name (local dev)

• To redirect requests coming to: ticketing.dev => localhost

• only for local development purposes

• MacOS/Linux:
  modify /etc/hosts file to include 127.0.0.1 ticketing.dev

• Windows:
  modify C:\Windows\System32\Drivers\etc\hosts file to include 127.0.0.1 ticketing.dev

• To skip the unskippable HTTPS warning in Chrome:
  try type thisisunsafe

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Skaffold (local dev)

Install Skaffold Dev Tool: brew install skaffold

From root project directory: run skaffold dev

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Authentication Strategies

• Want no backend session storage when using Microservices architecture - so stick with JWT.

• Want to use Server-Side Rendering and access user's auth information when HTML first gets rendered - so store and transmit JWT within Cookies, i.e. use cookies as a transport mechanism.

• Want to be able to revoke a user - so use short-lived JWT (e.g. expired in 15 minutes) with refresh mechanism.

CI/CD: Github Actions

Frontend Client

Built with NextJS

Minimalistic ReactJS framework for rendering React app on the server. https://nextjs.org/

Routes

• /
  Show list of all tickets

• /auth/signin
  Show sign in form

• /auth/signup
  Show sign up form

• /auth/signout
  Sign out

• /tickets/new
  Form to create a new ticket

• /tickets/:ticketId
  Details about a specific ticket

• /tickets/:orderId
  Show info about an order and payment button

Common NPM Module

All the commonly used classes, interfaces and middlewares, etc. are extracted into a published NPM Module.

• @ojticketing/common: https://www.npmjs.com/package/@ojticketing/common

  Contains commonly used Middlewares and Error Classes for ticketing microservices

Backend API

Microservices + Event-Driven Architecture

• NATS Streaming Server

Optimistic Concurrency Control

• Leverage mongoose-update-if-current npm module to update mongodb documents' version.

auth service

• GET /api/users/currentUser
  Get current user's information

• POST /api/users/signup
  { "email": "test@gmail.com", "password": "123456" }
  User Sign up

• POST /api/users/signin
  { "email": "test@gmail.com", "password": "123456" }
  User sign in

• POST /api/users/signout
  {}
  User sign out

tickets service

• GET /api/tickets
  Retrieve all tickets

• GET /api/tickets/:id
  Retrieve ticket with specific ID

• POST /api/tickets
  { title: string, price: string }
  Create a ticket

• PUT /api/tickets/:id
  { title: string, price: string }
  Update a ticket

orders service

• GET /api/orders
  Retrieve all active orders for the given user making the request

• GET /api/orders/:id
  Get details about a specific order

• POST /api/orders
  { ticketId: string }
  Create an order to purchase the specified ticket

• DELETE /api/orders/:id
  Cancel the order

expiration service

• BullJS
  Use Bull.js to manage job queues, with job delay option

• Redis
  Use Redis to store list of jobs

payments service

• StripeJS
  For handling payments

• POST /api/payments
  { token: string, orderId: string}
  Create new charge/payment

confirmation service

• BULLJS Use Bull.js to manage job queues

• Redis
  Use Redis to store list of jobs

• SENDGRID Email delivery service, used to send emails confirming purchase