Bay: ticket ordering platform build on Microservices architecture

Event based microservices

TODOs:

• Authentication with JWT
• Authorization with AC rules
• many more

Functional features:

• User signup/in
• Ticket creation and listing
• Placing order
• Purchasing tickets

Techs & languages & tools:

• React
• Next
• Chakra UI
• Skaffold
• Kubernetes
• Docker
• Node
• Express
• MongoDB
• PostgresSQL
• Redis
• NATS (Event Bus)
• TypeScript
• Golang
• RESTful APIs
• Postman

Some remarks

JWT_KEY is generated and maintained by kubernetes, it makes sure to make JWT_KEY available for pods in the form of env variables

• cmd: kubectl create secret generic jwt-secret --from-literal=JWT_KEY=some-very-secret-key

express-async-errors: we need to handle error thrown by express, by default it handles sync route handlers (function), but in case of we mark handler with async like: async (res, req) = {}, then the request just hangs, to fix this issue we used express-async-errors

Useful resources:

• secure-web-app-http-headers
• intro-to-yaml-creating-a-kubernetes-deployment
• ingress

NextJS

in order to load/add global packages/styles/anything into all components that we need provide custom _app.js add import all global packages inside it and if needed pass as props global options

Component is any file inside /pages (Next makes them into route-able pages)

https://github.com/vercel/next.js/blob/canary/errors/css-global.md

function _app({ Component, pageProps }) {
  return  <Component props={...pageProps} />
}

• When use SSR then we can only use cookies as Auth mechanism as in the initial render happens inside Server and we don't have javascript in browser when type somedomain.com into browser tab, so we can set neither request body (sending Auth token as part of body) nor we can set Authorization header, whereas, in typical SPA app (React) we can do this:

Options	Cookie	Authorization header	Request body
SSR (Next)	true	false	false
SPA (React)	true	true	true

TODO: use custom Formik in codesandbox in next client app

Error when NextJS run inside docker (Kubernetes)

We get some strange error when deploy NextJS app inside Kubernetes cluster, specifically, when we call getInitialProps we can TCP connect ECONNREFUSED 127.0.0.1:80 error

https://stackoverflow.com/questions/55617722/nextjs-getinitialprops-not-working-with-nginx

Some gotcha of getInitialProps:

getInitialProps almost always executed in Server in initial rendering but: getInitialProps can be executed from browser in some particular cases, which is when navigating from one page to another while in the app

from official docs:

For the initial page load, getInitialProps will run on the server only. getInitialProps will then run on the client when navigating to a different route via the next/link component or by using next/router. However, if getInitialProps is used in a custom _app.js, and the page being navigated to implements getServerSideProps, then getInitialProps will run on the server.

Cross Namespace Service Communication

kubectl get services -n ingress-nginx to find the correct service name for your specific Kubernetes provider.

when making request from Pod(container) namespace (but actual request is originated from browser into NextJS app) to another container in another namespace or ingress-nginx inside k8s cluster we need pass by all headers to another container in another namespace, especially Host and cookie

NextJS -> Cluster[ingres-nginx -> next-js-pod -> ingress-nginx -> auth-app-in-another-pod]

Global signup method for only testing purposes

  global.signup = async () => {
  const email = "test@test.com";
  const password = "password";

  const resp = await request(app).
  post('/api/users/signup').
  send({email, password}).
  expect(201);

  const cookie = resp.get('Set-Cookie');

  return cookie;
}

TODO: Mocking databases MongoDB in tests instead of using real mongodb connection

TODO: Test OCC related cases in orders/tests/test-script-to-check-occ.ts