Ticketing Project

Simple microservices project to practice microservices communication (here - NATS streaming server), handling concurrency etc.

Kubernetes for deployments - each service with its own database
Tests setup with mongo-memory-server

Taken from my other repository sebslon/Other/07-microservices-node-react/02-ticketing - extracted it to it's own repository to setup CI/CD. :)

Quick overview - Ticketing App

Users can list a ticket for an event (concert, sports) for sale
Other users can purchase this ticket
Any user can list tickets for sale and purchase tickets
When an user attempts to purchase a ticket, the ticket is 'locked' for 15 minutes (or another time). The user has 15 minutes to enter their payment info.
While locked, no other user can purchase the ticket. After 15 minutes, the ticket should 'unlock'
Ticket prices can be edited if they are not locked

Services are created separately to manage each type of resource - for education purposes only. Perhaps 'feature-based' design would be better.

Some of the problems & solutions in this project

Lots of duplicated code                               -> Central library as an NPM module to share code between our different projects
Hard to picture the flow of events between services   -> Precisely define all of our events in this shared library
Hard to remember what properties an event should have -> Write everything in TypeScript
Hard to test some event flows                         -> Write tests for as much possible/reasonable
Using too much of resources on local computer         -> Run a k8s cluster in the cloud and develop on it almost as quickly as local
Concurrency issues                                    -> Create a solutions for those (e.g versioning)

Services in the project

: service ( published events ) :

Auth - Everything related to user signup/signin/signout
Tickets - Ticket creation/editing. Knows whether ticket can be updated (ticket:created, ticket:updated)
Orders - Order creation/editing (order:created, order:cancelled)
Expiration - Watches for oders to be created, cancels them after 15 minutes (expiration:complete)
Payments - Handles credit card payments. Cancels orders if payments fails, completes if payment succeeds (payment:created)

Some Kubernetes stuff

Creating a secret kubectl create secret generict jwt-secret --from-literal=<key>=<value> - kubectl create secret generict jwt-secret --from-literal=JWT_KEY=<value>

Other stuff

Optimistic Concurrency Control (e.g. mongoose-update-if-current)
- In case of other databases etc. more preferable approach is implementing custom version control (/orders/models/ticket.ts - commented out $watch)

sebslon / microservices-node