u-c-s/tickete-assignment

Tickete Backend Assignment Submission

Technologies used

• Fastify
• Prisma (Schema file available under prisma/schema.prisma)
• PostgreSQL
• TypeScript

Deployed in Render - https://chanakya-tickete-test.onrender.com (deployed server can take a while to wake up)

How to run the project

1. Clone the repository
2. Run npm install to install all the dependencies
3. create a postgres database (hosted or local)
4. create .env file in the root directory and add the following variables

TICKETE_API_KEY=xxxx

POSTGRES_PRISMA_URL="postgresql://postgres:[email protected]:5432/postgres"

5. use npx prisma generate to generate the prisma client bindings and types
6. use npm run dev to run the project in development mode, while npm build and npm start:prod to run in production mode

API Created

Type Definitions are available in types/slotsResponse.d.ts

• /api/v1/experience/<id>/slots?date=<date> (sample api)
• /api/v1/experience/<id>/dates (sample api)
• /api/v1/sync/resume
• /api/v1/sync/pause
• /api/v1/sync/status
• /test

Additional Notes/Reasoning

Platform

• Initially, I had planned to use fastify and migrate the project to Nestjs as its been a while since I used Nestjs. but decided to stick with Fastify as I need extra bit of time to relearn it.
• I initially planned to Deploy in Vercel but due to it being only "Serverless" thus app loses state and has only 10secs runtime and vercel cron jobs are only limited to 2 runs per day as per docs in free plan. I had to look into Render very later on, which uses traditional servers that runs on, found that it is better suited for this.
• One MAJOR LIMITATION of Render is the server falls sleep after 15mins of idle time (Spinning down) because of this the periodic inventory fetching is halted. since I am also not storing any state related to inventory fetching, fetching after waking the server up starts from zero.

Code

• I have also tried to handle the errors as much as possible, but I am sure there are some edge cases that I have missed - like there is an occasional issue related to race conditions when pushing data to db, which throws Unique Constraint Violation error, which I fixed in most cases and also took most of my time in debugging (like 60-70% of assignment time).
• For Normalization of database schema, I took inspiration out of give sample apis (the holdup-api.tickete ones), managed to acheive the similar while handling the duplicate values during syncing.

Performance

• The current implementation of Inventory Syncing may not be ideal, but I tried my best in making it bit scalable. it uses chunking and batching to reduce the load on RAM. Thus, effictively reducing the rate of failure. (like I have noticed before using this technique)
• I have also managed to achieve effective time which can make syncing with 450products every 15mins possible. I have found this with during one of the benchmarks where I was able make 62requests (for 2 product Ids over a month) in 127secs. I have made the source code available under /others/months.ts that did this - runnable with npx ts-node ./others/month.ts

Other

• I have learnt the existence of some library functions like - sturturedClone and Prisma's Upsert while working on this assignment.