Shorten Url Demo

A complete shorten url application

Table of Contents

• Table of Contents
• Demo
• Features
• Design
• Limitation
• Redis
• CI/CD
• Kubernetes
• Core-ng
• Spring Boot
• Actix-web
• Authors

Demo

Let's play!

https://shorturl.hokamc.work

Features

• Add shorten url
• IP limiting (5 call for 1 hour)
• Redirect shorten url

Design

Use a distributed counter to encode the url to prevent duplicated url, and use a map to save all encoded and decoded url to fast look up. The whole design is for simplicity only, many other concerns like partitions, high available, CDN and more should be considered before production.

Limitation

• Non random url
• Single redis can only have 2^32 keys, so may need partitions design
• Single counter may become bottleneck

Statistic

Suppose we allow 6 characters only, there will be 62^6 (56800235584) possibles combinations for encoded url.

• HashTable for lookup: 62^6 * (2048 + 6) ~= 107 TB (*2048 longest url)

Analysis

Randomness

• Pre-generated combinations (Need large resource)
• Hash the url (Need conflict resolve)

Scalable

• Use a scalable database instead of redis, better for partitioning, persistent and replication
• A proper setup for CDN can reduce load from your application to CDN network

Redis

• Cache for shorten url mapping
• Cache for ip
• Safe incremental counter

CI/CD

I use Github action for CI. Major steps are building java, building image and push to registry.

You can check the image from hokamc/packages/shorten-url-demo

Kubernetes

A statefulset for redis and a deployment for app which is easy to scale up.

Core-ng

Spring Boot

Actix-web

Authors

• @hokamc