Zeelow Gallery

Zeelow Gallery is a scalable and clean image carousel designed to handle a large user base and optimized for speed. This project is an evolution of a legacy commentary system that sought to replicate Zillow's gallery component. Zeelow Gallery builds on the legacy project by introducing a number of improvements:

• 🚀 Transition from SQLite to a more robust and scalable MongoDB database
• 👍 Server and client enhancements to handle extreme bursts in concurrent requests
  • Completely revamped client-side code that behaves well when positioned behind a load balancer such as Nginx
• 🎯 Database schema improvements
  • Appropriate indexing based on most commonly requested endpoints
• 🚢 Dockerfile for rapid deployment

Related Projects

• Proxy Server

Table of Contents

1. Overview
2. Requirements
3. Usage
4. Environment Variables

Overview

Client Interface:

Stress tests:

• Database server hosted on a single EC2 t2.micro
  • 10 million house records
• Node.js component server hosted on 4 EC2 t2.micros load balanced with Nginx
• Each request is a GET request for a random API endpoint (a house with id between 1 and 10,000,000)

2,500 Requests Per Second Over 30 Seconds (<0.1% Error Rate)

Requirements

• Node v10.13.0 (LTS as of May 2019) or higher
• Nodemon if using the default npm script
• MongoDB for the database server

Usage

Server

1. Install dependencies with npm install
2. After connecting to the database, from the root directory run node database/mongoDB/seed.js
3. The main server file is server/server.js -- If nodemon is already installed globally (it is not part of the dependencies), you may start the server via npm run server-dev for development purposes or npm start for production -- The server uses port 3010 by default, but you may set it using an environment variable process.env.PORT

Client

The client side is built using Parcel:

npm run dev: Builds the client-side files in development mode and does not do full bundling. This also activates watch mode by default so it rebuilds whenever you make and save changes

npm run build: Builds the client-side files in production mode, with full bundling. This reduces file size, but is less useful in debugging (some errors do not provide as much detail as in development mode)

Environment Variables

The following environment variables must be provided to the Node.js server

• PORT: Port used by the HTTP server; defaults to 3010
• MONGO_DB: MongoDB host address; defaults to localhost