Large Scale Shopping App

Distributed shopping app prototype with a broker-based load-balancing layer and worker pool. Clients send shopping list operations to a broker, which routes requests to workers that persist data and return results. The design showcases message-based coordination, fault tolerance patterns, and scalable request handling.

Highlights

• Broker/worker architecture for load distribution
• Client UI flow with local database persistence
• ZeroMQ messaging and JSON payloads
• CRDT data structures for merge-friendly state

Architecture (high level)

Client -> Broker -> Worker Pool -> Database The broker owns routing and health checks. Workers process requests and write to storage. Clients interact via a simple CLI-driven UI.

Requirements

Tested on WSL2 (Ubuntu 20.04 LTS) and Arch Linux.

Dependencies:

• g++
• Make
• ZeroMQ
• Nlohmann JSON
• Pip (used by the provided dependency script)

Install system requirements:

make system-requirements

Build

make

Run

Start the broker:

make runBroker

Start one or more clients:

make runClient1
make runClient2

Or run a client directly:

mkdir -p database/local/user_name/
# Example: mkdir -p database/local/joao/
./src/client/client <broker_ip/port> <broker_heartbeat_ip/port> <path/to/database>

Start worker instances:

make runWorker1
make runWorker2
make runWorker3
make runWorker4
make runWorker5
make runWorker6
make runWorker7
make runWorker8

Or run a worker directly:

mkdir -p database/cloud/database_name/
# Example: mkdir -p database/cloud/my_database/
./src/worker/worker <broker> <service> <worker_pull_port> <worker_connect_address> <database_path>

Shutdown notes:

• Broker/worker processes: press CTRL+C in the terminal
• Client: choose the Exit option in the UI

Repo layout

• src/broker: broker entry point and routing logic
• src/worker: worker entry point and request handling
• src/client: client UI and local storage
• src/crdt: CRDT implementations
• test: unit tests
• doc: presentation and demo video

Documentation

Click on the links to view the Presentation slides and Demo Video.