Orders Project

A microservices-based food delivery system exploring event-driven architecture, distributed systems patterns, and container orchestration. Built with FastAPI, MongoDB, Redis Streams, and React.

Deployed on a self-hosted Kubernetes cluster (Raspberry Pi) at orders.karolmarszalek.me.

What Makes This Interesting

• Event-driven choreography – services communicate exclusively through Redis Streams, with no synchronous inter-service calls

• Guaranteed message delivery – consumer groups, automatic retries, and a dead-letter queue ensure no event is silently lost

• ACID transactions + eventual consistency – MongoDB transactions guard local state, while async events propagate changes across services

• Real-time push – WebSocket connections deliver order status updates to the browser the moment they happen

• Full observability – Prometheus metrics, Grafana dashboards, and Loki log aggregation with structured correlation IDs

• Dual deployment – runs identically on Docker Compose (local) and Kubernetes with Helm (production)

Contents

• Getting Started
  • Prerequisites
  • Docker Compose (Quickstart)
  • Kubernetes (Helm)
• Architecture
  • Design Patterns & Principles
  • System Overview
  • Redis Streams as an Event Bus
  • Event Flow
  • MongoDB & Transactions
  • Kubernetes Deployment
• Services
  • Overview
  • Order Service
  • Delivery Service
  • Notifications Service
  • Order Simulator
  • Frontend
  • Supporting Infrastructure
• Monitoring & Observability
  • Stack
  • Grafana Dashboards
  • Prometheus Metrics
  • Quick Links (Docker Compose)
  • Access Control
  • Data Retention
  • Correlation & Tracing
• Deployment
  • Docker Compose
  • Kubernetes (Helm)
• Development
  • Tech Stack
  • UV Workspace
  • Linting & Type Checking
  • Testing
  • Project Structure