RythmCast - Spotify Microservices App

Description

RythmCast lets users authenticate with Spotify, analyze listening habits, and generate/save personalized playlists. The project demonstrates a containerized microservices architecture with strict network isolation.

Technology Stack

• Frontend: Node.js + Express static server
• API 1: Node.js + Express + PostgreSQL (users/auth)
• API 2: Node.js + Express + PostgreSQL (Spotify tokens and recommendations)
• Reverse Proxy + Load Balancer: Nginx (gateway + round-robin on API2 replicas)
• Queue: Redis (job queue endpoints in API2)
• GraphQL: API1 /graphql
• API Documentation: Swagger UI on API1 /docs
• Orchestration: Docker Compose
• CI/CD + Security: Gitea Actions + Trivy + Docker Buildx

Architecture

flowchart LR
  U[User] --> G[Nginx Gateway]
  G --> F[Frontend]
  G --> A1[API 1 Users]
  G --> A2[API 2 Spotify]
  G --> A2R[API 2 Spotify Replica]
  A1 --> D1[(PostgreSQL db1)]
  A2 --> D2[(PostgreSQL db2)]
  A2R --> D2
  A2 --> R[(Redis Queue)]
  A2R --> R

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Network isolation rules implemented:

• Frontend can access API 1 and API 2.
• API 1 can access only db1.
• API 2 can access only db2.
• Databases are isolated from host and from each other.

Installation

1. Clone repository

git clone <your-repo-url>
cd RythmCast

2. Copy env template if needed

cp .env.example .env

3. Start all services

docker compose up --build

4. Open app

• Frontend: http://localhost:3000
• API 1 docs (Swagger): http://localhost:3000/docs
• API 1 GraphQL: http://localhost:3000/graphql
• API 2 queue status: http://localhost:3000/api/spotify/queue/status

Bonus Features Implemented

• Reverse proxy with Nginx gateway (proxy/nginx.conf)
• Load balancing with API2 round-robin (api2 + api2-replica upstream)
• Queue system with Redis and API2 queue endpoints:
  • POST /api/spotify/queue/enqueue
  • POST /api/spotify/queue/dequeue
  • GET /api/spotify/queue/status
• GraphQL endpoint on API1: GET/POST /graphql
• Multi-stage Docker builds for frontend, api1, and api2
• OpenAPI/Swagger docs for API1: GET /docs

Environment

Variable	Description	Example
FRONTEND_PORT	Frontend service port	3000
API1_PORT	API 1 service port	5001
API1_DATABASE_URL	PostgreSQL URL for API 1	postgresql://api1_user:api1_password@db1:5432/rythmcast_users
API2_PORT	API 2 service port	5002
API2_DATABASE_URL	PostgreSQL URL for API 2	postgresql://api2_user:api2_password@db2:5432/rythmcast_spotify
DOCKERHUB_USERNAME	Docker Hub namespace for CI push	iam2

Demo

• Click Se connecter avec Spotify on the frontend.
• Browse profile, top tracks, top artists, and recently played songs.
• Generate simple and smart playlists, then save to Spotify.
• Use API health endpoints to verify service status.

Data Persistence Proof

Two named volumes are configured:

• api1-db-data
• api2-db-data

Data remains after docker compose down and starting again with docker compose up.

CI/CD

Pipeline file: .gitea/workflows/ci.yaml

• Trivy security scan fails for MEDIUM, HIGH, CRITICAL.
• Builds all service images.
• Pushes images to Docker Hub on push events.

Team

See AUTHORS.md.

Presentation Assets

• Script: PRESENTATION_SCRIPT.md
• Live demo checklist: DEMO_FLOW.md
• Slide structure: SLIDES_OUTLINE.md