Concert Booking API

🚀 High-concurrency ticket booking backend designed for war tiket scenarios: no overselling, fair reservation, and operational visibility out of the box.

✨ Why This Project

Most ticket-war systems fail in one or more of these areas:

• ⚠️ race condition leads to overselling
• ⚠️ synchronous write path melts under spike
• ⚠️ poor incident visibility in real-time
• ⚠️ unfair reserve/confirm flow for users

This MVP addresses those directly:

• ✅ Atomic reserve in Redis for real-time stock consistency
• ✅ Kafka decoupling for async persistence and better API responsiveness
• ✅ TTL reservation + rollback for fairness and stock recovery
• ✅ Observability-first with Prometheus and Grafana
• ✅ Load-testable using k6 with practical SLO threshold

🎯 What You Get

• 🛠️ Admin event and ticket category management
• ⚡ Realtime availability endpoint (backed by Redis stock)
• 🧱 Reserve endpoint with queue/backpressure control
• 💳 Confirm endpoint with idempotency and payment simulation
• ♻️ Expiry reaper for automatic stock release
• 🔐 JWT role auth (admin / user) and IP throttling
• 📘 Source-generated Swagger/OpenAPI
• 🐳 End-to-end Docker stack (API, Worker, Redis, Kafka, Postgres, Prometheus, Grafana)

🧭 System Snapshot

Client
  -> API (Go)
     -> Redis (atomic stock + reservation TTL)
     -> Kafka (reserved/confirmed/expired events)
        -> Worker (Go consumer)
           -> PostgreSQL

Metrics: API + Worker -> Prometheus -> Grafana

⚡ Quick Start (2 Minutes)

# 1) 🚀 boot stack
docker compose up -d --build

# 2) 🔑 generate tokens
go run ./cmd/token --role=admin --sub=admin-1 --secret=dev-secret
go run ./cmd/token --role=user --sub=user-1 --secret=dev-secret

# 3) 📊 open docs and dashboards
# Swagger:    http://localhost:8080/swagger/index.html
# Prometheus: http://localhost:9090
# Grafana:    http://localhost:3000  (admin/admin)

📡 API Surface

Core endpoints:

• POST /events (admin)
• POST /events/{id}/ticket-category (admin)
• GET /events/{id}/availability
• POST /reserve (user)
• POST /confirm (user)
• GET /health
• GET /metrics
• GET /swagger/index.html

Detailed API examples and schemas:

• docs/api.md

🧪 Performance & Validation

k6 scenario included in repository:

• file: k6/reserve.js
• target threshold: p(95) < 200ms

Run benchmark:

USER_TOKEN=<USER_TOKEN> \
EVENT_ID=<EVENT_ID> \
BASE_URL=http://localhost:8080 \
RATE=150 DURATION=20s PRE_VUS=150 MAX_VUS=1000 \
k6 run k6/reserve.js

Test and validation playbook:

• docs/testing.md
• docs/operations.md

📚 Documentation Map

• Project overview: docs/overview.md
• Architecture: docs/architecture.md
• API guide: docs/api.md
• Operations runbook: docs/operations.md
• Testing guide: docs/testing.md
• Swagger artifacts: docs/swagger

👨‍💻 Developer Workflow

go test ./...

CI runs test on push/PR via:

• .github/workflows/ci.yml

📄 License

MIT License. See LICENSE.