Django WebSocket Blue/Green Deployment

A production-ready Django-based WebSocket service with zero-downtime blue/green Docker Compose deployment, observability, and health checks.

🚀 Features

• Blue/Green Deployment via Docker Compose (nginx reverse proxy with app_blue and app_green services)

• WebSocket Endpoint at /ws/chat/ powered by Uvicorn + Django Channels

• Observability with Prometheus metrics (/metrics) and Grafana dashboards

• Health Checks: /healthz (liveness) and /readyz (readiness)

• Automation Scripts:

  • scripts/promote.sh: Flip traffic from blue to green
  • scripts/monitor.sh: Tail logs for errors and print top‑5 Prometheus counters every 10 s
  • scripts/ws_test.js: k6 load test script for WebSocket performance

⚙️ Prerequisites

• Docker >= 27.0.0
• Docker Compose >= 2.29.0

🛠️ Quick Start

1. Clone the repository

git clone git@github.com:prxssh/prod-websocket-service && cd prod-websocket-service

2. Build and start the full stack

This command first spins up the required prerequisites for the application (Grafana, dashboards, k6, nginx) and then starts both app_blue and app_green services.

docker-compose --env-file dev.env -f docker/compose.yml up -d

3. Verify Services

• WebSocket: ws://localhost:80/ws/chat/?session=<uid>
• Liveness: http://localhost:80/healthz
• Readiness: http://localhost:80/readyz
• Metrics: http://localhost:80/metrics
• Grafana: http://localhost:3000 (default credentials admin/admin)

⚡ Blue/Green Deployment

To flip traffic from the current color to the standby color:

./scripts/promote.sh

This script will:

1. Build and start the next color stack
2. Run smoke tests against /healthz
3. Update nginx to route traffic
4. Tear down the old color stack

📊 Monitoring

Tail real-time logs for errors and see top‑5 Prometheus counters:

./scripts/monitor.sh

💥 Load Testing

By default, Docker Compose will run the k6 load test automatically when the application starts, writing results to k6-results/ (or you can view them via the k6 container logs).

To run the load test manually, execute:

k6 run scripts/ws_test.js

📚 Further Reading

• See DESIGN.md for concurrency and deployment rationale
• See OBSERVABILITY.md for Prometheus/Grafana setup