🚀 Takeoff Mailer A high-performance, resilient email consumer built in Rust to handle transactional email delivery for the TAKEOFF event. This service implements a decoupled, event-driven architecture using RabbitMQ for reliable message delivery and Protobuf for strict schema enforcement. 🏗 System Architecture The mailer is designed with a "Reliability First" philosophy to ensure no attendee ever misses a QR code or confirmation.

• Asynchronous Processing: Offloads email sending from the main API to a dedicated Rust worker.
• Protocol Buffers: Uses email.proto to ensure data integrity between the Node.js producer and Rust consumer.
• DLX (Dead Letter Exchange): Features an automated "Hospital" queue (email_failed_queue) for messages that fail after maximum retries or fail decoding. 🛠 Tech Stack
• Language: Rust (Tokio runtime)
• Broker: RabbitMQ (via lapin)
• Serialization: Google Protocol Buffers (prost)
• Monitoring: Datadog (Metrics/Traces) & Dozzle (Logs)
• Deployment: Docker / VPS 🚦 Getting Started Prerequisites
• Rust 1.75+
• protoc (Protobuf Compiler)
• Docker & Docker Compose Environment Variables Create a .env file in the root directory: AMQP_ADDR=amqp://guest:guest@localhost:5672/%2f SMTP_RELAY=smtp.example.com SMTP_USER=user@example.com SMTP_PASS=password RUST_LOG=info

Running Locally

• Start RabbitMQ: docker compose up -d rabbitmq

• Run the Worker: cargo run

🏥 Fault Tolerance & Recovery This repo includes a built-in recovery "stitch" for handling failures: The Dead Letter Pattern If a message fails delivery 3 times, it is automatically routed to the email_failed_queue. This prevents "Poison Pill" messages from clogging the main pipeline.

📊 Observability This service is fully instrumented for production visibility:

• Health Checks: Integrated with Docker health checks.
• Unified Tagging: Tags every log and metric with env:takeoff-prod and service:email-worker.
• Dashboard: Real-time throughput and error rates are monitored via Datadog. 📜 License Distributed under the MIT License. See LICENSE for more information.