🚀 Sentinel-Core

Sentinel-Core is an engineering laboratory for exploring event-driven architectures, observability, reliability, security, and modern DevOps practices.

Rather than being a finished product, Sentinel-Core serves as a hands-on environment for studying how modern systems communicate through events, process asynchronous workloads, recover from failures, and expose operational insights.

The goal is not to build a startup or a production platform, but to understand the architectural patterns and operational challenges behind real-world software systems.

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🎯 Objectives

• Explore event-driven architectures and asynchronous communication.
• Study resilient backend patterns and failure recovery strategies.
• Practice observability and monitoring workflows.
• Understand security concerns in distributed environments.
• Experiment with infrastructure and deployment pipelines.
• Develop a deeper understanding of how modern software systems operate.

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🏗️ Learning Focus

Sentinel-Core focuses on building and documenting small experiments that explore how different components of a distributed system interact.

Potential areas of exploration include:

Clients
    ↓
API Gateway
    ↓
Authentication & Authorization
    ↓
Message Queue
    ↓
Background Workers
    ↓
Database
    ↓
Monitoring & Observability

The architecture will evolve as new concepts and experiments are introduced.

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🧠 Concepts Explored

Event-Driven Systems

• Publish-and-subscribe patterns
• Asynchronous communication
• Event processing
• Background jobs

Reliability

• Retry strategies
• Idempotency
• Timeout handling
• Dead-letter queues

Scalability

• Worker pools
• Task distribution
• Horizontal scaling concepts

Observability

• Centralized logging
• Metrics collection
• Health checks
• Alerting concepts

Security

• JWT authentication
• Role-based access control
• Secrets management
• Rate limiting
• Audit logging

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⚙️ Technologies Being Explored

Backend

• Node.js
• TypeScript
• Express
• Fastify

Data & Caching

• PostgreSQL
• Redis

Event Infrastructure

• RabbitMQ
• BullMQ

DevOps & Tooling

• Docker
• Docker Compose
• GitHub Actions

Monitoring & Observability

• Prometheus
• Grafana
• Loki

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📂 Target Repository Structure

This structure represents a possible direction for the project and may change as new experiments are added.

sentinel-core/

├── apps/
│   ├── gateway/
│   └── auth-service/
│
├── workers/
│   ├── queue-worker/
│   └── email-worker/
│
├── infrastructure/
│   ├── docker/
│   ├── monitoring/
│   └── nginx/
│
├── shared/
│   ├── logger/
│   ├── config/
│   └── utilities/
│
└── docs/

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📈 Areas of Exploration

• Authentication and authorization
• Event-driven communication
• Background processing
• Queue management
• Metrics and dashboards
• Logging and monitoring
• CI/CD workflows
• Containerized deployments
• Security scanning

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🔬 Questions Explored

Sentinel-Core is built around questions such as:

• What happens when services fail?
• How do systems recover from errors?
• How are background tasks processed reliably?
• How do engineers debug production issues?
• How are distributed systems monitored?
• How do teams deploy software safely?

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🌱 Learning Philosophy

Sentinel-Core is not intended to become a startup or a production platform.

It is an engineering sandbox designed to explore how reliability, security, scalability, and operations come together in modern software systems.

The goal is not simply to build features.

The goal is to understand the systems behind them—one experiment at a time.