🚧 This README is under construction 🚧

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📰 HappyHeadlines — Distributed News Platform

A microservice-based system demonstrating caching, monitoring, and observability across globally replicated news articles.
Built as part of a software development course project.

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🧱 Overview

HappyHeadlines replicates news articles and comments across multiple continents.
It demonstrates:

• Redis caching
• OpenTelemetry tracing (Zipkin)
• Prometheus metrics & Grafana dashboards
• Serilog centralized logging (Seq)

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🧩 Architecture

Service	Description
ArticleService	Handles CRUD for articles, global replication, and background cache refresh.
CommentService	Handles CRUD for comments and includes an LRU-based comment cache.
ProfanityService	Independent service for text moderation.
CacheService	Shared Redis abstraction used by other services.
Shared	Common DTOs, logging, metrics, and tracing setup (MonitorService).

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⚙️ Features

🧠 Caching

• ArticleCache
  • Background service loads articles from the last 14 days.
  • Refreshes every hour to keep Redis warm.
• CommentCache
  • Uses a cache-miss approach (only cached when first fetched).
  • Holds comments for 30 most recently accessed articles.
  • Applies LRU eviction to remove the least recently used key.

📊 Monitoring

• Prometheus collects metrics such as:
  • *_cache_hits_total
  • *_cache_misses_total
  • *_requests_total
• Grafana visualizes system performance and cache ratios.

🔍 Tracing

• OpenTelemetry + Zipkin
  • End-to-end traces show how services communicate.
  • Example: Creating a comment → Article lookup → Profanity check → DB save → Cache invalidation.

🪵 Logging

• Serilog + Seq
  • Centralized structured logs for each microservice.
  • Unified correlation IDs through TraceId.

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🧩 Monitoring Setup

Tool	URL
Prometheus	http://localhost:9090
Grafana	http://localhost:3000
Zipkin	http://localhost:9411
Seq	http://localhost:5341

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🧰 Tech Stack

Area	Tool
Language	C# (.NET 9)
Database	SQL Server
Cache	Redis
Monitoring	Prometheus + Grafana
Tracing	OpenTelemetry + Zipkin
Logging	Serilog + Seq
Messaging	RabbitMQ

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