Level 5: Capstone Unified Service (API Integration & Gin)¶

Welcome to the final level! Here, you will integrate everything you have built in Levels 1 through 4 into a single, cohesive backend gateway using Gin.

This project simulates a professional, production-grade microservice gateway that handles HTTP requests, concurrent file parsing, shortlink redirection, database storage, and live WebSockets.

Architecture & Integration Diagram¶

graph TD
    Client["Web & API Clients"] <-->|"HTTP & WebSockets"| Gin["Gin Router / API Gateway"]

    subgraph CORE_MODULES ["Core Modules"]
        Gin <-->|CRUD| Level1["Level 1: Task Manager"]
        Gin --->|"Multipart Uploads"| Level2["Level 2: Log Analyzer"]
        Gin <-->|"Shortening & Hits"| Level3["Level 3: URL Shortener"]
        Gin <-->|"Event Dispatch"| Level4["Level 4: Real-time Websocket Hub"]
    end

    Level4 <-->|"Pub/Sub Sync"| Redis["Redis Broker"]

API Endpoints to Support¶

Your unified API server must handle:

1. Task Tracker CRUD (Level 1)¶

GET /tasks: Return all tasks in JSON.
POST /tasks: Expects {"description": "Task Text"}. Adds task and publishes a WebSocket event notification: {"event": "task_created", "task": ...}.
PUT /tasks/:id/complete: Marks task complete. Publishes WebSocket notification: {"event": "task_completed", "id": 1}.

2. Concurrent Log Analyzer (Level 2)¶

POST /logs/analyze: Expects multipart form file uploads. Parses all uploaded logs concurrently using your Level 2 concurrent engine, aggregates findings, and returns the unified LogResult summary JSON.

3. URL Shortener (Level 3)¶

POST /shorten: Expects {"url": "https://..."}. Saves short link and publishes WebSocket notification: {"event": "url_shortened", "code": "abcde"}.
GET /:short_code: Increments hit counter, redirects browser, and publishes WebSocket notification: {"event": "url_hit", "code": "abcde", "hits": 5}.

4. Live Event Feed (Level 4)¶

GET /ws: Upgrades the connection to WebSockets. Subscribes the client to the Level 4 Event Hub so they receive all the live event messages dispatched by the other endpoints.

Getting Started¶

Ensure the go.mod is set up with dependencies. Run this to fetch Gin and gorilla/websocket:
```
/usr/local/go/bin/go get github.com/gin-gonic/gin github.com/gorilla/websocket
```
See main.go for the integration router stubs.
See main_test.go for the endpoint test suite.

Run tests:

/usr/local/go/bin/go test -v ./level5_integrated_system/...