Monitoring

[yogeshnimangre007]

PR: Monitoring Dashboard & Accurate Byte Accounting

Summary

Add unified monitoring via /monitor (HTML dashboard + JSON API), correct byte accounting, documentation updates, and tests.

Changes

• Feature: /monitor HTML dashboard (auto-refresh) and /monitor?json=1 JSON stats
• Metrics: Requests, errors, bytes served (body only), uptime, upload statistics
• Fix: Accurate bytes_served tracking in send_response
• Tests: tests/monitor_test.rs (HTML presence, JSON schema subset, byte growth)
• Docs: Updated README.md, doc/API_REFERENCE.md, doc/ARCHITECTURE.md; added doc/MONITORING.md
• Refactor: Removed temporary counting wrapper; centralized stats recording in response path
• Template: Embedded monitor page (no external assets)

JSON Schema (Excerpt)

{
  "requests": { "total": 0, "successful": 0, "errors": 0, "bytes_served": 0, "uptime_secs": 0 },
  "downloads": { "bytes_served": 0 },
  "uploads": {
    "total_uploads": 0, "successful_uploads": 0, "failed_uploads": 0,
    "files_uploaded": 0, "upload_bytes": 0, "average_upload_size": 0,
    "largest_upload": 0, "concurrent_uploads": 0,
    "average_processing_time": 0.0, "success_rate": 0.0
  }
}

Rationale

Provides built-in observability without external dependencies and fixes previously static download byte counter.

Verification

• New monitor tests pass
• Manual file download increases bytes_served
• Existing endpoints unaffected (backward compatible)

Follow-Ups (Optional)

• Active connection count
• Per-endpoint metrics
• Prometheus/OpenMetrics exporter
• Rolling rate windows (RPS, throughput)
• Optional auth toggle for /monitor

Checklist

• Feature implemented
• Tests added
• Documentation updated
• Formatting & lint clean
• Backward compatible

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[dev-harsh1998]

LGTM