monitor/docs/backend.md

Backend Documentation

The backend is built with FastAPI, providing a high-performance API to serve system metrics.

Core Files

main.py

• Entry point of the application.
• Defines the FastAPI app and CORS middleware.
• Endpoints:
  • GET /: Serves the monitor.html file.
  • GET /api/status: Orchestrates the monitoring tasks and returns a JSON response.
• Parallel Execution: Uses asyncio.gather and asyncio.to_thread to run blocking SSH/HTTP calls concurrently.

monitor_logic.py

• Contains the low-level monitoring functions.
• get_ssh_data():
  • Connects via SSH using paramiko.
  • Executes commands to fetch:
    • CPU Usage: top
    • RAM Usage: free
    • Disk Space: df
    • Temperature: /sys/class/thermal/thermal_zone0/temp or vcgencmd.
• check_web_service():
  • Performs an HTTP GET request.
  • Calculates latency in milliseconds.

Environment Variables

• PC_PASS: SSH password for the Ubuntu Server.
• PI_PASS: SSH password for the Raspberry Pi.