SystemHealthHelper.cs

using System;
using System.Collections.Generic;
using System.Diagnostics;

public static class SystemInfoHelper
{
    // Stores last CPU and time samples to compute deltas
    private static TimeSpan _lastCpu = TimeSpan.Zero;
    private static DateTime _lastSampleTime = DateTime.UtcNow;

    /// <summary>
    /// Returns the CPU usage percentage of the current IIS worker process (w3wp).
    /// This method does NOT require PerformanceCounter or registry access.
    /// </summary>
    public static double GetCpuUsage()
    {
        var process = Process.GetCurrentProcess();
        var now = DateTime.UtcNow;

        var currentCpu = process.TotalProcessorTime;
        var cpuUsedMs = (currentCpu - _lastCpu).TotalMilliseconds;
        var elapsedMs = (now - _lastSampleTime).TotalMilliseconds;

        // Update deltas
        _lastCpu = currentCpu;
        _lastSampleTime = now;

        if (elapsedMs <= 0)
            return 0;

        // CPU percentage normalized by number of logical processors
        var cpuPercent = cpuUsedMs / (elapsedMs * Environment.ProcessorCount);

        // Clamp between 0–100%
        cpuPercent = Math.Max(0, Math.Min(cpuPercent, 1));

        return Math.Round(cpuPercent * 100, 2);
    }

    /// <summary>
    /// Returns the memory usage (Working Set) of the current IIS worker process in MB.
    /// </summary>
    public static double GetMemoryUsageMB()
    {
        var bytes = Process.GetCurrentProcess().WorkingSet64;
        return Math.Round(bytes / 1024.0 / 1024.0, 2);
    }

    /// <summary>
    /// Returns readable uptime text (e.g. "2 days, 3 hours, 12 minutes").
    /// </summary>
    public static string GetReadableUptime()
    {
        var process = Process.GetCurrentProcess();
        var uptime = DateTime.UtcNow - process.StartTime.ToUniversalTime();

        return TimeSpanToReadableString(uptime);
    }

    /// <summary>
    /// Converts a TimeSpan to a friendly human-readable string.
    /// </summary>
    private static string TimeSpanToReadableString(TimeSpan ts)
    {
        var parts = new List<string>();

        if (ts.Days > 0)
            parts.Add($"{ts.Days} day{(ts.Days > 1 ? "s" : "")}");

        if (ts.Hours > 0)
            parts.Add($"{ts.Hours} hour{(ts.Hours > 1 ? "s" : "")}");

        if (ts.Minutes > 0)
            parts.Add($"{ts.Minutes} minute{(ts.Minutes > 1 ? "s" : "")}");

        if (ts.Seconds > 0)
            parts.Add($"{ts.Seconds} second{(ts.Seconds > 1 ? "s" : "")}");

        if (parts.Count == 0)
            return "0 seconds";

        return string.Join(", ", parts);
    }
}

var metrics = new
{
Cpu = SystemHealthHelper.GetCpuUsage(),
Memory = SystemHealthHelper.GetMemoryUsageBytes(),
Version = SystemHealthHelper.GetAppVersion(),
AppName = SystemHealthHelper.GetAppName(),
Uptime = SystemHealthHelper.GetUptime(),
Timestamp = DateTime.UtcNow
};

LogService.LogHeartbeat(metrics);