Initial commit: Beszel fork with Domain Locker integration

agent/cpu.go

@@ -0,0 +1,131 @@
+package agent
+
+import (
+	"math"
+	"runtime"
+
+	"github.com/henrygd/beszel/internal/entities/system"
+	"github.com/shirou/gopsutil/v4/cpu"
+)
+
+var lastCpuTimes = make(map[uint16]cpu.TimesStat)
+var lastPerCoreCpuTimes = make(map[uint16][]cpu.TimesStat)
+
+// init initializes the CPU monitoring by storing the initial CPU times
+// for the default 60-second cache interval.
+func init() {
+	if times, err := cpu.Times(false); err == nil && len(times) > 0 {
+		lastCpuTimes[60000] = times[0]
+	}
+	if perCoreTimes, err := cpu.Times(true); err == nil && len(perCoreTimes) > 0 {
+		lastPerCoreCpuTimes[60000] = perCoreTimes
+	}
+}
+
+// CpuMetrics contains detailed CPU usage breakdown
+type CpuMetrics struct {
+	Total  float64
+	User   float64
+	System float64
+	Iowait float64
+	Steal  float64
+	Idle   float64
+}
+
+// getCpuMetrics calculates detailed CPU usage metrics using cached previous measurements.
+// It returns percentages for total, user, system, iowait, and steal time.
+func getCpuMetrics(cacheTimeMs uint16) (CpuMetrics, error) {
+	times, err := cpu.Times(false)
+	if err != nil || len(times) == 0 {
+		return CpuMetrics{}, err
+	}
+	// if cacheTimeMs is not in lastCpuTimes, use 60000 as fallback lastCpuTime
+	if _, ok := lastCpuTimes[cacheTimeMs]; !ok {
+		lastCpuTimes[cacheTimeMs] = lastCpuTimes[60000]
+	}
+
+	t1 := lastCpuTimes[cacheTimeMs]
+	t2 := times[0]
+
+	t1All, _ := getAllBusy(t1)
+	t2All, _ := getAllBusy(t2)
+
+	totalDelta := t2All - t1All
+	if totalDelta <= 0 {
+		return CpuMetrics{}, nil
+	}
+
+	metrics := CpuMetrics{
+		Total:  calculateBusy(t1, t2),
+		User:   clampPercent((t2.User - t1.User) / totalDelta * 100),
+		System: clampPercent((t2.System - t1.System) / totalDelta * 100),
+		Iowait: clampPercent((t2.Iowait - t1.Iowait) / totalDelta * 100),
+		Steal:  clampPercent((t2.Steal - t1.Steal) / totalDelta * 100),
+		Idle:   clampPercent((t2.Idle - t1.Idle) / totalDelta * 100),
+	}
+
+	lastCpuTimes[cacheTimeMs] = times[0]
+	return metrics, nil
+}
+
+// clampPercent ensures the percentage is between 0 and 100
+func clampPercent(value float64) float64 {
+	return math.Min(100, math.Max(0, value))
+}
+
+// getPerCoreCpuUsage calculates per-core CPU busy usage as integer percentages (0-100).
+// It uses cached previous measurements for the provided cache interval.
+func getPerCoreCpuUsage(cacheTimeMs uint16) (system.Uint8Slice, error) {
+	perCoreTimes, err := cpu.Times(true)
+	if err != nil || len(perCoreTimes) == 0 {
+		return nil, err
+	}
+
+	// Initialize cache if needed
+	if _, ok := lastPerCoreCpuTimes[cacheTimeMs]; !ok {
+		lastPerCoreCpuTimes[cacheTimeMs] = lastPerCoreCpuTimes[60000]
+	}
+
+	lastTimes := lastPerCoreCpuTimes[cacheTimeMs]
+
+	// Limit to the number of cores available in both samples
+	length := min(len(lastTimes), len(perCoreTimes))
+
+	usage := make([]uint8, length)
+	for i := 0; i < length; i++ {
+		t1 := lastTimes[i]
+		t2 := perCoreTimes[i]
+		usage[i] = uint8(math.Round(calculateBusy(t1, t2)))
+	}
+
+	lastPerCoreCpuTimes[cacheTimeMs] = perCoreTimes
+	return usage, nil
+}
+
+// calculateBusy calculates the CPU busy percentage between two time points.
+// It computes the ratio of busy time to total time elapsed between t1 and t2,
+// returning a percentage clamped between 0 and 100.
+func calculateBusy(t1, t2 cpu.TimesStat) float64 {
+	t1All, t1Busy := getAllBusy(t1)
+	t2All, t2Busy := getAllBusy(t2)
+
+	if t2All <= t1All || t2Busy <= t1Busy {
+		return 0
+	}
+	return clampPercent((t2Busy - t1Busy) / (t2All - t1All) * 100)
+}
+
+// getAllBusy calculates the total CPU time and busy CPU time from CPU times statistics.
+// On Linux, it excludes guest and guest_nice time from the total to match kernel behavior.
+// Returns total CPU time and busy CPU time (total minus idle and I/O wait time).
+func getAllBusy(t cpu.TimesStat) (float64, float64) {
+	tot := t.Total()
+	if runtime.GOOS == "linux" {
+		tot -= t.Guest     // Linux 2.6.24+
+		tot -= t.GuestNice // Linux 3.2.0+
+	}
+
+	busy := tot - t.Idle - t.Iowait
+
+	return tot, busy
+}