init xboard node

internal/monitor/monitor.go

@@ -0,0 +1,82 @@
+package monitor
+
+import (
+	"log/slog"
+	"runtime"
+	"time"
+
+	"github.com/shirou/gopsutil/v4/cpu"
+	"github.com/shirou/gopsutil/v4/disk"
+	"github.com/shirou/gopsutil/v4/mem"
+)
+
+var startTime = time.Now()
+
+func init() {
+	// Warm up the CPU sampler. The first cpu.Percent call with interval=0
+	// always returns 0% because it has no prior sample. This throwaway call
+	// seeds the baseline so subsequent Collect() calls return real values.
+	cpu.Percent(500*time.Millisecond, false)
+}
+
+// Status holds system resource metrics
+type Status struct {
+	Uptime     uint64
+	CPU        float64
+	CPUPerCore []float64
+	MemTotal   uint64
+	MemUsed    uint64
+	SwapTotal  uint64
+	SwapUsed   uint64
+	DiskTotal  uint64
+	DiskUsed   uint64
+
+	// GC metrics (process-wide)
+	NumGC       uint32
+	LastPauseMS float64
+}
+
+// Collect gathers current system metrics
+func Collect() Status {
+	var s Status
+
+	s.Uptime = uint64(time.Since(startTime).Seconds())
+
+	if cpuPercent, err := cpu.Percent(0, false); err == nil && len(cpuPercent) > 0 {
+		s.CPU = cpuPercent[0]
+	} else if err != nil {
+		slog.Debug("failed to get CPU usage", "error", err)
+	}
+
+	// Per-core CPU usage (best-effort; safe if it fails).
+	if perCore, err := cpu.Percent(0, true); err == nil && len(perCore) > 0 {
+		s.CPUPerCore = perCore
+	}
+
+	if vmStat, err := mem.VirtualMemory(); err == nil {
+		s.MemTotal = vmStat.Total
+		s.MemUsed = vmStat.Used
+	}
+
+	if swapStat, err := mem.SwapMemory(); err == nil {
+		s.SwapTotal = swapStat.Total
+		s.SwapUsed = swapStat.Used
+	}
+
+	if diskStat, err := disk.Usage("/"); err == nil {
+		s.DiskTotal = diskStat.Total
+		s.DiskUsed = diskStat.Used
+	}
+
+	// GC metrics
+	var ms runtime.MemStats
+	runtime.ReadMemStats(&ms)
+	s.NumGC = ms.NumGC
+	if ms.NumGC > 0 {
+		// PauseNs is a ring buffer of the most recent GC pause times.
+		idx := (ms.NumGC - 1) % uint32(len(ms.PauseNs))
+		s.LastPauseMS = float64(ms.PauseNs[idx]) / 1e6
+	}
+
+	return s
+}