init

2026-08-26 09:56:43 +08:00
parent 2b4974b561
commit 8e02a316fa
93 changed files with 21749 additions and 0 deletions
@@ -0,0 +1,123 @@
+//go:build linux
+
+package runtime
+
+import (
+	"bufio"
+	"context"
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
+	"time"
+)
+
+const cpuSampleInterval = 100 * time.Millisecond
+
+func hostCPUPercent(ctx context.Context) (float64, error) {
+	first, err := readLinuxCPUStat()
+	if err != nil {
+		return 0, err
+	}
+	timer := time.NewTimer(cpuSampleInterval)
+	defer timer.Stop()
+	select {
+	case <-ctx.Done():
+		return 0, ctx.Err()
+	case <-timer.C:
+	}
+	second, err := readLinuxCPUStat()
+	if err != nil {
+		return 0, err
+	}
+	totalDelta := second.total - first.total
+	busyDelta := second.busy - first.busy
+	if totalDelta == 0 || busyDelta > totalDelta {
+		return 0, fmt.Errorf("CPU counters did not advance")
+	}
+	return clampMetricPercent(100 * float64(busyDelta) / float64(totalDelta)), nil
+}
+
+type linuxCPUStat struct {
+	total uint64
+	busy  uint64
+}
+
+func readLinuxCPUStat() (linuxCPUStat, error) {
+	file, err := os.Open("/proc/stat")
+	if err != nil {
+		return linuxCPUStat{}, err
+	}
+	defer file.Close()
+	line, err := bufio.NewReader(file).ReadString('\n')
+	if err != nil {
+		return linuxCPUStat{}, err
+	}
+	fields := strings.Fields(line)
+	if len(fields) < 5 || fields[0] != "cpu" {
+		return linuxCPUStat{}, fmt.Errorf("/proc/stat CPU row is invalid")
+	}
+	values := make([]uint64, len(fields)-1)
+	for index, field := range fields[1:] {
+		value, parseErr := strconv.ParseUint(field, 10, 64)
+		if parseErr != nil {
+			return linuxCPUStat{}, fmt.Errorf("parse /proc/stat CPU counter: %w", parseErr)
+		}
+		values[index] = value
+	}
+	var total uint64
+	for _, value := range values {
+		total += value
+	}
+	idle := values[3]
+	if len(values) > 4 {
+		idle += values[4]
+	}
+	if idle > total {
+		return linuxCPUStat{}, fmt.Errorf("/proc/stat idle counter exceeds total")
+	}
+	return linuxCPUStat{total: total, busy: total - idle}, nil
+}
+
+func hostMemoryPercent() (float64, error) {
+	file, err := os.Open("/proc/meminfo")
+	if err != nil {
+		return 0, err
+	}
+	defer file.Close()
+	var total, available uint64
+	scanner := bufio.NewScanner(file)
+	for scanner.Scan() {
+		fields := strings.Fields(scanner.Text())
+		if len(fields) < 2 {
+			continue
+		}
+		value, parseErr := strconv.ParseUint(fields[1], 10, 64)
+		if parseErr != nil {
+			return 0, fmt.Errorf("parse /proc/meminfo: %w", parseErr)
+		}
+		switch fields[0] {
+		case "MemTotal:":
+			total = value
+		case "MemAvailable:":
+			available = value
+		}
+	}
+	if err := scanner.Err(); err != nil {
+		return 0, err
+	}
+	if total == 0 || available > total {
+		return 0, fmt.Errorf("/proc/meminfo memory counters are invalid")
+	}
+	return clampMetricPercent(100 * float64(total-available) / float64(total)), nil
+}
+
+func clampMetricPercent(value float64) float64 {
+	if value < 0 {
+		return 0
+	}
+	if value > 100 {
+		return 100
+	}
+	return value
+}