新增Linux GPU监控功能

参考了nezha-agent。实现了Linux服务器下NVIDIA显卡的监控。
通过 --gpu 参数启用显卡监控功能。
支持多显卡，显卡使用率，显存使用率监控
实现了AMD显卡的监控，但是未经过测试

monitoring/unit/gpu_nvidia_smi.go

@@ -0,0 +1,200 @@
+package monitoring
+
+// Modified from https://github.com/influxdata/telegraf/blob/master/plugins/inputs/nvidia_smi/nvidia_smi.go
+// Original License: MIT
+
+import (
+	"encoding/xml"
+	"errors"
+	"os"
+	"os/exec"
+	"strconv"
+	"strings"
+)
+
+type NvidiaSMI struct {
+	BinPath string
+	data    []byte
+}
+
+// NVIDIAGPUInfo 包含详细的NVIDIA GPU信息
+type NVIDIAGPUInfo struct {
+	Name        string  // GPU型号
+	MemoryTotal uint64  // 总显存 (字节)
+	MemoryUsed  uint64  // 已用显存 (字节)
+	Utilization float64 // GPU使用率 (0-100)
+	Temperature uint64  // 温度 (摄氏度)
+}
+
+func (smi *NvidiaSMI) GatherModel() ([]string, error) {
+	return smi.gatherModel()
+}
+
+func (smi *NvidiaSMI) GatherUsage() ([]float64, error) {
+	return smi.gatherUsage()
+}
+
+// GatherDetailedInfo 获取详细GPU信息
+func (smi *NvidiaSMI) GatherDetailedInfo() ([]NVIDIAGPUInfo, error) {
+	return smi.gatherDetailedInfo()
+}
+
+func (smi *NvidiaSMI) Start() error {
+	if _, err := os.Stat(smi.BinPath); os.IsNotExist(err) {
+		binPath, err := exec.LookPath("nvidia-smi")
+		if err != nil {
+			return errors.New("nvidia-smi tool not found")
+		}
+		smi.BinPath = binPath
+	}
+	smi.data = smi.pollNvidiaSMI()
+	return nil
+}
+
+func (smi *NvidiaSMI) pollNvidiaSMI() []byte {
+	cmd := exec.Command(smi.BinPath, "-q", "-x")
+	output, err := cmd.CombinedOutput()
+	if err != nil {
+		return nil
+	}
+	return output
+}
+
+func (smi *NvidiaSMI) gatherModel() ([]string, error) {
+	var stats nvidiaSMIXMLResult
+	var models []string
+
+	if err := xml.Unmarshal(smi.data, &stats); err != nil {
+		return nil, err
+	}
+
+	for _, gpu := range stats.GPUs {
+		if gpu.ProductName != "" {
+			models = append(models, gpu.ProductName)
+		}
+	}
+
+	return models, nil
+}
+
+func (smi *NvidiaSMI) gatherUsage() ([]float64, error) {
+	var stats nvidiaSMIXMLResult
+	var usageList []float64
+
+	if err := xml.Unmarshal(smi.data, &stats); err != nil {
+		return nil, err
+	}
+
+	for _, gpu := range stats.GPUs {
+		usage, err := parsePercentageValue(gpu.Utilization.GPUUtil)
+		if err != nil {
+			usage = 0.0 // 默认为0，不中断处理
+		}
+		usageList = append(usageList, usage)
+	}
+
+	return usageList, nil
+}
+
+func (smi *NvidiaSMI) gatherDetailedInfo() ([]NVIDIAGPUInfo, error) {
+	var stats nvidiaSMIXMLResult
+	var gpuInfos []NVIDIAGPUInfo
+
+	if err := xml.Unmarshal(smi.data, &stats); err != nil {
+		return nil, err
+	}
+
+	for _, gpu := range stats.GPUs {
+		utilization, _ := parsePercentageValue(gpu.Utilization.GPUUtil)
+		memTotal, _ := parseMemoryValue(gpu.FrameBufferMemoryUsage.Total)
+		memUsed, _ := parseMemoryValue(gpu.FrameBufferMemoryUsage.Used)
+		temp, _ := parseTemperatureValue(gpu.Temperature.GPUTemp)
+
+		gpuInfo := NVIDIAGPUInfo{
+			Name:        gpu.ProductName,
+			MemoryTotal: memTotal,
+			MemoryUsed:  memUsed,
+			Utilization: utilization,
+			Temperature: temp,
+		}
+
+		gpuInfos = append(gpuInfos, gpuInfo)
+	}
+
+	return gpuInfos, nil
+}
+
+// 解析百分比值 (例如 "25 %" -> 25.0)
+func parsePercentageValue(value string) (float64, error) {
+	cleaned := strings.TrimSpace(value)
+	cleaned = strings.TrimSuffix(cleaned, "%")
+	cleaned = strings.TrimSpace(cleaned)
+
+	if cleaned == "" {
+		return 0.0, nil
+	}
+
+	result, err := strconv.ParseFloat(cleaned, 64)
+	if err != nil {
+		return 0.0, err
+	}
+
+	return result, nil
+}
+
+// 解析内存值 (例如 "1024 MiB" -> 1073741824字节)
+func parseMemoryValue(value string) (uint64, error) {
+	cleaned := strings.TrimSpace(value)
+	cleaned = strings.TrimSuffix(cleaned, "MiB")
+	cleaned = strings.TrimSpace(cleaned)
+
+	if cleaned == "" {
+		return 0, nil
+	}
+
+	result, err := strconv.ParseUint(cleaned, 10, 64)
+	if err != nil {
+		return 0, err
+	}
+
+	// 转换MiB为字节 (1 MiB = 1024*1024 bytes)
+	return result * 1024 * 1024, nil
+}
+
+// 解析温度值 (例如 "65 C" -> 65)
+func parseTemperatureValue(value string) (uint64, error) {
+	cleaned := strings.TrimSpace(value)
+	cleaned = strings.TrimSuffix(cleaned, "C")
+	cleaned = strings.TrimSpace(cleaned)
+
+	if cleaned == "" {
+		return 0, nil
+	}
+
+	result, err := strconv.ParseUint(cleaned, 10, 64)
+	if err != nil {
+		return 0, err
+	}
+
+	return result, nil
+}
+
+// NVIDIA-SMI XML结构定义
+type nvidiaSMIXMLResult struct {
+	GPUs []nvidiaSMIGPU `xml:"gpu"`
+}
+
+type nvidiaSMIGPU struct {
+	ProductName string `xml:"product_name"`
+	Utilization struct {
+		GPUUtil string `xml:"gpu_util"`
+	} `xml:"utilization"`
+	FrameBufferMemoryUsage struct {
+		Total string `xml:"total"`
+		Used  string `xml:"used"`
+		Free  string `xml:"free"`
+	} `xml:"fb_memory_usage"`
+	Temperature struct {
+		GPUTemp string `xml:"gpu_temp"`
+	} `xml:"temperature"`
+}