Using Win32 API instead WMI

Signed-off-by: Jan-Otto Kröpke <mail@jkroepke.de>

docs/collector.logical_disk.md

@@ -23,7 +23,7 @@ If given, a disk needs to *not* match the exclude regexp in order for the corres
 
 Name | Description | Type | Labels
 -----|-------------|------|-------
-`windows_logical_disk_info` | A metric with a constant '1' value labeled with logical disk information | gauge | `disk`,`partition`,`filesystem`,`serial_number`,`volume`,`volume_name`
+`windows_logical_disk_info` | A metric with a constant '1' value labeled with logical disk information | gauge | `disk`,`filesystem`,`serial_number`,`volume`,`volume_name`,`type`
 `windows_logical_disk_requests_queued` | Number of requests outstanding on the disk at the time the performance data is collected | gauge | `volume`
 `windows_logical_disk_avg_read_requests_queued` | Average number of read requests that were queued for the selected disk during the sample interval | gauge | `volume`
 `windows_logical_disk_avg_write_requests_queued` | Average number of write requests that were queued for the selected disk during the sample interval | gauge | `volume`
@@ -37,6 +37,7 @@ Name | Description | Type | Labels
 `windows_logical_disk_size_bytes` | Total size of the disk in bytes (not real time, updates every 10-15 min) | gauge | `volume`
 `windows_logical_disk_idle_seconds_total` | Seconds the disk was idle (not servicing read/write requests) | counter | `volume`
 `windows_logical_disk_split_ios_total` | Number of I/Os to the disk split into multiple I/Os | counter | `volume`
+`windows_logical_disk_readonly` | Whether the logical disk is read-only | gauge | `volume`
 
 ### Warning about size metrics
 The `free_bytes` and `size_bytes` metrics are not updated in real time and might have a delay of 10-15min.
@@ -48,6 +49,15 @@ Query the rate of write operations to a disk
 rate(windows_logical_disk_read_bytes_total{instance="localhost", volume=~"C:"}[2m])
 ```
 
+Logical Volume information
+```
+windows_logical_disk_info{disk_id="0",filesystem="",serial_number="",type="",volume="HarddiskVolume2",volume_name=""} 1
+windows_logical_disk_info{disk_id="0",filesystem="",serial_number="",type="",volume="HarddiskVolume3",volume_name=""} 1
+windows_logical_disk_info{disk_id="0",filesystem="NTFS",serial_number="668EEC37",type="fixed",volume="C:",volume_name="Windows"} 1
+windows_logical_disk_info{disk_id="1",filesystem="NTFS",serial_number="50AE953B",type="fixed",volume="D:",volume_name="Temporary Storage"} 1
+windows_logical_disk_info{disk_id="1",filesystem="ReFS",serial_number="C69B59AD",type="fixed",volume="G:",volume_name="Volume"} 1
+```
+
 ## Useful queries
 Calculate rate of total IOPS for disk
 ```

pkg/collector/logical_disk/logical_disk.go

@@ -3,17 +3,18 @@
 package logical_disk
 
 import (
-	"errors"
+	"encoding/binary"
 	"fmt"
+	"golang.org/x/sys/windows"
 	"regexp"
+	"strconv"
 	"strings"
 
 	"github.com/alecthomas/kingpin/v2"
 	"github.com/go-kit/log"
 	"github.com/go-kit/log/level"
 	"github.com/prometheus-community/windows_exporter/pkg/perflib"
 	"github.com/prometheus-community/windows_exporter/pkg/types"
-	"github.com/prometheus-community/windows_exporter/pkg/wmi"
 	"github.com/prometheus/client_golang/prometheus"
 )
 
@@ -22,27 +23,8 @@ const (
 
 	FlagLogicalDiskVolumeExclude = "collector.logical_disk.volume-exclude"
 	FlagLogicalDiskVolumeInclude = "collector.logical_disk.volume-include"
-
-	win32LogicalDiskQuery            = "SELECT VolumeName,DeviceID,FileSystem,VolumeSerialNumber FROM WIN32_LogicalDisk"
-	win32LogicalDiskToPartitionQuery = "SELECT Antecedent, Dependent FROM Win32_LogicalDiskToPartition"
-)
-
-var (
-	reDiskID = regexp.MustCompile(`Disk #([0-9]+), Partition #([0-9]+)`)
 )
 
-type Win32_LogicalDisk struct {
-	VolumeName         string
-	VolumeSerialNumber string
-	DeviceID           string
-	FileSystem         string
-}
-
-type Win32_LogicalDiskToPartition struct {
-	Antecedent string
-	Dependent  string
-}
-
 type Config struct {
 	VolumeInclude string `yaml:"volume_include"`
 	VolumeExclude string `yaml:"volume_exclude"`
@@ -61,6 +43,7 @@ type collector struct {
 	volumeExclude *string
 
 	Information      *prometheus.Desc
+	ReadOnly         *prometheus.Desc
 	RequestsQueued   *prometheus.Desc
 	AvgReadQueue     *prometheus.Desc
 	AvgWriteQueue    *prometheus.Desc
@@ -82,6 +65,14 @@ type collector struct {
 	volumeExcludePattern *regexp.Regexp
 }
 
+type volumeInfo struct {
+	filesystem   string
+	serialNumber string
+	label        string
+	volumeType   string
+	readonly     float64
+}
+
 func New(logger log.Logger, config *Config) types.Collector {
 	if config == nil {
 		config = &ConfigDefaults
@@ -126,7 +117,13 @@ func (c *collector) Build() error {
 	c.Information = prometheus.NewDesc(
 		prometheus.BuildFQName(types.Namespace, Name, "info"),
 		"A metric with a constant '1' value labeled with logical disk information",
-		[]string{"disk", "partition", "volume", "volume_name", "filesystem", "serial_number"},
+		[]string{"disk", "type", "volume", "volume_name", "filesystem", "serial_number"},
+		nil,
+	)
+	c.ReadOnly = prometheus.NewDesc(
+		prometheus.BuildFQName(types.Namespace, Name, "readonly"),
+		"Whether the logical disk is read-only",
+		[]string{"volume"},
 		nil,
 	)
 	c.RequestsQueued = prometheus.NewDesc(
@@ -270,9 +267,6 @@ func (c *collector) Collect(ctx *types.ScrapeContext, ch chan<- prometheus.Metri
 // - https://msdn.microsoft.com/en-us/library/ms803973.aspx - LogicalDisk object reference
 type logicalDisk struct {
 	Name                    string
-	VolumeName              string
-	DiskID                  string
-	PartID                  string
 	CurrentDiskQueueLength  float64 `perflib:"Current Disk Queue Length"`
 	AvgDiskReadQueueLength  float64 `perflib:"Avg. Disk Read Queue Length"`
 	AvgDiskWriteQueueLength float64 `perflib:"Avg. Disk Write Queue Length"`
@@ -292,31 +286,14 @@ type logicalDisk struct {
 }
 
 func (c *collector) collect(ctx *types.ScrapeContext, ch chan<- prometheus.Metric) error {
-	var dst_Win32_LogicalDisk []Win32_LogicalDisk
-	var dst_Win32_LogicalDiskToPartition []Win32_LogicalDiskToPartition
-
-	if err := wmi.Query(win32LogicalDiskQuery, &dst_Win32_LogicalDisk); err != nil {
-		return err
-	}
-	if len(dst_Win32_LogicalDisk) == 0 {
-		return errors.New("WMI query returned empty result set")
-	}
-	if err := wmi.Query(win32LogicalDiskToPartitionQuery, &dst_Win32_LogicalDiskToPartition); err != nil {
-		return err
-	}
-	if len(dst_Win32_LogicalDiskToPartition) == 0 {
-		return errors.New("WMI query returned empty result set")
-	}
-
 	var (
-		filesystem   string
-		serialNumber string
-		volumeName   string
-		diskID       string
-		partID       string
-		dst          []logicalDisk
+		err    error
+		diskID string
+		info   volumeInfo
+		dst    []logicalDisk
 	)
-	if err := perflib.UnmarshalObject(ctx.PerfObjects["LogicalDisk"], &dst, c.logger); err != nil {
+
+	if err = perflib.UnmarshalObject(ctx.PerfObjects["LogicalDisk"], &dst, c.logger); err != nil {
 		return err
 	}
 
@@ -327,46 +304,26 @@ func (c *collector) collect(ctx *types.ScrapeContext, ch chan<- prometheus.Metri
 			continue
 		}
 
-		filesystem = ""
-		serialNumber = ""
-		volumeName = ""
-		diskID = "-1"
-		partID = "-1"
-
-		for _, logicalDisk := range dst_Win32_LogicalDisk {
-			if logicalDisk.DeviceID == volume.Name {
-				filesystem = logicalDisk.FileSystem
-				serialNumber = logicalDisk.VolumeSerialNumber
-				volumeName = logicalDisk.VolumeName
-
-				break
-			}
+		diskID, err = getDiskIDByVolume(volume.Name)
+		if err != nil {
+			_ = level.Warn(c.logger).Log("msg", fmt.Sprintf("failed to get disk ID for %s", volume.Name), "err", err)
 		}
 
-		for _, logicalDisk := range dst_Win32_LogicalDiskToPartition {
-			if strings.HasSuffix(logicalDisk.Dependent, volume.Name+`"`) {
-				ret := reDiskID.FindStringSubmatch(logicalDisk.Antecedent)
-				if len(ret) == 3 {
-					diskID = ret[1]
-					partID = ret[2]
-				} else {
-					_ = level.Warn(c.logger).Log("msg", "failed to parse disk ID", "antecedent", logicalDisk.Antecedent)
-				}
-
-				break
-			}
+		info, err = getVolumeInfo(volume.Name)
+		if err != nil {
+			_ = level.Warn(c.logger).Log("msg", fmt.Sprintf("failed to get volume information for %s", volume.Name), "err", err)
 		}
 
 		ch <- prometheus.MustNewConstMetric(
 			c.Information,
 			prometheus.GaugeValue,
 			1,
 			diskID,
-			partID,
+			info.volumeType,
 			volume.Name,
-			volumeName,
-			filesystem,
-			serialNumber,
+			info.label,
+			info.filesystem,
+			info.serialNumber,
 		)
 
 		ch <- prometheus.MustNewConstMetric(
@@ -484,3 +441,94 @@ func (c *collector) collect(ctx *types.ScrapeContext, ch chan<- prometheus.Metri
 
 	return nil
 }
+
+func getDriveType(driveType uint32) string {
+	switch driveType {
+	case windows.DRIVE_UNKNOWN:
+		return "unknown"
+	case windows.DRIVE_NO_ROOT_DIR:
+		return "norootdir"
+	case windows.DRIVE_REMOVABLE:
+		return "removable"
+	case windows.DRIVE_FIXED:
+		return "fixed"
+	case windows.DRIVE_REMOTE:
+		return "remote"
+	case windows.DRIVE_CDROM:
+		return "cdrom"
+	case windows.DRIVE_RAMDISK:
+		return "ramdisk"
+	default:
+		return "unknown"
+	}
+}
+
+// getDiskIDByVolume returns the disk ID for a given volume.
+func getDiskIDByVolume(rootDrive string) (string, error) {
+	// Open a volume handle to the Disk Root.
+	var err error
+	var f windows.Handle
+
+	// mode has to include FILE_SHARE permission to allow concurrent access to the disk.
+	mode := uint32(windows.FILE_SHARE_READ | windows.FILE_SHARE_WRITE | windows.FILE_SHARE_DELETE)
+	f, err = windows.CreateFile(
+		windows.StringToUTF16Ptr(`\\.\`+rootDrive),
+		windows.GENERIC_READ, mode, nil, windows.OPEN_EXISTING, uint32(windows.FILE_ATTRIBUTE_READONLY), 0)
+
+	if err != nil {
+		return "", err
+	}
+
+	defer windows.Close(f)
+
+	controlCode := uint32(5636096) // IOCTL_VOLUME_GET_VOLUME_DISK_EXTENTS
+	volumeDiskExtents := make([]byte, 16*1024)
+
+	var bytesReturned uint32
+	err = windows.DeviceIoControl(f, controlCode, nil, 0, &volumeDiskExtents[0], uint32(len(volumeDiskExtents)), &bytesReturned, nil)
+	if err != nil {
+		return "", err
+	}
+
+	if uint(binary.LittleEndian.Uint32(volumeDiskExtents)) != 1 {
+		return "", fmt.Errorf("could not identify physical drive for %s", rootDrive)
+	}
+
+	diskId := strconv.FormatUint(uint64(binary.LittleEndian.Uint32(volumeDiskExtents[8:])), 10)
+
+	return diskId, nil
+}
+
+func getVolumeInfo(rootDrive string) (volumeInfo, error) {
+	if !strings.HasSuffix(rootDrive, ":") {
+		return volumeInfo{}, nil
+	}
+
+	volPath := windows.StringToUTF16Ptr(rootDrive + `\`)
+
+	volBufLabel := make([]uint16, windows.MAX_PATH+1)
+	volSerialNum := uint32(0)
+	fsFlags := uint32(0)
+	volBufType := make([]uint16, windows.MAX_PATH+1)
+
+	driveType := windows.GetDriveType(volPath)
+
+	err := windows.GetVolumeInformation(volPath, &volBufLabel[0], uint32(len(volBufLabel)),
+		&volSerialNum, nil, &fsFlags, &volBufType[0], uint32(len(volBufType)))
+
+	if err != nil {
+		if driveType != windows.DRIVE_CDROM && driveType != windows.DRIVE_REMOVABLE {
+			return volumeInfo{}, err
+		}
+
+		return volumeInfo{}, nil
+	}
+
+	return volumeInfo{
+		volumeType:   getDriveType(driveType),
+		label:        windows.UTF16PtrToString(&volBufLabel[0]),
+		filesystem:   windows.UTF16PtrToString(&volBufType[0]),
+		serialNumber: fmt.Sprintf("%X", volSerialNum),
+		readonly:     float64(fsFlags & windows.FILE_READ_ONLY_VOLUME),
+	}, nil
+}