Add support for using globs in devices list of diskio input plugin (#3687)

plugins/inputs/system/diskio.go

@@ -0,0 +1,196 @@
+package system
+
+import (
+	"fmt"
+	"log"
+	"regexp"
+	"strings"
+
+	"github.com/influxdata/telegraf"
+	"github.com/influxdata/telegraf/filter"
+	"github.com/influxdata/telegraf/plugins/inputs"
+)
+
+var (
+	varRegex = regexp.MustCompile(`\$(?:\w+|\{\w+\})`)
+)
+
+type DiskIO struct {
+	ps PS
+
+	Devices          []string
+	DeviceTags       []string
+	NameTemplates    []string
+	SkipSerialNumber bool
+
+	infoCache    map[string]diskInfoCache
+	deviceFilter filter.Filter
+	initialized  bool
+}
+
+func (_ *DiskIO) Description() string {
+	return "Read metrics about disk IO by device"
+}
+
+var diskIOsampleConfig = `
+  ## By default, telegraf will gather stats for all devices including
+  ## disk partitions.
+  ## Setting devices will restrict the stats to the specified devices.
+  # devices = ["sda", "sdb", "vd*"]
+  ## Uncomment the following line if you need disk serial numbers.
+  # skip_serial_number = false
+  #
+  ## On systems which support it, device metadata can be added in the form of
+  ## tags.
+  ## Currently only Linux is supported via udev properties. You can view
+  ## available properties for a device by running:
+  ## 'udevadm info -q property -n /dev/sda'
+  # device_tags = ["ID_FS_TYPE", "ID_FS_USAGE"]
+  #
+  ## Using the same metadata source as device_tags, you can also customize the
+  ## name of the device via templates.
+  ## The 'name_templates' parameter is a list of templates to try and apply to
+  ## the device. The template may contain variables in the form of '$PROPERTY' or
+  ## '${PROPERTY}'. The first template which does not contain any variables not
+  ## present for the device is used as the device name tag.
+  ## The typical use case is for LVM volumes, to get the VG/LV name instead of
+  ## the near-meaningless DM-0 name.
+  # name_templates = ["$ID_FS_LABEL","$DM_VG_NAME/$DM_LV_NAME"]
+`
+
+func (_ *DiskIO) SampleConfig() string {
+	return diskIOsampleConfig
+}
+
+// hasMeta reports whether s contains any special glob characters.
+func hasMeta(s string) bool {
+	return strings.IndexAny(s, "*?[") >= 0
+}
+
+func (s *DiskIO) init() error {
+	for _, device := range s.Devices {
+		if hasMeta(device) {
+			filter, err := filter.Compile(s.Devices)
+			if err != nil {
+				return fmt.Errorf("error compiling device pattern: %v", err)
+			}
+			s.deviceFilter = filter
+		}
+	}
+	s.initialized = true
+	return nil
+}
+
+func (s *DiskIO) Gather(acc telegraf.Accumulator) error {
+	if !s.initialized {
+		err := s.init()
+		if err != nil {
+			return err
+		}
+	}
+
+	devices := []string{}
+	if s.deviceFilter == nil {
+		devices = s.Devices
+	}
+
+	diskio, err := s.ps.DiskIO(devices)
+	if err != nil {
+		return fmt.Errorf("error getting disk io info: %s", err)
+	}
+
+	for _, io := range diskio {
+		if s.deviceFilter != nil && !s.deviceFilter.Match(io.Name) {
+			continue
+		}
+
+		tags := map[string]string{}
+		tags["name"] = s.diskName(io.Name)
+		for t, v := range s.diskTags(io.Name) {
+			tags[t] = v
+		}
+		if !s.SkipSerialNumber {
+			if len(io.SerialNumber) != 0 {
+				tags["serial"] = io.SerialNumber
+			} else {
+				tags["serial"] = "unknown"
+			}
+		}
+
+		fields := map[string]interface{}{
+			"reads":            io.ReadCount,
+			"writes":           io.WriteCount,
+			"read_bytes":       io.ReadBytes,
+			"write_bytes":      io.WriteBytes,
+			"read_time":        io.ReadTime,
+			"write_time":       io.WriteTime,
+			"io_time":          io.IoTime,
+			"weighted_io_time": io.WeightedIO,
+			"iops_in_progress": io.IopsInProgress,
+		}
+		acc.AddCounter("diskio", fields, tags)
+	}
+
+	return nil
+}
+
+func (s *DiskIO) diskName(devName string) string {
+	if len(s.NameTemplates) == 0 {
+		return devName
+	}
+
+	di, err := s.diskInfo(devName)
+	if err != nil {
+		log.Printf("W! Error gathering disk info: %s", err)
+		return devName
+	}
+
+	for _, nt := range s.NameTemplates {
+		miss := false
+		name := varRegex.ReplaceAllStringFunc(nt, func(sub string) string {
+			sub = sub[1:] // strip leading '$'
+			if sub[0] == '{' {
+				sub = sub[1 : len(sub)-1] // strip leading & trailing '{' '}'
+			}
+			if v, ok := di[sub]; ok {
+				return v
+			}
+			miss = true
+			return ""
+		})
+
+		if !miss {
+			return name
+		}
+	}
+
+	return devName
+}
+
+func (s *DiskIO) diskTags(devName string) map[string]string {
+	if len(s.DeviceTags) == 0 {
+		return nil
+	}
+
+	di, err := s.diskInfo(devName)
+	if err != nil {
+		log.Printf("W! Error gathering disk info: %s", err)
+		return nil
+	}
+
+	tags := map[string]string{}
+	for _, dt := range s.DeviceTags {
+		if v, ok := di[dt]; ok {
+			tags[dt] = v
+		}
+	}
+
+	return tags
+}
+
+func init() {
+	ps := newSystemPS()
+	inputs.Add("diskio", func() telegraf.Input {
+		return &DiskIO{ps: ps, SkipSerialNumber: true}
+	})
+}