Introduce disk io stats metrics (#15512)

internal/disk/stat_linux.go

@@ -21,8 +21,14 @@
 package disk
 
 import (
+	"bufio"
 	"fmt"
+	"os"
+	"strconv"
+	"strings"
 	"syscall"
+
+	"golang.org/x/sys/unix"
 )
 
 // GetInfo returns total and free bytes available in a directory, e.g. `/`.
@@ -49,5 +55,138 @@ func GetInfo(path string) (info Info, err error) {
 		return info, fmt.Errorf("detected free space (%d) > total drive space (%d), fs corruption at (%s). please run 'fsck'", info.Free, info.Total, path)
 	}
 	info.Used = info.Total - info.Free
+
+	st := syscall.Stat_t{}
+	err = syscall.Stat(path, &st)
+	if err != nil {
+		return Info{}, err
+	}
+	//nolint:unconvert
+	devID := uint64(st.Dev) // Needed to support multiple GOARCHs
+	info.Major = unix.Major(devID)
+	info.Minor = unix.Minor(devID)
 	return info, nil
 }
+
+const (
+	statsPath = "/proc/diskstats"
+)
+
+// GetAllDrivesIOStats returns IO stats of all drives found in the machine
+func GetAllDrivesIOStats() (info AllDrivesIOStats, err error) {
+	proc, err := os.Open(statsPath)
+	if err != nil {
+		return nil, err
+	}
+	defer proc.Close()
+
+	ret := make(AllDrivesIOStats)
+
+	sc := bufio.NewScanner(proc)
+	for sc.Scan() {
+		line := sc.Text()
+		fields := strings.Fields(line)
+		if len(fields) < 11 {
+			continue
+		}
+
+		var err error
+		var ds IOStats
+
+		ds.ReadIOs, err = strconv.ParseUint((fields[3]), 10, 64)
+		if err != nil {
+			return ret, err
+		}
+		ds.ReadMerges, err = strconv.ParseUint((fields[4]), 10, 64)
+		if err != nil {
+			return ret, err
+		}
+		ds.ReadSectors, err = strconv.ParseUint((fields[5]), 10, 64)
+		if err != nil {
+			return ret, err
+		}
+		ds.ReadTicks, err = strconv.ParseUint((fields[6]), 10, 64)
+		if err != nil {
+			return ret, err
+		}
+		ds.WriteIOs, err = strconv.ParseUint((fields[7]), 10, 64)
+		if err != nil {
+			return ret, err
+		}
+		ds.WriteMerges, err = strconv.ParseUint((fields[8]), 10, 64)
+		if err != nil {
+			return ret, err
+		}
+		ds.WriteSectors, err = strconv.ParseUint((fields[9]), 10, 64)
+		if err != nil {
+			return ret, err
+		}
+		ds.WriteTicks, err = strconv.ParseUint((fields[10]), 10, 64)
+		if err != nil {
+			return ret, err
+		}
+
+		if len(fields) > 11 {
+			ds.CurrentIOs, err = strconv.ParseUint((fields[11]), 10, 64)
+			if err != nil {
+				return ret, err
+			}
+
+			ds.TotalTicks, err = strconv.ParseUint((fields[12]), 10, 64)
+			if err != nil {
+				return ret, err
+			}
+			ds.ReqTicks, err = strconv.ParseUint((fields[13]), 10, 64)
+			if err != nil {
+				return ret, err
+			}
+		}
+
+		if len(fields) > 14 {
+			ds.DiscardIOs, err = strconv.ParseUint((fields[14]), 10, 64)
+			if err != nil {
+				return ret, err
+			}
+			ds.DiscardMerges, err = strconv.ParseUint((fields[15]), 10, 64)
+			if err != nil {
+				return ret, err
+			}
+			ds.DiscardSectors, err = strconv.ParseUint((fields[16]), 10, 64)
+			if err != nil {
+				return ret, err
+			}
+			ds.DiscardTicks, err = strconv.ParseUint((fields[17]), 10, 64)
+			if err != nil {
+				return ret, err
+			}
+		}
+
+		if len(fields) > 18 {
+			ds.FlushIOs, err = strconv.ParseUint((fields[18]), 10, 64)
+			if err != nil {
+				return ret, err
+			}
+			ds.FlushTicks, err = strconv.ParseUint((fields[19]), 10, 64)
+			if err != nil {
+				return ret, err
+			}
+		}
+
+		major, err := strconv.ParseUint((fields[0]), 10, 32)
+		if err != nil {
+			return ret, err
+		}
+
+		minor, err := strconv.ParseUint((fields[1]), 10, 32)
+		if err != nil {
+			return ret, err
+		}
+		ret[DevID{uint32(major), uint32(minor)}] = ds
+	}
+
+	if err := sc.Err(); err != nil {
+		return nil, err
+	}
+
+	return ret, nil
+}