joshuar-go-hass-agent/internal/linux/disk/ioStats.go

146 lines
3.7 KiB
Go

// Copyright (c) 2024 Joshua Rich <joshua.rich@gmail.com>
//
// This software is released under the MIT License.
// https://opensource.org/licenses/MIT
//go:generate go run golang.org/x/tools/cmd/stringer -type=stat -output ioStats_generated.go -linecomment
package disk
import (
"bufio"
"bytes"
"errors"
"fmt"
"log/slog"
"os"
"path/filepath"
"slices"
"strconv"
"strings"
"github.com/joshuar/go-hass-agent/internal/linux"
)
const (
TotalReads stat = iota // Total reads completed
TotalReadsMerged // Total reads merged
TotalSectorsRead // Total sectors read
TotalTimeReading // Total milliseconds spent reading
TotalWrites // Total writes completed
TotalWritesMerged // Total writes merged
TotalSectorsWritten // Total sectors written
TotalTimeWriting // Total milliseconds spent writing
ActiveIOs // I/Os currently in progress
ActiveIOTime // Milliseconds elapsed spent doing I/Os
ActiveIOTimeWeighted // Milliseconds elapsed spent doing I/Os (weighted)
TotalDiscardsCompleted // Total discards completed
TotalDiscardsMerged // Total discards merged
TotalSectorsDiscarded // Total sectors discarded
TotalTimeDiscarding // Total milliseconds spent discarding
TotalFlushRequests // Total flush requests completed
TotalTimeFlushing // Total milliseconds spent flushing
)
// stat represents a specific statistic recorded by the kernel for the
// associated disk.
type stat int
type device struct {
id string
sysFSPath string
model string
}
var ErrParseDevices = errors.New("could not parse devices")
var deviceMajNo = []string{"8", "252", "253", "259"}
func getDeviceNames() ([]string, error) {
data, err := os.Open(filepath.Join(linux.ProcFSRoot, "partitions"))
if err != nil {
return nil, fmt.Errorf("getDevices: %w", err)
}
defer data.Close()
var devices []string
partitions := bufio.NewScanner(data)
// Skip first two lines (header + blank line).
for range 2 {
partitions.Scan()
}
// Read remaining lines.
for partitions.Scan() {
line := bufio.NewScanner(bytes.NewReader(partitions.Bytes()))
line.Split(bufio.ScanWords)
var cols []string
for line.Scan() {
cols = append(cols, line.Text())
}
if len(cols) == 0 {
return devices, ErrParseDevices
}
if validDeviceNo(cols) {
devices = append(devices, cols[3])
}
}
return devices, nil
}
func validDeviceNo(details []string) bool {
if slices.Contains(deviceMajNo, details[0]) {
if details[1] == "0" {
return true
}
}
return false
}
func getDevice(deviceName string) (*device, map[stat]uint64, error) {
// Create a new device.
dev := &device{
id: deviceName,
sysFSPath: filepath.Join(linux.SysFSRoot, "block", deviceName),
}
// Try to read the model from the appropriate file. Otherwise just leave
// it empty.
if model, err := os.ReadFile(dev.sysFSPath + "/device/model"); err == nil {
dev.model = strings.TrimSpace(string(model))
}
data, err := os.ReadFile(dev.sysFSPath + "/stat")
if err != nil {
return dev, nil, fmt.Errorf("getDeviceStats: %w", err)
}
line := bufio.NewScanner(bytes.NewReader(data))
line.Split(bufio.ScanWords)
stats := make(map[stat]uint64)
statno := stat(0)
// Parse the rest as stats.
for line.Scan() {
readVal, err := strconv.ParseUint(line.Text(), 10, 64)
if err != nil {
slog.Warn("Unable to parse device stat.",
slog.String("device", dev.id),
slog.String("stat", line.Text()),
slog.Any("error", err))
} else {
stats[statno] = readVal
}
statno++
}
return dev, stats, nil
}