Function parseStat

stat.go:182–259

parseStat parses the metrics from /proc/[pid]/stat.

(r io.Reader, fileName string)

// parseStat parses the metrics from /proc/[pid]/stat.
func parseStat(r io.Reader, fileName string) (Stat, error) {
	var (
		scanner = bufio.NewScanner(r)
		stat    = Stat{
			CPU: make(map[int64]CPUStat),
		}
		err error
	)

	// Increase default scanner buffer to handle very long `intr` lines.
	buf := make([]byte, 0, 8*1024)
	scanner.Buffer(buf, 1024*1024)

	for scanner.Scan() {
		line := scanner.Text()
		parts := strings.Fields(scanner.Text())
		// require at least <key> <value>
		if len(parts) < 2 {
			continue
		}
		switch {
		case parts[0] == "btime":
			if stat.BootTime, err = strconv.ParseUint(parts[1], 10, 64); err != nil {
				return Stat{}, fmt.Errorf("%w: couldn't parse %q (btime): %w", ErrFileParse, parts[1], err)
			}
		case parts[0] == "intr":
			if stat.IRQTotal, err = strconv.ParseUint(parts[1], 10, 64); err != nil {
				return Stat{}, fmt.Errorf("%w: couldn't parse %q (intr): %w", ErrFileParse, parts[1], err)
			}
			numberedIRQs := parts[2:]
			stat.IRQ = make([]uint64, len(numberedIRQs))
			for i, count := range numberedIRQs {
				if stat.IRQ[i], err = strconv.ParseUint(count, 10, 64); err != nil {
					return Stat{}, fmt.Errorf("%w: couldn't parse %q (intr%d): %w", ErrFileParse, count, i, err)
				}
			}
		case parts[0] == "ctxt":
			if stat.ContextSwitches, err = strconv.ParseUint(parts[1], 10, 64); err != nil {
				return Stat{}, fmt.Errorf("%w: couldn't parse %q (ctxt): %w", ErrFileParse, parts[1], err)
			}
		case parts[0] == "processes":
			if stat.ProcessCreated, err = strconv.ParseUint(parts[1], 10, 64); err != nil {
				return Stat{}, fmt.Errorf("%w: couldn't parse %q (processes): %w", ErrFileParse, parts[1], err)
			}
		case parts[0] == "procs_running":
			if stat.ProcessesRunning, err = strconv.ParseUint(parts[1], 10, 64); err != nil {
				return Stat{}, fmt.Errorf("%w: couldn't parse %q (procs_running): %w", ErrFileParse, parts[1], err)
			}
		case parts[0] == "procs_blocked":
			if stat.ProcessesBlocked, err = strconv.ParseUint(parts[1], 10, 64); err != nil {
				return Stat{}, fmt.Errorf("%w: couldn't parse %q (procs_blocked): %w", ErrFileParse, parts[1], err)
			}
		case parts[0] == "softirq":
			softIRQStats, total, err := parseSoftIRQStat(line)
			if err != nil {
				return Stat{}, err
			}
			stat.SoftIRQTotal = total