dstatcsv.go

package graph

import(
  "log"
  "fmt"
  "io"
  "bufio"
  "bytes"
  "time"
  "strings"
  "strconv"
  "encoding/csv"
)

func csvReadLine(r *bufio.Reader) ([]string, error) {
  line, _, err := r.ReadLine()
  if err != nil {
    return []string{}, err
  }

  reader := csv.NewReader(bytes.NewBuffer(line))
  return reader.Read()
}

func Parse(r io.Reader) ([]string, []DstatCSVRow, error) {
  csvlines := bufio.NewReader(r)

  log.Printf("debug: parse dstat csv header")
  head1, err := csvReadLine(csvlines)
  if err != nil {
    return nil, nil, err
  }
  if len(head1) < 1 {
    return nil, nil, fmt.Errorf("unknown Dstat 'version' header: %v", head1)
  }
  if strings.HasPrefix(head1[0], "Dstat") != true {
    return nil, nil, fmt.Errorf("unknown Dstat 'version' header: '%s'", head1[0])
  }

  head2, err := csvReadLine(csvlines)
  if err != nil {
    return nil, nil, err
  }
  if len(head2) < 1 {
    return nil, nil, fmt.Errorf("unknown Dstat 'Auther' header: %v", head2)
  }
  if strings.HasPrefix(head2[0], "Author") != true {
    return nil, nil, fmt.Errorf("unknown Dstat 'Auther' header: '%s'", head2[0])
  }

  head3, err := csvReadLine(csvlines)
  if err != nil {
    return nil, nil, err
  }
  if len(head3) < 1 {
    return nil, nil, fmt.Errorf("unknwon Dstat 'Host' header: %v", head3)
  }
  if strings.HasPrefix(head3[0], "Host") != true {
    return nil, nil, fmt.Errorf("unknwon Dstat 'Host' header: '%s'", head3[0])
  }

  head4, err := csvReadLine(csvlines)
  if err != nil {
    return nil, nil, err
  }
  if len(head4) < 1 {
    return nil, nil, fmt.Errorf("unknwon Dstat 'Cmdline' header: %v", head4)
  }
  if strings.HasPrefix(head4[0], "Cmdline") != true {
    return nil, nil, fmt.Errorf("unknwon Dstat 'Cmdline' header: '%s'", head4[0])
  }
  dateHead  := head4[len(head4) - 2]
  dateValue := head4[len(head4) - 1]
  if strings.HasPrefix(dateHead, "Date") != true {
    return nil, nil, fmt.Errorf("unknown Dstat 'Date' header: '%s'", dateHead)
  }
  if dateValue == "" {
    return nil, nil, fmt.Errorf("unknown Dstat 'Date' value: '%s'", dateValue)
  }
  // dstat date value = '05 Aug 2019 14:05:42 JST'
  baseTime, err := time.Parse("02 Jan 2006 15:04:05 MST", dateValue)
  if err != nil {
    return nil, nil, err
  }

  head5, err := csvReadLine(csvlines)
  if err != nil {
    return nil, nil, err
  }
  if len(head5) < 1 {
    return nil, nil, fmt.Errorf("unknwon field header: %v", head5)
  }
  log.Printf("debug: dstat fields: %v", head5)

  lines  := make([]DstatCSVRow, 0)
  reader := csv.NewReader(csvlines)
  columns, err := reader.Read()
  if err != nil {
    return nil, nil, err
  }
  if len(columns) < 1 {
    return nil, nil, fmt.Errorf("unknown Dstat columns header: %v", columns)
  }
  for {
    values, err := reader.Read()
    if err != nil {
      if err == io.EOF {
        break
      }
      return nil, nil, err
    }

    m := make(DstatRecord)
    t := ""
    for i, k := range columns {
      if k == "time" {
        t = values[i]
        continue // lazy
      }
      floatValue, e := strconv.ParseFloat(values[i], 64)
      if e != nil {
        log.Printf("error: parse fload error: %s", values[i])
        return nil, nil, e
      }
      m[k] = floatValue
    }
    // dstat time value: '05-08 14:07:32'
    recordTime, err := time.Parse("02-01 15:04:05", t)
    if err != nil {
      log.Printf("error: cant parse time value '%s'", t)
      return nil, nil, err
    }
    formatTime := time.Date(
      baseTime.Year(),
      recordTime.Month(),
      recordTime.Day(),
      recordTime.Hour(),
      recordTime.Minute(),
      recordTime.Second(),
      0,
      baseTime.Location(),
    )
    lines = append(lines, DstatCSVRow{
      Time:   formatTime,
      Values: m,
    })
  }
  recordColumns := make([]string, 0)
  for _, c := range columns {
    if c == "time" {
      continue // skip
    }
    recordColumns = append(recordColumns, c)
  }
  return recordColumns, lines, nil
}