telegraf/plugins/parsers/csv/parser.go

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package csv
import (
"bytes"
"encoding/csv"
"fmt"
"strconv"
"strings"
"time"
"github.com/influxdata/telegraf"
"github.com/influxdata/telegraf/metric"
)
type Parser struct {
MetricName string
HeaderRowCount int
SkipRows int
SkipColumns int
Delimiter string
Comment string
TrimSpace bool
ColumnNames []string
ColumnTypes []string
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TagColumns []string
MeasurementColumn string
TimestampColumn string
TimestampFormat string
DefaultTags map[string]string
TimeFunc func() time.Time
}
func (p *Parser) SetTimeFunc(fn metric.TimeFunc) {
p.TimeFunc = fn
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}
func (p *Parser) compile(r *bytes.Reader) (*csv.Reader, error) {
csvReader := csv.NewReader(r)
// ensures that the reader reads records of different lengths without an error
csvReader.FieldsPerRecord = -1
if p.Delimiter != "" {
csvReader.Comma = []rune(p.Delimiter)[0]
}
if p.Comment != "" {
csvReader.Comment = []rune(p.Comment)[0]
}
return csvReader, nil
}
func (p *Parser) Parse(buf []byte) ([]telegraf.Metric, error) {
r := bytes.NewReader(buf)
csvReader, err := p.compile(r)
if err != nil {
return nil, err
}
// skip first rows
for i := 0; i < p.SkipRows; i++ {
csvReader.Read()
}
// if there is a header and nothing in DataColumns
// set DataColumns to names extracted from the header
headerNames := make([]string, 0)
if len(p.ColumnNames) == 0 {
for i := 0; i < p.HeaderRowCount; i++ {
header, err := csvReader.Read()
if err != nil {
return nil, err
}
//concatenate header names
for i := range header {
name := header[i]
if p.TrimSpace {
name = strings.Trim(name, " ")
}
if len(headerNames) <= i {
headerNames = append(headerNames, name)
} else {
headerNames[i] = headerNames[i] + name
}
}
}
p.ColumnNames = headerNames[p.SkipColumns:]
} else {
// if columns are named, just skip header rows
for i := 0; i < p.HeaderRowCount; i++ {
csvReader.Read()
}
}
table, err := csvReader.ReadAll()
if err != nil {
return nil, err
}
metrics := make([]telegraf.Metric, 0)
for _, record := range table {
m, err := p.parseRecord(record)
if err != nil {
return metrics, err
}
metrics = append(metrics, m)
}
return metrics, nil
}
// ParseLine does not use any information in header and assumes DataColumns is set
// it will also not skip any rows
func (p *Parser) ParseLine(line string) (telegraf.Metric, error) {
r := bytes.NewReader([]byte(line))
csvReader, err := p.compile(r)
if err != nil {
return nil, err
}
// if there is nothing in DataColumns, ParseLine will fail
if len(p.ColumnNames) == 0 {
return nil, fmt.Errorf("[parsers.csv] data columns must be specified")
}
record, err := csvReader.Read()
if err != nil {
return nil, err
}
m, err := p.parseRecord(record)
if err != nil {
return nil, err
}
return m, nil
}
func (p *Parser) parseRecord(record []string) (telegraf.Metric, error) {
recordFields := make(map[string]interface{})
tags := make(map[string]string)
// skip columns in record
record = record[p.SkipColumns:]
outer:
for i, fieldName := range p.ColumnNames {
if i < len(record) {
value := record[i]
if p.TrimSpace {
value = strings.Trim(value, " ")
}
for _, tagName := range p.TagColumns {
if tagName == fieldName {
tags[tagName] = value
continue outer
}
}
// Try explicit conversion only when column types is defined.
if len(p.ColumnTypes) > 0 {
// Throw error if current column count exceeds defined types.
if i >= len(p.ColumnTypes) {
return nil, fmt.Errorf("column type: column count exceeded")
}
var val interface{}
var err error
switch p.ColumnTypes[i] {
case "int":
val, err = strconv.ParseInt(value, 10, 64)
if err != nil {
return nil, fmt.Errorf("column type: parse int error %s", err)
}
case "float":
val, err = strconv.ParseFloat(value, 64)
if err != nil {
return nil, fmt.Errorf("column type: parse float error %s", err)
}
case "bool":
val, err = strconv.ParseBool(value)
if err != nil {
return nil, fmt.Errorf("column type: parse bool error %s", err)
}
default:
val = value
}
recordFields[fieldName] = val
continue
}
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// attempt type conversions
if iValue, err := strconv.ParseInt(value, 10, 64); err == nil {
recordFields[fieldName] = iValue
} else if fValue, err := strconv.ParseFloat(value, 64); err == nil {
recordFields[fieldName] = fValue
} else if bValue, err := strconv.ParseBool(value); err == nil {
recordFields[fieldName] = bValue
} else {
recordFields[fieldName] = value
}
}
}
// add default tags
for k, v := range p.DefaultTags {
tags[k] = v
}
// will default to plugin name
measurementName := p.MetricName
if recordFields[p.MeasurementColumn] != nil {
measurementName = fmt.Sprintf("%v", recordFields[p.MeasurementColumn])
}
metricTime := p.TimeFunc()
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if p.TimestampColumn != "" {
if recordFields[p.TimestampColumn] == nil {
return nil, fmt.Errorf("timestamp column: %v could not be found", p.TimestampColumn)
}
tStr := fmt.Sprintf("%v", recordFields[p.TimestampColumn])
if p.TimestampFormat == "" {
return nil, fmt.Errorf("timestamp format must be specified")
}
var err error
metricTime, err = time.Parse(p.TimestampFormat, tStr)
if err != nil {
return nil, err
}
}
m, err := metric.New(measurementName, tags, recordFields, metricTime)
if err != nil {
return nil, err
}
return m, nil
}
func (p *Parser) SetDefaultTags(tags map[string]string) {
p.DefaultTags = tags
}