telegraf/plugins/parsers/csv/parser.go

318 lines
8.3 KiB
Go

package csv
import (
"bytes"
"encoding/csv"
"fmt"
"io"
"strconv"
"strings"
"time"
"github.com/influxdata/telegraf"
"github.com/influxdata/telegraf/internal"
"github.com/influxdata/telegraf/metric"
)
type TimeFunc func() time.Time
type Config struct {
ColumnNames []string `toml:"csv_column_names"`
ColumnTypes []string `toml:"csv_column_types"`
Comment string `toml:"csv_comment"`
Delimiter string `toml:"csv_delimiter"`
HeaderRowCount int `toml:"csv_header_row_count"`
MeasurementColumn string `toml:"csv_measurement_column"`
MetricName string `toml:"metric_name"`
SkipColumns int `toml:"csv_skip_columns"`
SkipRows int `toml:"csv_skip_rows"`
TagColumns []string `toml:"csv_tag_columns"`
TimestampColumn string `toml:"csv_timestamp_column"`
TimestampFormat string `toml:"csv_timestamp_format"`
Timezone string `toml:"csv_timezone"`
TrimSpace bool `toml:"csv_trim_space"`
SkipValues []string `toml:"csv_skip_values"`
gotColumnNames bool
TimeFunc func() time.Time
DefaultTags map[string]string
}
// Parser is a CSV parser, you should use NewParser to create a new instance.
type Parser struct {
*Config
}
func NewParser(c *Config) (*Parser, error) {
if c.HeaderRowCount == 0 && len(c.ColumnNames) == 0 {
return nil, fmt.Errorf("`csv_header_row_count` must be defined if `csv_column_names` is not specified")
}
if c.Delimiter != "" {
runeStr := []rune(c.Delimiter)
if len(runeStr) > 1 {
return nil, fmt.Errorf("csv_delimiter must be a single character, got: %s", c.Delimiter)
}
}
if c.Comment != "" {
runeStr := []rune(c.Comment)
if len(runeStr) > 1 {
return nil, fmt.Errorf("csv_delimiter must be a single character, got: %s", c.Comment)
}
}
if len(c.ColumnNames) > 0 && len(c.ColumnTypes) > 0 && len(c.ColumnNames) != len(c.ColumnTypes) {
return nil, fmt.Errorf("csv_column_names field count doesn't match with csv_column_types")
}
c.gotColumnNames = len(c.ColumnNames) > 0
if c.TimeFunc == nil {
c.TimeFunc = time.Now
}
return &Parser{Config: c}, nil
}
func (p *Parser) SetTimeFunc(fn TimeFunc) {
p.TimeFunc = fn
}
func (p *Parser) compile(r io.Reader) *csv.Reader {
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]
}
csvReader.TrimLeadingSpace = p.TrimSpace
return csvReader
}
func (p *Parser) Parse(buf []byte) ([]telegraf.Metric, error) {
r := bytes.NewReader(buf)
csvReader := p.compile(r)
// skip first rows
for i := 0; i < p.SkipRows; i++ {
_, err := csvReader.Read()
if err != nil {
return nil, err
}
}
// if there is a header and we did not get DataColumns
// set DataColumns to names extracted from the header
// we always reread the header to avoid side effects
// in cases where multiple files with different
// headers are read
if !p.gotColumnNames {
headerNames := make([]string, 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++ {
_, err := csvReader.Read()
if err != nil {
return nil, err
}
}
}
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 := p.compile(r)
// 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, " ")
}
// don't record fields where the value matches a skip value
for _, s := range p.SkipValues {
if value == s {
continue outer
}
}
for _, tagName := range p.TagColumns {
if tagName == fieldName {
tags[tagName] = value
continue outer
}
}
// If the field name is the timestamp column, then keep field name as is.
if fieldName == p.TimestampColumn {
recordFields[fieldName] = value
continue
}
// 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
}
// 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 p.MeasurementColumn != "" {
if recordFields[p.MeasurementColumn] != nil && recordFields[p.MeasurementColumn] != "" {
measurementName = fmt.Sprintf("%v", recordFields[p.MeasurementColumn])
}
}
metricTime, err := parseTimestamp(p.TimeFunc, recordFields, p.TimestampColumn, p.TimestampFormat, p.Timezone)
if err != nil {
return nil, err
}
// Exclude `TimestampColumn` and `MeasurementColumn`
delete(recordFields, p.TimestampColumn)
delete(recordFields, p.MeasurementColumn)
m := metric.New(measurementName, tags, recordFields, metricTime)
return m, nil
}
// ParseTimestamp return a timestamp, if there is no timestamp on the csv it
// will be the current timestamp, else it will try to parse the time according
// to the format.
func parseTimestamp(timeFunc func() time.Time, recordFields map[string]interface{},
timestampColumn, timestampFormat string, Timezone string,
) (time.Time, error) {
if timestampColumn != "" {
if recordFields[timestampColumn] == nil {
return time.Time{}, fmt.Errorf("timestamp column: %v could not be found", timestampColumn)
}
switch timestampFormat {
case "":
return time.Time{}, fmt.Errorf("timestamp format must be specified")
default:
metricTime, err := internal.ParseTimestamp(timestampFormat, recordFields[timestampColumn], Timezone)
if err != nil {
return time.Time{}, err
}
return metricTime, err
}
}
return timeFunc(), nil
}
// SetDefaultTags set the DefaultTags
func (p *Parser) SetDefaultTags(tags map[string]string) {
p.DefaultTags = tags
}