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// SPDX-License-Identifier: GPL-3.0-or-later
package logs
import (
"bytes"
"encoding/csv"
"errors"
"fmt"
"io"
"strconv"
"strings"
)
type (
CSVConfig struct {
FieldsPerRecord int `yaml:"fields_per_record" json:"fields_per_record"`
Delimiter string `yaml:"delimiter" json:"delimiter"`
TrimLeadingSpace bool `yaml:"trim_leading_space" json:"trim_leading_space"`
Format string `yaml:"format" json:"format"`
CheckField func(string) (string, int, bool) `yaml:"-" json:"-"`
}
CSVParser struct {
Config CSVConfig
reader *csv.Reader
format *csvFormat
}
csvFormat struct {
raw string
maxIndex int
fields []csvField
}
csvField struct {
name string
idx int
}
)
func NewCSVParser(config CSVConfig, in io.Reader) (*CSVParser, error) {
if config.Format == "" {
return nil, errors.New("empty csv format")
}
format, err := newCSVFormat(config)
if err != nil {
return nil, fmt.Errorf("bad csv format '%s': %v", config.Format, err)
}
p := &CSVParser{
Config: config,
reader: newCSVReader(in, config),
format: format,
}
return p, nil
}
func (p *CSVParser) ReadLine(line LogLine) error {
record, err := p.reader.Read()
if err != nil {
return handleCSVReaderError(err)
}
return p.format.parse(record, line)
}
func (p *CSVParser) Parse(row []byte, line LogLine) error {
r := newCSVReader(bytes.NewBuffer(row), p.Config)
record, err := r.Read()
if err != nil {
return handleCSVReaderError(err)
}
return p.format.parse(record, line)
}
func (p CSVParser) Info() string {
return fmt.Sprintf("csv: %s", p.format.raw)
}
func (f *csvFormat) parse(record []string, line LogLine) error {
if len(record) <= f.maxIndex {
return &ParseError{msg: "csv parse: unmatched line"}
}
for _, v := range f.fields {
if err := line.Assign(v.name, record[v.idx]); err != nil {
return &ParseError{msg: fmt.Sprintf("csv parse: %v", err), err: err}
}
}
return nil
}
func newCSVReader(in io.Reader, config CSVConfig) *csv.Reader {
r := csv.NewReader(in)
if config.Delimiter != "" {
if d, err := parseCSVDelimiter(config.Delimiter); err == nil {
r.Comma = d
}
}
r.TrimLeadingSpace = config.TrimLeadingSpace
r.FieldsPerRecord = config.FieldsPerRecord
r.ReuseRecord = true
return r
}
func newCSVFormat(config CSVConfig) (*csvFormat, error) {
r := csv.NewReader(strings.NewReader(config.Format))
if config.Delimiter != "" {
if d, err := parseCSVDelimiter(config.Delimiter); err == nil {
r.Comma = d
}
}
r.TrimLeadingSpace = config.TrimLeadingSpace
record, err := r.Read()
if err != nil {
return nil, err
}
fields, err := createCSVFields(record, config.CheckField)
if err != nil {
return nil, err
}
if len(fields) == 0 {
return nil, errors.New("zero fields")
}
format := &csvFormat{
raw: config.Format,
maxIndex: fields[len(fields)-1].idx,
fields: fields,
}
return format, nil
}
func createCSVFields(format []string, check func(string) (string, int, bool)) ([]csvField, error) {
if check == nil {
check = checkCSVFormatField
}
var fields []csvField
var offset int
seen := make(map[string]bool)
for i, name := range format {
name = strings.Trim(name, `"`)
name, addOffset, valid := check(name)
offset += addOffset
if !valid {
continue
}
if seen[name] {
return nil, fmt.Errorf("duplicate field: %s", name)
}
seen[name] = true
idx := i + offset
fields = append(fields, csvField{name, idx})
}
return fields, nil
}
func handleCSVReaderError(err error) error {
if isCSVParseError(err) {
return &ParseError{msg: fmt.Sprintf("csv parse: %v", err), err: err}
}
return err
}
func isCSVParseError(err error) bool {
return errors.Is(err, csv.ErrBareQuote) || errors.Is(err, csv.ErrFieldCount) || errors.Is(err, csv.ErrQuote)
}
func checkCSVFormatField(name string) (newName string, offset int, valid bool) {
if len(name) < 2 || !strings.HasPrefix(name, "$") {
return "", 0, false
}
return name, 0, true
}
func parseCSVDelimiter(s string) (rune, error) {
if isNumber(s) {
d, err := strconv.ParseInt(s, 10, 32)
if err != nil {
return 0, fmt.Errorf("invalid CSV delimiter: %v", err)
}
return rune(d), nil
}
if len(s) != 1 {
return 0, errors.New("invalid CSV delimiter: must be a single character")
}
return rune(s[0]), nil
}
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