tsv.go

package tsv

import (
	"encoding/csv"
	"errors"
	"fmt"
	"os"
	"strings"
	"time"
)

type TsvLog struct {
	headers    []string
	fileName   string
	timeFormat string
	tz         *time.Location
	writer     *csv.Writer
	tsvFile    *os.File
}

func (log *TsvLog) getOrCreateFile() {
	_, err := os.Stat(log.fileName)
	creatingNewFile := os.IsNotExist(err)

	log.tsvFile, err = os.OpenFile(log.fileName, os.O_CREATE|os.O_RDWR|os.O_APPEND, 0644)

	if err != nil {
		fmt.Println(err)
	}

	log.writer = csv.NewWriter(log.tsvFile)
	log.writer.Comma = '\t'

	if creatingNewFile {
		log.writer.Write(log.headers)
	}
}

func Create(params ...string) *TsvLog {
	headers := strings.Fields("ts " + params[0])
	path := params[1]
	format := params[2]
	zone := "UTC"
	if len(params) > 3 && params[3] != "" {
		zone = params[3]
	}

	tz, err := time.LoadLocation(zone)

	if err != nil {
		panic(fmt.Sprintf("invalid time zone %v", zone))
	}

	log := TsvLog{
		headers:    headers,
		fileName:   path,
		timeFormat: format,
		tz:         tz}

	return &log
}

func (log *TsvLog) Add(data []string) error {
	var err error

	if len(data) != len(log.headers)-1 {
		err = errors.New("csv data length doesnt match header length")
	} else {
		log.getOrCreateFile()

		log.writer.Write(append([]string{time.Now().In(log.tz).Format(log.timeFormat)}, data...))
		log.Close()
	}
	return err
}

func (log *TsvLog) Read() [][]string {
	file, err := os.Open(log.fileName)
	if err != nil {
		fmt.Println(err)
	}

	reader := csv.NewReader(file)
	reader.Comma = '\t'

	records, err2 := reader.ReadAll()
	if err != nil {
		fmt.Println(err2)
	}

	file.Close()
	return records
}

func (log *TsvLog) Delete() {
	os.Remove(log.fileName)
}

func (log *TsvLog) Close() {
	log.writer.Flush()
	log.tsvFile.Close()
}