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Copy pathmerge.go
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100 lines (80 loc) · 2.4 KB
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package csv_cli_tool
import (
"encoding/csv"
"fmt"
"os"
"path/filepath"
"time"
)
func mergeHeadWithFiles(head []string, dataFileNames []string, outputFolder string, trackingFileName string) error {
if !fileExists(trackingFileName) {
f, _ := os.Create(trackingFileName)
f.Close()
}
trackingFile, err := os.OpenFile(trackingFileName, os.O_RDWR|os.O_APPEND, 0660)
if err != nil {
return err
}
defer trackingFile.Close()
_, err = trackingFile.WriteString(fmt.Sprintf("MERGE STARTING... at: %s\\n", time.Now().String()))
if err != nil {
return err
}
for _, dataFileName := range dataFileNames {
fmt.Println("Merging file: " + dataFileName)
if err = mergeHeadWithFile(head, dataFileName, outputFolder); err != nil {
trackingFile.WriteString(fmt.Sprintf("filename: %s - could not be merged, err: %s\\n", dataFileName, err.Error()))
continue
}
trackingFile.WriteString(fmt.Sprintf("filename: %s - merged successfully\\n", dataFileName))
}
trackingFile.WriteString(fmt.Sprintf("MERGE FINISHED... files processed:%d at: %s\\n", len(dataFileNames), time.Now().String()))
trackingFile.Sync()
return nil
}
func mergeHeadWithFile(head []string, dataFileName string, outputFolder string) error {
outputFileName := fmt.Sprintf("%s/%s", outputFolder, filepath.Base(dataFileName))
if fileExists(outputFileName) {
return fmt.Errorf("output file already exists, program does not overwrite data, filename: %s", outputFileName)
}
dataFile, err := os.Open(dataFileName)
if err != nil {
return err
}
defer dataFile.Close()
reader := csv.NewReader(dataFile)
reader.FieldsPerRecord = -1
records, err := reader.ReadAll()
if err != nil {
return err
}
if len(records) == 0 {
return fmt.Errorf("file does not have any data")
}
firstRecord := records[0]
if len(head) != len(firstRecord) {
return fmt.Errorf("number of columns in head and data file do not match head count: %d record count: %d", len(head), len(firstRecord))
}
header := [][]string{head}
records = append(header, records...)
outputFile, err := os.Create(outputFileName)
if err != nil {
return err
}
defer outputFile.Close()
writer := csv.NewWriter(outputFile)
for _, record := range records {
if err = writer.Write(record); err != nil {
return err
}
}
writer.Flush()
return nil
}
func fileExists(filename string) bool {
info, err := os.Stat(filename)
if os.IsNotExist(err) {
return false
}
return !info.IsDir()
}