How to create slice with filenames - go

Question

There is a program which creates file per second. I want to append file names into slice and print them. Now my program executes incorrect, it appends names but only for one file name. So I expect to get []string{"1","2","3"}, instead I get []string{"1","1","1"}, []string{"2","2","2"}, []string{"3","3","3"}. How to correct my prog to get expected result?
package main
import (
"encoding/csv"
"fmt"
"os"
"strconv"
"time"
)
func main() {
for {
time.Sleep(1 * time.Second)
createFile()
}
}
func createFile() {
rowFile := time.Now().Second()
fileName := strconv.Itoa(rowFile)
file, err := os.OpenFile(fileName, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0644)
if err != nil {
fmt.Println(err)
}
defer file.Close()
writer := csv.NewWriter(file)
writer.Comma = '|'
err = writer.Write([]string{""})
if err != nil {
fmt.Println(err)
}
countFiles(fileName)
}
func countFiles(fileName string) {
arrFiles := make([]string, 0, 3)
for i := 0; i < 3; i++ {
arrFiles = append(arrFiles, fileName)
}
fmt.Println(arrFiles)// here I expect ["1","2","3"] then ["4","5","6"] and so on. But now there is ["1","1","1"] then ["2","2","2"] and so on
}

Answer 1

createFile() does not persist created file names in any way. You can do something like that:
package main
import (
"encoding/csv"
"fmt"
"os"
"strconv"
"time"
)
func main() {
files := []string{}
for {
time.Sleep(1 * time.Second)
files = append(files, createFile())
fmt.Println(files)
}
}
func createFile() string {
rowFile := time.Now().Second()
fileName := strconv.Itoa(rowFile)
file, err := os.OpenFile(fileName, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0644)
if err != nil {
fmt.Println(err)
}
defer file.Close()
writer := csv.NewWriter(file)
writer.Comma = '|'
err = writer.Write([]string{""})
if err != nil {
fmt.Println(err)
}
return fileName
}