How to create slice with filenames

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
}

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
}