How to walk through a directory in Go (using the 'modern' post-1.16 functionality)

go-testing-fs-readdir.go

// See this in action: https://go.dev/play/p/mA3RRGhyZRe
// Read more about it: https://bitfieldconsulting.com/golang/filesystems#generalising-the-file-counter (scroll down a bit)
//
// The following code excerpt is placed in the Public Domain (CC0) by Gwyneth Llewelyn (2023)

package main

import (
	"fmt"
	"io/fs"
	"os"
)

func main() {
	var entries []string

	root := "." // valid path, current working directory (wherever that might be)
	//root := "fakedir" // valid path, but directory doesn't exist
	//root := "../.../aa..us~\\\r" // invalid path

	fmt.Printf("[list of files] root is %q\n", root)
	if !fs.ValidPath(root) {
		entries = append(entries, "[Invalid path <"+root+">!]")
	} else {
		fileSystem := os.DirFS(root)
		dirEntries, err := fs.ReadDir(fileSystem, ".")
		if err != nil {
			entries = append(entries, "[Error reading directory <"+root+">]: "+err.Error())
		} else {
			// we've got to assemble all entries in a simple directory entry until I fix the template
			for entry := range dirEntries {
				if dirEntries[entry].IsDir() {
					entries = append(entries, "[DIR] "+dirEntries[entry].Name())
				} else {
					entries = append(entries, dirEntries[entry].Name())
				}
			}
		}
	}
	fmt.Printf("[list of files] entries are %#v\n", entries)
}