gen_dummy_files.go

package main

import (
	"fmt"
	"os"
	"path/filepath"
)

func main() {
	if len(os.Args) != 3 {
		fmt.Fprintf(os.Stderr, "Usage: gen_dummy_file <src directory> <dest directory>\n")
		os.Exit(1)
	}

	srcDir := os.Args[1]
	destDir := os.Args[2]

	if srcFi, err := os.Stat(srcDir); err != nil {
		fmt.Fprintf(os.Stderr, "Src dir '%v' does not exist.\n", srcDir)
		os.Exit(1)
	} else if !srcFi.IsDir() {
		fmt.Fprintf(os.Stderr, "The file '%v' is not a directory.\n", srcDir)
		os.Exit(1)
	}

	// Remove dest directory if exist
	if _, err := os.Stat(destDir); err == nil {
		if err := os.RemoveAll(destDir); err != nil {
			fmt.Fprintf(os.Stderr, "Removing dest directory failed : %v\n", err)
			os.Exit(1)
		}
	}
	if err := os.MkdirAll(destDir, 0755); err != nil {
		fmt.Fprintf(os.Stderr, "Creating dest directory failed : %v\n", err)
		os.Exit(1)
	}
	if err := genDummyFiles(srcDir, destDir); err != nil {
		fmt.Fprintf(os.Stderr, "Generating dummy files failed : %v\n", err)
		os.Exit(1)
	}
}

func genDummyFiles(srcDir, destDir string) error {
	return filepath.Walk(srcDir, func(path string, info os.FileInfo, err error) error {
		if err != nil {
			return err
		}
		rel, err := filepath.Rel(srcDir, path)
		if err != nil {
			return err
		}
		destPath := filepath.Join(destDir, rel)
		if info.IsDir() {
			return os.MkdirAll(destPath, 0755)
		}

		df, err := os.Create(destPath)
		if err != nil {
			return err
		}
		defer df.Close()
		_, err = df.Write([]byte("dummy\n"))
		return err
	})
}