Is there an easy way to copy a directory in go? I have the following function:
err = CopyDir("sourceFolder","destinationFolder")
Nothing so far has worked, including libraries such as github.com/cf-guardian/guardian/kernel/fileutils
One important thing to note is that I need to preserve directory structure, including the sourceFolder itself, not simply copy all contents of the folder.
I believe that docker implementation can be considered as complete solution for handling edge cases: https://github.com/moby/moby/blob/8e610b2b55bfd1bfa9436ab110d311f5e8a74dcb/daemon/graphdriver/copy/copy.go
There are following good things:
but because of a lot of imports your tiny application becomes huge.
I've tried to combine several solutions but use stdlib only:
func CopyDirectory(scrDir, dest string) error {
entries, err := ioutil.ReadDir(scrDir)
if err != nil {
return err
}
for _, entry := range entries {
sourcePath := filepath.Join(scrDir, entry.Name())
destPath := filepath.Join(dest, entry.Name())
fileInfo, err := os.Stat(sourcePath)
if err != nil {
return err
}
stat, ok := fileInfo.Sys().(*syscall.Stat_t)
if !ok {
return fmt.Errorf("failed to get raw syscall.Stat_t data for '%s'", sourcePath)
}
switch fileInfo.Mode() & os.ModeType{
case os.ModeDir:
if err := CreateIfNotExists(destPath, 0755); err != nil {
return err
}
if err := CopyDirectory(sourcePath, destPath); err != nil {
return err
}
case os.ModeSymlink:
if err := CopySymLink(sourcePath, destPath); err != nil {
return err
}
default:
if err := Copy(sourcePath, destPath); err != nil {
return err
}
}
if err := os.Lchown(destPath, int(stat.Uid), int(stat.Gid)); err != nil {
return err
}
isSymlink := entry.Mode()&os.ModeSymlink != 0
if !isSymlink {
if err := os.Chmod(destPath, entry.Mode()); err != nil {
return err
}
}
}
return nil
}
func Copy(srcFile, dstFile string) error {
out, err := os.Create(dstFile)
defer out.Close()
if err != nil {
return err
}
in, err := os.Open(srcFile)
defer in.Close()
if err != nil {
return err
}
_, err = io.Copy(out, in)
if err != nil {
return err
}
return nil
}
func Exists(filePath string) bool {
if _, err := os.Stat(filePath); os.IsNotExist(err) {
return false
}
return true
}
func CreateIfNotExists(dir string, perm os.FileMode) error {
if Exists(dir) {
return nil
}
if err := os.MkdirAll(dir, perm); err != nil {
return fmt.Errorf("failed to create directory: '%s', error: '%s'", dir, err.Error())
}
return nil
}
func CopySymLink(source, dest string) error {
link, err := os.Readlink(source)
if err != nil {
return err
}
return os.Symlink(link, dest)
}
This package seems to do exactly what you want to do, give it a try.
From the readme:
err := Copy("your/source/directory", "your/destination/directory")
An easy and lazy way would be to use the copy command of your system. This example just works on systems with the command cp (so not for Windows)
func CopyDir(src, dst string) error {
cmd := exec.Command("cp", "a")
log.Printf("Running cp -a")
return cmd.Run()
}
To preserve of the directories is not so easy to implement, so to use the system program for that is ok. But that solution does not work on all systems, because it needs an external program. I would just use it for internal purposes.