terraform/helper/copy/copy.go

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package copy
import (
"fmt"
"io"
"io/ioutil"
"os"
"path/filepath"
)
// From: https://gist.github.com/m4ng0squ4sh/92462b38df26839a3ca324697c8cba04
// CopyFile copies the contents of the file named src to the file named
// by dst. The file will be created if it does not already exist. If the
// destination file exists, all it's contents will be replaced by the contents
// of the source file. The file mode will be copied from the source and
// the copied data is synced/flushed to stable storage.
func CopyFile(src, dst string) (err error) {
in, err := os.Open(src)
if err != nil {
return
}
defer in.Close()
out, err := os.Create(dst)
if err != nil {
return
}
defer func() {
if e := out.Close(); e != nil {
err = e
}
}()
_, err = io.Copy(out, in)
if err != nil {
return
}
err = out.Sync()
if err != nil {
return
}
si, err := os.Stat(src)
if err != nil {
return
}
err = os.Chmod(dst, si.Mode())
if err != nil {
return
}
return
}
// CopyDir recursively copies a directory tree, attempting to preserve permissions.
// Source directory must exist, destination directory must *not* exist.
// Symlinks are ignored and skipped.
func CopyDir(src string, dst string) (err error) {
src = filepath.Clean(src)
dst = filepath.Clean(dst)
si, err := os.Stat(src)
if err != nil {
return err
}
if !si.IsDir() {
return fmt.Errorf("source is not a directory")
}
_, err = os.Stat(dst)
if err != nil && !os.IsNotExist(err) {
return
}
if err == nil {
return fmt.Errorf("destination already exists")
}
err = os.MkdirAll(dst, si.Mode())
if err != nil {
return
}
entries, err := ioutil.ReadDir(src)
if err != nil {
return
}
for _, entry := range entries {
srcPath := filepath.Join(src, entry.Name())
dstPath := filepath.Join(dst, entry.Name())
// If the entry is a symlink, we copy the contents
for entry.Mode()&os.ModeSymlink != 0 {
target, err := os.Readlink(srcPath)
if err != nil {
return err
}
entry, err = os.Stat(target)
if err != nil {
return err
}
}
if entry.IsDir() {
err = CopyDir(srcPath, dstPath)
if err != nil {
return
}
} else {
err = CopyFile(srcPath, dstPath)
if err != nil {
return
}
}
}
return
}