portainer/portainer

package filesystem

import (
    "errors"
    "io"
    "os"
    "path/filepath"
    "strings"
)

// CopyPath copies file or directory defined by the path to the toDir path
func CopyPath(path string, toDir string) error {
    info, err := os.Stat(path)
    if err != nil && errors.Is(err, os.ErrNotExist) {
        // skip copy if file does not exist
        return nil
    }

    if !info.IsDir() {
        destination := filepath.Join(toDir, info.Name())
        return copyFile(path, destination)
    }

    return CopyDir(path, toDir, true)
}

// CopyDir copies contents of fromDir to toDir.
// When keepParent is true, contents will be copied with their immediate parent dir,
// i.e. given /from/dirA and /to/dirB with keepParent == true, result will be /to/dirB/dirA/<children>
func CopyDir(fromDir, toDir string, keepParent bool) error {
    cleanedSourcePath := filepath.Clean(fromDir)
    parentDirectory := filepath.Dir(cleanedSourcePath)
    err := filepath.Walk(cleanedSourcePath, func(path string, info os.FileInfo, err error) error {
        if err != nil {
            return err
        }
        var destination string
        if keepParent {
            destination = filepath.Join(toDir, strings.TrimPrefix(path, parentDirectory))
        } else {
            destination = filepath.Join(toDir, strings.TrimPrefix(path, cleanedSourcePath))
        }

        if destination == "" {
            return nil
        }

        if info.IsDir() {
            return nil // skip directory creations
        }

        if info.Mode()&os.ModeSymlink != 0 { // entry is a symlink
            return nil // don't copy symlinks
        }

        return copyFile(path, destination)
    })

    return err
}

// copies regular a file from src to dst
func copyFile(src, dst string) error {
    from, err := os.Open(src)
    if err != nil {
        return err
    }
    defer from.Close()

    // has to include 'execute' bit, otherwise fails. MkdirAll follows `mkdir -m` restrictions
    if err := os.MkdirAll(filepath.Dir(dst), 0744); err != nil {
        return err
    }
    to, err := os.Create(dst)
    if err != nil {
        return err
    }
    defer to.Close()

    _, err = io.Copy(to, from)
    return err
}