undocker/internal/cmdrootfs/cmdrootfs.go

44 lines
944 B
Go

package cmdrootfs
import (
"errors"
"os"
goflags "github.com/jessevdk/go-flags"
"github.com/motiejus/code/undocker/rootfs"
"go.uber.org/multierr"
)
type CmdRootFS struct {
PositionalArgs struct {
Infile goflags.Filename `long:"infile" description:"Input tarball"`
Outfile string `long:"outfile" description:"Output path, stdout is '-'"`
} `positional-args:"yes" required:"yes"`
}
func (r *CmdRootFS) Execute(args []string) (err error) {
if len(args) != 0 {
return errors.New("too many args")
}
rd, err := os.Open(string(r.PositionalArgs.Infile))
if err != nil {
return err
}
defer func() { err = multierr.Append(err, rd.Close()) }()
var out *os.File
outf := string(r.PositionalArgs.Outfile)
if outf == "-" {
out = os.Stdout
} else {
out, err = os.Create(outf)
if err != nil {
return err
}
}
defer func() { err = multierr.Append(err, out.Close()) }()
return rootfs.New(rd).WriteTo(out)
}