package cmdrootfs import ( "errors" "fmt" "io" "os" goflags "github.com/jessevdk/go-flags" "github.com/motiejus/code/undocker/internal/cmd" "github.com/motiejus/code/undocker/rootfs" "go.uber.org/multierr" ) type ( rootfsFactory func(io.ReadSeeker) io.WriterTo // Command is "rootfs" command Command struct { cmd.BaseCommand PositionalArgs struct { Infile goflags.Filename `long:"infile" description:"Input tarball"` Outfile string `long:"outfile" description:"Output path, stdout is '-'"` } `positional-args:"yes" required:"yes"` rootfsNew rootfsFactory } ) // Execute executes rootfs Command func (c *Command) Execute(args []string) (err error) { if len(args) != 0 { return errors.New("too many args") } if c.rootfsNew == nil { c.init() } rd, err := os.Open(string(c.PositionalArgs.Infile)) if err != nil { return err } defer func() { err = multierr.Append(err, rd.Close()) }() var out io.Writer if fname := string(c.PositionalArgs.Outfile); fname == "-" { out = c.Stdout } else { outf, err := os.Create(fname) if err != nil { return fmt.Errorf("create: %w", err) } defer func() { err = multierr.Append(err, outf.Close()) }() out = outf } if _, err := c.rootfsNew(rd).WriteTo(out); err != nil { return err } return nil } // init() initializes Command with the default options. // // Since constructors for sub-commands requires lots of boilerplate, // command will initialize itself. func (c *Command) init() { c.BaseCommand.Init() c.rootfsNew = func(r io.ReadSeeker) io.WriterTo { return rootfs.New(r) } }