package main import ( "errors" "os" goflags "github.com/jessevdk/go-flags" "github.com/motiejus/code/undocker/rootfs" ) type ( params struct { RootFS cmdRootFS `command:"rootfs" description:"Unpack a docker container image to a single filesystem tarball"` Manifest cmdManifest `command:"manifest"` } cmdManifest struct{} // stub ) func main() { if err := run(os.Args); err != nil { os.Exit(1) } os.Exit(0) } func run(args []string) error { var opts params if _, err := goflags.ParseArgs(&opts, args[1:]); err != nil { return err } return nil } type cmdRootFS struct { PositionalArgs struct { Infile goflags.Filename `long:"infile" description:"Input tarball"` Outfile string `long:"outfile" description:"Output tarball (flattened file system)"` } `positional-args:"yes" required:"yes"` } func (r *cmdRootFS) Execute(args []string) error { if len(args) != 0 { return errors.New("too many args") } in, err := os.Open(string(r.PositionalArgs.Infile)) if err != nil { return err } defer in.Close() out, err := os.Create(string(r.PositionalArgs.Outfile)) if err != nil { return err } defer out.Close() return rootfs.Rootfs(in, out) }