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