107 lines
2.4 KiB
Go
107 lines
2.4 KiB
Go
package main
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import (
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"io"
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"os"
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"fmt"
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"github.com/containers/storage"
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"github.com/containers/storage/pkg/archive"
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"github.com/pkg/errors"
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"github.com/sirupsen/logrus"
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"github.com/urfave/cli"
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)
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type exportOptions struct {
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output string
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container string
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}
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var (
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exportFlags = []cli.Flag{
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cli.StringFlag{
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Name: "output, o",
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Usage: "Write to a file, default is STDOUT",
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Value: "/dev/stdout",
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},
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}
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exportDescription = "Exports container's filesystem contents as a tar archive" +
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" and saves it on the local machine."
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exportCommand = cli.Command{
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Name: "export",
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Usage: "Export container's filesystem contents as a tar archive",
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Description: exportDescription,
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Flags: exportFlags,
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Action: exportCmd,
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ArgsUsage: "CONTAINER",
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}
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)
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// exportCmd saves a container to a tarball on disk
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func exportCmd(c *cli.Context) error {
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args := c.Args()
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if len(args) == 0 {
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return errors.Errorf("container id must be specified")
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}
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if len(args) > 1 {
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return errors.Errorf("too many arguments given, need 1 at most.")
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}
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container := args[0]
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if err := validateFlags(c, exportFlags); err != nil {
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return err
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}
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config, err := getConfig(c)
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if err != nil {
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return errors.Wrapf(err, "could not get config")
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}
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store, err := getStore(config)
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if err != nil {
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return err
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}
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output := c.String("output")
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if output == "/dev/stdout" {
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file := os.Stdout
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if logrus.IsTerminal(file) {
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return errors.Errorf("refusing to export to terminal. Use -o flag or redirect")
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}
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}
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opts := exportOptions{
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output: output,
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container: container,
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}
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return exportContainer(store, opts)
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}
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// exportContainer exports the contents of a container and saves it as
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// a tarball on disk
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func exportContainer(store storage.Store, opts exportOptions) error {
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mountPoint, err := store.Mount(opts.container, "")
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if err != nil {
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return errors.Wrapf(err, "error finding container %q", opts.container)
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}
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defer func() {
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if err := store.Unmount(opts.container); err != nil {
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fmt.Printf("error unmounting container %q: %v\n", opts.container, err)
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}
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}()
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input, err := archive.Tar(mountPoint, archive.Uncompressed)
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if err != nil {
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return errors.Wrapf(err, "error reading container directory %q", opts.container)
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}
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outFile, err := os.Create(opts.output)
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if err != nil {
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return errors.Wrapf(err, "error creating file %q", opts.output)
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}
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defer outFile.Close()
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_, err = io.Copy(outFile, input)
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return err
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}
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