DockerCLI/cli/command/image/save.go

74 lines
1.7 KiB
Go

package image
import (
"context"
"io"
"os"
"path/filepath"
"github.com/docker/cli/cli"
"github.com/docker/cli/cli/command"
"github.com/pkg/errors"
"github.com/spf13/cobra"
)
type saveOptions struct {
images []string
output string
}
// NewSaveCommand creates a new `docker save` command
func NewSaveCommand(dockerCli command.Cli) *cobra.Command {
var opts saveOptions
cmd := &cobra.Command{
Use: "save [OPTIONS] IMAGE [IMAGE...]",
Short: "Save one or more images to a tar archive (streamed to STDOUT by default)",
Args: cli.RequiresMinArgs(1),
RunE: func(cmd *cobra.Command, args []string) error {
opts.images = args
return RunSave(dockerCli, opts)
},
}
flags := cmd.Flags()
flags.StringVarP(&opts.output, "output", "o", "", "Write to a file, instead of STDOUT")
return cmd
}
// RunSave performs a save against the engine based on the specified options
func RunSave(dockerCli command.Cli, opts saveOptions) error {
if opts.output == "" && dockerCli.Out().IsTerminal() {
return errors.New("cowardly refusing to save to a terminal. Use the -o flag or redirect")
}
if err := validateOutputPath(opts.output); err != nil {
return errors.Wrap(err, "failed to save image")
}
responseBody, err := dockerCli.Client().ImageSave(context.Background(), opts.images)
if err != nil {
return err
}
defer responseBody.Close()
if opts.output == "" {
_, err := io.Copy(dockerCli.Out(), responseBody)
return err
}
return command.CopyToFile(opts.output, responseBody)
}
func validateOutputPath(path string) error {
dir := filepath.Dir(path)
if dir != "" && dir != "." {
if _, err := os.Stat(dir); os.IsNotExist(err) {
return errors.Errorf("unable to validate output path: directory %q does not exist", dir)
}
}
return nil
}