github.com/justincormack/cli@v0.0.0-20201215022714-831ebeae9675/cli/command/image/save.go (about)

     1  package image
     2  
     3  import (
     4  	"context"
     5  	"io"
     6  
     7  	"github.com/docker/cli/cli"
     8  	"github.com/docker/cli/cli/command"
     9  	"github.com/pkg/errors"
    10  	"github.com/spf13/cobra"
    11  )
    12  
    13  type saveOptions struct {
    14  	images []string
    15  	output string
    16  }
    17  
    18  // NewSaveCommand creates a new `docker save` command
    19  func NewSaveCommand(dockerCli command.Cli) *cobra.Command {
    20  	var opts saveOptions
    21  
    22  	cmd := &cobra.Command{
    23  		Use:   "save [OPTIONS] IMAGE [IMAGE...]",
    24  		Short: "Save one or more images to a tar archive (streamed to STDOUT by default)",
    25  		Args:  cli.RequiresMinArgs(1),
    26  		RunE: func(cmd *cobra.Command, args []string) error {
    27  			opts.images = args
    28  			return RunSave(dockerCli, opts)
    29  		},
    30  	}
    31  
    32  	flags := cmd.Flags()
    33  
    34  	flags.StringVarP(&opts.output, "output", "o", "", "Write to a file, instead of STDOUT")
    35  
    36  	return cmd
    37  }
    38  
    39  // RunSave performs a save against the engine based on the specified options
    40  func RunSave(dockerCli command.Cli, opts saveOptions) error {
    41  	if opts.output == "" && dockerCli.Out().IsTerminal() {
    42  		return errors.New("cowardly refusing to save to a terminal. Use the -o flag or redirect")
    43  	}
    44  
    45  	if err := command.ValidateOutputPath(opts.output); err != nil {
    46  		return errors.Wrap(err, "failed to save image")
    47  	}
    48  
    49  	responseBody, err := dockerCli.Client().ImageSave(context.Background(), opts.images)
    50  	if err != nil {
    51  		return err
    52  	}
    53  	defer responseBody.Close()
    54  
    55  	if opts.output == "" {
    56  		_, err := io.Copy(dockerCli.Out(), responseBody)
    57  		return err
    58  	}
    59  
    60  	return command.CopyToFile(opts.output, responseBody)
    61  }