github.com/containerd/nerdctl/v2@v2.0.0-beta.5.0.20240520001846-b5758f54fa28/pkg/cmd/image/save.go (about)

     1  /*
     2     Copyright The containerd Authors.
     3  
     4     Licensed under the Apache License, Version 2.0 (the "License");
     5     you may not use this file except in compliance with the License.
     6     You may obtain a copy of the License at
     7  
     8         http://www.apache.org/licenses/LICENSE-2.0
     9  
    10     Unless required by applicable law or agreed to in writing, software
    11     distributed under the License is distributed on an "AS IS" BASIS,
    12     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13     See the License for the specific language governing permissions and
    14     limitations under the License.
    15  */
    16  
    17  package image
    18  
    19  import (
    20  	"context"
    21  	"fmt"
    22  
    23  	"github.com/containerd/containerd"
    24  	"github.com/containerd/containerd/images/archive"
    25  	"github.com/containerd/nerdctl/v2/pkg/api/types"
    26  	"github.com/containerd/nerdctl/v2/pkg/idutil/imagewalker"
    27  	"github.com/containerd/nerdctl/v2/pkg/platformutil"
    28  	"github.com/containerd/nerdctl/v2/pkg/strutil"
    29  )
    30  
    31  // Save exports `images` to a `io.Writer` (e.g., a file writer, or os.Stdout) specified by `options.Stdout`.
    32  func Save(ctx context.Context, client *containerd.Client, images []string, options types.ImageSaveOptions, exportOpts ...archive.ExportOpt) error {
    33  	images = strutil.DedupeStrSlice(images)
    34  
    35  	platMC, err := platformutil.NewMatchComparer(options.AllPlatforms, options.Platform)
    36  	if err != nil {
    37  		return err
    38  	}
    39  
    40  	exportOpts = append(exportOpts, archive.WithPlatform(platMC))
    41  	imageStore := client.ImageService()
    42  
    43  	savedImages := make(map[string]struct{})
    44  	walker := &imagewalker.ImageWalker{
    45  		Client: client,
    46  		OnFound: func(ctx context.Context, found imagewalker.Found) error {
    47  			if found.UniqueImages > 1 {
    48  				return fmt.Errorf("ambiguous digest ID: multiple IDs found with provided prefix %s", found.Req)
    49  			}
    50  			imgName := found.Image.Name
    51  			imgDigest := found.Image.Target.Digest.String()
    52  			if _, ok := savedImages[imgDigest]; !ok {
    53  				savedImages[imgDigest] = struct{}{}
    54  				exportOpts = append(exportOpts, archive.WithImage(imageStore, imgName))
    55  			}
    56  			return nil
    57  		},
    58  	}
    59  
    60  	// check if all images exist
    61  	if err := walker.WalkAll(ctx, images, false); err != nil {
    62  		return err
    63  	}
    64  
    65  	return client.Export(ctx, options.Stdout, exportOpts...)
    66  }