image.go

Documentation: github.com/google/go-containerregistry/pkg/v1/empty

     1  // Copyright 2018 Google LLC All Rights Reserved.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //    http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package empty
    16  
    17  import (
    18  	"fmt"
    19  
    20  	v1 "github.com/google/go-containerregistry/pkg/v1"
    21  	"github.com/google/go-containerregistry/pkg/v1/partial"
    22  	"github.com/google/go-containerregistry/pkg/v1/types"
    23  )
    24  
    25  // Image is a singleton empty image, think: FROM scratch.
    26  var Image, _ = partial.UncompressedToImage(emptyImage{})
    27  
    28  type emptyImage struct{}
    29  
    30  // MediaType implements partial.UncompressedImageCore.
    31  func (i emptyImage) MediaType() (types.MediaType, error) {
    32  	return types.DockerManifestSchema2, nil
    33  }
    34  
    35  // RawConfigFile implements partial.UncompressedImageCore.
    36  func (i emptyImage) RawConfigFile() ([]byte, error) {
    37  	return partial.RawConfigFile(i)
    38  }
    39  
    40  // ConfigFile implements v1.Image.
    41  func (i emptyImage) ConfigFile() (*v1.ConfigFile, error) {
    42  	return &v1.ConfigFile{
    43  		RootFS: v1.RootFS{
    44  			// Some clients check this.
    45  			Type: "layers",
    46  		},
    47  	}, nil
    48  }
    49  
    50  func (i emptyImage) LayerByDiffID(h v1.Hash) (partial.UncompressedLayer, error) {
    51  	return nil, fmt.Errorf("LayerByDiffID(%s): empty image", h)
    52  }
    53
View as plain text