oras.land/oras-go/v2@v2.5.1-0.20240520045656-aef90e4d04c4/internal/manifestutil/parser.go (about)

     1  /*
     2  Copyright The ORAS Authors.
     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  
    16  package manifestutil
    17  
    18  import (
    19  	"context"
    20  	"encoding/json"
    21  
    22  	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
    23  	"oras.land/oras-go/v2/content"
    24  	"oras.land/oras-go/v2/internal/docker"
    25  	"oras.land/oras-go/v2/internal/spec"
    26  )
    27  
    28  // Config returns the config of desc, if present.
    29  func Config(ctx context.Context, fetcher content.Fetcher, desc ocispec.Descriptor) (*ocispec.Descriptor, error) {
    30  	switch desc.MediaType {
    31  	case docker.MediaTypeManifest, ocispec.MediaTypeImageManifest:
    32  		content, err := content.FetchAll(ctx, fetcher, desc)
    33  		if err != nil {
    34  			return nil, err
    35  		}
    36  		// OCI manifest schema can be used to marshal docker manifest
    37  		var manifest ocispec.Manifest
    38  		if err := json.Unmarshal(content, &manifest); err != nil {
    39  			return nil, err
    40  		}
    41  		return &manifest.Config, nil
    42  	default:
    43  		return nil, nil
    44  	}
    45  }
    46  
    47  // Manifest returns the manifests of desc, if present.
    48  func Manifests(ctx context.Context, fetcher content.Fetcher, desc ocispec.Descriptor) ([]ocispec.Descriptor, error) {
    49  	switch desc.MediaType {
    50  	case docker.MediaTypeManifestList, ocispec.MediaTypeImageIndex:
    51  		content, err := content.FetchAll(ctx, fetcher, desc)
    52  		if err != nil {
    53  			return nil, err
    54  		}
    55  		// OCI manifest index schema can be used to marshal docker manifest list
    56  		var index ocispec.Index
    57  		if err := json.Unmarshal(content, &index); err != nil {
    58  			return nil, err
    59  		}
    60  		return index.Manifests, nil
    61  	default:
    62  		return nil, nil
    63  	}
    64  }
    65  
    66  // Subject returns the subject of desc, if present.
    67  func Subject(ctx context.Context, fetcher content.Fetcher, desc ocispec.Descriptor) (*ocispec.Descriptor, error) {
    68  	switch desc.MediaType {
    69  	case ocispec.MediaTypeImageManifest, ocispec.MediaTypeImageIndex, spec.MediaTypeArtifactManifest:
    70  		content, err := content.FetchAll(ctx, fetcher, desc)
    71  		if err != nil {
    72  			return nil, err
    73  		}
    74  		var manifest struct {
    75  			Subject *ocispec.Descriptor `json:"subject,omitempty"`
    76  		}
    77  		if err := json.Unmarshal(content, &manifest); err != nil {
    78  			return nil, err
    79  		}
    80  		return manifest.Subject, nil
    81  	default:
    82  		return nil, nil
    83  	}
    84  }