github.com/GoogleContainerTools/kpt@v1.0.0-beta.50.0.20240520170205-c25345ffcbee/pkg/oci/cache.go (about)

     1  // Copyright 2022 The kpt Authors
     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 oci
    16  
    17  import (
    18  	"bytes"
    19  	"context"
    20  	"fmt"
    21  	"io"
    22  	"path/filepath"
    23  
    24  	v1 "github.com/google/go-containerregistry/pkg/v1"
    25  )
    26  
    27  // CachedConfigFile fetches ConfigFile making use of the cache
    28  // TODO: This should be incorporated into the go-containerregistry, along with replacing a fetcher
    29  func (r *Storage) CachedConfigFile(ctx context.Context, imageName imageName) (*v1.ConfigFile, error) {
    30  	ociImage, err := r.ToRemoteImage(ctx, imageName)
    31  	if err != nil {
    32  		return nil, err
    33  	}
    34  
    35  	manifest, err := r.CachedManifest(ctx, ociImage)
    36  	if err != nil {
    37  		return nil, fmt.Errorf("error fetching manifest for image: %w", err)
    38  	}
    39  
    40  	digest := manifest.Config.Digest
    41  
    42  	fetcher := func() (io.ReadCloser, error) {
    43  		b, err := ociImage.RawConfigFile()
    44  		if err != nil {
    45  			return nil, err
    46  		}
    47  		r := bytes.NewReader(b)
    48  		return io.NopCloser(r), nil
    49  	}
    50  
    51  	f, err := WithCacheFile(filepath.Join(r.cacheDir, "config", digest.String()), fetcher)
    52  	if err != nil {
    53  		return nil, err
    54  	}
    55  	defer f.Close()
    56  
    57  	config, err := v1.ParseConfigFile(f)
    58  	if err != nil {
    59  		return nil, fmt.Errorf("error parsing config: %w", err)
    60  	}
    61  	return config, nil
    62  }
    63  
    64  // CachedManifest fetches Manifest making use of the cache
    65  // TODO: This should be incorporated into the go-containerregistry, along with replacing a fetcher
    66  func (r *Storage) CachedManifest(_ context.Context, image v1.Image) (*v1.Manifest, error) {
    67  	digest, err := image.Digest()
    68  	if err != nil {
    69  		return nil, fmt.Errorf("cannot get image manifest: %w", err)
    70  	}
    71  
    72  	fetcher := func() (io.ReadCloser, error) {
    73  		b, err := image.RawManifest()
    74  		if err != nil {
    75  			return nil, err
    76  		}
    77  		r := bytes.NewReader(b)
    78  		return io.NopCloser(r), nil
    79  	}
    80  
    81  	f, err := WithCacheFile(filepath.Join(r.cacheDir, "manifest", digest.String()), fetcher)
    82  	if err != nil {
    83  		return nil, err
    84  	}
    85  	defer f.Close()
    86  
    87  	manifest, err := v1.ParseManifest(f)
    88  	if err != nil {
    89  		return nil, fmt.Errorf("error parsing manifest: %w", err)
    90  	}
    91  	return manifest, nil
    92  }