mirror of https://github.com/containers/image.git
114 lines
3.9 KiB
Go
114 lines
3.9 KiB
Go
package directory
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import (
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"context"
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"fmt"
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"io"
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"os"
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"github.com/containers/image/v5/internal/imagesource/impl"
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"github.com/containers/image/v5/internal/imagesource/stubs"
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"github.com/containers/image/v5/internal/manifest"
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"github.com/containers/image/v5/internal/private"
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"github.com/containers/image/v5/internal/signature"
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"github.com/containers/image/v5/types"
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"github.com/opencontainers/go-digest"
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)
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type dirImageSource struct {
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impl.Compat
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impl.PropertyMethodsInitialize
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impl.DoesNotAffectLayerInfosForCopy
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stubs.NoGetBlobAtInitialize
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ref dirReference
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}
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// newImageSource returns an ImageSource reading from an existing directory.
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// The caller must call .Close() on the returned ImageSource.
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func newImageSource(ref dirReference) private.ImageSource {
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s := &dirImageSource{
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PropertyMethodsInitialize: impl.PropertyMethods(impl.Properties{
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HasThreadSafeGetBlob: false,
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}),
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NoGetBlobAtInitialize: stubs.NoGetBlobAt(ref),
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ref: ref,
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}
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s.Compat = impl.AddCompat(s)
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return s
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}
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// Reference returns the reference used to set up this source, _as specified by the user_
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// (not as the image itself, or its underlying storage, claims). This can be used e.g. to determine which public keys are trusted for this image.
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func (s *dirImageSource) Reference() types.ImageReference {
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return s.ref
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}
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// Close removes resources associated with an initialized ImageSource, if any.
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func (s *dirImageSource) Close() error {
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return nil
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}
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// GetManifest returns the image's manifest along with its MIME type (which may be empty when it can't be determined but the manifest is available).
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// It may use a remote (= slow) service.
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// If instanceDigest is not nil, it contains a digest of the specific manifest instance to retrieve (when the primary manifest is a manifest list);
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// this never happens if the primary manifest is not a manifest list (e.g. if the source never returns manifest lists).
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func (s *dirImageSource) GetManifest(ctx context.Context, instanceDigest *digest.Digest) ([]byte, string, error) {
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path, err := s.ref.manifestPath(instanceDigest)
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if err != nil {
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return nil, "", err
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}
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m, err := os.ReadFile(path)
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if err != nil {
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return nil, "", err
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}
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return m, manifest.GuessMIMEType(m), err
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}
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// GetBlob returns a stream for the specified blob, and the blob’s size (or -1 if unknown).
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// The Digest field in BlobInfo is guaranteed to be provided, Size may be -1 and MediaType may be optionally provided.
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// May update BlobInfoCache, preferably after it knows for certain that a blob truly exists at a specific location.
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func (s *dirImageSource) GetBlob(ctx context.Context, info types.BlobInfo, cache types.BlobInfoCache) (io.ReadCloser, int64, error) {
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path, err := s.ref.layerPath(info.Digest)
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if err != nil {
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return nil, -1, err
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}
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r, err := os.Open(path)
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if err != nil {
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return nil, -1, err
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}
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fi, err := r.Stat()
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if err != nil {
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return nil, -1, err
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}
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return r, fi.Size(), nil
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}
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// GetSignaturesWithFormat returns the image's signatures. It may use a remote (= slow) service.
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// If instanceDigest is not nil, it contains a digest of the specific manifest instance to retrieve signatures for
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// (when the primary manifest is a manifest list); this never happens if the primary manifest is not a manifest list
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// (e.g. if the source never returns manifest lists).
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func (s *dirImageSource) GetSignaturesWithFormat(ctx context.Context, instanceDigest *digest.Digest) ([]signature.Signature, error) {
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signatures := []signature.Signature{}
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for i := 0; ; i++ {
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path, err := s.ref.signaturePath(i, instanceDigest)
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if err != nil {
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return nil, err
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}
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sigBlob, err := os.ReadFile(path)
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if err != nil {
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if os.IsNotExist(err) {
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break
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}
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return nil, err
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}
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signature, err := signature.FromBlob(sigBlob)
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if err != nil {
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return nil, fmt.Errorf("parsing signature %q: %w", path, err)
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}
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signatures = append(signatures, signature)
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}
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return signatures, nil
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}
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