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Diffstat (limited to 'vendor/github.com/docker/distribution/blobs.go')
| -rw-r--r-- | vendor/github.com/docker/distribution/blobs.go | 257 |
1 files changed, 257 insertions, 0 deletions
diff --git a/vendor/github.com/docker/distribution/blobs.go b/vendor/github.com/docker/distribution/blobs.go new file mode 100644 index 000000000..01d309029 --- /dev/null +++ b/vendor/github.com/docker/distribution/blobs.go @@ -0,0 +1,257 @@ +package distribution + +import ( + "errors" + "fmt" + "io" + "net/http" + "time" + + "github.com/docker/distribution/context" + "github.com/docker/distribution/reference" + "github.com/opencontainers/go-digest" +) + +var ( + // ErrBlobExists returned when blob already exists + ErrBlobExists = errors.New("blob exists") + + // ErrBlobDigestUnsupported when blob digest is an unsupported version. + ErrBlobDigestUnsupported = errors.New("unsupported blob digest") + + // ErrBlobUnknown when blob is not found. + ErrBlobUnknown = errors.New("unknown blob") + + // ErrBlobUploadUnknown returned when upload is not found. + ErrBlobUploadUnknown = errors.New("blob upload unknown") + + // ErrBlobInvalidLength returned when the blob has an expected length on + // commit, meaning mismatched with the descriptor or an invalid value. + ErrBlobInvalidLength = errors.New("blob invalid length") +) + +// ErrBlobInvalidDigest returned when digest check fails. +type ErrBlobInvalidDigest struct { + Digest digest.Digest + Reason error +} + +func (err ErrBlobInvalidDigest) Error() string { + return fmt.Sprintf("invalid digest for referenced layer: %v, %v", + err.Digest, err.Reason) +} + +// ErrBlobMounted returned when a blob is mounted from another repository +// instead of initiating an upload session. +type ErrBlobMounted struct { + From reference.Canonical + Descriptor Descriptor +} + +func (err ErrBlobMounted) Error() string { + return fmt.Sprintf("blob mounted from: %v to: %v", + err.From, err.Descriptor) +} + +// Descriptor describes targeted content. Used in conjunction with a blob +// store, a descriptor can be used to fetch, store and target any kind of +// blob. The struct also describes the wire protocol format. Fields should +// only be added but never changed. +type Descriptor struct { + // MediaType describe the type of the content. All text based formats are + // encoded as utf-8. + MediaType string `json:"mediaType,omitempty"` + + // Size in bytes of content. + Size int64 `json:"size,omitempty"` + + // Digest uniquely identifies the content. A byte stream can be verified + // against against this digest. + Digest digest.Digest `json:"digest,omitempty"` + + // URLs contains the source URLs of this content. + URLs []string `json:"urls,omitempty"` + + // NOTE: Before adding a field here, please ensure that all + // other options have been exhausted. Much of the type relationships + // depend on the simplicity of this type. +} + +// Descriptor returns the descriptor, to make it satisfy the Describable +// interface. Note that implementations of Describable are generally objects +// which can be described, not simply descriptors; this exception is in place +// to make it more convenient to pass actual descriptors to functions that +// expect Describable objects. +func (d Descriptor) Descriptor() Descriptor { + return d +} + +// BlobStatter makes blob descriptors available by digest. The service may +// provide a descriptor of a different digest if the provided digest is not +// canonical. +type BlobStatter interface { + // Stat provides metadata about a blob identified by the digest. If the + // blob is unknown to the describer, ErrBlobUnknown will be returned. + Stat(ctx context.Context, dgst digest.Digest) (Descriptor, error) +} + +// BlobDeleter enables deleting blobs from storage. +type BlobDeleter interface { + Delete(ctx context.Context, dgst digest.Digest) error +} + +// BlobEnumerator enables iterating over blobs from storage +type BlobEnumerator interface { + Enumerate(ctx context.Context, ingester func(dgst digest.Digest) error) error +} + +// BlobDescriptorService manages metadata about a blob by digest. Most +// implementations will not expose such an interface explicitly. Such mappings +// should be maintained by interacting with the BlobIngester. Hence, this is +// left off of BlobService and BlobStore. +type BlobDescriptorService interface { + BlobStatter + + // SetDescriptor assigns the descriptor to the digest. The provided digest and + // the digest in the descriptor must map to identical content but they may + // differ on their algorithm. The descriptor must have the canonical + // digest of the content and the digest algorithm must match the + // annotators canonical algorithm. + // + // Such a facility can be used to map blobs between digest domains, with + // the restriction that the algorithm of the descriptor must match the + // canonical algorithm (ie sha256) of the annotator. + SetDescriptor(ctx context.Context, dgst digest.Digest, desc Descriptor) error + + // Clear enables descriptors to be unlinked + Clear(ctx context.Context, dgst digest.Digest) error +} + +// BlobDescriptorServiceFactory creates middleware for BlobDescriptorService. +type BlobDescriptorServiceFactory interface { + BlobAccessController(svc BlobDescriptorService) BlobDescriptorService +} + +// ReadSeekCloser is the primary reader type for blob data, combining +// io.ReadSeeker with io.Closer. +type ReadSeekCloser interface { + io.ReadSeeker + io.Closer +} + +// BlobProvider describes operations for getting blob data. +type BlobProvider interface { + // Get returns the entire blob identified by digest along with the descriptor. + Get(ctx context.Context, dgst digest.Digest) ([]byte, error) + + // Open provides a ReadSeekCloser to the blob identified by the provided + // descriptor. If the blob is not known to the service, an error will be + // returned. + Open(ctx context.Context, dgst digest.Digest) (ReadSeekCloser, error) +} + +// BlobServer can serve blobs via http. +type BlobServer interface { + // ServeBlob attempts to serve the blob, identified by dgst, via http. The + // service may decide to redirect the client elsewhere or serve the data + // directly. + // + // This handler only issues successful responses, such as 2xx or 3xx, + // meaning it serves data or issues a redirect. If the blob is not + // available, an error will be returned and the caller may still issue a + // response. + // + // The implementation may serve the same blob from a different digest + // domain. The appropriate headers will be set for the blob, unless they + // have already been set by the caller. + ServeBlob(ctx context.Context, w http.ResponseWriter, r *http.Request, dgst digest.Digest) error +} + +// BlobIngester ingests blob data. +type BlobIngester interface { + // Put inserts the content p into the blob service, returning a descriptor + // or an error. + Put(ctx context.Context, mediaType string, p []byte) (Descriptor, error) + + // Create allocates a new blob writer to add a blob to this service. The + // returned handle can be written to and later resumed using an opaque + // identifier. With this approach, one can Close and Resume a BlobWriter + // multiple times until the BlobWriter is committed or cancelled. + Create(ctx context.Context, options ...BlobCreateOption) (BlobWriter, error) + + // Resume attempts to resume a write to a blob, identified by an id. + Resume(ctx context.Context, id string) (BlobWriter, error) +} + +// BlobCreateOption is a general extensible function argument for blob creation +// methods. A BlobIngester may choose to honor any or none of the given +// BlobCreateOptions, which can be specific to the implementation of the +// BlobIngester receiving them. +// TODO (brianbland): unify this with ManifestServiceOption in the future +type BlobCreateOption interface { + Apply(interface{}) error +} + +// CreateOptions is a collection of blob creation modifiers relevant to general +// blob storage intended to be configured by the BlobCreateOption.Apply method. +type CreateOptions struct { + Mount struct { + ShouldMount bool + From reference.Canonical + // Stat allows to pass precalculated descriptor to link and return. + // Blob access check will be skipped if set. + Stat *Descriptor + } +} + +// BlobWriter provides a handle for inserting data into a blob store. +// Instances should be obtained from BlobWriteService.Writer and +// BlobWriteService.Resume. If supported by the store, a writer can be +// recovered with the id. +type BlobWriter interface { + io.WriteCloser + io.ReaderFrom + + // Size returns the number of bytes written to this blob. + Size() int64 + + // ID returns the identifier for this writer. The ID can be used with the + // Blob service to later resume the write. + ID() string + + // StartedAt returns the time this blob write was started. + StartedAt() time.Time + + // Commit completes the blob writer process. The content is verified + // against the provided provisional descriptor, which may result in an + // error. Depending on the implementation, written data may be validated + // against the provisional descriptor fields. If MediaType is not present, + // the implementation may reject the commit or assign "application/octet- + // stream" to the blob. The returned descriptor may have a different + // digest depending on the blob store, referred to as the canonical + // descriptor. + Commit(ctx context.Context, provisional Descriptor) (canonical Descriptor, err error) + + // Cancel ends the blob write without storing any data and frees any + // associated resources. Any data written thus far will be lost. Cancel + // implementations should allow multiple calls even after a commit that + // result in a no-op. This allows use of Cancel in a defer statement, + // increasing the assurance that it is correctly called. + Cancel(ctx context.Context) error +} + +// BlobService combines the operations to access, read and write blobs. This +// can be used to describe remote blob services. +type BlobService interface { + BlobStatter + BlobProvider + BlobIngester +} + +// BlobStore represent the entire suite of blob related operations. Such an +// implementation can access, read, write, delete and serve blobs. +type BlobStore interface { + BlobService + BlobServer + BlobDeleter +} |