mirror of https://github.com/docker/docs.git
95 lines
2.9 KiB
Go
95 lines
2.9 KiB
Go
package storage
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import (
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"fmt"
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"io"
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"time"
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"github.com/docker/docker-registry/digest"
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)
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// LayerService provides operations on layer files in a backend storage.
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type LayerService interface {
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// Exists returns true if the layer exists.
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Exists(name string, digest digest.Digest) (bool, error)
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// Fetch the layer identifed by TarSum.
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Fetch(name string, digest digest.Digest) (Layer, error)
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// Upload begins a layer upload to repository identified by name,
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// returning a handle.
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Upload(name string) (LayerUpload, error)
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// Resume continues an in progress layer upload, returning the current
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// state of the upload.
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Resume(uuid string) (LayerUpload, error)
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}
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// Layer provides a readable and seekable layer object. Typically,
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// implementations are *not* goroutine safe.
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type Layer interface {
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// http.ServeContent requires an efficient implementation of
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// ReadSeeker.Seek(0, os.SEEK_END).
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io.ReadSeeker
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io.Closer
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// Name returns the repository under which this layer is linked.
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Name() string // TODO(stevvooe): struggling with nomenclature: should this be "repo" or "name"?
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// Digest returns the unique digest of the blob, which is the tarsum for
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// layers.
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Digest() digest.Digest
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// CreatedAt returns the time this layer was created. Until we implement
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// Stat call on storagedriver, this just returns the zero time.
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CreatedAt() time.Time
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}
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// LayerUpload provides a handle for working with in-progress uploads.
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// Instances can be obtained from the LayerService.Upload and
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// LayerService.Resume.
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type LayerUpload interface {
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io.WriteCloser
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// UUID returns the identifier for this upload.
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UUID() string
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// Name of the repository under which the layer will be linked.
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Name() string
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// Offset returns the position of the last byte written to this layer.
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Offset() int64
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// Finish marks the upload as completed, returning a valid handle to the
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// uploaded layer. The final size and digest are validated against the
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// contents of the uploaded layer.
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Finish(size int64, digest digest.Digest) (Layer, error)
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// Cancel the layer upload process.
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Cancel() error
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}
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var (
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// ErrLayerUnknown returned when layer cannot be found.
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ErrLayerUnknown = fmt.Errorf("unknown layer")
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// ErrLayerExists returned when layer already exists
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ErrLayerExists = fmt.Errorf("layer exists")
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// ErrLayerTarSumVersionUnsupported when tarsum is unsupported version.
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ErrLayerTarSumVersionUnsupported = fmt.Errorf("unsupported tarsum version")
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// ErrLayerUploadUnknown returned when upload is not found.
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ErrLayerUploadUnknown = fmt.Errorf("layer upload unknown")
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// ErrLayerInvalidDigest returned when tarsum check fails.
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ErrLayerInvalidDigest = fmt.Errorf("invalid layer digest")
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// ErrLayerInvalidLength returned when length check fails.
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ErrLayerInvalidLength = fmt.Errorf("invalid layer length")
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// ErrLayerClosed returned when an operation is attempted on a closed
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// Layer or LayerUpload.
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ErrLayerClosed = fmt.Errorf("layer closed")
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)
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