forked from TrueCloudLab/distribution
3f479b62b4
This change separates out the remote file reader functionality from layer reprsentation data. More importantly, issues with seeking have been fixed and thoroughly tested.
94 lines
2.9 KiB
Go
94 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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