mirror of https://github.com/k3s-io/k3s
69 lines
2.0 KiB
Go
69 lines
2.0 KiB
Go
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package wclayer
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import (
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"io/ioutil"
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"os"
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"github.com/Microsoft/go-winio"
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"github.com/Microsoft/hcsshim/internal/hcserror"
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"github.com/sirupsen/logrus"
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)
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// ExportLayer will create a folder at exportFolderPath and fill that folder with
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// the transport format version of the layer identified by layerId. This transport
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// format includes any metadata required for later importing the layer (using
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// ImportLayer), and requires the full list of parent layer paths in order to
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// perform the export.
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func ExportLayer(path string, exportFolderPath string, parentLayerPaths []string) error {
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title := "hcsshim::ExportLayer "
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logrus.Debugf(title+"path %s folder %s", path, exportFolderPath)
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// Generate layer descriptors
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layers, err := layerPathsToDescriptors(parentLayerPaths)
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if err != nil {
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return err
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}
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err = exportLayer(&stdDriverInfo, path, exportFolderPath, layers)
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if err != nil {
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err = hcserror.Errorf(err, title, "path=%s folder=%s", path, exportFolderPath)
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logrus.Error(err)
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return err
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}
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logrus.Debugf(title+"succeeded path=%s folder=%s", path, exportFolderPath)
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return nil
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}
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type LayerReader interface {
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Next() (string, int64, *winio.FileBasicInfo, error)
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Read(b []byte) (int, error)
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Close() error
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}
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// NewLayerReader returns a new layer reader for reading the contents of an on-disk layer.
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// The caller must have taken the SeBackupPrivilege privilege
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// to call this and any methods on the resulting LayerReader.
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func NewLayerReader(path string, parentLayerPaths []string) (LayerReader, error) {
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exportPath, err := ioutil.TempDir("", "hcs")
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if err != nil {
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return nil, err
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}
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err = ExportLayer(path, exportPath, parentLayerPaths)
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if err != nil {
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os.RemoveAll(exportPath)
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return nil, err
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}
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return &legacyLayerReaderWrapper{newLegacyLayerReader(exportPath)}, nil
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}
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type legacyLayerReaderWrapper struct {
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*legacyLayerReader
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}
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func (r *legacyLayerReaderWrapper) Close() error {
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err := r.legacyLayerReader.Close()
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os.RemoveAll(r.root)
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return err
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}
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