/**
* Retrieves the {@link CachedLayer} for the layer with digest {@code layerDigest}.
*
* @param layerDigest the layer digest
* @return the {@link CachedLayer} referenced by the layer digest, if found
* @throws CacheCorruptedException if the cache was found to be corrupted
* @throws IOException if an I/O exception occurs
*/
public Maybe <CachedLayer> Retrieve(DescriptorDigest layerDigest)
{
layerDigest = layerDigest ?? throw new ArgumentNullException(nameof(layerDigest));
SystemPath layerDirectory = cacheStorageFiles.GetLayerDirectory(layerDigest);
if (!Files.Exists(layerDirectory))
{
return(Maybe.Empty <CachedLayer>());
}
CachedLayer.Builder cachedLayerBuilder = CachedLayer.CreateBuilder().SetLayerDigest(layerDigest);
foreach (SystemPath fileInLayerDirectory in Files.List(layerDirectory))
{
if (CacheStorageFiles.IsLayerFile(fileInLayerDirectory))
{
if (cachedLayerBuilder.HasLayerBlob())
{
throw new CacheCorruptedException(
cacheStorageFiles.GetCacheDirectory(),
"Multiple layer files found for layer with digest "
+ layerDigest.GetHash()
+ " in directory: "
+ layerDirectory);
}
cachedLayerBuilder
.SetLayerBlob(Blobs.From(fileInLayerDirectory))
.SetLayerDiffId(cacheStorageFiles.GetDiffId(fileInLayerDirectory))
.SetLayerSize(Files.Size(fileInLayerDirectory));
}
}
return(Maybe.Of(cachedLayerBuilder.Build()));
}
/**
* Writes an uncompressed {@link Blob} out to the cache directory in the form:
*
* <ul>
* <li>The {@code uncompressedLayerBlob} is written to the layer directory under the layers
* directory corresponding to the layer blob.
* <li>The {@code selector} is written to the selector file under the selectors directory.
* </ul>
*
* @param uncompressedLayerBlob the {@link Blob} containing the uncompressed layer contents to
* write out
* @param selector the optional selector digest to also reference this layer data. A selector
* digest may be a secondary identifier for a layer that is distinct from the default layer
* digest.
* @return the {@link CachedLayer} representing the written entry
* @throws IOException if an I/O exception occurs
*/
public async Task <CachedLayer> WriteUncompressedAsync(IBlob uncompressedLayerBlob, DescriptorDigest selector)
{
uncompressedLayerBlob = uncompressedLayerBlob ?? throw new ArgumentNullException(nameof(uncompressedLayerBlob));
// Creates the layers directory if it doesn't exist.
Files.CreateDirectories(cacheStorageFiles.GetLayersDirectory());
// Creates the temporary directory. The temporary directory must be in the same FileStore as the
// final location for Files.move to work.
Files.CreateDirectories(cacheStorageFiles.GetTemporaryDirectory());
using (TemporaryDirectory temporaryDirectory =
new TemporaryDirectory(cacheStorageFiles.GetTemporaryDirectory()))
{
SystemPath temporaryLayerDirectory = temporaryDirectory.GetDirectory();
// Writes the layer file to the temporary directory.
WrittenLayer writtenLayer =
await WriteUncompressedLayerBlobToDirectoryAsync(uncompressedLayerBlob, temporaryLayerDirectory).ConfigureAwait(false);
// Moves the temporary directory to the final location.
temporaryDirectory.MoveIfDoesNotExist(cacheStorageFiles.GetLayerDirectory(writtenLayer.LayerDigest));
// Updates cachedLayer with the blob information.
SystemPath layerFile =
cacheStorageFiles.GetLayerFile(writtenLayer.LayerDigest, writtenLayer.LayerDiffId);
CachedLayer.Builder cachedLayerBuilder =
CachedLayer.CreateBuilder()
.SetLayerDigest(writtenLayer.LayerDigest)
.SetLayerDiffId(writtenLayer.LayerDiffId)
.SetLayerSize(writtenLayer.LayerSize)
.SetLayerBlob(Blobs.From(layerFile));
// Write the selector file.
if (selector != null)
{
WriteSelector(selector, writtenLayer.LayerDigest);
}
return(cachedLayerBuilder.Build());
}
}