private async Task ReadFromBlobAsync(UnmanagedMemoryStream stream, CloudPageBlob blob, long sourceAddress, long destinationAddress, uint readLength)
{
Debug.WriteLine($"AzureStorageDevice.ReadFromBlobAsync Called target={blob.Name}");
try
{
await BlobManager.AsyncStorageReadMaxConcurrency.WaitAsync().ConfigureAwait(false);
int numAttempts = 0;
while (true) // retry loop
{
numAttempts++;
try
{
if (this.underLease)
{
await this.BlobManager.ConfirmLeaseAsync().ConfigureAwait(false);
}
Debug.WriteLine($"starting download target={blob.Name} readLength={readLength} sourceAddress={sourceAddress}");
if (readLength > 0)
{
await blob.DownloadRangeToStreamAsync(stream, sourceAddress, readLength,
accessCondition : null, options : this.BlobRequestOptionsWithoutRetry, operationContext : null, cancellationToken : this.BlobManager.CancellationToken)
.ConfigureAwait(BlobManager.ConfigureAwaitForStorage);
}
Debug.WriteLine($"finished download target={blob.Name} readLength={readLength} sourceAddress={sourceAddress}");
if (stream.Position != readLength)
{
throw new InvalidDataException($"wrong amount of data received from page blob, expected={readLength}, actual={stream.Position}");
}
break;
}
catch (StorageException e) when(this.underLease && IsTransientStorageError(e) && numAttempts < BlobManager.MaxRetries)
{
TimeSpan nextRetryIn = TimeSpan.FromSeconds(1 + Math.Pow(2, (numAttempts - 1)));
this.BlobManager?.HandleBlobError(nameof(ReadFromBlobAsync), $"could not write to page blob, will retry in {nextRetryIn}s", blob?.Name, e, false);
await Task.Delay(nextRetryIn).ConfigureAwait(false);
stream.Seek(0, SeekOrigin.Begin); // must go back to original position before retrying
continue;
}
catch (Exception exception) when(!IsFatal(exception))
{
this.BlobManager?.HandleBlobError(nameof(ReadFromBlobAsync), "could not read from page blob", blob?.Name, exception, false);
throw;
}
}
}
finally
{
BlobManager.AsyncStorageReadMaxConcurrency.Release();
stream.Dispose();
}
}
async Task ReadFromBlobAsync(UnmanagedMemoryStream stream, CloudPageBlob blob, long sourceAddress, uint readLength)
{
using (stream)
{
long offset = 0;
while (readLength > 0)
{
var length = Math.Min(readLength, MAX_DOWNLOAD_SIZE);
await this.BlobManager.PerformWithRetriesAsync(
BlobManager.AsynchronousStorageReadMaxConcurrency,
true,
"CloudPageBlob.DownloadRangeToStreamAsync",
"ReadFromDevice",
$"readLength={length} sourceAddress={sourceAddress + offset}",
blob.Name,
1000 + (int)length / 1000,
true,
async (numAttempts) =>
{
if (numAttempts > 0)
{
stream.Seek(offset, SeekOrigin.Begin); // must go back to original position before retrying
}
if (length > 0)
{
var blobRequestOptions = (numAttempts > 1 || length == MAX_DOWNLOAD_SIZE)
? BlobManager.BlobRequestOptionsDefault : BlobManager.BlobRequestOptionsAggressiveTimeout;
await blob
.DownloadRangeToStreamAsync(stream, sourceAddress + offset, length, accessCondition: null, options: blobRequestOptions, operationContext: null, cancellationToken: this.PartitionErrorHandler.Token)
.ConfigureAwait(false);
}
if (stream.Position != offset + length)
{
throw new InvalidDataException($"wrong amount of data received from page blob, expected={length}, actual={stream.Position}");
}
return(length);
});
readLength -= length;
offset += length;
}
}
}
public async Task DownloadRangeToStreamAsync(Stream stream, long offset, int length)
{
Require.NotNull("stream", stream);
Require.ZeroOrGreater("offset", offset);
Require.Positive("length", length);
try
{
await _blob.DownloadRangeToStreamAsync(stream, offset, length).ConfigureAwait(false);
}
catch (StorageException ex)
{
// if forbidden, then we might have an expired SAS token
if (ex.RequestInformation != null && ex.RequestInformation.HttpStatusCode == 403)
{
throw new ForbiddenException("Can't read blob", ex);
}
throw;
}
}
private async Task ReadFromBlobAsync(UnmanagedMemoryStream stream, CloudPageBlob blob, long sourceAddress, long destinationAddress, uint readLength)
{
Debug.WriteLine($"AzureStorageDevice.ReadFromBlobAsync Called target={blob.Name}");
try
{
if (this.underLease)
{
Debug.WriteLine($"confirm lease");
await this.BlobManager.ConfirmLeaseAsync().ConfigureAwait(false);
Debug.WriteLine($"confirm lease done");
}
Debug.WriteLine($"starting download target={blob.Name} readLength={readLength} sourceAddress={sourceAddress}");
await blob.DownloadRangeToStreamAsync(stream, sourceAddress, readLength,
accessCondition : null, options : this.BlobRequestOptions, operationContext : null, cancellationToken : this.BlobManager.CancellationToken);
Debug.WriteLine($"finished download target={blob.Name} readLength={readLength} sourceAddress={sourceAddress}");
if (stream.Position != readLength)
{
throw new InvalidDataException($"wrong amount of data received from page blob, expected={readLength}, actual={stream.Position}");
}
}
catch (Exception exception)
{
this.BlobManager?.HandleBlobError(nameof(ReadFromBlobAsync), "could not read from page blob", blob?.Name, exception, true);
throw new FasterException(nameof(ReadFromBlobAsync) + "could not read from page blob " + blob?.Name, exception);
}
finally
{
stream.Dispose();
}
}
public async Task DownloadRangeToStreamAsync(Stream stream, long offset, int length)
{
Require.NotNull("stream", stream);
Require.ZeroOrGreater("offset", offset);
Require.Positive("length", length);
try
{
var context = new OperationContext();
context.SendingRequest += (sender, e) => {
e.Request.Headers["if-match"] = "*";
};
await _blob.DownloadRangeToStreamAsync(stream, offset, length, null, null, context).ConfigureAwait(false);
}
catch (StorageException ex)
{
// if forbidden, then we might have an expired SAS token
if (ex.RequestInformation != null && ex.RequestInformation.HttpStatusCode == 403)
{
throw new ForbiddenException("Can't read blob", ex);
}
throw;
}
}
