public async Task <bool> MoveNext(CancellationToken cancellationToken)
{
// Try to walk to the next row for the current response being processed.
while (_singleResponseRowEnumerator?.MoveNext() != true)
{
// If not possible, dispose the old enumerator and create a new one from the
// next response, if any.
_singleResponseRowEnumerator?.Dispose();
if (await _stream.ResponseStream.MoveNext(cancellationToken).ConfigureAwait(false))
{
cancellationToken.ThrowIfCancellationRequested();
_singleResponseRowEnumerator = MergeResponseChunks(_stream.ResponseStream.Current);
}
else
{
_singleResponseRowEnumerator = null;
break;
}
}
// If the current response's enumerator has produced a row, this enumerator should produce
// that same row.
if (_singleResponseRowEnumerator != null)
{
cancellationToken.ThrowIfCancellationRequested();
Current = _singleResponseRowEnumerator.Current;
return(true);
}
if (IsRowInProgress &&
_stream.GrpcCall.GetStatus().StatusCode != StatusCode.Cancelled)
{
// TODO: Is there something we could/should do here? Stream prematurely closed
// with a row in progress
}
return(false);
IEnumerator <Row> MergeResponseChunks(ReadRowsResponse response)
{
foreach (var chunk in response.Chunks)
{
if (chunk.ResetRow)
{
Reset();
continue;
}
_rowMergeState = _rowMergeState.HandleChunk(this, chunk);
if (chunk.CommitRow)
{
_rowMergeState = _rowMergeState.CommitRow(this);
// TODO: Capture response.LastScannedRowKey here for smart retries
yield return(_currentCell.Row);
}
}
}
}
public async Task <bool> MoveNext(CancellationToken cancellationToken)
{
if (_stream == null)
{
await EstablishStream(_requestManager.OriginalRequest).ConfigureAwait(false);
}
// Try to walk to the next row for the current response being processed.
while (_singleResponseRowEnumerator?.MoveNext() != true)
{
try
{
// If not possible, dispose the old enumerator and create a new one from the
// next response, if any.
_singleResponseRowEnumerator?.Dispose();
_singleResponseRowEnumerator = null;
if (await _stream.ResponseStream.MoveNext(cancellationToken).ConfigureAwait(false))
{
cancellationToken.ThrowIfCancellationRequested();
_singleResponseRowEnumerator = MergeResponseChunks(_stream.ResponseStream.Current);
}
else
{
break;
}
}
catch (RpcException e) when(_retrySettings.RetryFilter(e))
{
var retryRequest = _requestManager.BuildUpdatedRequest();
if (retryRequest == null)
{
break;
}
// Reset the merging and re-connect to a new stream.
Reset();
await EstablishStream(retryRequest).ConfigureAwait(false);
}
}
// If the current response's enumerator has produced a row, this enumerator should produce
// that same row.
if (_singleResponseRowEnumerator != null)
{
cancellationToken.ThrowIfCancellationRequested();
Current = _singleResponseRowEnumerator.Current;
return(true);
}
if (IsRowInProgress &&
_stream.GrpcCall?.GetStatus().StatusCode != StatusCode.Cancelled)
{
throw new InvalidOperationException("The ReadRows stream has ended with a row in progress.");
}
return(false);
Task EstablishStream(ReadRowsRequest request) =>
ApiCallRetryExtensions.RetryOperationUntilCompleted(
() =>
{
_stream = _client.ReadRowsInternal(request, _callSettings);
return(Task.FromResult(true));
},
_client.Clock,
_client.Scheduler,
_callSettings,
_retrySettings);
IEnumerator <Row> MergeResponseChunks(ReadRowsResponse response)
{
ByteString previouslyProcessedKey = _lastCompletedRowKey;
foreach (var chunk in response.Chunks)
{
_rowMergeState = _rowMergeState.HandleChunk(this, chunk);
if (chunk.CommitRow)
{
_rowMergeState = _rowMergeState.CommitRow(this);
_lastCompletedRowKey = _currentCell.Row.Key;
_requestManager.IncrementRowsReadSoFar();
yield return(_currentCell.Row);
}
}
if (previouslyProcessedKey != _lastCompletedRowKey)
{
// There was a full row found in the response.
TryUpdateLastFoundKey(_lastCompletedRowKey);
}
else
{
// Otherwise, the service may have indicated that it processed rows that did not match the filter,
// and will not need to be reprocessed.
TryUpdateLastFoundKey(response.LastScannedRowKey);
}
void TryUpdateLastFoundKey(ByteString lastProcessedKey)
{
if (lastProcessedKey != null && !lastProcessedKey.IsEmpty)
{
_requestManager.LastFoundKey = lastProcessedKey;
}
}
}
}
public async Task <bool> MoveNext(CancellationToken cancellationToken)
{
// Try to walk to the next row for the current response being processed.
while (_singleResponseRowEnumerator?.MoveNext() != true)
{
// If not possible, dispose the old enumerator and create a new one from the
// next response, if any.
_singleResponseRowEnumerator?.Dispose();
if (await _stream.ResponseStream.MoveNext(cancellationToken).ConfigureAwait(false))
{
cancellationToken.ThrowIfCancellationRequested();
_singleResponseRowEnumerator = MergeResponseChunks(_stream.ResponseStream.Current);
}
else
{
_singleResponseRowEnumerator = null;
break;
}
}
// If the current response's enumerator has produced a row, this enumerator should produce
// that same row.
if (_singleResponseRowEnumerator != null)
{
cancellationToken.ThrowIfCancellationRequested();
Current = _singleResponseRowEnumerator.Current;
return(true);
}
if (IsRowInProgress &&
_stream.GrpcCall?.GetStatus().StatusCode != StatusCode.Cancelled)
{
throw new InvalidOperationException("The ReadRows stream has ended with a row in progress.");
}
return(false);
IEnumerator <Row> MergeResponseChunks(ReadRowsResponse response)
{
foreach (var chunk in response.Chunks)
{
if (chunk.ResetRow)
{
Assert(
(chunk.RowKey == null || chunk.RowKey.IsEmpty) &&
chunk.FamilyName == null &&
chunk.Qualifier == null &&
(chunk.Value == null || chunk.Value.IsEmpty) &&
chunk.TimestampMicros == 0,
"A reset should have no data");
Assert(_rowMergeState != NewRow.Instance, "NewRow must have a rowKey");
Reset();
continue;
}
_rowMergeState = _rowMergeState.HandleChunk(this, chunk);
if (chunk.CommitRow)
{
_rowMergeState = _rowMergeState.CommitRow(this);
// TODO: Capture response.LastScannedRowKey here for smart retries
yield return(_currentCell.Row);
}
}
}
}