/// <summary>
/// Gets the next checkpoint id
/// </summary>
/// <returns></returns>
private ulong GetNextCheckpoint()
{
var blobContainer = _blobClient.GetContainerReference(RootContainerName);
var checkpointBlob = WrappedPageBlob.CreateNewIfNotExists(blobContainer, CheckpointBlobName, 1);
((CloudPageBlob)checkpointBlob).SetSequenceNumber(SequenceNumberAction.Increment, null);
return((ulong)((CloudPageBlob)checkpointBlob).Properties.PageBlobSequenceNumber.Value);
}
/// <summary>
/// Gets commits from a given blobEntry and stream id that fall within min and max revisions.
/// </summary>
/// <param name="bucketId">The blobEntry id to pull from.</param>
/// <param name="streamId">The stream id.</param>
/// <param name="minRevision">The minimum revision.</param>
/// <param name="maxRevision">The maximum revision.</param>
/// <returns></returns>
public IEnumerable <ICommit> GetFrom(string bucketId, string streamId, int minRevision, int maxRevision)
{
var pageBlob = WrappedPageBlob.CreateNewIfNotExists(_primaryContainer, bucketId + "/" + streamId, _options.BlobNumPages);
HeaderDefinitionMetadata headerDefinitionMetadata = null;
var header = GetHeaderWithRetry(pageBlob, out headerDefinitionMetadata);
// find out how many pages we are reading
var startPage = 0;
var endPage = startPage + 1;
var startIndex = 0;
var numberOfCommits = 0;
foreach (var commitDefinition in header.PageBlobCommitDefinitions)
{
if (minRevision > commitDefinition.Revision)
{
++startIndex;
startPage += commitDefinition.TotalPagesUsed;
}
else if (maxRevision < commitDefinition.Revision)
{
break;
}
else
{
++numberOfCommits;
}
endPage += commitDefinition.TotalPagesUsed;
}
// download all the data
var downloadedData = pageBlob.DownloadBytes(startPage * BlobPageSize, endPage * BlobPageSize);
// process the downloaded data
var commits = new List <ICommit>();
for (var i = startIndex; i != startIndex + numberOfCommits; i++)
{
var commitStartIndex = (header.PageBlobCommitDefinitions[i].StartPage - startPage) * BlobPageSize;
var commitSize = header.PageBlobCommitDefinitions[i].DataSizeBytes;
using (var ms = new MemoryStream(downloadedData, commitStartIndex, commitSize, false))
{
var commit = _serializer.Deserialize <AzureBlobCommit>(ms);
commits.Add(CreateCommitFromAzureBlobCommit(commit));
}
}
return(commits);
}
/// <summary>
/// Adds a commit to a stream.
/// </summary>
/// <param name="attempt">The commit attempt to be added.</param>
/// <returns>An Commit if successful.</returns>
public ICommit Commit(CommitAttempt attempt)
{
var pageBlob = WrappedPageBlob.CreateNewIfNotExists(_primaryContainer, attempt.BucketId + "/" + attempt.StreamId, _options.BlobNumPages);
HeaderDefinitionMetadata headerDefinitionMetadata = null;
var header = GetHeaderWithRetry(pageBlob, out headerDefinitionMetadata);
// we must commit at a page offset, we will just track how many pages in we must start writing at
var startPage = 0;
foreach (var commit in header.PageBlobCommitDefinitions)
{
if (commit.CommitId == attempt.CommitId)
{
throw new DuplicateCommitException("Duplicate Commit Attempt");
}
startPage += commit.TotalPagesUsed;
}
if (attempt.CommitSequence <= header.LastCommitSequence)
{
throw new ConcurrencyException("Concurrency exception in Commit");
}
var blobCommit =
new AzureBlobCommit
{
BucketId = attempt.BucketId,
CommitId = attempt.CommitId,
CommitSequence = attempt.CommitSequence,
CommitStampUtc = attempt.CommitStamp,
Events = attempt.Events.ToList(),
Headers = attempt.Headers,
StreamId = attempt.StreamId,
StreamRevision = attempt.StreamRevision,
Checkpoint = GetNextCheckpoint()
};
var serializedBlobCommit = _serializer.Serialize(blobCommit);
header.AppendPageBlobCommitDefinition(new PageBlobCommitDefinition(serializedBlobCommit.Length, attempt.CommitId, attempt.StreamRevision,
attempt.CommitStamp, header.PageBlobCommitDefinitions.Count, startPage, blobCommit.Checkpoint));
++header.UndispatchedCommitCount;
header.LastCommitSequence = attempt.CommitSequence;
CommitNewMessage(pageBlob, serializedBlobCommit, header, headerDefinitionMetadata, startPage * BlobPageSize);
return(CreateCommitFromAzureBlobCommit(blobCommit));
}
/// <summary>
/// Not yet implemented.
/// </summary>
/// <param name="snapshot"></param>
/// <returns></returns>
public bool AddSnapshot(ISnapshot snapshot)
{
var pageBlob = WrappedPageBlob.CreateNewIfNotExists(_primaryContainer, snapshot.BucketId + "/ss/" + snapshot.StreamId, _options.BlobNumPages);
var serializedSnapshot = _serializer.Serialize(snapshot.Payload);
pageBlob.Metadata["ss_data_size_bytes"] = "0";
pageBlob.Metadata["ss_stream_revision"] = "0";
pageBlob.SetMetadata();
var pageAlignedSize = GetPageAlignedSize(serializedSnapshot.Length);
using (var serializedSnapshotStream = CreateAndFillStreamAligned(pageAlignedSize, serializedSnapshot))
{
pageBlob.Write(serializedSnapshotStream, 0, 0, new HeaderDefinitionMetadata());
}
pageBlob.Metadata["ss_data_size_bytes"] = serializedSnapshot.Length.ToString();
pageBlob.Metadata["ss_stream_revision"] = snapshot.StreamRevision.ToString();
pageBlob.SetMetadata();
return(true);
}
