/// <summary>
/// Sends the events.
/// </summary>
/// <param name="events">The events that need to be send.</param>
/// <remarks>
/// <para>
/// The subclass must override this method to process the buffered events.
/// </para>
/// </remarks>
protected override void SendBuffer(LoggingEvent[] events)
{
AppendBlobClient appendBlob = _cloudBlobContainer.GetAppendBlobClient(Filename(_directoryName));
if (!appendBlob.Exists())
{
appendBlob.Create();
}
else
{
_lineFeed = Environment.NewLine;
}
Parallel.ForEach(events, ProcessEvent);
}
public AzureBlobsLogWriter(BlobContainerClient blobsContainerClient,
string fileName,
bool appendOpen = false)
{
fileName = AzureBlobsLogsInterface.PathFixer(fileName);
_blobsContainerClient = blobsContainerClient;
_logClient = _blobsContainerClient.GetAppendBlobClient(fileName);
ETag currentETag;
if (_previousOpenAttempts.ContainsKey(fileName) && appendOpen)
{
// We've opened this blob before and want to be non-destructive. We don't need to CreateIfNotExists, which could be VERY slow.
currentETag = _logClient.GetProperties().Value.ETag;
}
else
{
try
{
// Create the file non-destructively if needed, guaranteeing write continuity on creation by grabbing the etag of the create, if needed
if (appendOpen)
{
var response = _logClient.CreateIfNotExists();
if (response != null)
{
currentETag = response.Value.ETag;
}
else
{
currentETag = _logClient.GetProperties().Value.ETag;
}
}
else
{
currentETag = _logClient.Create().Value.ETag;
}
}
catch { currentETag = _logClient.GetProperties().Value.ETag; }
}
// Try to grab the blob lease
_leaseClient = _logClient.GetBlobLeaseClient();
// The blob hasn't be touched since the last time. This is a candidate for breaking the lease.
if (_previousOpenAttempts.ContainsKey(fileName) && (_previousOpenAttempts[fileName].ToString().Equals(currentETag.ToString())))
{
_previousOpenAttempts[fileName] = currentETag;
// The blob hasn't been updated. Try to break the lease and reacquire
var requestConditions = new BlobRequestConditions();
requestConditions = new BlobRequestConditions();
requestConditions.IfMatch = currentETag;
// If the condition fails in the break, it's because someone else managed to touch the file, so give up
ETag newETag;
try
{
newETag = _leaseClient.Break(null, requestConditions).Value.ETag;
}
catch (Exception e) { newETag = currentETag; }
var etagCondition = new RequestConditions();
etagCondition.IfMatch = newETag;
// If the condition fails, someone snuck in and grabbed the lock before we could. Give up.
_curLease = _leaseClient.Acquire(TimeSpan.FromSeconds(-1), etagCondition).Value;
}
else
{
// Not a candidate for breaking the lease. Just try to acquire.
_previousOpenAttempts[fileName] = currentETag;
_curLease = _leaseClient.Acquire(TimeSpan.FromSeconds(-1)).Value;
}
_leaseCondition = new AppendBlobRequestConditions();
_leaseCondition.LeaseId = _curLease.LeaseId;
// We got the lease! Set up thread to periodically touch the blob to prevent others from breaking the lease.
_blobMetadata = _logClient.GetProperties().Value.Metadata;
_stopRelockThread = false;
_relockThreadStopped = false;
_leaseRenewThread = new Thread(() =>
{
while (!_stopRelockThread)
{
Thread.Sleep(100);
var response = _logClient.SetMetadata(_blobMetadata, _leaseCondition);
}
_relockThreadStopped = true;
})
{
IsBackground = true
};
_leaseRenewThread.Start();
_bytesToSend = new MemoryStream();
Debug.Assert(_logClient.Exists());
}
