private void FastWrite(WriteOp op, List <SessionState> sessions = null, ServerMonitor monitor = null)
{
// there should only be one primary server since we are in fast mode
string server = configuration.PrimaryServers.First();
ICloudBlob blob = ClientRegistry.GetCloudBlob(server, configuration.Name, blobName, false);
watch.Start();
op(blob);
watch.Stop();
// update server and session state
ServerState ss = (monitor == null) ? slaEngine.Monitor.GetServerState(server) : monitor.GetServerState(server);
ss.AddRtt(watch.ElapsedMilliseconds);
if (sessions == null)
{
slaEngine.Session.RecordObjectWritten(blobName, Timestamp(blob), ss);
}
else
{
foreach (SessionState session in sessions)
{
session.RecordObjectWritten(blobName, Timestamp(blob), ss);
}
}
}
private void DoDelete(Microsoft.WindowsAzure.Storage.Blob.DeleteSnapshotsOption deleteSnapshotsOption = DeleteSnapshotsOption.None, Microsoft.WindowsAzure.Storage.AccessCondition accessCondition = null, Microsoft.WindowsAzure.Storage.Blob.BlobRequestOptions options = null, Microsoft.WindowsAzure.Storage.OperationContext operationContext = null)
{
bool done = false;
while (!done)
{
using (PrimaryCloudBlobLease lease = new PrimaryCloudBlobLease(this.Name, configuration, true))
{
if (lease.HasLease)
{
Dictionary <ICloudBlob, IAsyncResult> results = new Dictionary <ICloudBlob, IAsyncResult>();
foreach (string serverName in configuration.PrimaryServers)
{
watch.Start();
ICloudBlob blob = ClientRegistry.GetCloudBlob(serverName, configuration.Name, Name);
results[blob] = blob.BeginDelete(deleteSnapshotsOption, lease.getAccessConditionWithLeaseId(accessCondition), options, operationContext, null, null);
ServerState ss = slaEngine.Monitor.GetServerState(serverName);
ss.AddRtt(watch.ElapsedMilliseconds);
slaEngine.Session.RecordObjectWritten(Name, Timestamp(blob), ss);
}
foreach (ICloudBlob blob in results.Keys)
{
blob.EndDelete(results[blob]);
}
done = true;
}
}
}
}
public void FetchAttributes(Microsoft.WindowsAzure.Storage.AccessCondition accessCondition = null, Microsoft.WindowsAzure.Storage.Blob.BlobRequestOptions options = null, Microsoft.WindowsAzure.Storage.OperationContext operationContext = null)
{
// TODO: use protocol
ServerState ss = slaEngine.FindServerToRead(Name);
ICloudBlob blob = ClientRegistry.GetCloudBlob(ss.Name, configuration.Name, Name);
watch.Start();
blob.FetchAttributes(accessCondition, options, operationContext);
ss.AddRtt(watch.ElapsedMilliseconds);
// slaEngine.SessionState.RecordObjectRead(blob.Name, Timestamp(blob), ss);
slaEngine.Session.RecordObjectRead(blob.Name, Timestamp(blob), ss, "");
}
private void MultiWriteUsingBlobLease(WriteOp op)
{
// TODO: recover from failed clients that may leave a write partially completed
// TODO: remove use of leases and replace with ETags
// throw new Exception("Write to multiple primaries not yet implemented.");
try
{
bool done = false;
while (!done)
{
// grab lease on blob to guard against concurrent writers
using (PrimaryCloudBlobLease lease = new PrimaryCloudBlobLease(blobName, configuration, true))
{
if (lease.HasLease)
{
// TODO: fix code for writing to multiple primaries (and remove it from here)
foreach (string server in configuration.PrimaryServers)
{
watch.Start();
ICloudBlob blob = ClientRegistry.GetCloudBlob(server, configuration.Name, blobName, false);
op(blob);
watch.Stop();
ServerState ss = slaEngine.Monitor.GetServerState(server);
ss.AddRtt(watch.ElapsedMilliseconds);
slaEngine.Session.RecordObjectWritten(blobName, Timestamp(blob), ss);
}
done = true;
}
}
}
}
catch (StorageException se)
{
throw se;
}
catch (Exception ex)
{
throw ex;
}
}
private void DoUploadFromStream(System.IO.Stream source, Microsoft.WindowsAzure.Storage.AccessCondition accessCondition = null, Microsoft.WindowsAzure.Storage.Blob.BlobRequestOptions options = null, Microsoft.WindowsAzure.Storage.OperationContext operationContext = null)
{
try
{
bool done = false;
while (!done)
{
using (PrimaryCloudBlobLease lease = new PrimaryCloudBlobLease(Name, configuration, true))
{
if (lease.HasLease)
{
foreach (string server in configuration.PrimaryServers)
{
watch.Start();
ICloudBlob blob = ClientRegistry.GetCloudBlob(server, configuration.Name, Name, false);
source.Position = 0;
blob.UploadFromStream(source, lease.getAccessConditionWithLeaseId(accessCondition), options, operationContext);
watch.Stop();
ServerState ss = slaEngine.Monitor.GetServerState(server);
ss.AddRtt(watch.ElapsedMilliseconds);
slaEngine.Session.RecordObjectWritten(Name, Timestamp(blob), ss);
}
done = true;
}
}
}
}
catch (StorageException se)
{
throw se;
}
catch (Exception ex)
{
throw ex;
}
}
private void MultiWrite(WriteOp op, AccessCondition access, List <SessionState> sessions = null, ServerMonitor monitor = null)
{
// This protocol uses three phases and ETags
// It assumes that the client is in fast mode and remains so throughout the protocol
// i.e. it assumes that the set of primaries does not change.
// TODO: recover from failed clients that may leave a write partially completed
ICloudBlob blob;
Dictionary <string, string> eTags;
// Phase 1. Mark intention to write with write-in-progress flags
eTags = SetWiPFlags();
if (eTags == null)
{
// flags were not successfully set, so abort the protocol
return;
}
// Phase 2. Perform write at all primaries
bool didAtLeastOne = false;
foreach (string server in configuration.PrimaryServers)
{
blob = ClientRegistry.GetCloudBlob(server, configuration.Name, blobName, false);
access.IfMatchETag = eTags[server];
watch.Start();
try
{
op(blob);
}
catch (StorageException)
{
// If writing fails at some primary, then abort the protocol
// It could be that a concurrent writer is in progress
// Note that some writes may have already been performed
// If so, then we leave the WiP flags set so the recovery process will kick in
// or so a concurrent writer can complete its protocol and overwrite our writes
// If not, then we can clear the WiP flags
if (!didAtLeastOne)
{
ClearWiPFlags(eTags);
}
return;
}
watch.Stop();
eTags[server] = blob.Properties.ETag;
didAtLeastOne = true;
// update session and server state
ServerState ss = (monitor == null) ? slaEngine.Monitor.GetServerState(server) : monitor.GetServerState(server);
ss.AddRtt(watch.ElapsedMilliseconds);
if (sessions == null)
{
slaEngine.Session.RecordObjectWritten(blobName, Timestamp(blob), ss);
}
else
{
foreach (SessionState session in sessions)
{
session.RecordObjectWritten(blobName, Timestamp(blob), ss);
}
}
}
// Phase 3. Clear write-in-progress flags to indicate that write has completed
ClearWiPFlags(eTags);
}
public void RecordObjectRead(string name, DateTimeOffset timestamp, ServerState server, long duration)
{
server.AddRtt(duration);
Session.RecordObjectRead(name, timestamp, server, Sla.Id);
DetermineHitSubSLA(name, timestamp, server, duration);
}
