public List <CloudBlobContainer> GetPrimaryContainers()
{
List <CloudBlobContainer> result = new List <CloudBlobContainer>();
PrimaryServers.ForEach(s => result.Add(ConfigurationLookup.GetCloudBlobContainer(s, this.Name)));
return(result);
}
/// <summary>
/// Removed already registered servers in session states if they don't exist anymore (because of some reconfiguration).
/// </summary>
private void garbageCollectOldServersFromSessionState()
{
List <string> allServers = new List <string>();
PrimaryServers.ForEach(o => allServers.Add(o));
SecondaryServers.ForEach(o => allServers.Add(o));
//State.UnregisterOldServers(allServers);
}
public override string ToString()
{
string result;
result = "Container: " + this.Name;
result += " Primaries: ";
PrimaryServers.ForEach(e => result += e + ",");
result += " Secondaries: ";
SecondaryServers.ForEach(e => result += e + ",");
return(result);
}
/// <summary>
/// Returns the list of servers that do not replicate this container.
/// </summary>
/// <returns></returns>
public List <string> GetNoReplicaServers()
{
List <string> result = new List <string>();
foreach (string server in ConfigurationLookup.AllServers)
{
if ((!PrimaryServers.Contains(server)) && (!SecondaryServers.Contains(server)))
{
result.Add(server);
}
}
return(result);
}
/// <summary>
/// Read the state of the container configuration from the Azure storage.
/// </summary>
internal void ReadConfiguration()
{
ICloudBlob blob;
try
{
try
{
blob = GetConfigurationContainer().GetBlockBlobReference(ConstPool.CURRENT_CONFIGURATION_BLOB_NAME);
blob.FetchAttributes();
}
catch (StorageException se)
{
//304 is azure's not modified exception.
//it means that the configuration is not modified since last read.
if (StorageExceptionCode.NotModified(se))
{
Console.WriteLine("ReadConfiguration returned without reading...");
return;
}
//404 is Azure's not-found exception
if (StorageExceptionCode.NotFound(se))
{
Console.WriteLine("ReadConfiguration did not find a configuration blob; it needs to be created...");
PrimaryServers = null;
return;
}
Console.WriteLine(se.ToString());
Console.WriteLine(se.StackTrace);
throw se;
}
using (MemoryStream stream = new MemoryStream())
{
blob.DownloadToStream(stream);
stream.Seek(0, 0);
BinaryFormatter formatter = new BinaryFormatter();
ContainerConfiguration tmp = (ContainerConfiguration)formatter.Deserialize(stream);
if (!blob.Metadata.ContainsKey(ConstPool.EPOCH_NUMBER))
{
Console.WriteLine("No Epoch in configuration metadata!"); // this should not happen
return; // stay with current configuration for now
}
int currentEpoch = Convert.ToInt32(blob.Metadata[ConstPool.EPOCH_NUMBER]);
if (currentEpoch > Epoch)
{
PrimaryServers = tmp.PrimaryServers;
PrimaryServers.Sort();
SecondaryServers = tmp.SecondaryServers ?? new List <string>();
MainPrimaryIndex = tmp.MainPrimaryIndex;
WriteOnlyPrimaryServers = tmp.WriteOnlyPrimaryServers ?? new List <string>();
SyncPeriod = tmp.SyncPeriod;
SyncPrimaryServersWithSessionState();
SyncSecondaryServersWithSessionState();
garbageCollectOldServersFromSessionState();
Epoch = currentEpoch;
if (blob.Metadata[ConstPool.EPOCH_MODIFIED_TIME] != null)
{
EpochModifiedTime = DateTimeOffset.Parse(blob.Metadata[ConstPool.EPOCH_MODIFIED_TIME]);
}
else
{
EpochModifiedTime = DateTimeOffset.MinValue;
}
}
}
}
catch (StorageException se)
{
Console.WriteLine(se.ToString());
Console.WriteLine(se.StackTrace);
throw se;
}
catch (Exception ex)
{
Console.WriteLine(ex.ToString());
Console.WriteLine(ex.StackTrace);
//throw ex;
}
}
/// <summary>
/// Periodically refresh the configuration.
/// </summary>
private void RefreshConfigurationPeriodically()
{
try
{
Stopwatch w = new Stopwatch();
CloudBlobContainer configurationContainer = GetConfigurationContainer();
ICloudBlob blob = configurationContainer.GetBlockBlobReference(ConstPool.CURRENT_CONFIGURATION_BLOB_NAME);
while (true)
{
while (!blob.Exists())
{
Console.WriteLine("Configuration blob is null for " + this.Name);
Thread.Sleep(ConstPool.CACHED_CONFIGURATION_VALIDITY_DURATION);
}
int oldEpoch = Epoch;
Epoch = -1;
w.Restart();
blob.FetchAttributes();
int newEpoch = Convert.ToInt32(blob.Metadata[ConstPool.EPOCH_NUMBER]);
if (newEpoch > 0)
{
if (newEpoch != oldEpoch)
{
//foreach (ConsistencySLAEngine engine in CapCloudBlobClient.slaEngines[this.Name])
//{
// engine.Sla.ResetHitsAndMisses();
//}
ReadConfiguration();
Console.WriteLine("New configuration for Epoch " + newEpoch + " is primaries: " + String.Join(", ", PrimaryServers.ToList()) + " secondaries:" + String.Join(", ", SecondaryServers.ToList()));
}
Epoch = newEpoch;
w.Stop();
if (ConstPool.CACHED_CONFIGURATION_VALIDITY_DURATION - Convert.ToInt32(w.ElapsedMilliseconds) > 0)
{
Thread.Sleep(ConstPool.CACHED_CONFIGURATION_VALIDITY_DURATION - Convert.ToInt32(w.ElapsedMilliseconds));
}
lock (this)
Monitor.PulseAll(this);
}
else
{
//Cached Configuration is changing, we need to wait for the meantime.
Thread.Sleep(ConstPool.CONFIGURATION_ACTION_DURATION);
}
}
}
catch (StorageException ex)
{
Console.WriteLine(ex.ToString());
throw ex;
}
catch (Exception exx)
{
Console.WriteLine(exx.ToString());
throw exx;
}
}