/// <summary>
/// Checks to see if deployment configuration has changed, by adding or removing silos.
/// If so, it updates the list of all silo names and creates a new resource balancer.
/// This should occure rarely.
/// </summary>
/// <param name="newSiloNames">new silo names</param>
/// <returns>bool, true if list of all silo names has changed</returns>
private bool UpdateAllSiloNames(IList <string> newSiloNames)
{
// Has configured silo names changed
if (allSiloNames.Count != newSiloNames.Count ||
!allSiloNames.ListEquals(newSiloNames))
{
// record new list of all instance names
allSiloNames = newSiloNames;
// rebuild balancer with new list of instance names
List <QueueId> allQueues = streamQueueMapper.GetAllQueues().ToList();
resourceBalancer = new BestFitBalancer <string, QueueId>(allSiloNames, allQueues);
return(true);
}
return(false);
}
public DeploymentBasedQueueBalancer(
ISiloStatusOracle siloStatusOracle,
IDeploymentConfiguration deploymentConfig,
IStreamQueueMapper queueMapper)
{
if (siloStatusOracle == null)
{
throw new ArgumentNullException("siloStatusOracle");
}
if (deploymentConfig == null)
{
throw new ArgumentNullException("deploymentConfig");
}
if (queueMapper == null)
{
throw new ArgumentNullException("queueMapper");
}
this.siloStatusOracle = siloStatusOracle;
this.deploymentConfig = deploymentConfig;
streamQueueMapper = queueMapper;
queueBalanceListeners = new List <IStreamQueueBalanceListener>();
mySiloName = this.siloStatusOracle.SiloName;
activeSiloNames = new List <string>();
allSiloNames = this.deploymentConfig.GetAllSiloInstanceNames();
List <QueueId> allQueues = streamQueueMapper.GetAllQueues().ToList();
resourceBalancer = new BestFitBalancer <string, QueueId>(allSiloNames, allQueues);
// get silo names for all active silos
foreach (SiloAddress siloAddress in this.siloStatusOracle.GetApproximateSiloStatuses(true).Keys)
{
string siloName;
if (this.siloStatusOracle.TryGetSiloName(siloAddress, out siloName))
{
activeSiloNames.Add(siloName);
}
}
// register for notification of changes to silo status for any silo in the cluster
this.siloStatusOracle.SubscribeToSiloStatusEvents(this);
}
public override IEnumerable <QueueId> GetMyQueues()
{
BestFitBalancer <string, QueueId> balancer = GetBalancer();
bool useIdealDistribution = this.options.IsFixed || isStarting;
Dictionary <string, List <QueueId> > distribution = useIdealDistribution
? balancer.IdealDistribution
: balancer.GetDistribution(GetActiveSilos(siloStatusOracle, immatureSilos));
List <QueueId> myQueues;
if (distribution.TryGetValue(siloStatusOracle.SiloName, out myQueues))
{
if (!useIdealDistribution)
{
HashSet <QueueId> queuesOfImmatureSilos = GetQueuesOfImmatureSilos(siloStatusOracle, immatureSilos, balancer.IdealDistribution);
// filter queues that belong to immature silos
myQueues.RemoveAll(queue => queuesOfImmatureSilos.Contains(queue));
}
return(myQueues);
}
return(Enumerable.Empty <QueueId>());
}