public int RemoveStaleEntries(uint expirationTime)
{
int removedCount = 0;
lock (this.innerList)
{
LinkedListNode <InstanceEndpoint> current = this.innerList.First;
while (current != null)
{
LinkedListNode <InstanceEndpoint> next = current.Next;
InstanceEndpoint instance = current.Value;
if (instance.LastRefreshTimestamp < expirationTime)
{
this.innerList.Remove(current);
removedCount++;
Debug.WriteLine("UpdateWorkerList: Removed worker {0} from the list.", (object)instance.IPAddress);
AntaresEventProvider.EventWriteLBHttpDispatchEndpointInfoMessage(site.Name, instance.IPAddress, "UpdateWorkerList", "Removing worker from routing list");
}
current = next;
}
}
return(removedCount);
}
internal void SetIsBusy(InstanceEndpoint instance)
{
lock (this.innerList)
{
uint duration = SiteRequestDispatcher.BusyStatusDuration;
instance.IsBusyUntil = HttpScaleEnvironment.TickCount + duration;
instance.IsBusy = true;
Debug.WriteLine("Set instance {0} as busy for the next {1}ms. New weight: {2}", instance.IPAddress, duration, instance.Weight);
AntaresEventProvider.EventWriteLBHttpDispatchEndpointInfoMessage(site.Name, instance.IPAddress, "SetIsBusy", string.Format("Set instance busy for {0}ms. New weight: {1}", duration, instance.Weight));
// Busy adds a large amount of weight to an instance, moving it towards the back.
this.UpdatePositionFromBack(instance.Node);
}
}
internal void ClearBusyStatus(InstanceEndpoint instance)
{
lock (this.innerList)
{
instance.IsBusy = false;
// Clearing the busy flag is going to give it a big priority boost,
// though it's not clear where it will end up. Since most instances will
// have similar status, it should be safe to assume clearing a busy flag
// will move it toward the front of the priority list.
this.UpdatePositionFromFront(instance.Node);
Debug.WriteLine("Removed busy status from {0}. New weight: {1}", instance.IPAddress, instance.Weight);
AntaresEventProvider.EventWriteLBHttpDispatchEndpointInfoMessage(site.Name, instance.IPAddress, "ClearBusyStatus", "Removing busy status. New weight: " + instance.Weight);
}
}
public InstanceEndpoint GetOrAdd(string ipAddress)
{
InstanceEndpoint newInstance;
lock (this.innerList)
{
InstanceEndpoint existingInstance;
if (this.TryGetValueInternal(ipAddress, out existingInstance))
{
return(existingInstance);
}
newInstance = new InstanceEndpoint(ipAddress);
newInstance.Node = this.innerList.AddFirst(newInstance);
}
Debug.WriteLine("UpdateWorkerList: Added worker {0}.", (object)ipAddress);
AntaresEventProvider.EventWriteLBHttpDispatchEndpointInfoMessage(this.site.Name, ipAddress, "UpdateWorkerList", "Added worker");
return(newInstance);
}
public void OnRequestCompleted(
string requestId,
string siteName,
int statusCode,
string statusPhrase,
string ipAddress)
{
SiteMetadata site;
if (!this.knownSites.TryGetValue(siteName, out site))
{
throw new ArgumentException(string.Format("Site '{0}' does not exist in the list of known sites.", siteName));
}
InstanceEndpoint instance;
if (!site.Endpoints.TryGetValue(ipAddress, out instance))
{
Debug.WriteLine("OnRequestCompleted: Worker '{0}' was not found.", (object)ipAddress);
AntaresEventProvider.EventWriteLBHttpDispatchEndpointInfoMessage(site.Name, ipAddress, "OnRequestCompleted", "Worker not found");
return;
}
site.Endpoints.OnRequestCompleted(instance);
// If this is the request we're using as a health sample, clear it so another request can be selected.
if (instance.HealthTrackingRequestId == requestId)
{
instance.HealthTrackingRequestId = null;
}
// If the request is rejected because the instance is too busy, mark the endpoint as busy for the next N seconds.
// This flag will be cleared the next time a request arrives after the busy status expires.
if (statusCode == 429 && statusPhrase == "Instance Too Busy")
{
site.Endpoints.SetIsBusy(instance);
}
}