public static NodeData.Types.NodeService LeastConnections(List <NodeData.Types.NodeService> services,
ConcurrentDictionary <string, SessionContext> keyContext,
out SessionContext hitSessionContext)
{
NodeData.Types.NodeService result = null;
hitSessionContext = null;
var availableServices = services.Where(s => s.ExpireTimestamp > DateTimeOffset.UtcNow.ToUnixTimeSeconds()).Select(s => s);
var count = availableServices.Count();
if (count != 0)
{
int index = 0;
int leastConnectionsIndex = 0;
int leastConnections = int.MaxValue;
foreach (NodeData.Types.NodeService service in availableServices)
{
SessionContext currentContext = GetSessionContext(keyContext, service.Hash);
int currentRequests = currentContext.GetCurrentRequests();
if (currentRequests < leastConnections)
{
hitSessionContext = currentContext;
leastConnectionsIndex = index;
leastConnections = currentRequests;
}
index++;
}
if (leastConnections != int.MaxValue)
{
result = availableServices.ElementAt(leastConnectionsIndex);
}
}
return(result);
}
public static NodeData.Types.NodeService NoLoadBalance(List <NodeData.Types.NodeService> services,
ConcurrentDictionary <string, SessionContext> keyContext,
out SessionContext hitSessionContext)
{
NodeData.Types.NodeService result = services.Where(s => s.ExpireTimestamp > DateTimeOffset.UtcNow.ToUnixTimeSeconds()).FirstOrDefault();
if (result == null)
{
hitSessionContext = null;
}
else
{
hitSessionContext = GetSessionContext(keyContext, result.Hash);
}
return(result);
}
public static NodeData.Types.NodeService SmoothWeightRoundRobin(List <NodeData.Types.NodeService> services,
ConcurrentDictionary <string, SessionContext> keyContext,
out SessionContext hitSessionContext)
{
NodeData.Types.NodeService result = null;
hitSessionContext = null;
var availableServices = services.Where(s => s.ExpireTimestamp > DateTimeOffset.UtcNow.ToUnixTimeSeconds()).Select(s => s);
var count = availableServices.Count();
if (count != 0)
{
// 调整权重
foreach (NodeData.Types.NodeService service in availableServices)
{
SessionContext currentContext = GetSessionContext(keyContext, service.Hash);
currentContext.SetCurrentLoadBalanceWeight(currentContext.GetCurrentLoadBalanceWeight() + service.Weight);
}
int index = 0;
// 原始权重之和
int weightSum = 0;
// 最大当前权重
int maxCurrentWeight = 0;
// 最大当前权重对象下标
int maxCurrentWeightIndex = 0;
foreach (NodeData.Types.NodeService service in availableServices)
{
weightSum += service.Weight;
SessionContext currentContext = GetSessionContext(keyContext, service.Hash);
int currentWeight = currentContext.GetCurrentLoadBalanceWeight();
if (currentWeight >= maxCurrentWeight)
{
hitSessionContext = currentContext;
maxCurrentWeightIndex = index;
maxCurrentWeight = currentWeight;
}
index++;
}
// 对选中的后端再次设置权重
hitSessionContext.SetCurrentLoadBalanceWeight(maxCurrentWeight - weightSum);
result = availableServices.ElementAt(maxCurrentWeightIndex);
}
return(result);
}
public static NodeData.Types.NodeService Random(List <NodeData.Types.NodeService> services,
ConcurrentDictionary <string, SessionContext> keyContext,
out SessionContext hitSessionContext)
{
var availableServices = services.Where(s => s.ExpireTimestamp > DateTimeOffset.UtcNow.ToUnixTimeSeconds()).Select(s => s);
var count = availableServices.Count();
NodeData.Types.NodeService result = null;
if (count == 0)
{
hitSessionContext = null;
}
else
{
result = availableServices.ElementAt(random.Next(count));
hitSessionContext = GetSessionContext(keyContext, result.Hash);
}
return(result);
}
public static NodeData.Types.NodeService SourceIpHash(int sourceIpAddressHashCode,
List <NodeData.Types.NodeService> services,
ConcurrentDictionary <string, SessionContext> keyContext,
out SessionContext hitSessionContext)
{
var availableServices = services.Where(s => s.ExpireTimestamp > DateTimeOffset.UtcNow.ToUnixTimeSeconds()).Select(s => s);
var count = availableServices.Count();
NodeData.Types.NodeService result = null;
if (count == 0)
{
hitSessionContext = null;
}
else
{
int length = availableServices.Count();
int hashCode = Math.Abs(sourceIpAddressHashCode);
int index = hashCode % length;
result = availableServices.ElementAt(index);
hitSessionContext = GetSessionContext(keyContext, result.Hash);
}
return(result);
}
