private void CheckAllocateNewInstance()
{
if (NotifiableSubServerRequirement != null)
{
lock (lckAllocate)
{
try
{
SubServer subServer = NotifiableSubServerRequirement.StartNewInstance();
if (subServer == null)
{
return;
}
AddSubServerInternal(subServer, true);
Logger.WriteLog("A new server instance was requested to meet the next requests", ServerLogType.ALERT);
Thread.Sleep(1000);
}
catch (Exception ex)
{
Logger.WriteLog($"Failed to request a new sub-server instance for the implementation of 'NotifiableSubServerRequirement': {ex.Message}",
ServerLogType.ERROR);
}
}
}
}
private SubServer GetAvailableSubServer()
{
lock (lckGtAvlb)
{
for (int i = 0; i < SubServers.Count; i++)
{
if (selectedSubServerIndex >= SubServers.Count)
{
selectedSubServerIndex = 0;
}
SubServer server = SubServers[selectedSubServerIndex];
if (IsServerUnavailable(server))
{
continue;
}
string key = $"unavailable-{server.Address}:{server.Port}";
if (!CanOperate(key, server))
{
continue;
}
selectedSubServerIndex += 1;
return(server);
}
return(null);
}
}
private bool IsServerUnavailable(SubServer server)
{
string key = $"unavailable-{server.Address}:{server.Port}";
Cache <bool> cached = CacheRepository <bool> .Get(key);
if (cached != null)
{
Logger.WriteLog($"The sub-server node '{server.Address}:{server.Port}' is unreachable. It is temporarily ignored but will be reconsidered in less than 120 seconds", ServerLogType.ALERT);
}
return(cached != null);
}
private int GetCurrentThreadCountOnServer(SubServer server)
{
using (ISocketClientConnection client = BuildClient(server))
{
Logger.WriteLog($"Querying availability on '{server.Address}:{server.Port}'", ServerLogType.INFO);
client.SendRequest("ServerInfoController", "GetCurrentThreadsCount");
int result = int.Parse(client.GetResult().Entity.ToString());
return(result);
}
}
public static void AddSubServer(string address, int port,
Encoding encoding, int maxConnectionAttempts,
int acceptableProcesses)
{
if (SubServers == null)
{
SubServers = new List <SubServer>();
}
var server = new SubServer(address, port, encoding,
maxConnectionAttempts, acceptableProcesses);
AddSubServerInternal(server);
}
private bool AreServerConnected(SubServer server, string cacheKey)
{
try
{
using (ISocketClientConnection client = BuildClient(server))
return(true);
}
catch
{
Logger.WriteLog($"Sub-server node '{server.Address}:{server.Port}' is unreachable", ServerLogType.ALERT);
CacheRepository <bool> .Set(cacheKey, true, 120);
return(false);
}
}
private ISocketClientConnection BuildClient(SubServer server)
{
try
{
return(SocketConnectionFactory.GetConnection(new SocketClientSettings(
server: server.Address,
port: server.Port,
encoding: server.Encoding,
maxAttempts: server.MaxConnectionAttempts
)));
}
catch (Exception ex)
{
Logger.WriteLog($"Fail to connect server {server.Address}:{server.Port} : {ex.Message}", ServerLogType.ERROR);
return(null);
}
}
public ActionResult RunAction(string receivedData)
{
SocketAppServerClient.RequestBody rb = JsonConvert.DeserializeObject <SocketAppServerClient.RequestBody>(receivedData,
AppServerConfigurator.SerializerSettings);
if (rb.Controller.Equals("ServerInfoController") &&
rb.Action.Equals("FullServerInfo"))
{
return(new ServerInfoController().FullServerInfo());
}
string cacheResultKey = BuildCacheResultKey(rb);
SubServer targetServer = GetAvailableSubServer();
if (targetServer == null)
{
CheckAllocateNewInstance();
if (retried)
{
return(ResolveResultOnUreachableServer(cacheResultKey));
}
else
{
retried = true;
return(RunAction(receivedData));
}
}
using (ISocketClientConnection client = BuildClient(targetServer))
{
client.SendRequest(rb);
SocketAppServerClient.OperationResult result = client.GetResult();
if (EnabledCachedResultsForUnreachableServers)
{
CacheRepository <SocketAppServerClient.OperationResult> .Set(cacheResultKey, result, 380);
}
targetServer.RefreshLifetimeIfHas();
return(ActionResult.Json(result));
}
}
private static void AddSubServerInternal(SubServer server, bool isDynamicInstance = false)
{
if (Logger == null)
{
Logger = ServiceManager.GetInstance().GetService <ILoggingService>();
}
SubServers.Add(server);
if (SubServers.Count > 1)
{
if (isDynamicInstance)
{
if (NotifiableSubServerRequirement != null)
{
server.EnableLifetime(NotifiableSubServerRequirement, ServersLifetimeInMinutes);
server.OnLifeTimeEnded += SubServer_OnLifeTimeEnded;
}
}
}
Logger.WriteLog($"Added sub-server node named as '{server.Address}:{server.Port}'", ServerLogType.INFO);
}
private bool CanOperate(string key, SubServer server)
{
int serverCurrentThreadsCount;
try
{
serverCurrentThreadsCount = GetCurrentThreadCountOnServer(server);
}
catch
{
CacheRepository <bool> .Set(key, true, 120);
return(false);
}
if (serverCurrentThreadsCount > server.AcceptableProcesses)
{
Logger.WriteLog($"Sub-server node '{server.Address}:{server.Port}' is too busy", ServerLogType.ALERT);
return(false);
}
return(true);
}
private static void SubServer_OnLifeTimeEnded(SubServer subServer)
{
Logger.WriteLog($"Sub-server '{subServer.Address}:{subServer.Port}' is no longer needed and will be detached from the pool of sub-servers. A notification was issued for the target sub-server to be shut down", ServerLogType.ALERT);
SubServers.Remove(subServer);
}
