Fix GC collection on every REST connection

Author: LordHepipud

doc/100-General/10-Changelog.md

@@ -19,6 +19,7 @@ Released closed milestones can be found on [GitHub](https://github.com/Icinga/ic
 * [#480](https://github.com/Icinga/icinga-powershell-framework/pull/480) Fixes service locking during Icinga Agent upgrade and ensures errors on service management are caught and printed with internal error handling
 * [#483](https://github.com/Icinga/icinga-powershell-framework/issues/483) Fixes REST-Api SSL certificate lookup from the Icinga Agent, in case a custom hostname was used or in certain domain environments were domain is not matching DNS domain
 * [#490](https://github.com/Icinga/icinga-powershell-framework/pull/490) Fixes the command `Uninstall-IcingaComponent` for the `service` component which is not doing anything
+* [#491](https://github.com/Icinga/icinga-powershell-framework/issues/491) Fixes GC collection with `Optimize-IcingaForWindowsMemory` for every incoming REST connection call
 * [#497](https://github.com/Icinga/icinga-powershell-framework/pull/497) Fixes loop sleep for idle REST-Api threads by replacing them with [BlockingCollection](https://docs.microsoft.com/en-us/dotnet/api/system.collections.concurrent.blockingcollection-1?view=net-6.0) [ConcurrentQueue](https://docs.microsoft.com/en-us/dotnet/api/system.collections.concurrent.concurrentqueue-1?view=net-6.0)
 
 ### Enhancements

lib/core/framework/New-IcingaEnvironmentVariable.psm1

@@ -62,5 +62,6 @@ function New-IcingaEnvironmentVariable()
         $Global:Icinga.Protected.Add('RunAsDaemon', $FALSE);
         $Global:Icinga.Protected.Add('Minimal', $FALSE);
         $Global:Icinga.Protected.Add('ThreadName', '');
+        $Global:Icinga.Protected.Add('GarbageCollector', @{ });
     }
 }

lib/core/tools/Optimize-IcingaForWindowsMemory.psm1

@@ -11,6 +11,10 @@
     properly
 .PARAMETER ClearErrorStack
     Also clears the current error stack to free additional memory
+.PARAMETER SmartGC
+    Ensures that memory is not flushed whenever this function is called, but instead
+    every 30 attempts this function is called to reduce CPU load. Only works for
+    PowerShell sessions with "$Global:Icinga.Protected.ThreadName" being set
 .EXAMPLE
     Optimize-IcingaForWindowsMemory;
 .EXAMPLE
@@ -21,9 +25,26 @@
 function Optimize-IcingaForWindowsMemory()
 {
     param (
-        [switch]$ClearErrorStack = $FALSE
+        [switch]$ClearErrorStack = $FALSE,
+        [switch]$SmartGC         = $FALSE
     );
 
+    if ([string]::IsNullOrEmpty($Global:Icinga.Protected.ThreadName) -eq $FALSE -And $SmartGC) {
+        if ($Global:Icinga.Protected.GarbageCollector.ContainsKey($Global:Icinga.Protected.ThreadName) -eq $FALSE) {
+            $Global:Icinga.Protected.GarbageCollector.Add($Global:Icinga.Protected.ThreadName, 0);
+
+            return;
+        } else {
+            $Global:Icinga.Protected.GarbageCollector[$Global:Icinga.Protected.ThreadName] += 1;
+        }
+
+        if ($Global:Icinga.Protected.GarbageCollector[$Global:Icinga.Protected.ThreadName] -le 30) {
+            return;
+        }
+
+        $Global:Icinga.Protected.GarbageCollector[$Global:Icinga.Protected.ThreadName] = 0;
+    }
+
     # Clear all errors within our error stack
     if ($ClearErrorStack) {
         $Error.Clear();

lib/daemon/Add-IcingaForWindowsDaemon.psm1

@@ -20,9 +20,12 @@ function Add-IcingaForWindowsDaemon()
     }
 
     while ($TRUE) {
-        Start-Sleep -Seconds 1;
+        Start-Sleep -Seconds 10;
 
         # Handle possible threads being frozen
         Suspend-IcingaForWindowsFrozenThreads;
+
+        # Force Icinga for Windows Garbage Collection
+        Optimize-IcingaForWindowsMemory -ClearErrorStack -SmartGC;
     }
 }

lib/daemons/RestAPI/daemon/New-IcingaForWindowsRESTApi.psm1

@@ -78,7 +78,7 @@ function New-IcingaForWindowsRESTApi()
     while ($TRUE) {
 
         # Force Icinga for Windows Garbage Collection
-        Optimize-IcingaForWindowsMemory -ClearErrorStack;
+        Optimize-IcingaForWindowsMemory -ClearErrorStack -SmartGC;
 
         $Connection = Open-IcingaTCPClientConnection `
             -Client (New-IcingaTCPClient -Socket $Socket) `

lib/daemons/RestAPI/threads/New-IcingaForWindowsRESTThread.psm1

@@ -101,6 +101,6 @@ function New-IcingaForWindowsRESTThread()
         Close-IcingaTCPConnection -Client $Connection.Client;
 
         # Force Icinga for Windows Garbage Collection
-        Optimize-IcingaForWindowsMemory -ClearErrorStack;
+        Optimize-IcingaForWindowsMemory -ClearErrorStack -SmartGC;
     }
 }

lib/daemons/ServiceCheckDaemon/daemon/Add-IcingaServiceCheckDaemon.psm1

@@ -78,7 +78,8 @@ function Add-IcingaServiceCheckDaemon()
             }
         }
 
-        Optimize-IcingaForWindowsMemory;
+        # Force Icinga for Windows Garbage Collection
+        Optimize-IcingaForWindowsMemory -SmartGC;
 
         Start-Sleep -Seconds 10;
     }

lib/daemons/ServiceCheckDaemon/task/Add-IcingaServiceCheckTask.psm1

@@ -36,7 +36,7 @@ function Add-IcingaServiceCheckTask()
             Clear-IcingaCheckSchedulerEnvironment;
 
             # Force Icinga for Windows Garbage Collection
-            Optimize-IcingaForWindowsMemory -ClearErrorStack;
+            Optimize-IcingaForWindowsMemory -ClearErrorStack -SmartGC;
 
             continue;
         }
@@ -133,6 +133,6 @@ function Add-IcingaServiceCheckTask()
         # Reset certain values from the scheduler environment
         Clear-IcingaServiceCheckDaemonEnvironment;
         # Force Icinga for Windows Garbage Collection
-        Optimize-IcingaForWindowsMemory -ClearErrorStack;
+        Optimize-IcingaForWindowsMemory -ClearErrorStack -SmartGC;
     }
 }